G. M. Nakhimson.

MATERIALS

FOR THE STUDY

OF THE DEVONIAN DEPOSITS

OF THE MUGODZHAR MOUNTAINS.

With 3 tables.

DIPLOMA THESIS

from the Paleontological Cabinet of the Tomsk Technological Institute.

Materialien zur Kenntniss der devonischen Ablagerungen des Gebirges Mugodjari von G. Nachimson

(mit 3 Tafeln).

Tomsk.

Typo-Lithography of the Siberian Commercial Printing House. Corner of Dvoryanskaya Street and Yamskoy Lane, own building.

1911.

MATERIALS

for the study of the Devonian deposits of the Mugodzhar Mountains.

Diploma thesis

by G. M. Nakhimson.

with 3 tables.

The Mugodzhar Mountains, as is evident from the article by Prof. M. Yanishevsky, “Report (preliminary) on an assignment to the Mugodzhar and Guberlin Mountains. Tomsk, 1905, p. 8,” lie between 49½ and 48° north latitude and constitute narrow mountain ridges that are a continuation of the southern Urals. Beginning near the sources of the Ori River (a tributary of the Ural), they extend almost in a meridional direction along the boundary between the Ural and Turgai regions and, gradually narrowing, end at Mount Yaman-Tau. The highest summit of this range, Mount Airok, reaches an elevation of 1,890 feet above sea level, which of course indicates that the Mugodzhar Mountains do not belong to the high mountain ranges. Although in tectonic terms the Mugodzhars are simple folded mountains, they nevertheless are distinguished by a very complex relief. The reason for this circumstance is both the large participation of volcanic rocks in the composition of the mountains and the significant and prolonged denudation processes to which these mountains have been subjected. As is evident from the same report, the Mugodzhar Mountains form the watershed between the basins of the rivers flowing into the Caspian and Aral seas. Here originate the Chiyli and Tashla-Or rivers, which flow into the Or (a tributary of the Ural River); then the rivers Dzhalay, Kunduzdu, Ak-Tykent, and Karagandy, which flow into the Emba River. Of the rivers flowing eastward, here originate the Tyulet, Kaindy, and Shuldak, which flow into the Chit-Irgiz, a tributary of the Irgiz River, as well as the Kauldzhur River, which gradually loses itself in a southeasterly direction in sandy deposits. Many small ravines also begin here, flowing into the rivers just listed. The vegetation of the Mugodzhars is extremely sparse. The mountains only here and there po-

covered with small thickets of tree species. Most of it consists of steppe and salt-marsh flora.

The Mugodzhar Mountains have to the present time been very little studied, and one of the immediate tasks of Russian geologists is a detailed examination of this range. In their day, well-known Russian naturalists—Hofmann, Severtsov, Borshchev, Helmersen, Yakovlev and others—undertook excursions to the Mugodzhars, and their works in many respects illuminated the geological structure of these mountains, which, of course, greatly facilitates their detailed study. Among the works presenting the result of a more detailed investigation of the Mugodzhar Mountains, it is necessary to note Venyukov’s article “Deposits of the Devonian System in the Mugodzhar Mountains” (Proceedings of the St. Petersburg Society of Naturalists, 1895), which was the result of an excursion to these mountains equipped by the St. Petersburg Society of Naturalists in 1889, in which the author and Prof. Levinston-Lessing took part.

The task of our work is the treatment of part of the Devonian paleontological material brought by Prof. M. Yanishevsky from a summer field trip to the Mugodzhars (1904). The material handed over to us was taken from two points: from quarries near the station Bert-Chugur of the Orenburg–Tashkent Railway, and from a cutting at the 500th verst of the same railway, between the stations Bert-Chugur and Karagandy. As Prof. Yanishevsky indicates,¹ in both places deposits of the Upper Devonian are developed, with characteristic representatives of this division.

In the present work, more detailed data are reported concerning the Devonian outcrops at the indicated points.

Near the station Bert-Chugur, situated on the eastern side of the Mugodzhar Mountains, in a railway cutting there is a small section of Devonian rocks, which exposes only an insignificant part of the rocks forming the locality situated near the station Bert-Chugur to the NE. This locality is a comparatively level area, elongated in the meridional direction, and in its western part adjoining the foothills of the Mugodzhars; in its eastern part it ends in a scarp above a steppe lowland stretching far to the E. The width of this scarp reaches one verst. Since there are quarries in this area, it is possible to become acquainted with its geological structure through a whole series of artificial exposures. The following stratigraphic picture can be traced (Table I):

¹ Loc. cit., pp. 10 and 12.

In the excavation, porphyrite crops out, upon which gray crystalline limestone rests, being separated from the porphyrite by a layer of light greenish-gray clay. All the beds dip rather steeply (about 45°) to the W. To the east, the limestone is followed by beds of siliceous shale, upon which, in turn, lies a thickness of conglomerate. Within the latter occur interbeds of brown clay. On the conglomerates lie alternating beds of conglomerates and sandstones, and farther to the east these beds are covered by beds of various limestones and sandstones in the following order: crystalline gray limestone, calcareous sandstone, sandy limestone, brownish-gray calcareous sandstone, partly conglomerate, whitish-gray fine-grained, partly oolitic limestone, conglomerate with pebbles and blocks (up to 1 arshin in diameter) of limestone, dark-gray sandy limestone, gray crystalline limestone, brownish crinoidal limestone, and, finally, gray crystalline, partly sandy limestone. This entire stratigraphic picture is visible in the schematic section (Table I). In the stone quarries situated in this locality, paleontological material was obtained, consisting of the following forms:

Amplexus sp.
Actinostroma sp.
Segments of Crinoidea.
Productus Mugodjaricus nov. sp.
Productella subaculeata Murch. var. angustior Gürich.
Productella subaculeata Murch. var. latior Gürich.
Orthis striatula Schloth.
Orthis granulosa (?) Phill.
Spirifer Archiaci Murh.
Spirifer tenticulum Vern.
Spirifer subcomprimatus Tschern.
Cyrtia Murchisoniana de Kon.
Retzia tulensis (Pander) Romanowsky var.
Athyris concentrica v. Buch.
Rhynchonella pugnus Mart.
Rhynchonella pleurodon Rhill.
Nucula lineata Phill.?
Conocardium sp.
Pleurotomaria sp.
Pleurotomaria sp.
Natica piligera Sandb.

Loxonema cf. piligera Sandb.
Orthoceras Helmerseni Pacht.
Orthoceras sp.
Phragmoceras sp.
Tornoceras simplex v. Buch.
Phacops sp.

The majority of the forms in this list belong to typical representatives of the fauna of the upper division of the Devonian system: among them we find, for example, Spirifer Archiaci Murch., Spirifer tenticulum Vern., Cyrtia Murchisoniana de Kon., Rhynchonella pugnus Mart., Tornoceras simplex v. Buch, and others. For comparison it is most convenient to take the neighboring deposits—the Uralian ones, studied in detail by F. Chernyshev). Examining the lists of forms given by Chernyshev, it is not difficult to establish a complete analogy between the fauna of Ber-Chugur and the fauna of the goniatite and cuboid beds of the Urals. The common forms amount to about 35%, notwithstanding the rather large number of forms described as sp., which of course considerably lowers this percentage. It is true that at the Ber-Chugur locality the form characteristic of the lower horizons of the upper division—Rhynchonella cuboides* Sow.—has not been found, but this circumstance changes the matter not at all, since the failure to find this form may be due to chance, while the character of the entire fauna undoubtedly testifies to the correctness of our conclusion.

The remaining material at our disposal was obtained from the railway cutting at the 500th verst, between the Ber-Chugur and Karaganda stations. In this cutting a section is visible of an entire series of rocks: thin- and thick-bedded brownish-gray limestones alternating with brown and brownish-gray, partly sandy clays. The dip of the beds is to W or WWS at an angle of about 20°–30° (see the report on the assignment by Prof. M. Yanishevsky).

The fauna of this locality, rich in number of specimens, is extremely uniform and poor in species: from this material we were able to determine only a few species, among which Cyrtia Murchisoniana de Kon. is especially numerous. It occurs here in such abundance that other forms are completely lost among it. The entire fauna consists of the following forms:

Productus Mugodjaricus nov. sp.
Productella subaculeata Murch. var. angustior Gürich
Strophalosia productoides Murch.

