Vol 63 Iss. 2

The classic section of the Lower Phamene is considered to be the section of the central regions of the Russian Platform. In it, the Zadonian and Yeletsky layers with numerous representatives of the Cyrtospirifer archiaci Murch group lie on the Upper Nefranian sediments with theodossia, covered by the Dankov-Lebedian layers with C. lebedianicus Nal.

Upper Ordovician and Lower Silurian sediments are widespread in the Altai-Sayan folded region. They have been studied to varying degrees, paleontologically characterized differently, and have different relationships with each other.

In the extreme southwest of Tuva, the Silurian sediments are composed of small isolated mulds. The largest of these is the Mugur syncline, and two other small folds are located in the area of the Ordovician Kargin syncline...

In the eastern part of the Malguzar Mountains (northwestern spur of the Turkestan Ridge, the basin of the upper Zaamin-su River), the Silurian-Devonian boundary deposits occupy a significant area. They compose the wings of the latitudinal synclinal structure and are represented by very diverse terrigenous-carbonate rocks. The most complete section of them is known on the northern wing of the structure near the village of Myk in the upper part of the river. Myk in the upper reaches of the Yettkichu River, the left component of the Zaaminsu River. Zaaminsu River. Here, an alternation of organogenic and slam limestones, limestone conglomerates, clay shales, siltstones with lenses of sandstones, conglomerates and gravelites is exposed. The sediments contain abundant organic remains: stromatopores, corals, brachiopods, bryozoans, gastropods, pelecypods, nautiloids, and ostracods. Upper Silurian and Devonian sediments in this area were studied by V. D. Chekhovich [1965], A. I. Kim, and N. M. Larin (1960-1962). The author became acquainted with these sediments in the summer of 1968. The collected material is the basis of this article.

Representatives of the family Megalodontidae are widely distributed on the Southern and Northern Islands of Novaya Zemlya, as evidenced by the collections of B. A. Alferov (1934). A. Alferov (1934), A. A. Petrenko (1936), and B. V. Miloradovich (1936). V. Miloradovich (1936), processed by us for the present article.

The tier affiliation of the Kosva horizon is debatable. The existing points of view are based on different interpretation of geological and faunistic data. Ostracods of the Kosvinsky horizon were studied in two sections of the western slope of the Urals - “Shirokovsky” (Middle Urals, Kizelovsky district) and “Usuili” (Zilim River basin).

In the Kalba Range and the western part of the Southern Altai, coal-bearing sediments sharply dominate over other sedimentary formations. They participate in the formation of the Kalba-Narym, West Kalba and Zharma structural-formational zones, differing in the nature of their section.

Within the Mezenskaya Depression, the Carboniferous and Permian sediments have no natural outcrops on the day surface; they are uncovered by boreholes drilled in the last decade in the settlements of Verkhny Smolenets, Koinas, Selishche, Maibas and Fominskoye.

Deposits of the Artinskian Stage in the Middle Urals have been studied in the basins of the Yurezan, Ufa, Sylva, Kosva, and Usva rivers.

During the study of the Lower Permian sediments of the Southern Urals, massive reef algal limestones were encountered in the Artinskian Stage roof, which are analogous to the reef algal limestones of the Sylva River basin in the Middle Urals in terms of their position in the section, reef-forming organisms, and fauna complex. They are most well exposed in the Shafeevsky section.

Pamir is one of the areas where adrianitids are quite fully represented. From the Permian sediments of the southeastern Pamir, the family Adrianitidae belongs to: Emiliiesaff. incertum (Bose), Crimites pamiricus Toum., C. spathi Toum., C. murgabensis Pav. A, Neocrimites nalivkini Toum.,N. dutkevitchi sp. nov., N. pamiricussp. nov., Pamiritella vinogradovi Toum., P.sp., Istycoceras bodylevskyi Pav., Pamirioceras markovskii Pav.

The distribution of brachiopods in the sediments of the Artinskian Stage of the Urals has been repeatedly considered in the literature by F. N. Chernyshev [1889, 1902], G. N. Fredericks [1918], B. V. Miloradovich [1949], and D. L. Stepanov [1939, 1951]. However, all researchers did not divide the Artinskian Stage into horizons based on brachiopods, although the abundance and diversity of Artinskian brachiopods have long suggested the possibility of using them to distinguish two subarcs and even local horizons of the Artinskian Stage [Stepanov, 1939, Miloradovich, 1949, 1951]. In addition, a controversial stratigraphic position is occupied by the so-called Sylven reefs, which M. V. Kulikov [1948], V. D. Nalivkin [1949] and D. L. Stepanov [1951] attributed to the uppermost part of the Artinskian Stage, bordering the Kungur; B. V. Miloradovich [1949] defined their age as the Kungurian.

Inoceramids (retroceramids) are widespread in the Middle Jurassic sediments of the eastern USSR. They are the dominant and often the only fossil remains in rocks of this age. Unfortunately, ammonite finds are extremely rare in layers with inoceramids, which makes it difficult to determine the age range of representatives of this most important group of Jurassic bivalves. Usually, their age is determined either conditionally or within very wide limits, whereas more precise dating from inoceramids will undoubtedly make it possible to develop a sufficiently detailed stratigraphy of Middle Jurassic deposits. Therefore, each joint find of retroceramids and ammonites is of great interest. Such finds were made by the author in the Western Priokhotie on the coast of the Tugur Bay of the Sea of Okhotsk. Here, rocks of the lower part of the Middle Jurassic - Aalenian and Bajosian stages, containing rich complexes of inoceramids, are exposed in coastal cliffs. The Aalenian deposits in this area are characterized by numerous ammonites, which make it possible to identify local zones and relate them to a standard scale. The accompanying retroceramas are dated accordingly.

Marine sediments of the Albian Stage in Southern and Western Turkmenistan are represented by a stratum of alternating clays, siltstones and sandstones with horizons of calcareous nodules and rare beds of limestone-shells. They contain numerous fossils, among which ammonites are the most important for determining the age of the sediments under consideration, allowing to draw up a fractional stratigraphic scheme of the Albian sediments of Turkmenistan. The second place in importance for determining the age of the sediments containing them is occupied by bivalves and, first of all, inoceramas. Different species of this family in the sections of the Albian of Turkmenistan usually occupy a certain stratigraphic interval from one or two zones to two or three subaerials

Almost throughout the Devonian, there were marine basins around the Pacific Ocean that belonged mainly to geosynclines. Caledonian folding, manifested in the second half of the Silurian in the Paleozoic geosynclines, gave rise to young mountain chains and island archipelagos that separated the continental seas.