626 GEOLOGY. 



had been receiving deposits during that period was exposed to ero- 

 sion at its close. Subsequently, through further changes, much of 

 the same surface was again brought into a position for renewed depo- 

 sition, partly from fresh and partly from salt waters. The Permian 

 system thus formed is on the whole much more distinct from the Car- 

 boniferous than the Permian of the eastern part of North America, 

 and is much better known. 



During this period Europe was divided into two somewhat dis- 

 tinct provinces, a division which began to show itself in the later part 

 of the Carboniferous period, when the Upper Carboniferous limestone 

 was in process of deposition in southern and eastern Europe. Corre- 

 sponding in a general way with these two provinces, the Permian 

 has two somewhat different phases known as the Dyas and the Per- 

 mian respectively. The former name had its origin in the twofold 

 division of the system, and the latter came from a province of Russia 

 where the formation is well developed. In England, both phases 

 of the system are represented, the Dyas in the east and the Per- 

 mian in the west, 1 and in the Baltic province of Russia, the Dyas 

 phase is found. In general, the Permian system is somewhat more 

 wide-spread than the Upper Carboniferous which it overlies, often 

 unconformably, and which it overlaps in various directions. 



Except in Russia, where its extent is great, the Permian appears 

 at the surface around mountain cores and in narrow strips only; but 

 from the positions of these outcrops, it is inferred that the formation, 

 is in reality widespread beneath younger beds. 



Lower Permian. — Where the Dyas phase of the formation is developed 

 as generally in western and central Europe, the Lower Permian (Roth- 

 liegende) consists of a series of fragmental beds made up of shale, 

 sandstone, conglomerate and breccia, with which there is associated 

 a large amount of igneous rock, now in the form of lava-sheets, now 

 in the form of dikes, and now in the form of volcanic material. The 

 amount of igneous matter is so great (especially in Scotland, Bavaria, 

 and southern France 2 ) and is so widely distributed (occurring also 

 in England, the Vosges and Thuringerwald mountains, the Alps, etc.) 

 that it is to be looked upon as rather characteristic of the Lower Per- 

 mian. 



1 Geikie's Text-book of Geology, p. 1070. 



2 Ibid., pp. 1070, 1073, 1075. 