) F. N. Chernyshev—The Fauna of the Middle and Upper Devonian of the Western Slope of the Urals*, 1887.

Spirifer Archiaci Murch.
Orthis striatula Schloth.
Cyrtia Murchisoniana de Kon.
Rhynchonella acuminata Mart.
Rhynchonella pugnus Mart.

Despite the poverty of this fauna, it is so characteristic in the presence of Spirifer Archiaci Murch. and Cyrtia Murchisoniana de Kon., and also of Productus Mugodjaricus n. sp., that the analogy between the fauna of this locality and the Ber–Chugur fauna, and thereby also with the fauna of the goniatite and cuboid horizon of the Urals, seems to us quite clear. The total number of forms in common with the above-mentioned beds of the Urals reaches 90%.

Venukov indicates the discovery by him of an analogous fauna, i.e., one also belonging to the goniatite and cuboid horizon, at three points in the Mugodzhar Mountains: from the limestones of Ak-Tkiinde-Aulie near the outlet of the Aulie River from the mountains into the steppe, from limestones and conglomerates developed at the headwaters of the Kauldzhur River, and from the limestones of the Shuldak mountain chain.

Summarizing the foregoing, we arrive at the following general conclusion:

The fauna of the Ber–Chugur and Karaganda localities consists of mixed goniatite and cuboid elements and is entirely analogous to that same horizon of the Urals, which in turn, as the investigations of Th. Chernyshev have shown, corresponds fully to the Iberg limestone in the Harz.*)

With respect to the corresponding horizons \(D^1_3\) and \(D^2_3\) of other localities, both in Russia and in western Europe and America, we may draw the following parallelization, which, for greater clarity, we present in a table:

	Ber–Chugur.	Karaganda.	Urals.	Kirghiz Steppe.	Harz.	Rhine.	North America.
\(D^1_3\)	Goniatite and cuboid beds.	Goniatite and cuboid beds.	Goniatite and cuboid beds.	Limestones with Tornoceras cf. bifer Sow. Limestones with Spirifer disjunctus, Spirifer Archiaci, Cryptonella planirostra Hall. Cryptonella rectirostra Hall.	Goniatite and cuboid beds.	Goniatite beds. Cuboid beds.	Chemung group; Portage group; Naples beds; Genesee beds.

) I. Clarke—Die Fauna des Iberger Kalkes*.

Upper Devonian forms of Ber-Chugur and Karaganda	Mugodzhar: Ber-Chugur	Mugodzhar: Karagaily	Mugodzhar: Ak-Tyube-Aulie	Mugodzhar: Kaulzhur	Mugodzhar: Shulak	Ural: Goniatite and cuboid layers	Harz: Iberger Klippen (Goniatite and cuboid layers)
Amplexus sp.	+	−	−	−	−	−	−
Actinostroma sp.	+	−	−		−	−	−
Productus Mugodjaricus n. sp.	+	+	−	−	−	−	−
Productella subaculeata Murch.	+	+	−	−	+	+	+
Strophalosia productoides Mursch.		+	−	−	−	+	+
Orthis striatula Schloth.	+	+	+	+	−	+	+
Orthis granulosa (?) Phill.	+	[[unclear]]	−	−		[[unclear]]	−
Spirifer Archiaci Mursch.	+	+	+	−	+	+	+
Spirifer tenticulum Vern.	+	−	[[unclear]]		−	−	−
Spirifer subcomprimatus Tschern.	+	−	−	−	−	−	−
Cyrtia Murchisoniana de K n.	+	+	−	+	−	+	+
Retzia tulensis (Pander) Romanowski var.	+	−	−	−	−	−	−
Athyris concentrica v. Buch.	+	[[unclear]]	−	[[unclear]]	−	+	+
Rhynchonella acuminata Mart.	−	+	−	[[unclear]]	−	+	+
Rhynchonella pugnus Mart.	+	+	+	[[unclear]]	−	+	+
Rhynchonella pleurodon Phill.	+		−	−	−		−
Nucula lineata Phill (?)	+	[[unclear]]	−		−	−	−
Ctenocardium sp.	+	−	−	[[unclear]]	−		−
Pleurotomaria sp.	+	−	−	−	−	−	−
Pleurotomaria sp.	+	−	−	−	[[unclear]]	−	−
Natica piligera Sandb.	+	[[unclear]]	+	−	−	−	−
Loxonema cf. piligera Sandb.	+	−	−	[[unclear]]	[[unclear]]	−	−
Orthoceras Helmerseni Pacht.	+	−	+	−	[[unclear]]	+	−
Orthoceras sp.	+	−	−	−	−	−	[[unclear]]
Phragmoceras sp.	+	−	−	−	−	−	−
Trmooceras simplex v. Buch.	+		+	−	−	−	+
Phacops sp.	+	−	[[unclear]]	−	−	−	−

COELENTERATA

Hydrozoa

Stromatoporidea

Actinostromidae

Actinostroma Nicholson

Actinostroma sp.

Plate II, fig. 1.

The material contains several fragments of polyparies of this form. Their surface is strongly rounded by abrasion, and therefore the structure can be observed only in sections. Tangential sections (Plate II, fig. 1) reveal a transverse section of the radial pillars. In the transverse section a reticulate pattern is visible. Further, the passage of the radial pillars through several intervals between the tangential laminae can be seen. Astrorhizae could not be detected. There are about 4–5 tangential laminae per millimeter. It was not possible to provide a species determination of this form, in view of the poor preservation, which does not reveal the external appearance. One may indicate only a similarity to Actinostroma stellulata Nicholson. It was encountered at the Bert-Chugur locality.

Anthozoa

Zaphrentidae E. H.

Amplexus Sowerby

Amplexus sp.

At our disposal are two fragments in very poor preservation, owing to their partial silicification. All that can be done is to assign them to the genus Amplexus. This is indicated by the thin, short radial septa. The form is conical. The diameter of the transverse section is 6 mm. This form was found at the Bert-Chugur locality.

ECHINODERMATA

Crinoidea

As in almost all deposits of Devonian limestones, so also in the Bert-Chugur deposits, fragments of crinoid stems occur in greater or lesser quantity. Before us is an entire series of such ossicles from the layer of crinoidal limestone (see table I), completely silicified, so that there is no possibility of saying anything more definite about them.

MOLLUSCOIDEA.

Brachiopoda.

Productidae Gray.

Productus Sowerby.

Productus Mugodjaricus n. sp.

Table II, fig. 2.

The form of the shell is almost rectangular. The ventral valve is strongly inflated; at the hinge margin it reaches its greatest width, forming ears of rather considerable size, extending at approximately a right angle from the lateral part of the valve. The beak is small, sharply bent downward. The entire surface of the ventral valve is covered with wrinkled growth folds, especially sharply projecting in the hinge region. In the region of the beak, at some distance from it, a sinus begins to be outlined, which becomes ever more distinct and on the frontal margin forms a shallow but rather broad groove. The spines are arranged in regular rows on the growth marks. The dorsal valve is concave; the growth folds on it project more sharply than on the ventral valve. The spines are arranged in the same regular rows as on the ventral valve. The internal structure of the shell cannot be studied, since the material does not allow preparation. Dimensions in millimeters:

Length	Width
25	39
23	33

In its external outlines this new species resembles in part Productus Meisteri Petz, but differs essentially from Petz’s species both in the absence of longitudinal ribbing and in the presence of a clearly expressed sinus, which in Productus Meisteri is either entirely absent or is found only in a rudimentary state even on large specimens. Productus Mugodjaricus n. sp. is found both at the Berchugur locality and at Karaganda.

Productella Hall.

Productella subaculeata Murch.

Table II, fig. 3.

1. Productus subaculeatus Murchison—Bulletin de la société géologique de France T. XI, p. 255 pl. II, f. 9. Orthis productoides Idem, Ibidem, p. 254 pl. II. f. 7 a, b, c.

