THE PENNSYLVANIAN PERIOD. 



587 



southern Europe, the Lower and Upper Carboniferous are less dis- 

 tinctly separated. 



In Russia, the two types of Carboniferous formations, the marine 

 and the non-marine, are found, but not in the same relations as in 

 the western part of the continent. Instead of the marine type below, 

 and the lake-marsh-lagoon type above, the order seems to be so far 

 reversed that the Lower Carboniferous contains most of the coal, 

 while the Upper is made up chiefly of limestone. There is however 

 much marine limestone in the Lower Carboniferous, and in southern 

 Russia (Donetz coal-field) some coal in the Upper. The Upper Car- 

 boniferous limestone of Russia (Fusulina limestone) is represented 



Fig. 272a. — Sketch map showing the position of the Carboniferous coal beds (black 

 areas) in the lower Rhine basin (Kayser.) 



by similar formations in southern Europe, where the system is more 

 like that of eastern than that of western Europe. The faunas of the 

 marine system in southern Europe, and of the marine part of the sys- 

 tem in eastern Europe have much likeness to those of western North 

 America, suggesting that marine life was able to pass between these 

 continents, via northern Asia. < 



The upper part of the Coal Measures system of Europe at various 

 points and at various horizons contains bowlders, sometimes of large 

 size, and beds of breccia or conglomerate of sub-angular fragments. 

 The bowlders are of granite, gneiss, schist, quartzite, etc., and occur 

 sometimes singly, and sometimes in groups. They have often been 

 thought to represent deposits made by icebergs, and so to point to 



