CRETACEOUS DEPOSITS OF THE CHULYM–YENISEI DEPRESSION

I. V. LEBEDEV

(Presented by Professor Doctor L. L. Khalfin)

Introduction

Within the loose strata of the Chulym–Yenisei depression, along with Jurassic and Tertiary deposits, continental Cretaceous deposits are widely developed; they have a very complex structure and composition.

The entire complex of Cretaceous deposits, according to lithological composition and to the composition of the paleontological remains contained in them, is at present subdivided into a number of formations, ranging in age from the lower parts of the Lower Cretaceous to the Danian stage. The Ilek and Kiya formations are assigned to the Lower Cretaceous; the Simonovo, Kaska, and Sym formations to the Upper Cretaceous.

Cretaceous deposits are exposed only along the margins of the Chulym–Yenisei depression. In its central part they are submerged beneath a thickness of Tertiary and Quaternary deposits, but drilling operations have revealed them in all areas.

Ilek Formation

The deposits assigned to this formation rest unconformably upon Jurassic deposits and at the base contain a thick member of sandstones. The sandstones are gray, of greenish-blue tones, usually fine-grained, more rarely medium- and coarse-grained, silty; upon weathering at the surface they acquire a greenish-yellow tint. In their composition, fragments of various shales, quartz, and feldspars predominate, the latter, as a rule, being fresh. Their bedding is oblique or else parallel, thin, indistinct, and is caused by alternation of gray and weakly ocher-colored varieties of sand of the same composition. In the sandstones there are numerous irregular calcareous concretions, most often arranged along the bedding. The dimensions of such concretions along the long axis, parallel to the bedding, reach 3 m, while their thickness rarely exceeds 0.5 m.

Sometimes the sandstone contains conglomerates consisting of small rounded pebbles of quartz. In the Tyazhin district, in the soil of the basal sandstone of the Ilek Formation, there are burned and slagged Jurassic siltstones and sandstones. The thickness of the sandstones at Tyazhin Station reaches 140 m, and at the Sobolev coal deposit it exceeds 150 m. Toward the center of the depression the basal sandstones gradually wedge out.

The upper horizons of the Ilek Formation are composed of reddish-brown, brick-red, brownish, and bluish-gray calcareous

siltstones, more rarely argillites, lenses and thin interbeds of light-gray and greenish calcareous sandstones and sands, sometimes passing into fine gravelites with gravel composed of calcareous variegated siltstones. In the sandstones and sands there are horizons strongly enriched in biotite. It is characteristic that northward the red color of the Ilek Formation gradually disappears.

In natural outcrops the Ilek Formation is exposed on the right bank of the Chulym River below the town of Achinsk, on the Bolshoi Kemchug River below the mouth of the Terekhtyul, in the upper course of the Maly Kemchug near the village of Gladkova, along the Uryup River, and on the right bank of the Kiya River above and below the village of Shestakova; it has been penetrated in all reference boreholes. In the central part of the West Siberian Lowland, near the village of Maksimkin Yar and the town of Kolpashevo, the lower horizons of the Ilek Formation, corresponding to the Valanginian, pass into marine deposits.

The thickness of the Ilek Formation on the southeastern margin of the Chulym-Yenisei depression reaches only tens of meters, but increases considerably toward the northwest. Its greatest thickness, equal to 746 m, has been established on the Chulym River near the village of Teguldet.

On the Kiya River near the village of Shestakova, above the basal sandstones in the Ilek Formation, remains of a dinosaur were found which, according to the determination of A. K. Rozhdestvensky (1955), belongs to the genus Psittacosaurus, characteristic of the lower horizons of the Lower Cretaceous of Mongolia and North China. In the Itatka district this formation contains conchostracans: Euestheria asiatica Novoj., Paleoleptestheria ilekensis Novoj., Cyclograpta tingi Novoj., Opsipolygrapta przewalskii Novoj., Leptimnadia driachlovaе Novoj., which, in the opinion of N. I. Novozhilov (1956), belong to the lower part of the Lower Cretaceous. On the Uryup River below the village of Stary Uryup, pelecypods characteristic of the Valanginian have been found in this formation: Unio porrectus Sow. and Cyrena subtransversa Röm. At Tyazhin station, in borehole 5 at a depth of 200–204 m, ostracods have been identified in this formation: Darwinula barabinskiensis Mandelst., Darwinula contracta Mandelst., Cypidea faveolata (Egger), Cypidea vitimica Mandelast., Timiriasevia versabilis Mandelst., Lycopterocypris eggeri Mandelst., Mongolinella cf. palmosa Mandelst., and the foraminifer Rotalia sp. This microfaunal assemblage, according to T. A. Kazmina, indicates a Hauterivian–Barremian age.