2. Productus subaculeatus Verneuil Paléontologie de la Russie p. 282 pl. XVI fig. 9.

3. Productus subaculeatus Keyserling. Reise in das Petschoraland S. 199 Taf. IV fig 1.

4. Productus subaculeatus Pacht—Geognostic investigation from Voronezh to Samara, p. 91.

5. Strophalosia subaculeata Eichwald—Lethaea Rossica Vol. I. p. 883.

6. Productus subaculeatus Davidson. Monogr. Brit. Devonian Brachiopoda p. 99 pl. XX fig. 1,2,

7. Productella subaculeata Hall·Pal. New York Vol. IV, p. 154 pl. XXII fig. 4–5.

8. Strophalosia subaculeata Stuckenberg—Devonian basin of European Russia, p. 485.

9. Productus subaculeatus Kayser·Richthofen ’China S. 93 Taf. XIII fig. 5.

10. Productus (Productella) subaculeatus Walcott—Paleontology of the Eureka district p. 128 pl VIII fig. 2 pl. XIII fig. 19–20.

11. Productus subaculeatus—Venukov Fauna of the Devonian system of northwestern and central Russia, p. 41 Table II fig. 7.

12. Productus subaculeatus Chernyshev—Transactions of the Geological Committee Vol. III No. 3 p. 112.

13. Productella subaculeata Whidborne·Dev. Fauna South of England V II pt III p. 154.

14. Productella subaculeata Venukov·Proceedings of the St. Petersburg Society of Naturalists Vol. XXIII p. 125 Table I fig. 11.

15. Productella subaculeata f. Petts—Transactions of the Geological Section of the Cabinet of His Majesty Vol. IV p. 52.

This species, in general subject to considerable variations both with respect to the form of the shell and to the character of the tubercles, is very widespread in the Devonian deposits of Germany, Belgium, France, England, Russia, Persia, Asia Minor, the Altai, China, and North America. Hall, in view of the significant changes to which, as has already been said, this species is subject, split it into a whole series of new species (Productella shumardiana, Productella pyxidata, Productella subalata),

which, however, after Walcott’s work must again be united into a single species, Productella subaculeata (Th. Tchernyshev). More rational is the subdivision of Productella subaculeata proposed by Gürich) into two varieties: var. latior and var. angustior. The first is flatter, broader, and has a smaller number of tubercles. In our possession there are forms belonging both to var. angustior and to var. latior. Incidentally, let us note that Productella subaculeata var. kirgisica ) established by P. Venukov (from the limestones of the Shuldak Range) comes very close, if it does not entirely coincide, with Gürich’s var. latior. Venukov also indicates the joint occurrence in the same deposits of var. kirgizica (latior) and the “typical form” (var. angustior*).

Productella subaculeata is characteristic of the middle division of the Devonian system of Western Europe and America, but it also extends into the upper division, as, for example, in the Urals and in Central Russia. In our material there are forms obtained both from the Ber-Chugur locality and from Karagandy; moreover, in the first locality both varieties occur, while in the second only var. angustior.

Strophalosia King.

Strophalosia productoides Murch

1. Orthis productoides Murchison, Bulletin de la Société géologique de France, T. XI, p. 254, pl. II, fig. 7.

2. Productus productoides Verneuil, Paléontologie de la Russie, p. 283, pl. XVIII, fig. 4.

3. Productus membranaceus Idem, ibidem, p. 285, pl. XV, fig. 11.

4. Productus subaculeatus Keyserling (pars)—Reise in das Petschoraland, S. 199, Taf. IV, fig. 2.

5. Productus productoides Pacht—Geognostic investigation from Voronezh to Samara, p. 91.

6. Strophalosia subaculeata Eichwald (pars), Lethaea Rossica, p. 883.

7. Strophalosia membranacea. Idem, ibidem, 884.

1864–65. Strophalosia productoides Davidson, Brit. Dev. Brachiopoda, p. 97, pl. XIX, fig. 13–21.

1. Strophalosia productoides Stuckenberg—Devonian basin of European Russia, p. 485.

2. Strophalosia productoides Venukov, Fauna of the Devonian system of north-western and central Russia, p. 45, Table II, figs. 5–6.

) Proceedings of the Mineralogical Society, Vol. XXXII, pp. 217–218.
*) Venukov—Proceedings of the St. Petersburg Society of Naturalists, Vol. XXIII, p. 125.

1. Strophalosia productoides Chernyshev, Fauna of the Middle and Upper Devonian of the western slope of the Urals, p. 111.

2. Strophalosia productoides Φ Petz. Proceedings of the Geological Section of His Imperial Majesty’s Cabinet, Vol. IV, p. 58.

We have at our disposal only two ventral valves of this species. The shell is semicircular and slightly convex. The umbo is of irregular shape, owing to the fact that it served as the place by which the shell was attached to foreign objects. The surface of the valve is covered with numerous concentric growth folds, which have an irregular, as it were wavy, form. Among these folds there appear numerous spines or, rather, their remains in the form of small tubercles with openings at their summits. This species occurs in the Middle division of the Devonian system of Western Europe, central Russia, and the Urals, but it is most widespread in the Upper division of the same localities.

Found at the Karagandy locality.

Spiriferidae King.

Spirifer Sowerby.

Group of Spirifer disjunctus Sow.

In almost all special works on Devonian fauna one may encounter the most diverse opinions concerning the place that forms, in recent times assigned to this group, should occupy in paleontological systematics. Until a comparatively recent time, when some investigators finally came to a general, not too broad and not too narrow, understanding of the species, Spirifer Archiaci Murch., Spirifer disjunctus Sow., Spirifer tenticulum Verneuil were either identified with one another, or various combinations were formed subordinating some of these forms to others. In this respect there existed almost as many opinions as there were investigators of Devonian fauna. In 1884 F. Chernyshev, on the basis of a whole series of characters, separated Spirifer Archiaci from Spirifer disjunctus as a distinct species equivalent to it. In 1886 Wenjukow united all four forms named above, and also a fifth form established by him—Spirifer Brodi Wen.—as varieties into one group, Spirifer disjunctus. In 1893 Whidborne united these five forms, as varieties, into one general group, Spirifer Verneuili. In 1900 Scupin, in his work “Die Spiriferen Deu-

“tschlands” subordinates three of these forms, namely Spirifer Archiaci, Spirifer tenticulum, and Spirifer Brodi, as varieties to Spirifer Verneuili. Finally, in 1901 F. Frech, on the basis of all the literature and material available on this question, and also on the basis of a detailed study of the internal structure of the shells, arrives at what, in our opinion, is the only correct conclusion: that in the present case we are dealing with a group of forms passing one into another, and that N. Venukov with full justification united them into one general group—Spirifer disjunctus. Owing to this gradual transition, it is not even possible to draw more or less sharp boundaries between the individual forms, and each of them represents a whole stage in this process of development. Spirifer Vernesnli F. Frech, like F. Chernyshev, excludes from this group, in view of its almost complete identity with Spirifer Archiaci, retaining for the form the second name, as “having received wider currency in Russian works, and also because the form figured by Murchison under this name more closely corresponds to the character of the typical Russian forms.”) And indeed, comparing the Spirifer Archiaci described by Murchison) with the Russian representatives of this species, we must establish their complete identity down to the smallest details. From all this F. Frech quite rightly draws the conclusion that these forms do not constitute separate species, but belong to one common species, representing its varieties, and agrees with Whidborne’s opinion that this species is “a species in process of solution,” that is, that the joint occurrence of all the varieties cited above belongs to the period of disintegration of this species into a number of others. F. Frech considers the preservation of a single general species name inconvenient, because an excessively great difference is already observed between the individual varieties, especially between the extreme members of this group, and also because their occurrence characterizes certain facies of the Upper Devonian deposits; therefore he proposes to retain for them their separate names, uniting them, after Venukov, into the general group Spirifer disjunctus. Of the four varieties included in this group, two—Spirifer Archiaci and Spirifer tenticulum*—occur in large numbers in the Devonian deposits of the Mugodzhar Mountains in general, and at our two localities in particular.

) F. Chernyshev, Materials for the Study of the Devonian Deposits of Russia, p. 14.
) Bulletin de la Société géologique de France*, v. XI, p. 252.

Spirifer Archiaci Murch.

Table II, figs. 4 and 4-a.

