Kerkidon Fm

Along the hydrographic basin of Kerkidon, in the northern-western part of the Karachatyr Range, South Fergana. F.R. Bensh et al., 1975 (110, p. 26; 82-86). Stratotype in East Karachatyr on the northern wing of the homonymous syncline, along the Bulaksay and Dangibulaksay.

Synonym: Kerkidon Suite, Керкидонская св., Kerkidonian

Divided into three sub-stages. Lower sub-stage (thickness of 336-350m) - thin-bedded, gray, dark gray, greenish-gray siltstone (aleurolites) and sandstones with layers of clayey, sandy, organogenic limestones, sometimes with layers of massive and thick-bedded fine- and coarse-grained sandstones. Middle sub-stage (thickness of 600-650m) in the lower part extensive lenses and packs of biomorph-laminated algal limestones (M. 5-20, sometimes up to 40 m), between which thin-bedded siltstone (aleurolites) and sandstones with layers of limestones are developed. Upper part - siltstone (aleurolites) and claystones with layers of sandstones and limestones, clayey or sandy.

Lower sub-stage - contains foraminifers - Triticites vulgaris M.-Macl., Dutkevitchia complicata (Schell.), Daixina (Daixina) bipartita plicatissima Bensh, D. (D.) vasilkovskyi Bensh, Occidentoschwagerina alpina (Kahl. et Kahl.), O. cf. kokpectensis Scherb., Licharevites paranitidus (Bensh), Pseudofusulinoides subooscurus Bensh, Eoparafusulina ferganensis (Dutk.), E. subcylindrica Bensh, Grozdilovia aff. garezkyi Scherb.; brachiopods - Dictyoclostus cf. donetzianus (Lich.), Marginifera schellwieni Tschern., Neophricodothyris asiatica (Grab. et Chao) and others, gastropods - Bellerophon kirgisicum Lich., Goniasma lassalensis vulgaris Lich., Sphaerodoma veberi Lich., S. ferganense Lich., conodonts - Streptognathodus elongatus Gunn., S. simplex Gunn., S. wabauensensis Gunn., S. constrictus Chern. et Resh., S. barskovi Kozur. and others.