The deposits of the Ilek Formation occur as large lenses; within them traces of intraformational erosion are observed in the form of fossil ravines or river valleys. At the base of the large lenses there are gravelly interbeds formed as a result of erosion of the underlying calcareous siltstones of the same formation. Within the large lenses, individual interbeds of variegated siltstones can be traced over considerable distances. All this, taken together, indicates a lacustrine-deltaic and fluvial origin of the formation.

Kiya Formation

The Kiya Formation is composed of brightly colored rocks occurring as rapidly pinching-out lenses. The most commonly encountered rocks of this formation are brick-red, reddish-brown, yellow, green, gray, and white, often mottled and carbonaceous clays, interbedded with lenses of white kaolinitic sands, and coals. Dark-brown ferruginous sandstones and conglomerates are not infrequently found in the formation. From the rocks of the underlying Ilek Formation, the deposits of this formation differ in the almost complete absence of calcareous cement, a high concentration of iron and aluminum, and the formation of brown iron ores,

siderites and bauxites, and in the northern part of the territory under consideration—by coal-bearing strata.

In the Kiya Formation, sharp facies variability is observed. Near ancient mountain structures composed of intrusive and terrigenous rocks, coarse-clastic sandy-conglomeratic facies predominate in the deposits of the Kiya Formation; farther from the latter and near ancient carbonate sequences, clayey varieties of rocks predominate. North of the Teguldet River and west of the mouth of the Maly Kas River, the red-colored rocks in the Kiya Formation gradually pinch out and are replaced by coal-bearing deposits. The coal-bearing deposits of this formation join coeval deposits of the Ust-Yenisei and farther the Khatanga depressions, forming the enormous Yenisei–Khatanga coal-bearing basin.

On the margins of the Chulym–Yenisei Depression, the Kiya Formation lies on the eroded surface of the Ilek Formation; in the section of the Mariinsk reference borehole, at its base there occurs a basal conglomerate composed of quartz pebbles, but in the central parts of the depression, between the Ilek and Kiya formations, no traces of a hiatus or erosion have been recorded. In the deposits of the Kiya Formation on the Kiya River there is an Albian flora, which includes: Ginkgo cf. digitata Brongn., Ginkgo cf. polaris Nath., Baiera cf. longifolia Heer, Elatocladus smittiana (Heer) Sew., Thuites cf. expanus Sternb., Sequoia sp., Platanus cuneiformis Krasser, Rulac Janschinii Vachr., Aralia palmatiformis Heer, and others. On the right bank of the Yenisei River, 12 km below Podkamennaya Tunguska, in the ferruginous sandstones of this formation there occur Sequoia concinna Heer and Nilssonia sp.

The spore-pollen assemblage of the Kiya Formation in the southern part of the Chulym–Yenisei Depression, according to A. N. Bolkhovitina (1953), also indicates an Albian age.

In the southern part of the territory under consideration, the Kiya Formation was formed under river conditions; it occurs as rapidly pinching-out lenses of sandy-clayey rocks and pebble beds, and farther from the margins it passes into lacustrine-swamp and then marine deposits. In the Kiya age, climatic zonality was well expressed, manifested in the lithological composition of the rocks and in the composition of the spore-pollen assemblage. In the southeast of the depression, under conditions of a warm and humid climate, a variegated bauxite-bearing sequence was formed. In the spore-pollen assemblage of the Kiya Formation in the southeast of the lowland, angiosperms are encountered in abundance. Farther north, variegated rocks are replaced by gray-colored ones; from the spore-pollen assemblage, according to a number of researchers, angiosperms almost completely disappear.