1. Spirifer Archiaci Murchison—Bulletin de la société géologique de France v. XI pl. II fig. 4 a, b, c.
2. Spirifer Archiaci Verneuil—Paléontologie de la Russie, p. 155, pl. IV, fig. 2.
3. Spirifer Archiaci Keyserling, Reise in das Petschoraland.
4. Spirifer Archiaci Schnur—Brachiopoden der Eifel. S. 37, Taf. XIV, fig. 3, 4.
5. Spirifer Archiaci—Chernyshev, Transactions of the Geological Committee, vol. I, No. 3, p. 13, Table II, fig. 5.
6. Spirifer Archiaci Venyukov—Devonian fauna of northwestern and central Russia, p. 68.
7. Spirifer Archiaci Chernyshev—Transactions of the Geological Committee, vol. III. No. 3, p. 60.
8. Spirifer Archiaci Venyukov—Transactions of the St. Petersburg Society of Naturalists, vol. XXIII, p. 27.
9. Spirifer Archiaci—G. F. Petz.—Transactions of the Geological Section of the Cabinet of His Majesty, vol. IV, p. 105.

We have at our disposal a large number of specimens of this species, the size of which varies within considerable limits (from 7 mm, taking the greatest width of the shell, to 18 mm). All of them are entirely identical with the descriptions cited above. In the table, fig. [[unclear: number not visible]] depicts one variety of Spirifer Archiaci, which differs from the typical form by the appearance, on the sinus-like depression, alongside the striation usual for this form, of two sharp folds. The remaining specimens (about 50) are entirely identical with one another.

This form has been encountered both at Berchogur and at Karagandy.

Spirifer tenticulum Vern.

Table II, fig. 5.

1. Spirifer tenticulum Verneuil—Paléontologie de la Russie, p. 159, pl. V, f. 7.
   1850—1856. Spirifer tenticulum Sandberger, Die Versteinerungen des Rheinischen Schichtensystems in Nassau, S. 323, T. V, f. 7.
2. Spirifer tenticulum Stuckenberg, Devonian basin of European Russia, p. 182.

1. Spirifer tenticulum Chernyshev, Transactions of the Geological Committee, Vol. III, No. 3, p. 69, Pl. X, fig. 13.

2. Spirifer tenticulum G. F. Petz, Transactions of the Geological Section of the Cabinet of His Majesty, Vol. IV, p. 106.

This form differs from Spirifer Archiaci in the smaller number of folds, their larger size, and their sharp dichotomizing. The area is high, triangular, and perfectly straight, giving the shell a characteristic appearance. This form apparently occupies the oldest position in the group of Spirifer disjunctus: it already occurs in the Stringocephalus beds of Western Europe. In the material we have studied, Spirifer tenticulum occurs in rather large numbers and differs in no way from representatives of this species from European Russia. It was found only at the Berch-Chugur locality.

Spirifer subcomprimatus Tschern.

Pl. II, fig. 6.

1. Spirifer subcomprimatus Chernyshev, Transactions of the Geological Committee, Vol. III, No. 3, p. 66, Pl. VIII, fig. 9.

Our form is fully identical with that described by F. Chernyshev from the Stringocephalus beds of the Urals. It resembles Spirifer subcuspidatus Schnur, but differs from it in the smaller number of folds on the sides. The high, almost straight area distinguishes our form from Steininger’s Spirifer elegans. F. Petz indicates the occurrence of Spirifer subcomprimatus in the Upper Devonian limestones near Pozharishcheva together with Spirifer Archiaci. The form was found at Berch-Chugur.

Cyrtia Dalman.

Cyrtia Murchisoniana de Kon.

Pl. II, fig. 7.

1. Spirifer Murchisonianus de Koninck, Précis élémentaire de géologie par d’Omalius d’Halloy, p. 523.

2. Spirifer Murchisonianus Verneuil, Paléontologie de la Russie, pp. 160–161, pl. IV, fig. 1.

3. Spirifer Glinkanus Idem ibidem, p. 170, pl. III, fig. 8.

4. Cyrtia Murchisoniana Davidson, Quart. Journ. Geol. Soc., Vol. IX, p. 355, pl. XV, figs. 6–9.

5. Cyrtia Murchisoniana Kayser, Devonische Versteinerungen aus dem südwestlichen China, S. 89, Taf. XII, fig. 2.

1. Cyrtia Murchisoniana Chernyshev. Fauna of the Middle and Upper Devonian of the western slope of the Urals, p. 77. Pl. XIII, figs. 3—7.

2. Cyrtia Murchisoniana Venukov. Transactions of the St. Petersburg Society of Naturalists, Vol. XXIII, p. 133.

This cosmopolitan form occurs in large numbers at the Bert-Chugur locality, and in especially great abundance at Karagandy. Specimens of very good preservation are encountered. Our Cyrtia Murchisoniana do not differ in any way from the Belgian specimens described by Koninck, the Chinese specimens described by Kayser, and the Ural specimens described by Chernyshev. In some of our specimens, on the folds, one can observe the finest riblets, crossed by equally fine, very closely spaced, wave-like growth striae. With good preservation, on the longitudinal riblets and between them, one can observe the tiniest tubercles elongated downward, in the form of commas. Chernyshev points to the circumstance that Cyrtia Murchisoniana and Spirifer Glinkanus Vern. represent one and the same form, and that the distinctive features of Spirifer Glinkanus—a smooth sinus and elevation—depend exclusively on the mode of preservation. And indeed, in our collection, on one specimen in the sinus there are several patches of the very outer layer, covered only with growth marks, whereas in the same sinus, below a patch of the outer layer, folding appears. If one takes into account the circumstance that the outer layer of the shell is very rarely preserved, then it is clear why Spirifer Glinkanus Vern. has such a weak distribution.

Cyrtia Murchisoniana de Kon. was first found in the Upper Devonian of Belgium; it has been encountered in the Upper Devonian of France*), in the stringocephalid beds of the Paffrath**), in the Upper Devonian of Armenia, Persia, Turkestan, China, and Russia (in the Urals). In the Mugodzhar Mountains this species has been encountered, as we have already indicated, at the localities Bert-Chugur and Karagandy, and was also found by Venukov at the sources of the Kauldzhur River (in conglomerates).

Retzia King.

Retzia tulensis (Pander) Romanowskii n. var.

Pl. II, fig. 8.

1. Retzia tulensis Θ. Chernyshev. Materials for the Study of the Devonian Deposits of Russia, p. 11, Pl. II, fig. 1.

*) Gosselet—Esquisse géologique du Nord de France.
*) [[unclear: author name]]—Das obere Mitteldevon.

In our collection there are three specimens of this species, which are almost completely identical with the form cited by F. Chernyshev. The shape of the shell, the character of the beak, the deltidia, and also the dimensions and number of riblets coincide fully. Only the character of the ribbing does not quite coincide: our specimens are covered with much sharper riblets than the typical form of Retzia tulensis, which compels us to regard our form as a variety of Retzia tulensis.

Dimensions:

Length	Width	Thickness
7	6	3.5
8	—	—

This form was encountered at the Ber-Chugur locality.

Athyris M’Coy.

Athyris concentrica v. Buch.

Table III, fig. 9.

1. Terebratula concentrica v. Buch, Die Terebrateln, p. 103.
2. Terebratula concentrica Verneuil, Paleontologie de la Russie, p. 53, pl. VIII, fig. 10–11.
3. Terebratula concentrica Keyserling, Reise in das Petschoraland, p. 237.
4. Terebratula concentrica Schnur, Brachiopoden der Eifel, p. 23, Taf. XXIII, fig. 8–10.
5. Spirigera concentrica Eichwald, Lethaea Rossica, v. 1, p. 735.
6. Athyris concentrica Davidson, Mon. Brit. Devonian Brachiopoda, p. 14, pl. III, fig. 11–15, 24.
7. Terebratula concentrica Quenstedt, Petrefactenkunde Deutschlands, p. 440, Taf. fl, fig. 38–58.
8. Athyris concentrica Kayser, Brachiopoden des mittleren und oberen Devon der Eifel. Zeitschrift der Deutschen geologischen Gesellschaft, Bd. XXIII, p. 547.
9. Athyris concentrica Chernyshev, Materials for the Study of the Devonian Deposits of Russia, p. 11, Table I, fig. 21.
10. Athyris concentrica Venukov, Fauna of the Devonian System of North-Western and Central Russia, p. 95, Table IV, fig. 16–17.
11. Athyris concentrica Venukov, Transactions of the St. Petersburg Society of Naturalists, vol. XXIII, p. 134.
12. Athyris concentrica G. F. Petz, Transactions of the Geological Section of the Cabinet of His Majesty, vol. IV, p. 132.

