32 G. SchucJiert — Russian Carboniferous and Permian. 



Argillaceous limestones and marls of variegated tints. No 



fossils. 

 G-ypsiferous group of limestone, gypsum, and clay. No 



fossils. 



Permo-Carboniferous, or Artinskian (Lower Permian of many 



authors). 



Horizon CPc, or dolomitic-limestone zone. A gray or yellow- 

 ish gray cavernous limestone passing often into dolomite, 

 brecciated or conglomeratic in composition, with interca- 

 lated beds of oolite and occasionally shale. 

 Has a fauna smaller than, and almost identical with, that 

 of horizon C Pg. Cladodus, Dielasma hastata, D. elongata, 

 Spiriferina cristata, Phynchopora nikitini, Chonetes 

 variolaris, G. verneuiliana, Productus purdoni, P. cora, 

 Marginifera typica, Fusulina verneuili, and Bradyina 

 nautili formis. 



Horizon CPg, or Artinskian sensu stricto. " Peppery " sand- 

 stone, with intercalations of shales. In places conglomer- 

 ates, limestone, shales, and slates. 



Has Phillipsia gruenewaldti, Pronorites prwpermicus, 

 Agathiceras uralicum,, Medlicottia artiensia, Gastrio- 

 ceras, Popanoceras, Paraprone rites. Of Upper Carbon- 

 iferous brachiopods, 61 species pass into this zone. Among 

 the more prominent fossils of the zone are the following : 

 Dielasma elongata, Spiriferfasciger, S. alatus, Spirifer- 

 ina cristata, Spiriferella saranm, Phynehopora nikitini, 

 Camarophoria plicata, Streptorhynchus pelargonatus, 

 Productus spiralis, P. lineatus, Marginifera typica, 

 Fusulina verneuili. 



Upper Carboniferous, or Uralian. 



Schwagerina zone (Cf), about 60 meters thick in Timan. 



Abounds in Schwagerina princeps. Other Foraminifera 

 are Fusulina verneuili, F. longissima. Of corals, there 

 are many species, mostly of the compound t} T pe. Of Bryo- 

 zoa, the most striking is Archimedes. This is the horizon 

 par excellence for brachiopods, Tschernyschew recording 

 194 forms. Dielasma in greatest abundance, with 13 

 species ; Ilemipty china 4, none below ; Notothyris 3 ; 

 Aulacothyris 2 ; Keyserlingina 2, none below ; Terebrat- 

 tdoidea 2, none below ; Pugnax 8 ; Camarophoria 14 ; 

 Spiriferina 8 ; Spiriferella 4 ; Spirifer 21 ; Martiniopsis 

 7, none below ; Martinia 13 ; Peticidaria 4 ; MeeJeella 2 ; 

 Grthotichia 1, none below; Chonetes 11; Atdostegesl; 

 Productus 40 ; Proboscidella 3 (these are not of the 

 type of the Lower Carboniferous, having had another 



