Proceedings of the Tomsk Technological Institute of Emperor Nicholas II.

Vol. XXI. 1911. No. 1.

Materials for the Study of the Fauna of the Devonian Deposits in the Mugodzhar Mountains.

(with 3 phototype plates).

The present work is an examination of part of the material delivered to the Paleontological Cabinet of the Tomsk Technological Institute by Prof. M. E. Yanishevsky in 1904, upon his return from a field trip to the Mugodzhar and Guberlin Mountains.

The material examined comes from a ravine situated on the southern side of Mt. Alabas (the eastern foothills of the Mugodzhars), approximately 15 versts in a southeasterly direction from the “Mugodzhary” station of the Orenburg–Tashkent Railway. According to M. E. Yanishevsky’s notes, in this ravine one can see an outcrop of limestone forming beds that dip approximately to the W. In the upper reaches of the ravine the limestone beds are visible on the right slope, dipping SE at an angle of 25°. The exposures of this part are marked in Yanishevsky’s diary as point 94, and the western, middle, and eastern parts are distinguished in succession, since the direction of the ravine is latitudinal. In the part where, from the N side, Mt. Alabas adjoins the ravine, the exposures are visible on the left slope. This part is marked as point 95. The length of the ravine from the western part, 94, to 95 is approximately 250 sazhens.

Without giving a detailed list of the literature used in working up the material—references to which are found in the synonymy cited in the description of the fauna—I shall indicate several works closely related to the present question:

Venyukov. Deposits of the Devonian system in the Mugodzhar Mountains, 1895.*)

Yanishevsky. Report (preliminary) on a field trip to the Mugodzhar and Guberlin Mountains, 1905.

Chernyshev. Materials for the study of the Devonian deposits of Russia, 1884.

I consider it my duty to express my deep gratitude to Prof. M. E. Yanishevsky, under whose immediate supervision and personal guidance the processing of the material was carried out.

A. Nifantov.

*) The part of the cited work that deals with Mt. Alabas pertains to the present work.

DESCRIPTION OF THE FAUNA.

COELENTERATA. Anthozoa.

Remains of corals are found in rather considerable quantity throughout the entire extent of the ravine, imparting a reef-like character to its deposits. P. Venyukov, in that part of his work*) where the deposits of the town of Alabasa are discussed, likewise notes precisely this peculiarity of these deposits. Strictly speaking, such accumulations of corals are observed only in Middle Devonian deposits; in the present case, however, as will be seen below, we are dealing with deposits more closely related to the upper division. This peculiarity should not go unnoted. The coral fauna indicated by P. Venyukov is richer in species than that yielded by our material. Venyukov indicates the following species of corals:

Cyathophyllum ceratites Goldf.
Cyathophyllum caespitosum Goldf.
Phillipsastrea Hennahi Lonsd.
Phillipsastrea Bowerbankii M. Edw. et Heim.
Phillipsastrea pentagona Goldf.
Phillipsastrea Torreana M. Edw. et Heim.
Phillipsastrea Alabasi n. sp
Alveolites suborbicularis Lam.

Of the 8 species found, 3 are also encountered in our material, namely:

Cyathophyllum caespitosum Goldf.
Phillipsastrea Hennahi Lonsd.
Alveolites suborbicularis Lam.

The other five were not found. At the same time, among our material there is Favosites polymorpha Goldf., indicated by Venyukov from another point of Mugodzhar, namely from the beds at the sources

*) Venyukov. Remains of the Devonian system in the Mugodzhar Mountains. 1895.

r. Kauldzhur; this is explained, of course, by the fact that the points at which the material was collected are not the same.

TETRACORALLIA. Haeckel.

CYATHOPHYLLIDAE. E. H. Cyathophyllum Goldf.

Cyathophyllum caespitosum Goldf.

1862 . . . . . Cyathophyllum caespitosum Goldf. Petrefacta Germ. Th. I.
  s. 60 Taf. XIX Fig. 2.

1885 . . . . . Cyathophyllum caespitosum Frech. Die Korallenfauna d.
  Oberdevons in Deutschland. Zeitschr. Bd. XXXVII.
  s. 33.

1895 . . . . . Cyathophyllum caespitosum. Chernyshev. Fauna of the Middle
  and Upper divisions of the Devonian of the Urals, p. 117.

Small cylindrical or conical specimens of this species are encountered both at points 94 and 95. In almost all specimens one may observe the character of the primary septa, reaching the center of the polypnyak.

In the Urals, C. caespitosum represents one of the widespread forms in the Middle Devonian deposits, also occurring in deposits of the Upper Devonian—(r. Minyar. Chernyshev). Veniukov indicates this species in the limestones of the city of Alabast.

Phillipsastrea D’Orbigny.

Phillipsastrea Hennahi Lonsdale.

(Table I, figs. 2 and 4).

1853 . . . . . Smithia Hennahi. M. Edward and Haim. Brit. fos. Co-
  rals p. 240, tab. LIV f. 4.

1895 . . . . . Phillipsastrea Hennahi. Frech. Korallenfauna d. Oberde-
  von in Deutschland. Zeitschr. d. Deutsch. geol. Ges.
  Bd. XXXVII s. 59. Taf. 4.

1895 . . . . . Phillipsastrea Hennahi. Veniukov. Deposits of the Devonian
  system, in the Mug. Mts., p. 18, tab. I, fig. 1.

This species, typical of the lower beds of the Upper Devonian (Frech.), is found in the middle part of point 94. Veniukov also indicates it in the deposits of the city of Alabast. A detailed description of this form is found in the work by Frech cited above.

HEXACORALLIA.

FAVOSITIDAE E. H.

Favosites. Lamarck.

Favosites polymorpha Goldfuss.

1862 . . . . . Calamopora polymorpha. Goldfuss. Petref. Germ. I, Tf. S. 74. Tf. XXVII. Fig. 2—4.

1885 . . . . . Favosites polymorpha. Frech. Korallenfauna d. Oberdevon in Deutschland. Zeitschr. d. geol. Ges. Bd. XXXVII, 103. Taf. XI. Fig. 1—3.

1895 . . . . . Favosites polymorpha. Venyukov. Sediments of the Devonian system in Mugodzhar, p. 21.

Numerous fragments of this polypnyary occur very frequently at localities 94 and 95.

This form has a wide distribution in the stringocephalid limestone of western Europe. Venyukov indicates it in the deposits at the sources of the Kauldzhur River, which he assigns to the goniatite horizon of the Urals.

Alveolites Lamarck.

Alveolites suborbicularis Lamarck.

(Pl. I, fig. 3. Pl. III, fig. 34).

1885 . . . . . Alveolites suborbicularis. Frech. Zeitsch. d. Deutsch. geol. Ges. Bd. XXXVII. S. 108. Taf. VII. Fig. 2.

1895 . . . . . Alveolites suborbicularis. Venyukov. Sediments of the Devonian system in Mugodzhar, p. 21.

A very characteristic polypnyary, occurring at both localities in the form of large irregular masses enveloping foreign bodies, chiefly remains of stromatoporoids. Among our specimens there are examples on which interbedding of stromatoporoids with the polypnyary of this species is observed (see Pl. I, fig. 3).

The vertical distribution of A. suborbicularis, according to Frech, is from the calceola beds (Eifel) to the lower horizons of the upper division of the Devonian (Germany, Belgium, southern England, Poland). Its presence in the limestones of Mount Alabas is also indicated by Venyukov.

HYDROZOA.

HYDROMEDUSAE. TABULARIAE ALMAN.

Actinostromidae. Actinostroma Nich.

Actinostroma stellulatum Nich. 1886.

Plate I, fig. 1. Plate II, figs. 1—2.

1886—92 . . . Actinostroma stellulatum. Nicholson. A Monogr. of the Br. Strom. p. 140. pl. XIV fig. 1—7, and pl. XV (for details, see Nicholson’s).

Several specimens, assigned partly to locality 94 and partly to locality 95, belong to this species, A. stellulatum. Vertical sections reveal the typical structure, discernible with the naked eye. Thin laminae, up to 5 per 1 mm, are arranged one above another, forming sharply expressed folds. The interlaminar pillars pass through 2—3, sometimes more, laminae, numbering up to 4 per 1 mm. Tangential sections reveal the horizontal arrangement of the pillars in rows. Traces of astrorhizae are seen as punctate openings in vertical sections and partly may be observed on preserved areas of the surface. It is distributed in the Middle Devonian of western Europe.

Actinostroma sp.

Plate I, fig. 3. Plate II, figs. 3, 4, 5.

The fragments of polyparies belonging here have a great similarity to the preceding species, differing from it by a somewhat greater distance between the laminae and pillars. At the same time, this species has Caunopora tubes (caunopora tubes).

One may think that the presence of the latter accounts for the above-mentioned increase in the distances between the laminae and the interlaminar pillars, indicating, as it were, intensified growth, which apparently must have occurred when the polypary became overgrown by bush-like arranged Caunopora tubes.

The nature of the Caunopora tubes remains insufficiently clarified to this day, but in any case the prevailing opinion as to their independence from the organism of the polypary overgrowing them to some extent supports the assumption stated above.

Stromatoporidae.

Stromatopora Goldfuss. 1826.

Stromatopora sp.

Pl. I, figs. 5—7. Pl. II, fig. 8.

Several fragments from locality 95, undoubtedly belonging to polyparia of the genus Stromatopora, are present in our material. Unfortunately, their poor preservation does not permit a precise specific determination of the form.