Simonovka Formation

Within the Simonovka Formation, sands, clays, siltstones, sandstones, and conglomerates are widely developed. The sandstones are usually light gray, vari-grained, and consist of angular-rounded quartz sand; their cement is siliceous, in places finely recrystallized and contaminated with clayey material. Conglomerates, having the same cement, consist of small rounded quartz, quartzitic, and siliceous pebbles. The siltstones are dark gray, flaggy, and often contain impressions of the well-known “Chulym flora.” White sands consist mainly of quartz and are weakly rounded. According to many researchers, the light fraction of the sands consists almost exclusively of quartz, and only small amounts of microquartzite, weathered feldspar, and kaolinite occur in it.

Clays, white and gray in color, dense, argillite-like; but in exposures at the surface they are often transformed into soft clays.

The Simonovskaya Formation is widely distributed. In the north, in the basin of the Eloguy River, according to A. N. Rezapov and A. N. Cherkashin, the Simonovskaya Formation passes into paralic deposits containing seams of coal and limestone. It is replaced by marine deposits also in the central part of the West Siberian Lowland.

In the lower part of the Simonovskaya Formation, distinguished under the name of the Chulym Subformation, on the Chulym River there are Cenomanian plants (Anan’ev and Lebedev, 1955): Glyptostrobus groenlandica Heer, Greinitzia formosa Heer, Cedrus Lopattonii Heer, Menispermites sibirica Heer, Platanus embicola Vachr., Laurus plutonia Heer, Platanus Newberryana Heer, Platanus septentrionalis Hollick, Credneria spatiosa Hollick, Credneria mixta Hollick, Platanus simonovskiensis Leb., Pseudoaspidiaphyllum latifolium Hollick, Anacardites Neuburgae Vachr., Magnolia alternans Heer, Dalbergites simplex (Newb.) Shap.

The upper part of the Simonovskaya Subformation, distinguished as the Suchkovskaya Subformation (Ragozin, 1936) in the basin of the Chulym River and the Kemi River, lies on the eroded surface of the Chulym Subformation. This subformation contains a plant assemblage characteristic of the Turonian: Juglans arctica Heer, Celtidophyllum cretaceum Krass., Ficus denveriana Cockerell, Nelumbites Kempii (Hollick) Berry, Magnolia cf. alternans Heer, Trochodendroides arctica (Heer) Berry, Platanus cuneifolia Bronn, Platanus cuneiformis Krasser, Dalbergites angustifolia (Newb.) Shap., Rulac quercifolium Hollick, Zizyphus kolymensis Krysht., and others.

In this same subformation an impression of the Turonian neuropteran insect Grammopsichops lebedevi O. Mart. was found (Martynova, 1954).

On the margins of the Chulym-Yenisei Depression the Simonovskaya Formation lies on the eroded surface of the Kiyskaya Formation; in the central parts of the lowland, traces of a hiatus between these formations have not been established. The thickness of the Simonovskaya Formation in these areas reaches 700 m; toward the margins it wedges out.

The Simonovskaya Formation was formed under conditions of a humid and warm climate that produced a kaolin weathering crust. Allites, characteristic of the Kiyskaya Formation, did not form during Simonovskaya time. The confluent siliceous-clayey cement contained in this formation indicates stages of aridization of the climate.

Climatic zonality in Simonovskaya time was expressed more weakly, being manifested only in the accumulation of coal-bearing deposits in the north.

Kasskaya Formation

The Kasskaya Formation is at present known only from the basins of the Bolshoy Kas, Sym, Eloguy, and Kemi rivers.

The rocks of the Kasskaya Formation include sands, clays, siltstones, and more rarely pebble beds. The sands of the Kasskaya Formation are usually fine-grained, dense, and “saccharoidal,” with an admixture of kaolin material. Their color is usually white, grayish, or yellowish in tone. Sometimes the sands are cemented by siderite cement. The light fraction of the sand mineral consists of a large amount of weakly rounded quartz, a small amount of feldspars, and kaolinite. The feldspars include orthoclase, microcline, and plagioclase.

