INTRODUCTION, 



15 



The Cakboniferous Sequence in Russia. 



The Carboniferous series of Russia is given in the accompanying table, which 

 is quoted from a paper bj Mons. Tschernichew in the ' Annales de la Societe 

 Geologique du Nord,' tome xvii, 1890, p. 201. 



Oural. 



Timane. 



Centre Russe. 



c. 



c. Horizon a Spirifer fasiger, Conocardium Urali- 



cum, Scliwagerina princeps, &c. 

 B. Horizon A, Productus cora, Marginifera TIralica, 

 &c. 

 . A. Horizon a Syringopora parallela, Ompalofrochus 

 W/iitnegi, Spirifer striatus, &c. 



Idem 

 Idem 

 Idem 



Idem. 

 Idem. 

 Idem. 



B. Calcaire a Spirifer Mosquensis ^ 



Idem 



Idem. 



Calcaire a Productus giganteus, ^ — - 

 P. striatus, Chonetes ^ 



^ argilleux a Stigmaria 



- — ficoides. Couches de calcaires a 



Productus mesoJobus subordonnees. 



Manque. 



Calcaire a Productus 



giganteus. 

 Couches Houilleres. 



The same author goes on to state that he considers his Stage A to represent 

 the Yoredale, Carboniferous Limestone and Calciferous Sandstone beds of Great 

 Britain, while his Stage B is equivalent to the Gannister and Millstone Grit 

 Series, and Stage C to the Upper and Middle Coal-measures. Certainly, from a 

 palseontological point of view, such a comparison of strata, differing widely in its 

 fauna and in lithological characters, seems absurd, and it points to the utter 

 hopelessness of attempting to make the Carboniferous series of widely separated 

 areas conform to subdivisions typical only of a single area in Great Britain. In 

 Russia it is evident that marine conditions persisted steadily through the greater 

 part of Carboniferous time, and that the rate of deposit must have been identical 

 with the rate of depression, consequently the lacustrine and terristial conditions 

 necessary for the growth of plants to form the coal only obtained at the 

 commencement of the period. 



1 In the text Productus corrugafus, P. semireticulatus, P. longispinus, P. scahriculus, Rhynclio- 

 nella pleurodon, Athyris amhigua, OrtJiis resupinata, &c., are said to occur in stage B. These fossils 

 are, however, in Great Britain characteristic of the Mountain Limestone, though some of them do 

 pass up into the Coal-measures of Coalbrookdale and certain Yoredale beds. 