Stromatoporidae have a rather wide distribution both in the Devonian deposits of the Urals and in Russia. The presence of stromatoporoids in the fauna of the deposits of Mt. Alabas was also noted by Mr. Venyukov, although he did not make a detailed determination of them.

Labechiidae.

Labechiidae Edwards and Haim. 1851.

Labechia sp.

(Pl. II, figs. 6—7).

The polyparium belonging here comes from locality 95. The thick radial pillars of the polyparium are easily distinguishable with the naked eye. In vertical sections a network is clearly visible, formed as a result of the contact of the curved portions of the horizontal laminae with one another. This form very much resembles the species Labechia conferta Lonsd., which is distributed in the Silurian. The genus Labechia has its principal distribution in the Devonian, chiefly in its middle division.

Judging by the number of available specimens of the genera of Hydromedusae described above, it may be said that in the deposits of Mt. Alabas the species Actinostroma is predominantly distributed.

Fragments of polyparia are also encountered very often in which interbedding of actinostromes with stromatoporas is observed, and, finally, both of these with Alveolites suborbicularis.

Devonian Fauna of Mugodzhar

MOLLUSCOIDEA.

BRACHIOPODA.

INARTICULATA. Lingulidae King.

Lingula Brug.

Lingula sp.

Found in the eastern part of locality 94, among one specimen. In view of the poor preservation, it is difficult to say anything definite concerning this form. Concentric lines are observed; the form is somewhat elongated. Dimensions: about 5 mm in length, 2–3 mm in width. In general this form very much recalls L. minima Sow. (Davidson. Mon Brit. Sil. Brach. p. 48. pl II. (36—44).

The vertical range of L. minima Sow. is from the Silurian almost to the present.

ARTICULATA. Strophomenidae King.

Stropheodonta Hall.

Stropheodonta interstrialis Phillips.

1853 . . . Leptaena interstrialis. Schnur. Brach. d. Eifel. Palaeontogr. Bd. III. S. 222, Tf. XVI. fig. 2.

1864–65 . . . Leptaena interstrialis Davidson. Mon. Br. Dev. Boch, p. 85 pl. XVIII. fig. 15—18.

This form was found in the western part of locality 94 and in locality 95. Without giving a description of this form, which can be found in the works cited above, we shall point out that among Devonian deposits in the Urals and in the Mugodzhar Mountains it has hitherto been found only in the middle division. In Siberia it is indicated by F. Petz on the margins of the Kuznetsk basin in beds with Rhizophyllum Gervillei at the Krekovskaya mill, along the Chulym River, with Pentamerus baschkiricus, and in the Upper Devonian deposits of the village of Polonina on the Tom River. In Western Europe it passes through the whole Devonian.

Orthis Dalman.

Orthis striatula Schlotheim.

1813 . . . . Terebratulites striatulus Schlotheim Leonhards Mineral. Taschenbuch v. VII, pt. I; Taf. 1, f. 6.

1863 . . . . Orthis striatula. Davidson. Mon Brit. Dev. Brach. p. 87. pl. XVII. f. 4—7.

This form occurs in a large number of specimens at both localities. Without giving its description, we shall note that among the Uralian and Mugodzhar deposits it is widely distributed. Chernyshev indicates it in the deposits of Lake Koltuban,—on the eastern slope of the Urals; Venyukov—in the Mugodzhar Mountains. Without being confined to a definite horizon, it passes through all three divisions of the Devonian, both among the Russian and among the Western European deposits.

Productidae Gray.

Productus Sowerby.

Productus sericeus Buch.

1837 . . . . . Orthis sericeus Buch. Ueber Deltyris oder Spirifer etc.
Ges. Schrift. Bd. VI. s. 347.

1868 . . . . . Productus sericeus Dames. Zeitschr. d. Deutsch. geol. Ges.
Bd. XV. S. 500 Tf. XI Fig 4.

1872 . . . . . Productus sericeus Kayser. Zeitschr. d. Deutsch. geol.
Ges. Bd. XXIV. S. b. 94. Taf. XXVII. Fig. 9.

This form, in a limited number of specimens, was found throughout locality 94.

On the specimens available to us, especially from the western part of locality 94, the radial striation of the surface of the ventral valve is clearly visible. The latter is convex, of semicircular outline. The beak extends somewhat beyond the hinge margin. The ears are clearly separated. The species is comparatively rare in the Russian deposits. Chernyshev indicates it in the Upper Devonian limestones of Lake Koltuban. In Western Europe Productus sericeus is assigned to the Clymenia horizon.

Productus sp.

It is present only in one specimen from the western part of locality 94. Poor preservation and deformation of the specimen do not permit a precise determination. The form is elongately stretched, the beak strongly bent. The hinge margin is straight. The surface of the ventral valve is covered with linearly arranged elongated tubercles, giving the appearance of radial ribbing. Concentric growth marks are sharply visible only near the beak. The dimensions are about 3 cm in length and about 2 cm in width.

Atrypidae Dall. Atrypa Dallman.

Atrypa desquamata Sow.

Plate III, figs. 1–3, 11–12, 14.

1840 . . . . Atrypa desquamata Sowerby. Geolog Transact. Ser II v. V. pl. LVI, Fig. 19–20.

1865 . . . . Atrypa desquamata Davidson. Mon Brit. Brach. p. 58 pl. X fig. 9–13. pl. XI, fig 1–9.

1889–92 . . . Atrypa desquamata (pars) Whidborne. Monogr. Dev. Fauna South of England. v. II. pl. III. p. 117, pl. XIII. f. 13–15.

A form very close to A. reticularis, differing from the latter, according to Widborn, by the lesser curvature of the beak of the ventral valve. In addition, a false hinge area is also observed. Davidson distinguishes A. desquamata from A. reticularis generally by the lesser convexity of the valves and the lesser curvature of the beaks of the ventral valve. The specimens we have from localities 95 and 94, belonging to one and the same species, differ sharply in the size and external surface of the valve. Whereas some are smaller and have a finer sculpture (see pl. III fig. 1), others, on the contrary, are larger and have a coarser sculpture (pl. III figs. 11–12, 14); sometimes plume-like prolongations of the ventral valve are observed. Along with this, the reverse relation between the size and sculpture of the shell is sometimes also observed. By the character of the beak all of them belong to the species A. desquamata. As to the degree of convexity of the valves, since it is not constant in this species, they too should be referred to A. desquamata. By the character of the sculpture, the belonging of some to A. desquamata cannot be doubted; others, however, come closer to A. aspera, but are not identical with it. Among the latter forms there are also such that, according to the sculpture, should already be regarded as varietas A. aspera.

In plate III figs. 1–3, 11–12 and 14 represent individual specimens of shells of A. desquamata.

Atrypa aspera Schloth. var.

Plate III, figs. 4–10, 13.

1813 . . . . Terebratula aspera Schlotheim. Leonhard’s Taschenbuch, p. 74. pl. I, f. 7.

1886 . . . . . Atrypa aspera. Wenjukow. Fauna of the Devonian system of Russia, p. 103, pl. IV, fig. 2.
Detailed synonymy, see Davidson, Mon. Brit. Dev. Brach. p. 57.

These forms occur in large numbers at both localities 94 and 95. The external sculpture of the valves, being considerably coarser than in the preceding species, more closely recalls A. aspera, but does not yet attain the relief characteristic of that species, and therefore is regarded as a varietas.

Atrypa Alabasi n. sp.

Pl. III, figs. 15 and 16.

A small form, with average dimensions: width—10 mm., length 8 mm., height 4 mm.; rounded in outline. In external appearance it very much recalls A. salairica v. Petz, differing from the latter in its coarser radial ribs. On the ventral valve there is a sharply expressed keel-like elevation, running from the umbo toward the margin and disappearing in the middle of the shell. On the dorsal valve there corresponds to it a radial furrow. The frontal margin is straight. The form was found in a large number of specimens in the central and eastern part of locality 94.

Atrypa striata n. sp.

Pl. III, fig. 17.

Several specimens found at both localities 94 and 95 belong here. In general habitus they recall A. reticularis, but at the same time they differ considerably from the latter in dimensions, not exceeding 16 in length, 14 in width, and 11 mm. in height, and in sculpture. The latter is represented by very fine radial, dichotomizing striae. The frontal margin is strongly curved. The umbo of the ventral valve is considerably bent toward the dorsal one.

SPIRIFERIDAE KING.

Spirifer Sowerby.

Spirifer (Reticularia) Uri Fleming

1865 . . . . . Spirifer Uri Davidson. Mon. Brit. Dev. Brach. p. 41
pl. IV fig. 25–28.

1871 . . . . Spirifer Urii Kayser. Brach. mitt. und od.—Dev. Eifel. Zeitschr. d. Deutsch. geol. Geselsch. Bd. XXIII. s. 584.

1884 . . . . Reticularia Urii Chernyshev. Materials for the study of the Devonian deposits of Russia, p. 18, pl. III, fig. 2.

Small shells of semicircular form, with a straight hinge margin, somewhat smaller than the greatest width of the shell. The ventral valve is more convex, with a bent beak, beneath which a triangular area with a broad opening in the middle is visible. On both valves, along the middle, beginning from the beak, there runs a flat furrow, gradually widening and disappearing at the frontal margin; the latter is slightly curved.