The clays of the Kasskaya Formation are dense, argillite-like, gray carbonaceous or brownish; in the raw state they are easily cut with a knife, sometimes contain—

contain some amount of sand. According to Yu. P. Kazansky (1954), the clays contain halloysite and hydromicas; kaolinite is also encountered.

Conglomerates in the Kaska Formation occur rarely, only as small lenses of fine pebbles, which include kaolinized crystalline schists, white quartz, quartzite, jaspers, and flints.

The siltstones of the Kaska Formation are gray or dark-gray in tone, often carbonaceous, and occur as thin interbeds in the clays.

The Kaska Formation contains remains of the following Senonian plants: Podozamites tenuinervis Heer, Ginkgo crenulata Hollick, Tumion sibiricum Leb., Populites pseudoplatanoides Leb., Taxodium angustifolium Heer, Betulites rhomboidales Leb., Menispermites sibirica Leb., Magnolia Inglefieldii Heer, Platanus marginata Heer, Platanus Newberryana Hollick, Pseudoprotophyllum viburnifolium Hollick, Pseudoprotophyllum magnum Hollick, Pseudoprotophyllum angarense Leb., Pseudoprotophyllum evenkiense Leb., Pseudoprotophyllum sibiricum Leb., Pseudoprotophyllum turukhanskiense Leb., Cissites sibirensis Leb., Viburnum multinerve Heer, and others (Lebedev, 1956, 1954).

On the Eloguy River, marine beds appear in the deposits of the Kaska Formation.

On the Kem River, the Kaska Formation is incised into deposits of the Simonovo Formation; in other regions these formations lie conformably. The thickness of the Kaska Formation exceeds 150 m. The Kaska Formation was deposited under conditions close to those of deposition of the Simonovo Formation.

Sym Formation

Deposits of the Sym Formation are widely distributed in the eastern part of the Chulym–Yenisei depression—in the basin of the Sym and Dubches rivers. Farther north they crop out in the middle course of the Eloguy, on the Taz River near the mouth of the Ratta, and are penetrated by boreholes in the upper reaches of the Turukhan. In the southern part of the Chulym–Yenisei depression, in the basin of the Kiya River, sediments partly coeval with the Sym Formation and partly older, corresponding to all the Upper Cretaceous formations, were distinguished under the name of the Anti-Bes Formation (Ananyev, 1948).

Within the deposits of the Sym Formation, sands, argillites, siltstones, and conglomerates are widespread. In outward appearance these rocks are almost indistinguishable from the deposits of the Kaska Formation. Within the Sym Formation itself, a change in rocks is observed from bottom to top. In the upper horizons of the Sym Formation the content of sandy-pebbly material increases, indicating a general intensification of erosional activity. Often the sandy-pebbly material contains pebbles of clays from the underlying strata. The colloidal minerals of the Sym Formation, as shown by the studies of Yu. P. Kazansky, consist of kaolinite, hydromicas, and iron hydroxides.

The Sym Formation contains numerous impressions of leaves of Danian plants: Cladophlebis septentrionalis Hollick, Ginkgo minor Hollick, Taxodium angustifolium Heer, Sequoia concinna Heer, Cephalotaxopsis intermedia Hollick, Tumion sibiricum Leb., Trochodendroides arctica (Heer) Berry, and others.

The deposits of the Sym Formation overlie the deposits of the Kaska Formation without a break. Its thickness exceeds 150 m.

The Sym Formation, in comparison with the Kaska and Simonovo formations, was formed under conditions of a more temperate climate. In this formation, heat-loving plants gradually disappear from bottom to top. In this same direc-

…an increase is observed in the content of fresh feldspars (Kazansky, 1956).

Grounds for subdividing the Cretaceous deposits of the Chulym–Yenisei Depression into individual formations

The subdivision and correlation of the Cretaceous deposits of various areas of the Chulym–Yenisei Depression encounter great difficulties. The absence of marker horizons, the apparent uniformity at first glance of the rock composition, and the poor study of paleontological records have led to the creation, for this little-studied region, of very numerous stratigraphic schemes; moreover, the basis for subdivision used by different investigators consists of “tectono-denudational breaks” between formations, “cycles of sediment accumulation,” “formations of weathering crusts,” lithological-mineralogical investigations, and, finally, paleontological data.

