$28 HISTORICAL PALAEONTOLOGY. 



PERMIAN PERIOD. 



ROCKS OF THE PERIOD. The Carboniferous series is suc- 

 ceeded by a group of beds, which complete the Palaeozoic 

 formations, and which were termed Permian Rocks by Sir 

 Roderick Murchison, from the province of Perm, in Russia, 

 where they are extensively developed. Formerly these rocks 

 were grouped with the succeeding formation of the Trias under 

 the common name of " New Red Sandstone." This name 

 was given them because they contain a good deal of red sand- 

 stone, and because they are superior to the Carboniferous 

 rocks, while the Old Red Sandstone is inferior. Nowadays, 

 however, the term " New Red Sandstone " is rarely employed, 

 unless it be for red sandstones and associated rocks, which are 

 seen to overlie the Coal-measures, but which contain no fossils 

 by which their exact age may be made out. Under these 

 circumstances it is sometimes convenient to employ the term 

 " New Red Sandstone." The New Red, however, of the older 

 geologists is now broken up into the two formations of the 

 Permian and Triassic rocks, the former being the top of the 

 Palaeozoic series, and the latter constituting the base of the 

 Mesozoic. 



The Permian rocks, as a rule, repose unconformably upon 

 the underlying Carboniferous rocks, but seem to pass upward 

 conformably into the Trias, in most instances. The division, 

 therefore, between the Permian and Triassic rocks, and, con- 

 sequently, between the Palaeozoic and Mesozoic series, is not 

 founded upon any marked or universal physical break, but 

 upon the difference in the life of the two periods. 



The Permian rocks exhibit their most typical features in 

 Russia and Germany, though they are very well developed in 

 parts of Britain, and they occur in North America. When 

 well developed, they exhibit three main divisions : a lower set 

 of sandstones, a middle group, generally calcareous, and an 

 upper series of sandstones, constituting respectively the Lower, 

 Middle, and Upper Permians. 



In Russia, Germany, and Britain, the Permian rocks con- 

 sist of the following members : 



i. The Lower Permians consisting mainly of a great series 

 of sandstones, of different colours, but usually red. The base 

 of this series is often constituted by massive breccias with 

 included fragments of the older rocks, upon which they may 

 happen to repose ; and similar breccias sometimes occur in 

 the upper portion of the series as well. The thickness of this 