This form occurs in a large number of specimens at both localities 94 and 95. It should be noted that Chernyshev indicates it in the Upper Devonian deposits along the Minyar River, on Lake Koltuban. In the Kuznetsk Basin of Siberia it is indicated by F. Petz in the beds—with Rhiz. Gervillei with Pent. baschk., with Str. Burtini and in the beds with Sp. Archiaci, i.e. it passes through the entire Devonian. In the Urals its distribution is not limited to the above-mentioned Upper Devonian deposits—excluding the horizons with clymenias, it occurs in all divisions.

Spirifer undiferus F. Roemer.

1844 . . . . Spirifer undiferus F. Roemer. R. Ueb. p. 73, pl. XIV f. b.

1864—65 . . . Spirifer undifera Davidson. Brit. Dev. Brach. Monog. v. III. p. 36 pl. VII. fig. 1—10.

1871 . . . . Spirifer undiferus Kayser. Zeitsch. d. Deutsch. geol. Ges. Bd. XXII. s. 575.

1885 . . . . Reticularia (?) undifera Chernyshev, Proceedings of the Geological Committee, vol. III No. 3 p. 75.

1886 . . . . Spirifer undiferus Stuckenberg. Mem. Ac. Imp. Sc de St. Petersb. ser. VII. v. XXXIV No. 1, p. 8; pl. II fig. 10; pl. III, fig. 14, pl. IV, fig. 14.

Without giving a description of this form (see the works cited above), we shall point out the somewhat distinctive sculpture of our specimens—the number of ribs on each valve reaches 34, whereas usually it does not exceed 20—(8—20).

This species occurs in the Urals in the goniatite and cuboid horizons. Fön-Petz likewise indicates it in the deposits

of the Kuznetsk Basin in beds with Pent. baschkiricus and Str. Burtini along the rivers Tom and Chulym.

Found at point 95 and on Mt. Alabas.

Spirifer zickzack F. Röemer.

1843 . . . . . Spirifer zickzack F. Röemer. Verst. d. Harzgeb. S. 14. Taf. IV. Fig. 17.

1895 . . . . . Spirifer zickzack Venyukov. Deposits of the Devonian system in the Mugodzhary Mountains. Proceedings of the St. Petersburg Society of Naturalists, vol. XXIII, p. 130, pl. III, fig. 9.

There is only one specimen of a ventral valve, of semicircular outline, somewhat elongated in width. The angles of the hinge margin are rounded. From the beak there extends a broad sinus with three furrows. The area is insignificant.

It comes from point 95.

In the Urals this form is distributed on both slopes. Chernyshev indicates this form in cuboid beds along the Minyar River. Fontannes indicates it in beds with Str. Burtini and Sp. Archiac in the Kuznetsk Basin of Siberia. In Western Europe it belongs to the upper division of the Devonian.

Spirifer tenticulum Vern.

1845 . . . . . Spirifer tenticulum Verneuil. Geol. d. la Russie. v. II. p. 159 pl. V fig. 7.

1886 . . . . . Spirifer tenticulum Venyukov. Fauna of the Devonian system of northwestern and central Russia, p. 64. pl. III fig. 1–2.

There are several specimens belonging to the middle part of point 94. In the Urals it is indicated in Middle Devonian deposits near Sergeevka. In Western Europe it is confined to limestones with Str. Burtini. The form is Middle Devonian.

Spirifer Archiaci Murch.

1840 . . . . . Spirifer Archiaci Murchison. Bal. Soc. Geol. France v. XI. p. 251. pl. II fig. 2–4.

1886 . . . . . Spirifer Archiaci Venyukov. Fauna of the Devonian system of northwestern and central Russia. P. 64, pl. III, fig. 2, 5, 7. Pl. IV, fig. 1–3.

A characteristic Upper Devonian form. It is present among two young specimens from the western point 94. Fairly well preserved ...

preserved ventral valves with a high area, radial furrowing, and a sinus covered with the same radial striae—allows them to be assigned precisely to this species. It has a wide distribution in the Ural deposits, corresponding to the upper division. F. Petz indicates it in the deposits of the Kuznetsk Basin.

ATHYRIS M’ COY.

Athyris concentrica Buch.

1834 . . . . . Terebratula concentrica. Buch. Ueber Terebrat. Gesam. Schr. B. W. s. 266.

1862 . . . . . Athyris concentrica. Davidson. Mon Brit. Dev. Brach., p. 14, pl. III. f 11—15. et 24.

Without entering into a description of this form, which is fairly common, I shall indicate only the dimensions of the specimen encountered at locality 94: length—12, width—12, and height 6 mm.

The form occurs in the upper and middle divisions of the Devonian.

Athyris lineata. n. sp.

Tab. III fig. 18 a—b—c.

To this belong fairly well-preserved specimens from the eastern part of locality 94. A characteristic feature of this species, somewhat reminiscent of A. concentrica, is the development of the shell in width and the zigzag bend of both the frontal margin and the lateral margins.

The surface is covered with fine concentric lines, arranged very regularly.

Dimensions of the shell: length 11, width 14, and height 5 mm.

PENTAMERIDAE M’ COY.

Pentamerus Sowerby.

Pentamerus galeatus Dalman.

1845 . . . . . Pentamerus galeatus. Verneuil. Paléont. de la Russie, p. 120. pl. VIII. fig. 3.

1885 . . . . . Pentamerus galeatus. Chernyshev. Fauna of the Middle and Upper Devonian of the Western Slope of the Urals, p. 101, tab. XIV fig. 12.

1886 . . . . . Pentamerus galeatus. Venyukov. Deposits of the Dev. Syst. of N.—W. and Central Russia, p. 129, tab. V. f. 13.

There are several small specimens of the indicated form with a beautifully expressed plication of the frontal margin. Larger specimens have not been found. Locality: the eastern and middle parts of locality 94. The vertical distribution of this form among the Ural deposits embraces two horizons—the lower one of the Upper division, the Goniatite horizon, and the upper one of the Middle division, the Stringocephalus horizon. Among the Devonian deposits of the Kuznetsk Basin of Siberia it passes through all the horizons found here, from the Pesterovo beds to the horizon with Sp. Archiaci inclusive. In the Devonian of Western Europe it passes through all three divisions.

Pentamerus globus Schnur.

1853 . . . . . Pentamerus globus Schnur. Brach. d Eifel. Palaeontogr. Bd. III. S. 197 Taf. XXXI. f. 4.

1864—65 . . . Pentamerus globus Davidson. Mon Brit. Dev. Brac. p. 73, pl XV, f. 7—12.

1883—85 . . . Pentamerus globus Chernyshev. Materials for the Study of the Devonian Strata of Russia, p. 21, vol. III, fig. 9.

Specimens from locality 94 (western and middle parts) belong to this species. This form is indicated by Chernyshev among the Upper Devonian deposits of Lake Koltuban. In Western Europe it occurs in the Upper and Middle divisions of the Devonian.

Pentamerus biplicatus Schnur.

Table III, figs. 19—22.

1853 . . . . . Pentamerus biplicatus. Schnur. Palaeont. Bd. III. s. 196. Taf. XXXI. f. 3.

1864—65 . . . Pentamerus biplicatus. Davidson. Mon Brit. Dev. Brach., p. 73, pl. XII, f. 31—32.

This form, not mentioned at all from Russian deposits, was found at two localities—95 and 94 (middle part). The characteristic feature of this species, indicated by Schnur—namely the peculiar plication of the frontal margin—is excellently observed on our specimens. Near the frontal margin, on the dorsal valve, two folds are noticeable, which, when joined with the ventral valve, give sharply expressed denticles of the frontal margin. Along the sides, one smaller fold is observed on each side.

Near the beak the shell is smooth. The plication on adult specimens is rather strongly noticeable—in the form of an undulating bend of the valve in the middle, which gives rise on the frontal margin to the above-mentioned folds.

Kayser regards this form as intermediate between Pent. galeatus Schn. and Pent. multiplicatus F. Roemer, along with P. acutolobatus and formosus. At the same time, P. multiplicatus F. Roemer is considered a variety of P. laevis (= optatus Schnur).

Among our specimens, some are in very good preservation. The small specimens have dimensions: length 6, width 7, and height 4 mm.

This form belongs to the rare ones and, in the deposits of western Europe, occurs there in the middle division of the Devonian.

Camarophoria King.

Camarophoria microrhyncha F. Roemer.

1853 . . . . . Terebratula microrhyncha Schnur. Palaeont. Bd. III. S. 173.
　　　　　　Taf. XXII f. 73.

1871 . . . . . Camarophoria microrhyncha Kayser. Die Brach. d. mitt.
　　　　　　und ob. Dev. d. Eifel. Zeitschr. d. Deutsch g. Gesel-
　　　　　　sch. Bd. XXIII. S. 531.

1885 . . . . . Camarophoria microrhyncha. Chernyshev. Fauna of the Middle
　　　　　　and Upper Devonian of the western slope of the Urals, p. 98. Pl. IV, fig. 11.

1895 . . . . . Cam. ascedens Steiniger. Wenukow. The Lower Devonian System
　　　　　　in Mugodzhar, vol. II, fig. 8.

The form was found in the western part of locality 94. Dimensions: length 18, width 20, and height 13 mm. The angle formed by the hinge margin at the beak is about 110–120°. Chernyshev indicates this species from the Chikman River in the Urals.

Camarophoria sp.