The fossil flora of the Cretaceous deposits of the Chulym–Yenisei Depression, as determined by various investigators, ranges in age from Aptian to Danian. It is characteristic that even from one and the same locality, in different collections, the composition of the flora proves to be highly variable. According to P. A. Nikitin, from one and the same point (the village of Kubaevo on the Kiya River), seed floras of different ages occur in different collections.

Furthermore, if, for example, one considers the flora of the Kiya Formation according to the collections of A. R. Ananyev (1948), then Jurassic elements predominate in the latter and elements of Upper Cretaceous floras are almost absent. In the collections of A. S. Kirillov (1948) from the same, or almost the same, place, on the contrary, any forms archaic for the Upper Cretaceous are completely absent.

The Kass Formation, according to plant remains collected on the Kass River, has a typical Senonian flora characteristic only of it. In collections from the Sym River, typical elements of the Sym Formation are admixed with the Kass complex. The flora of the Antibes siding in the collections of V. A. Khakhlov (1930) and V. K. Cherepnin (1940) has one composition, whereas in the collections of A. R. Ananyev (1948) the composition is already different: it contains more ancient plants.

Until recently, an exception to the general rule was the flora of the village of Simonova, which was regarded by all as Cenomanian–Turonian. But in the well-known flora locality “Verkhnyaya Glinka” there are two floral horizons, differing from one another in plant composition. Ultimately, at present there are already two Chulym floras of D. Simonova of different ages.

A number of investigators of the Cretaceous of the Chulym–Yenisei Depression rightly point out that products of redeposition of the crust, or of crusts of chemical weathering, and “neoeluvium” (Kazarinov, 1948) participated in its formation. But the degree of their participation and the stages of development of the crust of chemical weathering did not remain constant throughout the entire Cretaceous. The fine-grained sands of the lower part of the Ilek Formation still consist of weakly weathered products. In them, along with stable minerals, feldspars are widely distributed and hornblendes are present. The deposits of this formation are the product of the first stages in the development of the weathering crust. The high calcareousness and absence of organic remains in the Ilek Formation, at the same time, apparently are also an indicator of the aridity of the climate.

The deposition of products of siallitic weathering at the end of the Lower Cretaceous, in Kiian time, was rather quickly replaced by the deposition of products of allitic weathering in the form of bauxites and siderites; the latter, in turn, at the beginning of the formation of the Simonovka Formation, was replaced by the accumulation of strata of white halloysite, kaolin, and hydromicaceous clays. This change, like the change of rocks between other formations of the Upper Cretaceous, is regarded by V. P. Kazarinov as the result of a major cycle of denudation and the formation of a new weathering crust. However, traces of sharp facies transitions and breaks in sedimentation, as well as traces of a sharp change in the plant world between these two formations, have not been noted. At a number of localities it has been established that white kaolin rocks already increase in the upper parts of the Kiian Formation. It should be assumed that in the Upper Cretaceous of the Chulym-Yenisei depression there occurred a more rapid redeposition of products from deeper horizons of the crust of chemical weathering.

The transitions between the overlying formations of the Upper Cretaceous are also gradual. Traces of a sharp change in rock composition and traces of a sharp change in the composition of plant remains buried in the different formations of the Upper Cretaceous are not observed; consequently, there are no data on the formation of new weathering crusts.

However, it was not only redeposition of weathering products that took place. The content in the Cretaceous strata of thermophilic plants, such as, for example, laurels, shows that the climatic setting in Late Cretaceous time was quite favorable for kaolin weathering. This explains the content, in many strata, of grains of feldspars that underwent kaolinization already after deposition. But the processes of chemical weathering in Cretaceous time proceeded unevenly, now intensifying, now dying down. The increased content of kaolinite in some horizons apparently represents the result of the superposition of kaolin weathering on products redeposited from an ancient weathering crust; that is, this horizon is a clearly expressed neoeluvium. It is characteristic that precisely at this time tropical plants appear in the composition of the Cretaceous flora. From what has been said it follows that in the Chulym-Yenisei depression there are no data indicating repeated manifestations of chemical weathering in Cretaceous time.