This cosmopolitan form, along with a very wide distribution, shows a certain variability, which gave Verneuil occasion to establish a whole series of new species. Kayser, as early as 1871, pointing to this fact, supposed that with the accumulation of more extensive material concerning this form, the number of new species established by Verneuil would be greatly reduced. And, indeed,

further investigations showed that, however sharply the stable forms of Athyris concentrica may differ from one another, it is nevertheless always possible to establish a gradual transition between the extreme members of this group, which differ greatly from one another; this, of course, indicates that all these forms belong to the species Athyris concentrica as varieties. Our form comes closest to the one described by Schnur as var. ventrosa (Terebratula ventrosa). The dimensions of one of our specimens are even exactly the same as those we found in Kayser’s description of this variety*), namely: length—11.4, width—11, and thickness—8 mm.

Some specimens in our collection exhibit the longitudinal striation that is so rarely encountered, which, appearing in Athyris concentrica together with the concentric growth rings, forms an elegant lattice-like pattern (zierliche Gitterzeichnung)**).

Athyris concentrica is especially widespread in the middle division of the Devonian system of Western Europe, but also extends into the upper division. In the Urals and in central Russia this species is likewise encountered in both divisions. The 7 specimens at our disposal were delivered from the Chugur locality.

Strophomenidae King.

Orthis Dalman.

Orthis striatula Schloth.

1. Anomia terebratulites striatulus Schlotheim Mineralogisches Taschenbuch VIII Tab. I Fig 6.

2. Orthis resupinata var. striatula Verneuil Paleontologie de la Russie p. 183 pl XII f 6.

3. Orthis striatula Keyser’ling Reise in das Petschoraland S. 223.

4. Orthis striatula Schnur Brachiopoden der Eifel S. 215 Taf. XXXVIII fig. 1.

5. Orthis striatula Sandberger Versteinerungen des Rheinischen Schichtensystem’s in Nassau S. 355 Taf. XXXIV fig. 4.

6. Orthis striatula Davidson Mon. Britisch Devonian Brachiopoda p. 87. Pl XVII fig. 4—7.

7. Orthis striatula Semenov and Meller Gornyi zhurnal 1864, vol. I, p. 214, table 2, fig. 11.

8. Orthis striatula Kayser Brachiopoden des Mittel ung oberdevon der Eifel S. 598.

*) Zeitschr. der Deutsch. Geolog. Gesellschaft, 1871 S. 548.

1. Orthis striatula Romanovsky, Materials for the Paleontology of the Turkestan Region, issue I, p. 134, pl. XVII, figs. 3–4.
2. Orthis striatula Kayser, Richthofen’s China, Bd IV, S. 90, Taf. XVIII, fig. 1.
3. Orthis striatula Chernyshev, Materials for the Study of the Devonian Deposits of Russia, p. [[unclear: page number]], pl. III, fig. 18.
4. Orthis striatula Venukov, Fauna of the Devonian System of North-Western and Central Russia, p. 49.
5. Orthis striatula Venukov, Proceedings of the St. Petersburg Society of Naturalists, pl. XXIII, p. 126.

This well-known species has a very wide distribution in the Devonian deposits both of Western Europe and of Persia, China, Turkestan, America, etc. The specimens of Orthis striatula encountered in considerable numbers from the localities of Ber-Chugur and Karaganda do not differ in any way from the representatives of this species described by the above-mentioned authors.

Orthis granulosa? Phill.

Pl. III, fig. 10.

1. Orthis granulosa Phillips. Pal. Foss. Devon, Cornwall etc., p. 65, pl. XXVI, fig. 111.
   1884–1865. Orthis granulosa. Davidson, British Devonian Brachiopoda, p. 92, pl. XVII, fig. 24.

We have at our disposal only a single ventral valve, and even that is half stripped, so that we do not venture to insist categorically on the accuracy of this determination. In any case, our fragment is very similar to Davidson’s figure, which compelled us to assign, albeit conditionally, this form to Orthis granulosa.

The shell is almost round. The hinge margin is shorter than the greatest width of the shell. The area is not high. The sculpture is sharp, and the riblets running from the beak to the frontal margin dichotomize clearly.

This form was delivered from the locality of Ber-Chugur.

Rhynchonellidae Gray.

Rhynchonella Fischer.

Rhynchonella acuminata Martin.

1. Conchyliolithus anomites acuminatus Martin, Petrificata Derbiensis, Tab. XXXII, figs. 7–8 and XXXIII, figs. 5–6.

1. Terebratula acuminata Sowerby, Mineral Conchology, Pl. CCCXXIV, fig. 1.

2. Terebratula acuminata var. sulcata et. plicata, Ibidem, Pl. CCCCXCV, fig. 1 et. 3.

3. Terebratula cordiformis, Ibidem, Pl. CCCCXCV, fig. 2 et 4.

4. Terebratula platyloba, Ibidem, Pl. CCCCXCIV, fig. 5 et 6.

5. Terebratula acuminata var. rhomboidea, Pacht, Geological investigation from Voronezh to Samara, p. 86, Pl. IV, fig. 1 d—f.

6. Terebratula acuminata, Ibidem, Pl. IV, fig. 1 a—c.

7. Rhynchonela pugnus, Sandberger—Versteinerungen des Rheinischen Schichtensystem’s in Nassau, S. 42, Taf. XXXIII, fig. 6.

8. Rhynchonella acuminata, Davidson, Mon. of. Brit. Devonian Brachiopoda, p. 60, fl. XIII, fig. 1—4.

9. Rhynchonella acuminata, Kayser, Die Brachiopoden der Eifel, S. 524, Taf. IX, fig. 7.

10. Rhynchonella acuminata, Chernyshev, Transactions of the Geological Committee, Vol. I, No. 3, p. 21, Pl. III, fig. 12—14.

11. Rhynchonella acuminata, Venyukov, Fauna of the Devonian system of the northwestern [region], etc., p. 123, Pl. V, fig. 9.

12. Rhynchonella acuminata, Venyukov, Transactions of the St. Petersburg Society of Naturalists, Vol. XXIII, p. 137.

13. Rhynchonella acuminata, F. Petz, Transactions of the Geological Section of the Cabinet of His Majesty, Vol. IV, p. 157.

Our specimens do not differ in any way from the typical forms of this species: they have a strongly inflated biconvex dorsal valve, into which an elevated sharp fold of the ventral valve cuts. This species ranges from Middle Devonian to Upper Carboniferous deposits. Our specimens were found at the locality of Karagandy.

Rhynchonella pugnus Martin

1. Terebratula pugnus v. Buch’s gesammelte Schriften, S. 200, Taf. XX, fig. 19.

2. Terebratulla pugnus, Verneuil, Paléontologie de la Russie, p. 78, pl. X, fig. 1 a, b.

3. Terebratula acuminata var. pugnus, Pacht, Geological investigation, etc., p. 86, Pl. IV, fig. 1 d—i.

4. Rhynchonella pugnus, Eichwald, Lethaea Rossica, p. 751.

5. Rhynchonella pugnus, Davidson, Mon. of Brit. Dev. Brachiopoda, p. 63, pl. XII, fig. 12—14, pl. XIII, fig. 8—10.

1. Rhynchonella pugnus Kayser, Die Brachiopoden der Eifel, p. 522.
2. Rhynchonella pugnus Chernyshev, Transactions of the Geological Committee, Vol. II, No. 3, p. 22, Pl. III, fig. 16.
3. Rhynchonella pugnus Venyukov, Fauna of the Devonian System, etc., p. 125, Pl. V, fig. 8.
4. Rhynchonella pugnus Venyukov, Transactions of the St. Petersburg Society of Naturalists, Vol. XXIII, p. 137.
5. Rhynchonella pugnus f. Petini, Transactions of the Geological Section of the Cabinet of His Majesty, p. 156.

This form, which has a rather extensive vertical distribution (from the Middle Devonian to the Carboniferous deposits, in which it reaches its greatest development), occurs, as Venyukov indicates,* in the Devonian deposits of Russia rather rarely. At the Ber-Chugut locality it occurs in fairly large numbers. Our specimens do not differ in any way from the Ural and Western European ones.

