C. Schuchert — Russian Carboniferous and Permian. 41 



" An upper, pure marine ) 



" A middle, glacio-marine \ division. 



" A lower, glacial ) 



"... This arrangement is intended only to express the 

 relative participation of ice and sea-water in these deposits. 

 Nowhere do we see a stratigraphic break or discordance ; 

 through local intercalations of drift horizons, the lower glacial 

 deposits, the stratified beds, and the Conularia layer are closely 

 united with the glacio-marine division (Olive-sandstone and 

 Lavender-clay), and from the latter there occurs a very grad- 

 ual transition into the pure marine division. 



" Again, three very unequal faunal divisions may be distin- 

 guished, namely: 



" An upper division : characterized by an abundance of Cer- 

 atites. 



" A middle division : characterized by an abundance of Pal- 

 eozoic brachiopods and sparingly of Ammonites. 



" A lower division : thus far without such fossils. 



" These three faunistic divisions do not wholly agree with 

 the three genetic sections. The lower division without fossils 

 is of course in harmony with the glacial division, but the mid- 

 dle section embraces the glacio-marine and the lower portion 

 of the marine divisions, while the upper member includes the 

 upper part of the marine section. The following table will 

 make this clear : — 



' ' Genetic 

 divisions 



Faunistic divisions 



Stratigraphic 

 divisions 



Pure 



Characterized by the 

 absence of Paleozoic 

 brachiopods and the 

 appearance of a 

 great abundance of 

 Ceratites 



Paleozoic brachiopods 

 absent. Ceratites 

 occurring in abun- 

 dance 



Ceratite 

 beds 



marine 

 beds 



Characterized by the 

 retreat of the Cera- 

 tites and the appear- 

 ance of an abun- 

 dance of Paleozoic 

 brachiopods 



Paleozoic brachiopods 

 abundant. Ceratites 

 rare 



Productus 

 limestone 



Glacio- 

 marine 

 beds 



Paleozoic brachiopods 



unknown 

 Conularia fauna 



Lavender-clay 

 Olive-sandstone 



T -, ! Without fossils 

 beds 



Without fossils 



Bowlder 



clay " 