The gradual change of physiographic and climatic conditions during the Upper Cretaceous also explains the peculiarities of the Cretaceous floras. Like the lithological composition, the Cretaceous floras are clearly distinguished in the classic localities and have a mixed and transitional composition in closely adjacent horizons. The age of the flora of these transitional horizons is precisely what is disputed, and it cannot but be disputed if each formation is considered as a sharply isolated sequence that arose after a tectono-denudational break (Ragozin, 1936) or after the formation of a new weathering crust (Kazarinov, 1948). In the study of Cretaceous deposits and Cretaceous floras, one cannot fail to take into account that the Chulym-Yenisei depression represents one of the rare areas of the Earth’s crust where, over a small territory and without major breaks in the geological record, it is possible to trace sediment accumulation and the development of the plant world from the beginning of the Lower Cretaceous to the beginning of the Paleogene.

The prolonged accumulation of sediments under similar conditions is also connected with the difficulties in subdividing the Cretaceous rocks into formations. For their subdivision, a tectonostratigraphic scale based on the identification of phases of tectogenesis is not applicable. The available factual material does not confirm assumptions about the manifestation in the West Siberian low-

of the Upper Kimmerian, Austrian, and Laramide phases of folding. At least there are no data on structures created by them.

The cyclicity of sediment accumulation, associated with oscillatory movements of the earth’s crust, is clearly manifested in the Cretaceous deposits of the Chulym–Yenisei depression, but, taken separately, it is likewise insufficient for distinguishing formations. The Ilek and Kiya formations constitute two cycles of sediments separated by a slight break, but geochemically they belong to a single cycle, which began with the deposition of carbonate products of the weathering crust and ended with the deposition of gellites.

The Simonovo formation begins after a small erosion interval. The cause that produced this interruption in sediment accumulation was slight oscillatory movements of the earth’s crust, which led not only to the washing away of the variegated strata of the weathering crust from areas of denudation but, apparently, also partly eroded already deposited strata in the area of accumulation. This explains the sharp replacement of the variegated rocks of the Kiya formation by the light-colored rocks of the Simonovo formation and the presence between them of conglomerate horizons. However, this break was insignificant and affected only the margins of the West Siberian Lowland; it did not lead to a sharp change in the composition of the flora, did not alter the process of sediment accumulation, and did not create any new structures. Here one can speak only of weak epeirogenic oscillations, but not of phases of folding.

A break of another type occurs between the Chulym and Suchkovo subformations of the Simonovo formation, where not even a sharp change in the facies composition of the sediments is observed. After the break, pebble beds and sands, similar in composition to the former, were deposited upon the conglomerates and sandstones of the Chulym subformation; but between them there are unquestionable traces of erosion of more ancient underlying strata in the form of pebble beds containing pebbles from sandstones and conglomerates of the Chulym formation. This erosion is regarded by some investigators as the result of major tectonic movements, but at present there is likewise no reason to speak of them.

The distinction of the Kassy formation is based chiefly on paleobotanical data, indicating a Senonian age of the strata, i.e., one younger than the underlying formations. No breaks between them are established. In the present state of knowledge of the Cretaceous of the Chulym–Yenisei depression, it may even be considered that this formation, together with the Suchkovo subformation, represents deposits of a single cycle of sediment accumulation; however, this cycle, embracing two stages, developed under different conditions. Analysis of the plant assemblages of these formations shows a noticeable change toward a luxuriant flourishing of vegetation and the predominance of the most thermophilous forms in Kassy time. In this case, as a result of the superposition upon one and the same cycle of sediment accumulation, caused by oscillatory movements of the earth’s crust, of a new climatic cycle not coinciding with it in time, two independent stratigraphic units were formed.