Rhynchonella pleurodon Phill.

Pl. III, fig. 11.

1. Terebratula pleurodon Phillips, Geology of Yorkshire, Part II, p. 222, pl. 12, fig. 25—30.
2. Terebratula pleurodon Verneuil, Paléontologie de la Russie, p. 79, pl. X, fig. 2 a, b, c.
3. Rhynchonella pleurodon Davidson, Mon. of Brit. Devonian Brachiopoda, p. 62, pl. XIII, fig. 12, 13.
4. Rhynchonella pleurodon Tokarenko, Transactions of the Society of Naturalists at Kazan University, Vol. XXXVII, issue 2.

This form, which reaches its principal development in the Carboniferous formation, is partly similar to the preceding species, especially to those varieties of it in which up to five lateral, clearly expressed folds appear. Nevertheless, these two species are easily distinguished from one another by the circumstance that in Rhynchonella pleurodon the folding never reaches the beak, as it does in Rhynchonella pugnus.

This form was encountered at the Ber-Chugut locality.

* Venyukov, Fauna of the Devonian System of North-Western and Central Russia.

MOLLUSCA.

Lamellibranchiata.

Nuculidae Gray.

Nucula Lamarck.

Nucula lineata (?) Phill. (non Goldfussi)

Table III, fig. 12.

1. Nucula lineata Semenov and Meller, Mining Journal, 1864, p. 203, Table IV, fig. 11.
2. Nucula lineata F. Petz, Proceedings of the St. Petersburg Society of Naturalists, Vol. XXII, p. 70.

The internal molds of our form fully correspond to the description that we find in Semenov and Meller: an almost triangular outline, apices almost not curved, brought close to the anterior truncated margin, and a somewhat elongated posterior margin—all these characters are also present in our specimens. Unfortunately, we do not have Phillips’s work*) at our disposal, and therefore we are deprived of the possibility of tracing to what extent the sculpture of our specimens, consisting of fine concentric lines (which in all probability gave Phillips reason to call his species lineata), corresponds to Phillips’s description. Goldfuss**) describes, under the name Nucula lineata, a specimen from the Trias of the Tyrolean mountains, which, however, differs completely from Phillips’s species, at least as regards the internal mold. As for the sculpture of Goldfuss’s species, it consists of “gedrängte concentrische Linien die ganze Oberfläche bedeckend,” so that it is possible that the sculpture is precisely the only common feature of these two forms. But concerning this circumstance we, unfortunately, can say nothing definite, since Phillips’s original source, as we have already mentioned, is not available to us, while Semenov and Meller in their work depicted only internal molds of Nucula lineata, without any trace of sculpture.

*) Phillips, British palaeoz. fossils.
**) Goldfuss, Petrefacta Germaniae.

Dimensions:

Length	Height	Thickness
6.5	5	4.5
9	7.5	5.5
1.1	—	—

This form was encountered at the locality Bert-Chugur.

Conocardiidae Neumayr.

Conocardium Bronn.

Conocardium sp.

Table III, fig. 13.

The single, very poorly preserved impression does not make it possible to establish a precise species diagnosis. The cast shows the following*): the rostrum is not visible; the heart-shaped anterior part is large—its diameter near the anterior keel reaches 6 mm. In view of the absence of the median keel, which usually separates the middle part from the lateral part, the latter merge. On the convex heart-shaped part, 9 ribs are visible, with equal intervals between them, cut by numerous fine transverse striae, so that a fine reticulate pattern results. The anterior keel is not sharp, with a rounded edge. Behind the median keel another 6 ribs are visible, the distance between which increases as they approach the posterior part. As we have already indicated, the middle part is not delimited from the lateral part, owing to the absence of the median keel. The posterior part of the shell, because of the poor preservation of the impression, is almost entirely invisible. This form partly recalls Conocardium rhenanum Beushausen, but differs essentially from it in the convex form of the heart-shaped part, whereas in Beushausen’s form this part is concave.

Our form in all probability represents a new species, but in view of its quite insufficient preservation, we could not describe it as such, and this must be postponed until a specimen of more perfect preservation is found.

This form was delivered from the locality Bert-Chugur.

*) Barrois, in his work “Faune du calcaire d’Erbray,” proposes, when describing the genus Conocardium, to adhere to the following subdivision of the shell into 8 parts, beginning with the anterior part: 1) rostrum, 2) heart-shaped anterior part, 3) anterior keel, 4) middle part, 5) median keel, 6) lateral part, 7) sinus, and 8) swollen posterior part. Considering this order quite rational, we shall adhere to it.

Gasteropoda.

Pleurotomariidae d’Orb.

Pleurotomaria Defrance.

Pleurotomaria sp.

Plate III, fig. 14.

The form of the shell is conical. The sutures are not deep. The sinus band is faintly indicated on the outer side of the whorls. The surface of the shell is covered with longitudinal ribs extending parallel to the suture, so that a tuberculate sculpture is formed. In view of the poor preservation of our specimen (the shell is deformed, and only a few small patches of the sculpture have been preserved), it is necessary to refrain from a specific determination, although we consider it necessary to point out the similarity of our form to Pleurotomaria Auliei Wenjukowi.* Our specimen differs from Wenjukow’s species in that the latter lacks the transverse ribbing so sharply expressed on our specimen.

Delivered from the locality Ber-Chugur.

Pleurotomaria sp.

At our disposal there is another fragment of Pleurotomaria: the shell is flatly conical. The sculpture consists of fine longitudinal riblets and coarse transverse riblets crossing them, thus forming a tuberculate pattern. The umbilicus is low. The preservation is very poor and, consequently, a specific determination is impossible. This specimen was delivered from the locality Ber-Chugur.

Naticidae Forbes.

Natica Lam.

Natica piligera Sandb.

Plate III, fig. 15.

1. Natica piligera Sandberger, Versteinerungen des Rheinischen Schichtensystems in Nassau, p. 235, Taf. XXVI, fig. 6.

2. Natica piligera Sandb. affinis Wenjukow, Fauna of the Devonian system of central and northwestern Russia, p. 203, pl. IX, fig. 18.

* Proceedings of the St. Petersburg Society of Naturalists, Vol. XXIII, 1895, p. 141, Plate III, fig. 9.

1. Naticia piligera Venukov, Transactions of the St. Petersburg Society of Naturalists, Vol. XXIII, p. 155, pl. III, fig. 14.

The form of the shell fully agrees with Sandberger’s description. As for the sculpture—which, incidentally, is in general rarely preserved in this species—on our single specimen, in several places under a magnifying glass, traces are visible of numerous fine, somewhat wavy growth striae extending across the whorls. If, despite the very poor preservation of our form, we decide to recognize in it Sandberger’s species, this is due, in addition to the considerations given above, also to the fact that we had the opportunity to examine several well-preserved specimens of this form from Mount Alabas; after this, the identity of our specimen with Naticia piligera became unquestionable to us.

In western Europe Naticia piligera has been found in the stringocephalid limestone at Villmar and Oranienstein (Nassau). Venukov described Naticia piligera from the limestones of Ak-Tyube-Aulie.

Our specimen was encountered at the locality Ber-Chugur.

Pyramidellidae Gray.

Loxonema Phillips.

Loxonema cf. piligera Sandb.

Pl. III, fig. 16.

1. Holopella piligera Sandberger, Versteinerungen des Rheinischen Schichtensystem’s in Nassau, S. 228, Taf. XXXV, fig. 9 a, b, c.

2. Holopella piligera Holzapfel, Das obere Mitteldevon, Abhandl. der Königl. Preuss. Geologischen Landesanstalt, Neue Folge, Heft 16. S. 194, Taf. 12, f. 19.

Before us is only a single specimen of this species, which broke during preparation. The shell is turret-shaped. The whorls are convex, separated by deep sutures, and covered with numerous very fine growth striae, slightly bent backward. Longitudinal spiral striae, characteristic of this genus, are not at all visible, which is apparently explained by the extremely poor preservation of our specimen, or rather, fragment. It should be noted that, for some reason, Sandberger says nothing about these spiral striae in his description of this form, despite the fact that in the figures given in his work they are visible. All this leads us to the conclusion that here we apparently have to do precisely with Loxonema piligera.