There is only one specimen, in very poor preservation. In external appearance, as far as can be judged, it resembles Camar. megistana, indicated by Chernyshev in the Middle Devonian deposits of the Urals. This latter species in western Europe occurs in the upper division. Found in the western part of locality 94.

RHYNCHONELLIDAE GRAY.

Rhynchonella Fischer.

Rhynchonella livonica Buch.

1834 . . . . . Terebratula livonica. Buch. Ges. Schr. Bd. IV. S. 203.
　　　　　　Taf. XXI. fig. 30.

1845 . . . . . Terebratula livonica. Verneuil. Paléont. de la Russie, p. 80.
  pl. X. fig. 3.

1846 . . . . . Terebratula livonica. Keyserling. Petschora-Land, p. 240.

1885 . . . . . Rhynchonella livonica. Chernyshev. Fauna of the Middle and Upper
  Devonian deposits of the western slope of the Urals, p. 89, vol. XI, figs. 8—9.

A detailed description of this form is found in the works cited above. There are two specimens from the western part of locality 94.

The vertical distribution of this form in the Urals and in Siberia is generally limited to the middle division. In western Europe it passes through all three divisions.

Rhynchonella pugnus Mart.

1809 . . . . . Conchyliolithus anomites pugnus. Martin. Petrif. Derb. pl.
  XXII. fig. 4—5.

1856 . . . . . Terebratula acuminata var. pugnus. Pacht. Geol. studies
  from Voronezh to Samara, p. 86, vol. IV, fig. 1.

1864—65 . . . Rhynchonella pugnus. Davidson. Mon Brit. Dev. Brach.
  p. 63, pl. XII. fig. 12—14. pl. XIII. fig. 8—10.

1871 . . . . . Rhynchonella pugnus. Kayser. Die Brach. d. Eifel. s. 522.

A detailed description of the forms is found in the works indicated. There are several specimens in sufficiently good preservation. It is present at both localities 94 and 95.

The vertical distribution of this species in the Urals and in Siberia is limited to the upper division; in western Europe—to the upper and middle.

Rhynchonella reniformis Sowerby.

1825 . . . . . Terebratula reniformis. Sowerby. Min. Conchpl. CCCCXCVI
  fig. 1—4.

1865 . . . . . Rhynchonella reniformis. Davidson. Mon Brit. Dev. Brach.
  p. 62 pl. XIII fig. 6—7.

1885 . . . . . Rhynchonella reniformis. Chernyshev. Materials for the study
  of the Devonian deposits of Russia, p. 23, tab. III fig. 15.

There is only one specimen, well preserved. The smooth valve has a folded sinus. The angle at the apex along the line of the hinge margin is about 140°. The form was encountered at locality 95.

The vertical distribution of this form is the same as that of the preceding species.

Rhynchonella cuboides Sowerby.

1840 . . . . . Atrypa cuboides. Sowerby. Trans. Geol. Soc. 2 Ser. v V. pl. LVI f. 24.

1865 . . . . . Rhynchonella cuboides. Davidson. Mon Brit. Dev. Brach. p. 65. pl. XIII. fig. 17—21.

There are several specimens of different age and form. Possessing all the very distinctive structural features of R. cuboides, they differ among themselves in sculpture. Whereas some appear with coarser rounded folds, others are covered with finer, flatter ones. The specimens were taken at both localities 94 and 95.

The vertical distribution of this form in the Urals and in western Europe is limited to the cuboid beds.

It is not superfluous to note the fact that the given species is present at both localities, defining a horizon parallel to the cuboid Upper Devonian deposits of the Urals.

Rhynchonella Goldfussi (?) Schnur.

1851 . . . . . Terebratula Goldfussi. Schnur. Ueb. d. Eifel. Brach. p. 188. T. XXVI fig. 4.

There is only one dorsal valve, which is why doubt arose as to the correctness of assigning it to Schnur’s species. In its habitus it resembles the large forms of the species R. livonica. However, the character of the ribs, which according to Schnur’s description are keeled on the internal molds and rounded on the valves, sharply distinguishes it from the species livonica, in which we have observed the opposite phenomenon.

The form belongs to locality 95. In western Europe R. Goldfussi occurs in Stringocephalus limestone.

Rhynchonella gracilis n. sp.

Plate III, fig. 23.

In the material from the middle part of locality 94 there was found, in very good preservation, a form resembling R. cuboides. Upon closer examination, however, it differs very sharply from the indicated species by the abnormal inflation of the frontal margin of the dorsal valve. At the same time the lateral margins of the valve are raised, owing to which the ventral valve is not flat but somewhat concave. The greatest height of the shell is at the frontal margin. The dimensions in all directions are identical—11 mm., although from the side of the frontal margin the shell appears somewhat elongated in height.

TEREBRATULIDAE KING.

Dielasma King. (Waagen).

Dielasma elongata. Schlotheim. For a detailed synonymy see Chernyshev, “Fauna of the Middle and Upper Devonian of the Urals,” p. 53.

The described form was encountered only in one locality, 94 (middle part), in a single specimen, and is distinguished by its insignificant dimensions: length 13, width 10, and height 6 mm.

This species of Dielasma, characteristic of Permian deposits, also occurs in the Devonian, beginning with the upper beds, from which it continues through to the Permian, attaining its principal development in the latter. This indicated vertical distribution is the same for Russian as for western European deposits.

As can be seen, the brachiopod fauna is sufficiently rich. Considering its character from the standpoint of the species most widely distributed within it, we find that the forms Orthis striatula Schl., Sp. Urii Flem., Atrypa desquamata Sow., Atrypa aspera Schl. var. have a dominant significance in terms of the number of specimens; turning to the vertical distribution of the named forms, we see that they do not characterize any particular horizon of the Devonian deposits, occurring alike in all three divisions of the Devonian.

But among these forms we see, as it were, separately scattered representatives of the upper division, occurring at both points sometimes in single specimens, sometimes in several specimens. Here we find such forms as Prod. sericeus, Sp. Archiaci, Sp. undiferus, Sp. zickzack, Rhynch. cuboides, R. pugnus, R. reniformis, Camar. microrhyncha, Pent. globus, and Dielasma elongata. The last form begins its existence precisely with the upper division. After these forms come such as Stroph. interstrialis, Sp. tenticulum, Athyris concentrica, which are distributed in the Middle Devonian deposits of the Urals, but at the same time occur also, and almost exclusively, in the upper division of the Devonian of Siberia, alongside Sp. Archiaci. The form Athyris concentrica also occurs in the Urals partly in the upper division—in the goniatite cuboid horizon.

The forms Rhynch. livonica and Camar. megistana, which have a Middle Devonian distribution in the Urals, occur in western Europe—the former in all three divisions of the Devonian, while the latter only in the upper.

Finally, we have forms which in general play no role either in their distribution in the Devonian or in quantity in our material; forms that are indeterminable or doubtful because of poor preservation and, in conclusion, new forms.

The conclusion from this is obvious—the absence in the brachiopod fauna of typical representatives of the Middle Devonian and, on the contrary, the presence of Upper Devonian species argues for assigning the deposits of both points 94 and 95 to the upper division. Below is given a table of the vertical distribution of the forms by which the horizon of the given deposits is most precisely determined.

MOLLUSCA.

LAMELLIBRANCHIATA.

ANISOMYARIA. NEUMAYR.

Aviculidae. Lam.

Aviculopecten M’Coy

Aviculopecten concentricus n. sp.

Pl. III. fig. 28.

The shell is equilateral and almost equivalved, rounded in outline. The posterior ear is longer than the anterior. The surface of the valves is covered with very fine concentric lines, which pass onto the ears in a vertical direction. The margins of the shell are somewhat thickened in the form of a narrow flat rim. Dimensions: length and height 22 mm., thickness 10 mm. This species, in a single specimen, belongs to the middle part of point 94.

HOMOMYARIA.

Astartidae. Gray.

Cypricardinia. Hall.

Cypricardinia lamellosa Sandberger.

1856 . . . . Cypricardia lamellosa Sandberger. Verst. in Nassau S. 262. Taf. XXXVII. Fig. 13.

1887 . . . . Cypricardium lamellosa Chernyshev. Fauna of the Middle and Upper Devonian of the Urals, p. 49, pl. VII, fig. 3.

1895 . . . . Cypricardinia lamellosa. Venukov. Devonian deposits in the Mugodzhary Mountains, p. 44.

The form described by Sandberger was encountered at locality 95. Chernyshev indicates it from the upper horizons of the Middle Devonian near Serpievka. Venyukov found it in the deposits of Mount Alabas and in the Upper Devonian beds near Ak-Tkinde-Aulie. In Nassau it occurs in the Stringocephalus limestone.

GASTROPODA. PROSOBRANCHIA.

Porcelliidae. Koken.

Porcellia Leveille.

Porcellia bifida Sanberger

1850—56 . . . Pleurotom. bifida Sandberger. Verst. in Nassau, S. 185 Taf. XXVII, Fig. 10.

1884 . . . . . Porcellia bifida Chernyshev. Materials for the Study of the Devonian Deposits of the Urals, p. 4, pl. 1, fig. 3.

1895 . . . . . Porcellia bifida Venyukov. Devonian Deposits in the Mugodzhary Mountains, p. 49.

Separate nuclei belonging to this species were found at locality 95. Venyukov indicates the occurrence of P. bifida (also in the form of nuclei) in the limestones of Ak-Tkinde-Aulie in the upper division of the Devonian.