The upper formation of the Cretaceous in the southeastern part of the western depression is readily distinguished by paleontological data and by the cyclicity of sediment accumulation. It rests on the clayey rocks of the underlying formation and begins with coarser clastic rocks, which contain rounded fragments from the clays of the underlying strata. The upper boundary of the Sym formation is as yet unknown. Apparently, this formation passes without interruption into the lower Paleogene.

The review of the Cretaceous deposits given above shows that the proper subdivision and study of this thick sequence, formed

under conditions of a complex combination of tectonic, geochemical, and climatic factors, is possible only with their comprehensive study.

LITERATURE

Anan’ev A. R.—On the study of the Cretaceous deposits of the Chulym-Yenisei basin. Scientific Notes of Tomsk State University, No. 3, 1948.

Anan’ev A. R.—Geology of the Mesozoic deposits in the area of the village of Ust’-Serta on the Kiya River. Scientific Notes of Tomsk State University, No. 10, 1948.

Anan’ev A. R. and Lebedev I. V.—The Chulym complex. Atlas of Guide Forms of the Fauna and Flora of Western Siberia, vol. II, 1955.

Bolkhovitina N. A.—Spore-and-pollen characteristics of the Cretaceous deposits of the central regions of the USSR. Transactions of the Institute of Geological Sciences, Academy of Sciences of the USSR, issue 145, geological series No. 61, 1953.

Kazanskii Yu. P.—The Kaska Formation of the northeast of the Chulym-Yenisei depression. Transactions of Tomsk State University, vol. 132, 1954.

Kazanskii Yu. P.—An experiment in the comprehensive petrographic-mineralogical study of deposits of the Sym Formation in the basin of the Sym River. Transactions of Tomsk State University, vol. 135, 1956.

Kazarinov V. P.—The problem of the geology of quartz sands of Western Siberia. Bulletin of the West Siberian Geological Administration, No. 2, 1948.

Kazarinov V. P.—The Tertiary-Cretaceous weathering crust of the western part of the junction of the Kuznetsk Alatau and the Chulym-Yenisei depression. Bulletin of the West Siberian Geological Administration, No. 1, 1948.

Kazarinov V. P.—Phases and facies of structural eluvium. Bulletin of the West Siberian Geological Administration, Nos. 3–4, 1948.

Kazarinov V. P.—On the question of the genesis of Mesozoic and Cenozoic bauxites in Western Siberia. Bulletin of the West Siberian Geological Administration, Nos. 3–4, 1948.

Kirillov A. S.—On the stratigraphic subdivision of the Cretaceous deposits in the basin of the Kiya River. Bulletin of the West Siberian Geological Administration, No. 2, 1948.

Lebedev I. V.—Upper Cretaceous Platanaceae from the Chulym-Yenisei depression. Transactions of V. V. Kuibyshev Tomsk State University, vol. 132, 1954.

Lebedev I. V.—The Cretaceous system. Stratigraphic outline. Atlas of Guide Forms of the Fauna and Flora of Western Siberia, vol. II, 1955.

Martynova O. M.—A neuropteran insect from the Cretaceous deposits of Siberia. Reports of the Academy of Sciences of the USSR, vol. 98, 1954.

Novozhilov N. I.—Fossil bivalved phyllopod crustaceans of the Kuznetsk Basin. Questions of the Geology of Kuzbass, 1, 1956.

Ragozin L. A.—Geological outline of the area of the Achinsk–Yeniseisk route. Materials on the Geology of the West Siberian Territory, No. 30, 1936.

Rozhdestvenskii A. K.—New data on psittacosaurs—Cretaceous ornithopods. Questions of the Geology of Asia, vol. 2, 1955.

Khakhlov V. A.—Remains of Tertiary flora from the Antibes siding of the Tomsk Railway. Proceedings of the West Siberian Department of the Geological Committee, vol. X, issue 2, 1930.

Cherepnin V. K.—New data on the age of the Antibes flora of angiosperms. Transactions of the Conference on the Study and Development of the Productive Forces of Siberia, vol. II, 1940.

Corrections and Noted Misprints

In S. A. Stroitelev’s article “Investigation of the Crystallization of Epsomite and Mirabilite,” for technical reasons braces have been replaced by square brackets, for example: [100] instead of {100}, etc.