406 PROCEEDINGS OF THE ACADEMY OF [1897. 



the following measured section from the summit of one of the hills 



473 ft. above water level. 



Feet. 



Argilo-arenaceous Quaternary and Mesozoic 70 



Middle Carbonic (Muscovian) limestones 592 



Lower Carbonic limestones, 243 



Coal bearing Argilo-arenaceous stage of the same horizon, 161 

 Devonic limestones and Marls, 438 



Total, 1504 



The bottom of the bore hole was left in the horizon last mentioned. 



Briefly stated the middle Carbonic or Muscovian of the vicinity 

 of Moscow is typical of this stage, containing many fossil forms of 

 which half are identical with those found in lower beds of the 

 Carbonic of western Europe, while others have been found for the 

 first time in the Muscovian. 



The Jurassic fauna is practically in perfect accord with that of 

 western Europe, except that the Sequanian is not suspectible of 

 differentiation and the Kimmeridgian is petrographically and 

 stratigraphically confounded with the overlying Volgian. 



On the question of the Volgian appears the first of several sub- 

 jects of debate among the Russian geologists. The author of the 

 brochure (L. G., I.) M. Nikitin thus defines the Volgian to which 

 he gave the tiame : — 



" The Volgian comprises all those deposits in central and northern 

 Russia which are found between the beds of the Kimmeridgian of 

 Hoplites eudoxus and those of the middle Neocomian, lower part of 

 the upper Neocomian (Hauterivian) stage containing Olcostephanus 

 versicolor." The author, while admitting the possibility that in many 

 parts of Russia where the Volgian is represented by only a portion 

 of its beds, the explanation may be found in the non-deposition or 

 subsequent erosion of the missing parts, inclines to the opinion that 

 so far as the vicinity of Moscow is concerned the apparent absence of 

 Kimmeridgian is caused by the insufficient preservation of fossils, 

 while the absence of the upper Volgian and of the middle Neo- 

 comian is to be attributed to the first two mentioned reasons. 



These measures have been principally studied by Nikitin, Bogos- 

 lovsky and Pavlov of the University of Moscow. 



Nikitin thinks that the Volgian group possesses a type of its own 

 not recognized in the classification and terminologies of western 