In Western Europe it is confined to the Stringocephalus limestone (Vilmar).

Porcellia primordialis Schloth.

1885 . . . . . Porcellia primordialis Chernyshev. Fauna of the Middle and Upper Devonian of the Urals, p. 34, pl. V, fig. 11. (For more detailed synonymy, see Chernyshev.)

Representatives of this species of Porcellia, indicated by Chernyshev in the Upper Devonian limestones near Lake Koltuban, and also by Venyukov in the limestones of Ak-Tkinde-Aulie (in the Devonian), were found in the limestones of Mount Alabas and at locality 95.

The nucleus of the shell, with a clearly visible keel bounded on the sides by two grooves, and in places with well-preserved sculpture of the outer surface, with clearly distinguishable longitudinal ribs and arcuately curved transverse growth marks, makes it possible to assign it without doubt to the given species.

The vertical distribution of P. bifida in Western Europe is confined to the Stringocephalus limestone.

Porcellia Alabasi n. sp.

Pl. III, fig. 24.

The shell is flat-coiled, with 4 whorls rapidly increasing in height and width. The umbilicus is open. Along the middle of the outer side of the last whorl runs a narrow furrow, bounded by two longitudinal riblets. The surface of the shell is ornamented with transverse fine lines and with coarser, thick ridges, bent backward on the outer side—traces of the aperture. The number of the latter is 6 on one whorl.

PLEUROTOMARIIDAE D’ORB.

Rhaphistoma Hall.

Rhaphistoma (cf) Bronni Goldfuss.

1840–41 . . . Euomphalus Bronni Goldfuss. Petrefact. Germ. Th. 3 S. 81. Taf. CLXXXIX fig. 4.

1885 . . . . . Rhaphistoma Bronni Chernyshev. Fauna of the Middle and Upper Devonian of the Urals, p. 37, vol. V, fig. 15, pl. VI, fig. 2.

One specimen, belonging to locality 95. Its poor preservation does not allow a fully exact determination to be given; it may be said that in general habitus it very much resembles the species R. Bronni Goldfuss, indicated by Chernyshev in the limestones of Batyr Cape, together with String. Burtini.

Pleurotomaria Defrance.

Pleurotomaria Koltubanica Tschern.

1887 . . . . . Pleurotomaria Koltubanica. Chernyshev. Fauna of the Middle and Upper Devonian of the Urals, p. 31, pl. VI figs. 10–11.

1895 . . . . . Pleurotomaria Koltubanica. Venyukov. Devonian deposits in the Mugodzhar Mountains, p. 45, vol. III p. 1.

The form was found at locality 95. The outlines of the shell and the external sculpture, as far as can be judged from the preserved portions, correspond to the description of Pl. Koltubanica given by Chernyshev in the work cited above. Venyukov describes this same form from the limestones of Ak-Tyunde-Aulie, with sculpture somewhat different from Chernyshev’s species: the sinus band is bounded above and below by thin and sharp ribs; along the sinus band, besides the arcuately

passing over the bending folds of growth, in places faintly noticeable, thin longitudinal ribs. This feature—namely the peculiarity in the sculpture of the sinus band—is not noticeable in our specimen. According to Chernyshev, only one longitudinal riblet is visible (under a magnifying glass), which can also be observed in ours.

In the limestones near the village of Koltubanica, Pl. Koltubanica occurs in the goniatite-cuboid horizon.

Pleurotomaria Alabasi n. sp.

Table III, figs. 25—27.

Several specimens, with well-preserved sculpture, belong to item 95. A conical shell, with 4 rounded whorls. Along the outer part of the last whorl, somewhat nearer to the lower surface, there passes a narrow sinus band, marked by two low longitudinal riblets. On the sinus band very fine transverse striae are observed. Along the upper side of the whorls, together with sharp transverse riblets curved posteriorly, there run sharp longitudinal ones, so that the surface of the shell appears covered with regularly and very densely arranged tubercles. The lower surface is covered with fine longitudinal riblets.

In the character of the whorls of the shell and of its outer sculpture, this form very much recalls the Nassau form Catantostoma clathratum Sandb., but it lacks the feature characteristic of the latter—the turning-back of the outer lip of the apertural opening, with its considerable thickening. In our form, on the contrary, the lip is very thin and is preserved with difficulty.

Euomphalidae de Koninck.

Euomphalus planorbis Archiaci and Vern.

1854 . . . . Euomphalus planorbis F. Roëmer. Paleontogr. Bd. III. S. 37. Taf. V. Fig. 24.

1864 . . . . Euomphalus serpens. Semenov and Meller. Mining Journal, 1864, pt. I, sect. III, p. 200, table IV, fig. 4.
Euomphalus serpens Phillips. Fauna of the Malevka Muryaev beds.

1885 . . . . Euomphalus planorbis. Chernyshev. Fauna of the middle and upper Devonian deposits of the western slope of the Urals, p. 38. Table VI, fig. 5.

1889—92 . . . Euomphalus (Philoxene laevis) d’Archiaci and Verneuil. Whidborn. Pal. Soc. p. 239 pl. XXIII, f. 18—19.

Discoidal, with slightly embracing whorls. The outer side of the whorls is rounded. The sculpture consists of thin transverse, arcuately curving lines. Found at point 95 and in the eastern part of 94. Chernyshev describes this form from the Stringocephalus limestone of Cape Batyr by the river Ai.

Semenov and Meller describe from the Malëvka-Muravnya stage the form E. serpens Phillips, which, according to the characters indicated by them (flat), comes close to ours. On the other hand, E. planorbis and E. serpens differ from one another solely in that the former form is flat, whereas the latter is slightly conical. According to the study of Verneuil and Archiac, precisely by this character E. planorbis and E. laevis differ (the latter is identical with Phillips’s species: E. serpens). On this basis it is more correct to regard also the form E. serpens, described by Meller and Semenov, as E. planorbis.

Phanerotinus Sow.

Phanerotinus (cf.) serpula de Koninck.

1855 . . . . Euomphalus serpula Sandberger. Versteing. in Nassau.
S. 214, Taf. XXV, f. 9.

1884 . . . . Phanerotinus serpula Chernyshev. Materials for the study of the Devonian deposits of Russia, p. 3.

1889—92 . . . Phanerotinus militaris Whidborn. A Mon. of the Dev. Fauna, p. 259, pl. XXV, f. 9—11.

Separate fragments of nuclei, probably belonging to this species, were found at point 95.

Chernyshev indicates P. serpula from the limestones of the village of Koltuban (Upper Devonian goniatite horizon).

The vertical distribution of this form embraces the period from the Middle Devonian through the Carboniferous inclusive.

Capulidae Cur.

Capulus Montf.

Capulus tylotus Widborn.

1889—92 . . . Capulus tylotus Whidborn. As Monogr. ofs the D. Fauna v. I p. 216 pl. XXI, fig. 9; pl. XXII f. 1.

A form encountered at point 95 and in the eastern part of 94, with a spirally coiled apex and rapidly growing outer whorls, form—

a rather large open aperture. The surface of the shell is covered with sparsely spaced tubercles.

Capulus sp.

The single specimen, belonging to locality 95, is very poorly preserved. The absence of any precise characters does not permit it to be assigned to a definite species.

Naticidae Forbes.

Natica Lam.

Natica piligera Sandberger.

1850–56 . . . Natica piligera Sandberger. Verst. in Nassau, S. 235.
Taf. XXVI, fig. 6.

1886 . . . . . Natica piligera Venyukov. Fauna of the Devonian System of Russia, p.
203, pl. IX, fig. 18.

1895 . . . . . Natica piligera Venyukov. Deposits of the Devonian System in the Mugodzhary Mts.,
p. 155, vol. III, fig. 14.

Several specimens, found at locality 95, partly with preserved external sculpture of the shell, allow them to be assigned with certainty to the species N. piligera Sandb. In places with preserved sculpture, fine transverse lines—growth marks—are clearly visible. Venyukov indicates this species from the Upper Devonian limestones of Ak-Tyube-Aulie. According to Sandberger, Natica piligera characterizes the Stringocephalus limestone of Nassau (Wilmar and Oraniencustan).

CEPHALOPODA. TETRABRANCHIATA.

Orthoceratidae. M’Coy.

Orthoceras Breyn.

Orthoceras Helmerseni Pacht.

1858 . . . . . Orthoceras Helmerseni Pacht. Geological investigations of Voronezh Province,
p. 83, pl. 3, fig. 3.

1885 . . . . . Orthoceras Helmerseni Chernyshev. Fauna of the Middle and
Upper Devonian of the Urals, p. 16.

1895 . . . . . Orthoceras Helmerseni Venyukov. Deposits of the Devonian System
in the Mugodzhary Mts., p. 54.

Without giving a description of this species (see synonymy), we shall point out that the available specimens belong to locality 95 (Mt. Alabas). According to Venyukov and Chernyshev, Orthoc. Helmerseni is assigned in the Ural deposits to the goniatite-cuboid horizon. Venyukov indicates it from the limestones of Ak-Tkiande-Aulie.

Orthoceras obliquiseptatum (cf) Sandb.

1850--56 . . . Orthoceras obliquisiptatum Sandberger. Verst. in Nassau.
S. 160. Taf. XVIII, fig. 2.

