46 GEOLOGICAL HISTORY. [CH. 



Lancashire, Westmoreland, the Eden Valley, and in the East of 

 England from Sunderland to Nottingham, there occurs a suc- 

 cession of limestones, sandstones, clays and other rocks with 

 occasional beds of rock-salt and gypsum, which represent the 

 various forms of sediment and chemical precipitates formed on 

 the floor of Permian lakes. The poverty of the fauna and 

 flora of Permian strata points to conditions unfavourable to 

 life ; and there can be little doubt that the characteristic red 

 rocks of St Bees Head, and the creamy limestones of the 

 Durham coast are the upraised sediments of an inland salt- 

 water lake. The term Dyas was proposed by Marcou for this 

 series of strata as represented in Germany, where the rocks are 

 eonveniently grouped in two series, the Magnesian limestone 

 or Zechstein and the red sandstones or Rotheliegendes. The 

 older and better known name of Permian was instituted by 

 Murchison for the I'ocks of this age, from their extreme de- 

 velopment in the old kingdom of Permia in Russia. Unfortu- 

 nately considerable confusion has arisen from the employment 

 of different names for rocks of the same geological period ; and 

 the grouping of the beds varies in different parts of the world. 

 It is of interest to note, that in the Tyrol, Carinthia, and other 

 places there are found patches of old marine beds which were 

 originally laid down in an open sea, which extended over the 

 site of the Mediterranean, into Russia and Asia. In Bohemia, 

 the Harz district, Autun in Burgundy, and other regions, 

 there are seams of Permian coal interstratified with the marls 

 and sands. From these last named beds many fossil plants 

 have been obtained, and important palaeobotanical facts brought 

 to light by the investigations of continental workers. Volcanic 

 eruptions, accompanied by lava streams and showers of ash, 

 have been recognised in the Permian rocks of Scotland, and 

 elsewhere. 



In North America, Australia, and India the term Permo- 

 Carboniferous is often made use of in reference to the continu- 

 ous and regular sequence of beds which were formed towards 

 the close of the Carboniferous and into the succeeding Permian 

 epoch. The enormous series of freshwater Indian rocks, to 

 which geologists have given the name of the Gondwana 



