318 



PALAEOZOIC TIME — CARBONIFEROUS AGE. 



FOREIGN SUBCARBONIFEROUS. 



The Subcarboniferous period was a time of limestone-making 

 also in Britain and Europe. There is proof, therefore, of a wide 

 extension of those geographical conditions that characterized Ame- 

 rica, — that is, of an extensive submergence of the continental lands, 

 as a prelude to the period of emergence and terrestrial vegetation 

 that followed. 



The limestone is often called the " mountain limestone." It 

 occurs in southern England and Wales, over large areas in Russia, 

 in Germany, Belgium, France, Spain, etc. In Ireland the thickness 

 is stated as varying between 1200 and 6400 feet. In the Hartz 

 there are slates and sandstones of the same age. 



Life. 



Plants. — Small coal-seams and many species of coal-plants occur in 

 the strata. The plants are related to those of the lower Coal measures, 

 and are, for the most part, the same in species. In some places, as 

 in northern Scotland, the rocks of the Subcarboniferous and Car- 

 boniferous periods so run together, by the intercalations of lime- 

 stones with the latter, that they have not yet been well distin- 

 guished. The plants are further considered under the Carbonife- 

 rous period. 



Animals. — The " mountain limestone," like the American beds, 

 is noted for its Crinoids ; its Brachiopods of the genera Productus and 

 Spirifer ; its Corals of the genus Lithostrotion ; its Ganoid Fishes and 

 Sharks ; its few Reptilian relics ; and also for the absence of Trilo- 

 bites of all the old genera. 



Characteristic Species. 

 The following are a few of its characteristic species. Fig. 550, Streptorhynchus 

 (formerly Orthis) Umbraeulum (common in the American Carboniferous) ; fig. 551,' 



Fi^s. 550-552 



Fig. 550, Streptorhynchus Umbraeulum ; 551, Athyris lamellosa ; 552, Terebratula hastata. 

 Athyris (Spirigera) lamellosa; fig. 552, Terebratula hastata; fig. 553, Productus 