A very insignificant fragment of the internal mold of a shell of this species, and moreover of young age, was found at locality 95. On the mold the transverse septa are sharply visible, running at an angle of 90° to the siphon. The siphon is marginal. The septa descend from the siphon in the direction toward the opposite side of the shell. According to Sandberger, this form is assigned to the Middle Devonian (orthoceratite beds of Wessenbach).

Gomploceras Sow.

Gomphoceras scapus Wenjuk.

. . . . . . Gomphoceras scapus Wenjukov. Fauna of the Devonian System of Russia,
p. 215, pl. X, fig. 9.

A fragment of a shell belonging to this species was found at locality 95 of Mt. Alabas. The transverse section is almost round. The siphon is marginal, thin, slightly convex in the middle between the septa. With a diameter at the septa of 25 mm, the distance between them is 4 mm; with a diameter of 25 mm, the distance is 3.5 mm.

Venyukov indicates this species along the Syas River and near Chudovo.

As is evident from the description of the molluscan fauna, almost all the indicated species, except Aviculopecten concentricus n. sp. and Cap. tylotus, are assigned to locality 95 of Mt. Alabas. Almost as exceptions, in the eastern part of locality 94, adjacent to locality 95, there occur forms of Capulus tylotus and Euomphalus planorbis. The fauna may be considered relatively rich in species and poor in the number of representatives of each species. In most cases, solitary forms are encountered.

Turning to the vertical distribution of the forms indicated in the description, we see that, of 12 determinable species, 7 are assigned to the goniatite-cuboid horizon of the Ural Devonian deposits, 3 were encountered in the Urals only in the Middle Devonian. Ta-

Thus the majority of the representatives belong to the upper division of the Devonian. Comparing these deposits with the deposits of Western Europe (Nassau), we see that most of them—9 out of 12—belong to the middle division, being confined chiefly to the stringocephalid limestone. This fact is not superfluous to note, as indicating that we are dealing with a transitional horizon (between the stringocephalid and cuboid horizons).

ARTHROPODA. CRUSTACEA.

Malacostraca. Phyllocarida. Packard.

Dithyrocaris Scouler.

Dithyrocaris sp.

Plate III, figs. 29–33.

This genus of crustacean, established by Scouler and having its principal distribution in the Carboniferous, is also encountered in Upper Devonian deposits (D. Kochi Ludw., D. Neptuni Hall., etc.). Unfortunately, the extremely poor preservation entirely eliminates the possibility of a specific determination of the specimen we possess, consisting of separate fragments of the head shield and segments of the abdomen, as well as separate parts of the keeled tail spines. It can only be stated with certainty that all these fragments belong to one individual of the genus Dithyrocaris.

Found in the middle part of locality 94.

In concluding the review of the fauna, we must also point out the presence in it of Crinoidea, separate columnal segments of whose stems occur in considerable quantity. Their determination was not carried out, in view of their minor importance.

For a comparative review of the vertical distribution of the forms encountered, a table is given below, in which are indicated the horizons of the Uralian Devonian deposits, Siberian deposits, and, finally, Western European deposits.

Devonian Fauna of Mugodzhar.

Taxon	94 western point	94 middle point	94 eastern point	95, Mt. Albas	Torma with limestone	Goniatite and coal horizon	Beds with Str. Burtini and Sp. Anossofi	Horizon with Pr. baschkiricus	Beds with Sp. Archiaci	Beds with Str. Burtini and Sp. Anossofi	Beds with Pent. baschkiricus and calc. sand.	Beds with Rhiz. (Gervill.) and Leperditia Norden	Pestrotskie beds	Upper division	Middle division	Lower division
Coelenterata. Anthozoa.
Cyathophyllum caespitosum Goldf.	+	+	+	+	−	+	+	−	+	+	+	−	−	−	+	−
Phillipsastrea Hennahi Lonsd.	−	+	−	−	−	+	−	−	−	−	−	−	−	+	−	−
Alveolites suborbicularis Lam.	+	+	−	+	−	−	+	−	−	+	+	−	−	−	−	−
Favostes polymorpha Goldf.	+	+	+	+	−	+	−	−	+	+	+	+	−	−	+	−
Hydrozoa.
Stromatopora sp.	+	+	+	+	−	−	−	−	−	−	−	−	−	−	+	−
Actinostroma stellulatum Nich.	+	+	+	+	·	−	−	−	−	−	−	−	−	−	+	−
Actinostroma sp.	+	+	+	+	−	−	−	−		−	−	−	−	−	+	−
Labechia sp.	+	+	+	+	−	−	−	−	−	−	−	−	−	−	+	−
Molluscoidea. Brachiopoda.
Productus sericeus Buch.	+	+	+	−	−	−	−	−	−	−	−	−	−	+	−	−
Productus sp.	+
Stropheodonta interstrialis Phill.	+	+	+	+	−	−	+	−	+	−	+	+	−	+	+	+
Orthis striatula Schloth.	+	+	+	+	+	+	+	+	−	−	−	−	−	+	+	+
Spirifer (Reticularia) Urii Flem.	+	+	+	+	−	+	+	+	+	+	+	+	−	+	+	+
Spirifer undiferus F. Roemer	−	−	−	+	−	+	−	−	−	+	+	−	−	−	+	−
Spirifer zickzack F. Roemer	−	+	·	−	−	+	−	−	+	+	−	−	−	+	·	−
Spirifer tenticulum Vern.	−	−	−	+		−	+	−	+	·	−	−	−	·	−	−
Spirifer Archiaci Murch.	+	−	−	−	+	+	+	−	+	−	−	−	−	+	−	−
Atrypa desquamata Sow.	+	+	+	+	−	+	+	+	−	+	+	−	−	−	+	−

A. P. Pifantov.

Species	94, western point	94, middle point	94, eastern point	95, Alab.	Ural: city of Kamen	Ural: Voitovyi and Pod”emnyi horizons	Ural: beds with Str. Burtini and Sp. Anossoffi	Ural: beds with Pent. baschkiricus	Ural: beds with Sp. altaica	Siberia, Kuznetsk Basin: beds with Str. Bartrami and Sp. Anossoffi	Siberia, Kuznetsk Basin: beds with Pent. baschkiricus and Orle. striatula	Siberia, Kuznetsk Basin: beds with Rhizoph. Chernyshevi and Lepta. Nortsinsk.	Siberia, Kuznetsk Basin: Iset layers	Western Europe: Upper division	Western Europe: Middle division	Western Europe: Lower division
Atrypa aspera Schloth. var.	+	+	+	+	−	+	+	+	+	+	+	+	+	+	+	+
Atrypa Alabasi n. sp.	+	+	+	+	−	−	−	−	−	−	−	−	−	−	−	−
Atrypa striata n. sp.	+	+	+	+	−	−	−	−	−	−	−	−	−	−	−	−
Athyris concentrica Buch.	−	+	−	−	−	+	+	−	+	−	−	−	−	+	+	−
Athyris lineata n. sp.	−	−	+	−	−	−	−	−	−	−	−	−	−	−	−	−
Rhynchonella livonica Buch.	+	−	−	−	−	−	+	−	−	−	+	−	−	+	+	+
Rhynchonella pugnus Mart.	−	+	+	−	−	+	−	−	+	−	−	−	−	+	+	−
Rhynchonella reniformis Sow.	−	−	−	+	−	+	−	−	−	−	−	−	−	+	+	−
Rhynchonella cuboides Sow.	+	+	+	+	−	+	−	−	−	−	−	−	−	+	−	−
Rhynchonella gracilis n. sp.	−	+	−	−	−	−	−	−	−	−	−	−	−	−	−	−
Rhynchonella Goldfussi (?) Schloth.	−	−	−	−	−	−	−	−	−	−	−	−	−	−	+	−
Camarophoria microrhyncha F. Röem.	+	−	−	−	−	+	−	−	−	−	−	−	−	−	+	−
Camarophoria (megistana Le-Hon)	+	−	−	−	−	−	+	−	−	−	−	−	−	+	−	−
Pentamerus galeatus Dalm.	−	+	+	−	−	+	+	−	+	+	+	+	+	+	+	+
Pentamerus globus Bronn	+	+	−	+	−	+	−	−	−	−	−	−	−	+	+	−
Pentamerus biplicatus Schnur.	−	+	+	−	−	−	−	−	−	−	−	−	−	−	+	−
Dielasma elongata Schloth.	−	+	−	−	−	+	−	−	−	−	−	−	−	+	−	−
Lingula sp. (minima? Sow.)	−	−	+	−	−	−	−	−	−	−	−	−	−	+	+	+