Zandberger had the specimen described by him from the Stringocephalus horizon in Villmar. This form has also been encountered in Devonshire and Canada.

Our specimen was found at the Berg-Chugur locality.

Cephalopoda.

Orthoceratidae M’Coy.

Orthoceras Breunius.

Orthoceras Helmersenii Pacht.

Table III, fig. 17.

1. Orthoceras Helmersenii Pacht. Geognostic investigation from Voronezh to Samara, p. 83, table III, fig. 3.

1860 Orthoceras compressiusculum Eichwald. Lethaea Rossica, Vol. I, p. 1214, Taf. XVIX, fig. 3.

1886 Orthoceras Helmersenii Venyukov. Fauna of the Devonian system of central Russia, etc., p. 210, table X, figs. 5–6.

1. Orthoceras Helmersenii Chernyshev. Fauna of the Middle and Upper Devonian, etc., p. 26, table IV, figs. 1–4.

At our disposal there are only fragments of this species, but the characteristic features of Orthoceras Helmersenii are very clearly expressed in some of them. The shell is apparently rather long, conical. The form of the transverse section is elliptical. The septa are regularly concave; the distance between them in the young part of the shell is 3, and, gradually increasing, reaches in our specimens (fragments representing the lower part of the shell) up to 5 mm. The siphon is somewhat eccentric and is situated on the short axis of the ellipse. At the places where it intersects the septa it is compressed, and its separate segments assume an elongate-oval form. As for the sculpture, in view of the poor preservation of the shells, nothing definite can be said about it; only on one fragment is a longitudinal ribbing of the core barely noticeable.

This form was encountered at the Berg-Chugur locality.

Orthoceras sp.

Table III, fig. 18.

A specimen preserved so poorly that there is no possibility of referring it to any definite species. The shell is long, conical. The form of the transverse section,

apparently round. The nucleus is smooth. The septa are rather strongly concave. The distance between them is 9 mm. The siphuncle is thin, situated centrally. Some features of this specimen suggest a resemblance to the Orthoceras regulare v. Schloth. described by Sandberger (Versteinerungen des Rhein. Schichtensystems in Nassau, p. 173, Pl. XX, fig. 2—2), but the preservation of our specimen is so poor that even the question of this resemblance must be left open.

This specimen was delivered from the locality of Bert-Chugur.

We also have at our disposal a whole series of fragments representing living chambers of Orthoceras, but their mutilated condition does not permit any conclusions to be drawn regarding their specific attribution.

Phragmoceras Broderip.

Phragmoceras sp.

Table III, fig. 19.

The poor preservation of the single specimen available to us permits only the following to be said about it. The shell is swollen, not especially curved; on the ventral side the curvature is almost not visible, while on the dorsal side it is rather considerable. The cross-section is apparently elliptical. The siphuncle is eccentric, close to the ventral side. The sculpture of the shell is apparently smooth, although, in view of its very poor preservation, this cannot be asserted categorically. The distance between the chambers is small—about 2 mm in the lower ones; the higher up, the more this distance decreases, so that in the upper part of our fragment it reaches 1 mm.

Because of the extremely poor preservation, we do not venture to indicate a resemblance between our fragment and any of the described species of Phragmoceras; we present only its illustration.

Delivered from the locality of Bert-Chugur.

Goniatidae v. Buch.

Goniatites de Haan.

Goniatites (Tornoceras) simplex v. Buch.

Table III, figs. 20 and 20a.

1. Ammonites simplex Buch, Ueber Ammoniten und Goniatiten etc. (L. v. Buch gesammelte Schriften, Bd IV) S. 123 Taf. XII fig. 8.

1. Ammonites retrorsus Beyrich. Beiträge zur Bestimmung des Rheinischen Uebergangsgebirges S. 30 Taf. I fig. 10.

2. Goniatites retrorsus Keyserling Petschoraland S. 278 Taf. XII fig. 5.

3. Goniatites retrorsus var. typus Sandberger. Versteinerungen des Rheinischen Schichtensystem in Nassau S. 101 Taf. X fig. 14—16; Taf. Xa fig. 3—6 10—11.

4. Goniatites (Tornoceras) simplex. Chernyshev. Fauna of the Middle and Upper Devonian, etc., p. 23, pl. I, fig. 22; pl. II, fig. 9.

5. Goniatites (Tornoceras) simplex Venyukov. Proceedings of the St. Petersburg Society of Naturalists, Vol. XIII, p. 157, pl. III, fig. 15.

6. Tornoceras simplex Holzapfel Das Obere Mittel Devon S. 95 Taf. IV fig. 8, 9; Taf. VI f. 11; Taf. VIII fig 9.

7. Tornoceras simplex Holzapfel. Die Cephalopoden des Domanik im südlichen Timan S. 14 Taf. 8 fig. 1—9.

This species, represented in our collection in very large numbers (about 120 specimens), is completely identical with the specimens described by Beyrich, Sandberger, Holzapfel, and Chernyshev, as well as with the specimens in the paleontological cabinet of the Tomsk Technological Institute. The dimensions of the specimens in our collection range from 9 to 65 mm in diameter. The suture line has a fairly large lateral lobe and a broad saddle, which on its inner side descends rather steeply toward the umbilical suture. The shell is in most cases smooth, and only on very few specimens can constrictions or constrictions be observed at a more or less equal distance from one another, on the side (Pl. III, fig. 20a). The wrinkled layer is entirely absent, as in the Western European specimens, which, according to Holzapfel, may be the result of the manner of preservation, since the wrinkled layer is very easily detached.

Goniatites simplex was found at the Berch-Chugur locality, as already indicated, in very large numbers, and this circumstance invalidates the statement of P. Venyukov, who examined the western slope of the Mugodzhar Mountains, that Goniatites simplex is “a form rarely encountered in the Devonian deposits of the Mugodzhar.”

ARTHROPODA.

Crustacea.

Trilobitae.

Phacopidae Salter.

Phacops Emmrich.

Phacops sp.

Table III, fig. 21.

At our disposal is a cephalic shield, undoubtedly belonging to the genus Phacops. Unfortunately, a single caput alone does not make it possible to establish the specific character of this form, and the resolution of this question must be postponed until other parts of this fossil are found in the locality that interests us. The cephalic shield is of parabolic form. The genal angles are rounded. The glabella is almost pentagonal in outline, swollen, widened at the frontal margin. The sulcus marginalis is sharply expressed. The ocular tubercles, with large, round, facetted eyes, sit at the very apex of the angle formed by the sulcus marginalis and the glabella. The surface is finely shagreen-like.

This cephalic shield strongly resembles the specimen described by L. Tokarenko from the Upper Devonian limestone of the environs of Verkhne-Uralsk*).

Our specimen was delivered from the locality Ber-Chugur.

In conclusion, I consider it my pleasant duty to express my deep gratitude to Professor Mikhail Erastovich Yanishevsky, who supervised the present work.

Tomsk, May 1909.
G. Nakhimson.

*) L. Tokarenko. Fauna of the Upper Devonian limestone of the environs of the town of Verkhne-Uralsk. Proceedings of the Society of Naturalists at Kazan University, Vol. XXXVII, issue 2.

G. Nachimson.

On the Knowledge of the Devonian Deposits of the Mugodjary Mountains

(with 3 plates). Brief excerpt.

The Mugodjary Mountains lie between 49½° and 48° north latitude and constitute a narrow mountain chain forming the continuation of the southern Urals. Extending in a meridional direction, this range forms the boundary between the Ural and Turgai regions. The mountains are not high: the highest summit of this range, Airjuk, reaches only 1890 feet. From a tectonic point of view, the Mugodjary mountain chain represents a simple folded mountain system. Nevertheless, it is distinguished by a very complicated relief, which is attributable both to volcanic masses participating in the structure of the mountains and to significant and long-lasting denudation processes. The vegetation is very sparse and represents a typical steppe flora.

The material that the author has studied was collected by Prof. M. Janischewsky during his excursion in 1904 and comes from two points: from the vicinity of the railway station of the Orenburg–Tashkent Railway, Ber–Tschugur, and from a point at the 500th verst between the stations Ber-Tschugur and Karagandy. The railway cuttings make possible a rather precise view of the geological bedding conditions.

