The Permian formations of northeast U.S.S.R. form part of the Boreal biogeographic realm. Marine faunas are characterized by a scarcity or absence of colonial corals, fusulinids, etc., and by the presence of endemic forms, making correlation with type sections in European Russia extremely difficult.

Permian sections described from the area comprise three main facies types: terrigenous sediments up to 8,000 m (approximately 26,240 ft) thick in the Verkhoyan area and the Kula Basin; clastics, mainly of Upper Permian age and reaching 1,000 m (approximately 3,280 ft) in the Kolyma region and the Gizhiga Basin; and carbonates, represented by Upper Permian limestones reaching 400m (approximately 1,312 ft) in thickness, occurring in the Omolon Massif region. In this latter section, Lower Permian strata are absent.

The Kygyltass Formation and most of the Echiy Formation of the Verkhoyan region, and the Munugudzhak unit of the area to the east, are clearly of Lower Permian age. These strata have yielded Artinskian ammonoids, such as Paragastrioceras and Uraloceras and the brachiopod Jakutoproductus verchoyanicus. Extremely shallow-water benthos includes the Lower Permian brachiopods Spiriferella saranae, Horridonia

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cf. timanica, Anidanthus bojkovi and Neospirifer paranitiensis. This part of the section corresponds to the Asselian-Artinskian stages.

The middle part of the Permian section is assigned to the Lower Permian by some investigators and to the Upper Permian by others. Included here are the Tumara and Khabakh formations of the Verkhoyan region, and the Dzhigdali unit of the Omolon Massif region. Characteristic of this part of the section is the Upper Balakhonsky floral complex (usually considered to be Lower Permian) and the Baigendzhinsky ammonoid association. Among brachiopods represented are typical Upper Permian forms, such as Spiriferella keilhavii and Rhynchopora lobjaensis. However, forms typical of the Lower Permian are also present. The bivalve genus Kolymia is common. This part of the section should probably be correlated with the Kungurian and most of the Ufimian stages.

Upper Permian deposits are represented by the Delenzha and Dulgalakh Formations in the Verkhoyan area, and the associated Omolon, Gizhiga and Khivatsch units. The brachiopods Licharewia, Stepanoviella and Megousia are abundant, while the ammonoid Spirolegoceras and the Kolchuginsky floral complex are also present. These deposits are equivalent to the Kazanian and Tatarian stages (and probably also to the uppermost Ufimian Stage).

Sedimentary units of obviously glacial-marine origin occur in the Permian section of northeast U.S.S.R. and are of great importance in correlation. The thickest and most persistent of these units occurs in the middle Upper Permian, in the lower part of the Dulgalakh Formation. A second unit is present in the lower part of the Permian section, but its exact stratigraphic position has not yet been determined.

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