Devonian Fauna of Mugodzhar

	94 western point	94 middle point	94 eastern point	95 Alabas River	Urals: bed with clymenias	Urals: goniatite and cuboid-hornstone	Urals: bed with Str. Burtini and Sp. Anossofi	Urals: bed with Pent. baschkiricus	Urals: bed with Sp. Archiaci	Siberia, Kuznetsk Basin: bed with Str. Burtini and Sp. Anossofi	Siberia, Kuznetsk Basin: bed with Pent. baschkiricus	Siberia, Kuznetsk Basin: bed with Rhizodus, Crenella and Cyrtina Nordenskiöldi	Siberia, Kuznetsk Basin: variegated beds	Western Europe: Upper division	Western Europe: Middle division	Western Europe: Lower division
Mollusca.
Cypricardinia lamellosa Sandberg.	−	−	−	+	−	−	+	−	−	−	−	−	−	−	+	−
Aviculopecten concentr n. sp.	+	−	−	−	−	−	−	−	−	−	−	−	−	−	−	−
Natica piligera Sandberg.	−	−	−	+	−	+	−	−	−	−	−	−	−	−	+	−
Capulus tylotus Whidborn	−	−	−	+	−	−	−	−	−	−	−	−	−	−	+	−
Capulus sp.	−	−	+	+	−	−	−	−	−	−	−	−	−	−	−	−
Euomphalus planorbis Arch.	−	−	−	+	−	−	+	−	−	−	−	−	−	−	+	−
Rhaphistoma Bronni (cf.) Goldf.	−	−	−	+	−	−	+	−	−	−	−	−	−	−	+	−
Phanerotinus (cf.) serpula d’Koninck.	−	−	−	+	−	+	−	−	−	−	−	−	−	+	+	−
Pleurotomaria Koltubanica Tsch.	−	−	−	+	−	+	−	−	−	−	−	−	−	−	−	−
Pleurotomaria Alabasi n. sp.	−	−	−	+	−	−	−	−	−	−	−	−	−	−	−	−
Porcellia Alabasi n. sp.	−	−	−	+	−	−	−	−	−	−	−	−	−	−	−	−
Porcellia bifida Sandberg.	−	−	−	+	−	+	−	−	−	−	−	−	−	−	+	−
Porcellia primordialis Schloth.	−	−	−	+	−	+	−	−	−	−	−	−	−	−	+	−
Orthoceras Helmerseni Pucht.	−	−	−	+	−	+	+	−	−	−	−	−	−	−	+	−
Orthoceres obliquiseptatus (cf.) Sand.	−	−	−	+	−	−	−	−	−	−	−	−	−	−	+	−
Gomphoceras scapus Wen.	−	−	−	−	−	+	−	−	−	−	−	−	−	−	−	−
Arthropoda. Crustacea.
Dithyrocaris sp.	−	+	−	−	−	−	−	−	−	−	−	−	−	−	+	−

A. P. Nifantov.

Comparing the data of this table for each locality separately, we obtain the following picture of the vertical distribution of the forms occurring in them.

Fauna and locality	Urals: \(D_2\), horizons with modifications	Urals: \(D_2\), goniatite and cephalopod horizon	Urals: \(D_3\), bed with Str. Buchtimi and Sp. Anossoffi	Urals: \(D_3\), bed with Product. sublaevis	Siberia, Kuznetsk basin: \(D_3\), bed with Sp. Archiaci	Siberia, Kuznetsk basin: \(D_2\), bed with Str. Buchtimi and Sp. Anossoffi	Siberia, Kuznetsk basin: \(D_2\), bed with Product. Ia sublaevis and Chon. sunda.	Siberia, Kuznetsk basin: \(D_1\), bed with Rhynchonella acuminata and Leptaena Nordansk.	Siberia, Kuznetsk basin: Devonian bed	Western Europe: \(D_3\), upper division	Western Europe: \(D_2\), middle division	Western Europe: \(D_1\), lower division
Coral fauna:
94 western locality	—	1	2	—	1	3	3	1	—	—	6	—
94 middle locality	—	3	2	—	1	3	3	1	—	1	6	—
94 eastern locality	—	2	2	—	1	3	3	1	—	—	6	—
95 locality near the town of Alabas	—	2	2	—	1	3	3	1	—	—	6	—
Brachiopod fauna:
94 western locality	2	9	8	4	4	3	5	3	1	10	8	5
94 middle locality	1	12	7	4	7	5	5	4	2	12	10	5
94 eastern locality	1	8	6	4	5	4	5	4	2	9	9	6
95 locality near the town of Alabas	1	7	6	4	4	4	5	3	1	6	9	4
Molluscan fauna:
94 western locality	—	—	—	—	—	—	—	—	—	—	—	—
94 middle locality	—	—	—	—	—	—	—	—	—	—	—	—
94 eastern locality	—	—	1	—	—	—	—	—	—	—	2	—
95 locality near the town of Alabas	—	7	4	—	—	—	—	—	—	1	10	—

Taking into account the character of the occurrence of the limestones at both localities—their dip to the east, the insignificant angle of dip, and the impossibility of the existence of an overturned fold—we must accept that the most ancient beds will be those lying below; the localities situated farther west will have exposures of more ancient beds than the eastern ones. Turning to western locality 94, we see that, in terms of the coral fauna, it occupies an intermediate position between the cuboid horizon of the Urals and the beds with Str. Burtini; its parallelization with the Devonian deposits of the Kuznetsk Basin of Siberia indicates an age more closely approaching the Middle Devonian; the same comparison with West European deposits already directly indicates the Middle Devonian. Most important, of course, is the comparison with the nearer Ural deposits. On the basis of the latter, in terms of the coral fauna, the deposits of the western locality 94 are transitional between the middle and upper divisions of the Devonian. Approximately the same picture is given by comparison according to the brachiopod fauna (11 forms of the upper division to 12 forms of the middle). At the same time, comparison with West European deposits already gives 10 forms of the upper division to 8 of the middle. Mollusks have not been found in it. Thus the limestone beds in the exposures of western locality 94 are transitional between Middle Devonian and Upper Devonian. Next follows middle locality 94. Its parallelization with the above-mentioned Ural, Siberian, and West European deposits according to the coral fauna gives approximately the same picture as for the preceding locality; according to the brachiopod fauna, however, the limestones of the indicated locality are younger (13 forms of the upper division to 11 of the middle according to the Ural deposits, and 12 forms of the upper to 10 of the middle according to the West European). Nevertheless, they do not pass entirely out of the Middle Devonian and are likewise transitional to Upper Devonian deposits.

At localities 94 eastern and 95 we do not have characteristic figures; those available also indicate the transitional character of the deposits. Only according to the molluscan fauna of locality 95 do we see that Upper Devonian forms considerably predominate over the forms of the Middle Devonian—when they are compared with the deposits of the Urals. Be that as it may, on the basis of the data which we have and in view of their relatively younger age compared with the preceding ones (according to the stratigraphic conditions of occurrence), we must also regard them as transitional between Upper and Middle Devonian deposits.

Thus, the deposits of both localities 94 and 95 occupy an intermediate position between the cuboid and stringocephalid horizons of the Urals.

P. Venyukov, who in 1905 described the deposits of the Devonian system in the Mugodzhar Mountains, visited, in addition to Mt. Alabas, the sources of the Kauldzhur River, the sources of Ak-Tkinde-Aulie (near where the Aulie River emerges from the mountains into the steppe), and the Shuldak Range; according to his indications, the environs of Ak-Tkinde-Aulie are composed of Upper Devonian limestones with typical representatives of the goniatite and cuboid horizons of the Urals, e.g. Sp. Archiaci Murch., Rhynch. cuboides Sow., Goniatites simplex Buch., and others. The fauna of Shuldak is distinguished by the same character. The fauna of the limestones at the sources of the Kauldzhur River, while possessing the same character, differs from the preceding ones in being expressed almost exclusively by brachiopods. As for the fauna of Mt. Alabas, P. Venyukov, pointing out its somewhat transitional character between the Middle and Upper Devonian, is more inclined to define it as Middle Devonian, only partly including forms of the Upper Devonian. The fauna indicated by him for the deposits of Mt. Alabas is as follows:

Cyathophyllum ceratites Goldfuss.
Cyathophyllum caespitosum Goldfuss.
Phillipsastrea Hennahi Lonsd.
Phillipsastrea Bowerbanki M. Edw. et Haime.
Phillipsastrea pentagona Goldfuss.
Phillipsastrea Torreana M. Edw. et Haime.
Phillipsastrea Alabasi n. sp.
Alveolites suborbicularis Lam.
Orthis striatula Schloth.
Stropheodonta interstrialis Phill.
Orthotetes umbraculum Schloth.
Skenidium areola Quenst.
Spirifer tenticulum Vern.
Spirifer Anossofi Vern.
Spirifer zickzack F. Röemer.
Spirifer pseudopachirhynchus Tsch.
Reticularia Urii Flem.
Reticularia lineata Mart.
Martinia glabra Mart.
Athyris concentrica Buch.
Athyris subpyriformis Sem. et Möl.
Atrypa reticularis Lüm.
Atrypa desquamata Sow.
Atrypa aspera Schloth.

Atryra Duboisi Vern.
Rhynch. aptycha Schnur., aff.
Rhynch. anisodonta Phill
Camarophoria rhomboidea Phill.
Camarophoria ascedens Steiniger
Pentamerus galeatus Dalm.
Pentamerus globus Bronn.
Merista plebeja Sow.
Dielasma sacculus Mart.
Cypricardinia lamellosa Sandberg.
Goldius granulatus Goldfuss.

Of the 35 species cited, 13 occur in our material. Such a small number of common forms, and the apparent disagreement in determining the age of the deposits of the town of Alabast by us and by Venyukov, is explained, of course, by the fact that the material studied by us comes from another point of the town of Alabast, from beds lying below those belonging to our western locality 94. Unfortunately, from the description given by Venyukov it is impossible to determine exactly where precisely his material was collected. One thing is beyond doubt: it is older than ours. In all, our material yielded 53 species; of these, as stated above, 13 are common to those indicated by Venyukov, 6, because of poor preservation, have not been identified to species, and 4 have doubtful determinations. Thus 30 species add to the composition of the fauna of the town of Alabast. Of these, 8 are new, namely:

Atryra Alabasi.
Atrypa striata.
Athyris lineata.
Rhynchonella gracilis.
Aviculopecten concentricus.
Pleurotomaria Alabasi.
Porcellia Alabasi.