At Ber-Tschugur we are dealing with a complex of strata which, with a dip of approximately 45°, consists of alternating beds of various conglomerates, sandstones, and crystalline limestones (Plate I). The fauna here consists of the following forms:

Actinostroma sp.
Amplexus sp.
Crinoid stem segments.
Productus Mugodjaricus nov. sp.
Productella subaculeata Murch. var. angustior Gürich.
Productella subaculeata Murch. var. latior Gürich,

Orthis striatula Schloth.
Orthis granulosa (?) Phill.
Spirifer Archiaci Murch.
Spirifer tenticulum Vern.
Spirifer subcomprimatus Tschern.
Cyrtia Murchisoniana, de Kon.
Retzia tulensis (Pander) Romanowskii var. (n. var.)
Athyris concentrica v. v. Buch.
Rhynchonella pugnus Mart.
Rhynchonella pleurodon Phill.
Nucula lineata (?) Phill.
Conocardium sp.
Pleurotomaria sp.
Pleurotomaria sp.
Natica piligera Sandb.
Loxonema cf. piligera Sandb.
Orthoceras Helmerseni Pacht.
Orthoceras sp.
Phragmoceras sp.
Tornoceras simplex v. Buch.
Phacops sp.

Here we find typical representatives of the Upper Devonian (e.g., Spirifer Archiaci, Spirifer tenticulum, Cyrtia Murchisoniana, Tornoceras simplex, etc.). For comparison, it is best to take the nearest Upper Devonian deposits of the Urals, which in their time were subjected to detailed study by Th. Tschernyschew. A complete analogy can be demonstrated between the fauna of Ber-Tschugur and the fauna of the Cuboides and Goniatite stage of the Urals. It also follows from this that the beds of Ber-Tschugur are analogous to the Iberg limestones of the Harz.

The second locality, Karagandy, yielded us the following fauna:

Productus Mugodjaricus nov. sp.
Productella subaculeata Murch, var. angustior Gürich.
Strophalosia productoides Murch.
Spirifer Archiaci Murch.
Orthis striatula Schloth.
Cyrtia Murchisoniana de Kon.
Rhynchonella acuminata Mart.
Rhynchonella pugnus Mart.

In this locality Cyrtia Murchisoniana appears in very great abundance, in which the other species virtually disappear. The Karagandy locality is therefore very poor in species. Of these 8 species, 6 are also present at the Ber-Tschugur locality. Moreover, the forms Spirifer Archiaci and Cyrtia Murchisoniana are, in and of themselves, so characteristic of the Cuboides and Goniatite stage of the Iberg limestone and of the Urals that the analogy between the fauna of the Karagandy and Ber-Tschugur localities, and consequently also that of the Cuboides and Goniatite stage of the Urals and of the Iberg limestone, is beyond doubt.

In preparing the palaeontological part, the author established one new species and one variety:

Productus Mugodjaricus nov. sp.

Plate II, Fig. 2.

The shape of the shell is almost rectangular. The ventral valve is strongly arched. The greatest width is formed by the hinge margin, with a small beak curved steeply downward. The entire surface of the ventral valve is provided with wrinkled growth striae, which stand out especially sharply in the region of the hinge margin. At some distance from the hinge margin begins a slightly indicated sinus, which gradually becomes more distinct and at the frontal margin develops into a shallow but broad indentation. The spines are arranged regularly on the growth striae. The dorsal valve is hollowed out; the growth striae are more sharply expressed here than on the ventral valve and are likewise regularly covered with spines. The internal structure had to remain uninvestigated, since the material cannot be prepared in this respect.

Dimensions:

Length	Width
25 mm.	21 mm.
23 mm.	17 mm.

This new species resembles Productus Meisteri v. Petz. in external form, but is readily distinguished from the latter by the sinus, which in Productus Meisteri is either entirely absent or, even in very large specimens, only indicated. Productus Mugodjaricus also lacks the longitudinal striation that is characteristic of Productus Meisteri.

This form has been found at the Ber-Tschugur and Karagandy localities.

Retzia tulensis (Pander) Romanowsky nov. var.

Plate II, Fig. 8.

We possess three specimens of this species, which are completely identical with the form cited by Th. Tschernyschew*) The form of the shell, the beak, the deltidial plates, the dimensions, and the number of riblets coincide. Our form differs from the typical tulensis (Pander) Romanowsky in the character of the riblets: the typical Retzia tulensis has far fewer sharply expressed riblets than our form. This circumstance compels us to establish a new variety. Dimensions:

Length	Width	Thickness
7 mm.	6 mm.	3.5 mm.
8 mm.	—	—

It comes from the locality Ber-Tschugur.

*) Retzia tulensis—Th. Tschern. Materialien zur Kenntniss der devonischen Ablagerungen Russlands, 1884, p. 11, Pl. II, fig. 11.

Explanations for Plates II and III

Erklärung der Tafeln II und III.

Plate II.	Tafel II.
1. Actinostroma sp. Tangential section.	1. Actinostroma sp. Tangential-schnitt.
2. Productus Mugodjaricus n. sp.	2. Productus Mugodjaricus n. sp.
3. Productella subaculeata Murch. Left—varietas angustior Gürich; right—varietas latior Gürich.	3. Productella subaculeata Murch. links—var. angustior Gürich; rechts—var. latior Gürich.
4. Spirifer Archiaci Murch.	4. Spirifer Archiaci Murch.
4a. Variety with 2 folds in the sinus depression (enlarged twofold).	4-a. Varietät mit 2 Fältchen im Sinus (2-x vergrössert).
5. Spirifer tenticulum Vern.	5. Spirifer tenticulum Vern.
6. Spirifer subcomprimatus Tschern.	6. Spirifer subcomprimatus Tschern.
7. Cyrtia Murchisoniana de Kon.	7. Cyrtia Murchisoniana de Kon.
8. Retzia tulensis (Pander) Romanowsky var. (double enlargement).	8. Retzia tulensis (Pander) Romanowsky (2 x vergrössert).

Plate III.	Tafel III.
9. Athyris concentrica v. Buch.	9. Athyris concentrica v. Buch.
10. Orthis granulosa (?) Phill.	10. Orthis granulosa (?) Phill.
11. Rhynchonella pleurodon Phill.	11. Rhynchonella pleurodon Phill.
12. Nucula lineata (?) Phill.	12. Nucula lineata (?) Phill.
13. Conocardium sp. impression.	13. Conocardium sp. Abdruck.
14. Pleurotomaria sp.	14. Pleurotomaria sp.
15. Natica piligera Sandb.	15. Natica piligera Sandb.
16. Loxonema cf. piligera Sandb.	16. Loxonema cf. piligera Sandb.
17. Orthoceras Helmerseni Pacht.	17. Orthoceras Helmerseni Pacht.
18. Orthoceras sp.	18. Orthoceras sp.
19. Phragmoceras sp.	19. Phragmoceras sp.
20. Goniatites (Tornoceras) simplex v. Buch.	20. Goniatites (Tornoceras) simplex v. Buch.
20a. Specimen with constrictions.	20-a. Exemplar mit Einschnürungen.
21. Phacops sp.	21. Phacops sp.

Table I.

Schematic geological section of the southeastern limb and core of the anticline of the Veselinskaya ridge.

Drawn by [[unclear: E. Novitsky / E. Novitskaya]]

Legend

Symbol	Explanation
[[graphic symbol: layered rectangular pattern]]	Black argillaceous limestone, [[unclear]]
[[graphic symbol: dense horizontal hatching]]	Siliceous shale
[[graphic symbol: vertical hatching]]	Clay shale
[[graphic symbol: pebble pattern]]	Conglomerate
[[graphic symbol: dotted pattern]]	Sandy shale
[[graphic symbol: dotted-and-pebble pattern]]	Sandy shale with pebbles on the surface
[[graphic symbol: coarse pebble pattern]]	Conglomerate, [[unclear]]
[[graphic symbol: block/brick pattern]]	Sandy limestone
[[graphic symbol: cross-hatched pattern]]	[[unclear: breccia-like?]] limestone, [[unclear]]
[[graphic symbol: small repeated oval pattern]]	[[unclear]] limestone

Table II.

Phot. P. Pavlov.

Plate III.

9

10

11

12

13

14

15

16

17

18

19

20

20a

21

Photo by P. Pavlova.