Further, 4 forms not previously encountered in the Urals:

Capulus tylotus Whidb.
Pentamerus biplicatus Schn.
Dithyrocaris Scouler.
Gomphoceras scapus Wen.

Moreover, the first three forms are not indicated at all in Russian deposits.

A. Nifantov.

RÉSUMÉ.

The material studied comes from Mount Alabas (the forehills of Mugodzhary).

In 1895 a work appeared by P. Wenjukow on the Devonian deposits of Mugodzhary, in which there is also a description of Mount Alabas. His conclusions may be supplemented to the effect that the age of Mount Alabas is very different at different points; P. Wenjukow regards these deposits as close to the Middle Devonian; the study of our material shows us, however, that the strata in question stand nearer to the Upper Devonian and occupy an intermediate position between the Cuboides and Stringocephalus beds of the Urals.

The list of all forms encountered is given on pages 49–51. Among them are 7 new species:

Aviculopecten concentricus.
Pleurotomaria Alabasi.
Porcellia Alabasi.
Atrypa Alabasi.
Atrypa striata.
Athyris lineata.
Rhynchonella gracilis.

Aviculopecten concentricus n. sp.

Taf. III. Fig. 28 a—b.

The shell is equivalve, almost equilateral, oval. The posterior little wing is longer than the anterior one and is covered with very fine vertical threads, which continue onto both valves and cover their entire surface as closely spaced, fine concentric lines. The margins of the shell are somewhat thicker and form a narrow and flat band. The length is 22 mm, the width likewise 22 mm, and the thickness 10 mm.

Pleurotomaria Alabasi n. sp.

Plate III. Figs. 25—27.

The shell is conical, with 4 rounded whorls; the outer part of the last whorl is distinguished by a narrow sinus band. The sinus band is bounded by 2 low longitudinal riblets, and very fine curved transverse bands are perceptible. The upper part of the whorls has sharp, backward-curved transverse riblets and equally sharp longitudinal riblets, which together form a lattice pattern. In part this ornamentation is also to be observed on the lower surface. The whorls and the sculpture of the shell strongly recall Cantatostoma clathratum Sandberg. (from the Nassau beds), but it does not possess the characteristic feature of this form, the sharp deflection of the aperture lip. The latter is very thin.

Porcellia Alabasi n. sp.

Plate III. Figs. 24 a—b.

The shell is coiled flat, of 4 rapidly increasing whorls. The umbilicus is open. In the middle of the outer part of the last whorl there is a narrow sinus band, which is bounded by 2 longitudinal riblets. The surface is covered with fine transverse lines and large, thick ribs curved backward. Each whorl has 6 such ribs.

Atrypa Alabasi n. sp.

Plate III. Figs. 15—16.

These small forms are of rather variable size, but do not exceed 10 mm in width, 1—8 [[unclear: unit/measurement]] and 4 in height. The shells are very reminiscent of Atrypa salaïrica V. Petz., but differ from the latter by larger radial riblets. The ventral valve is distinguished by a sharp keel-like elevation, which extends from the beak to the anterior margin and disappears in the middle of the shell. Corresponding to this elevation on the dorsal valve is a radial furrow. The anterior margin is straight.

Atrypa striata n. sp.

Plate III. Figs. 17—a—b.

In its general habitus this form resembles Atrypa reticularis, but differs in smaller dimensions (the larg—

... specimens have a length of 16 mm, a width of 14 mm, and a height of 11 mm, and by the external sculpture in the form of very thin, radially dichotomizing ribs. The frontal margin is strongly curved. The beak of the ventral valve is strongly drawn toward the dorsal valve.

Athyris lineata n. sp.

Pl. III. Fig. 18 a—b—c.

The characteristic features of this species are the considerable width of the shell and the zigzag-shaped curvature both of the frontal margin and of the lateral margins. The surface is covered with thin, concentric, very regular lines. Dimensions: length—11 mm, width—14 mm, and height 5 mm.

Rhynchonella gracilis n. sp.

Pl. III. Fig. 23—a—d.

Alongside the typical Rhynch. cuboides there is in our collection a form which is distinguished by an abnormal bending of the frontal margin of the ventral valve. In addition, the lateral margins of the ventral valve are somewhat raised, so that the valve is not flat, as usual, but somewhat hollowed out. The greatest dimension of the shell in all directions is 11 mm, although from the frontal margin it appears that the height is greater than the width.

A. Nifantof.

Explanation of the Plates.

TAFELNERKLÄRUNG

Plate I.

1. Actinostroma stellulatum Nich.
   Transverse section, natural size.

2 and 4. Phillipsastrea Hennahi Lonsd. longitudinal and transverse sections. Natural size.

1. Encrustation by the coral Alveolites suborbicularis of Actinostroma and Stromatopora. Magnified 5–6 times. Transverse section.

2. Stromatopora sp. Vertical section. Magnified 5–6 times.

3. The same. Horizontal section. Magnified 5–6 times.

4. Horizontal section of Stromatopora sp. Magnified 5–6 times.

Plate I.

1. Actinostroma stellulatum Nich.
   Transverse section at natural size.

2 and 4. Phillipsastrea Hennahi Lonsd. 2—view from the side; 4—view from above.

1. Alveolites suborbicularis Lam., encrusting Actinostroma and Stromatopora sp., magnified 5–6 times.

2. Stromatopora sp. Vertical section, magnified 5–6 times.

3. Idem. Transverse section, magnified 5–6 times.

4. Idem. Transverse section, magnified 5–6 times.

Table I.

1.

2.

3.

4.

5.

6.

7.

Phot. P. Pavlov.

Table II.

1. Actinostroma stellulatum Nich.
   Transverse section, magnified 5–6 times.

2. Same. Horizontal section, magnified 5–6 times.

3. Actinostroma sp. (with Caunopora). Vertical section, magnified 5–6 times.

4. Same. Horizontal section, magnified 5–6 times.

5. Same. View from the side. Vertical section, natural size.

6. Labechia sp. Vertical section, magnified 5–6 times.

7. Same. Horizontal section, magnified 5–6 times.

8. Stromatopora sp. Horizontal section, magnified 5–6 times.

Plate II.

1. Actinostroma stellulatum. Nich.
   Vertical section, magnified 5–6 times.

2. Idem. Horizontal section, magnified 5–6 times.

3. Actinostroma sp., (with Caunopora). Vertical section, magnified 5–6 times.

4. Idem. Horizontal section, magnified 5–6 times.

5. Idem. View from the side. Vertical section, natural size.

6. Labechia sp. Vertical section, magnified 5–6 times.

7. Idem. Horizontal section, magnified 5–6 times.

8. Stromatopora sp. Horizontal section, magnified 5–6 times.

Table II.

6. 7.

Phot. I. Pavlo

Table III.

1. Atrypa desquamata Sow. a—view from the dorsal valve, b—side view.

2. The same. a—view from the dorsal valve, b—side view.

3. The same. a—view from the dorsal valve, b—side view.

4. Atrypa aspera Schloth., var. a—view from the dorsal valve, b—side view.

5—9. The same, a—view from the dorsal valve, b—side view.

1. The same. View from the ventral valve.

2. Atrypa desquamata Sow. View from the dorsal and ventral valves.

3. Atrypa desquamata Sow. Ventral valve.

4. Atrypa aspera Schloth. var. Ventral valve.

5. Atrypa desquamata Sow. Ventral valve.

6. Atrypa Alabasi n. sp. a—view from the dorsal valve, b—side view.

7. The same. Ventral valve.

8. Atrypa striata n. sp. a—view from the dorsal valve, b—side view.

9. Athyris lineata n. sp. a—view from the dorsal valve, b—side view, c—view from the ventral valve.

Tafel III.

1. Atrypa desquamata Sow. a—view from the side of the dorsal valve, b—view from the side.

2. Idem. a—view from the side of the dorsal valve, b—view from the side.

3. Idem. a—view from the side of the dorsal valve, b—view from the side.

4. Atrypa aspera Schloth., var. a—view from the side of the dorsal valve, b—view from the side.

5—9. Idem. a—view from the side of the dorsal valve, b—view from the side.

1. Idem. View from the side of the ventral valve.

2. Atrypa desquamata Sow. View from the side and from the dorsal valve.

3. Idem. The ventral valve.

4. Atrypa aspera Schloth. v. Ventral valve.

5. Atrypa desquamata Sow. Ventral valve.

6. Atrypa Alabasi n. sp. a—view from the side of the dorsal valve, b—view from the side.

7. Idem. Ventral valve.

8. Atrypa striata n. sp. a—view from the side of the dorsal valve, b—view from the side.

9. Athyris lineata n. sp. a—view from the side of the dorsal valve, b—view from the side, c—view from the side of the ventral valve.

1. Pentamerus biplicatus Schn.

2. The same. Side view.

21–22. The same. View of the ventral valve.

1. Rhynchonella gracilis n. sp.

2. Porcellia Alabasi n. sp.

25–26. Pleurotomaria Alabasi n. sp.

1. The same. Enlarged 2 times.

2. Aviculopecten concentricus n. sp.

29–33. Dithyrocaris. Separate fragments.

1. Alveolites suborbicularis Lam., enveloping a foreign body. Enlarged 5–6 times in cross-section.

Plate III.

Photo by P. Pavlov