170 THE STORY OF THE EARTH AND MAN. 



Nova Scotia. In truth, the peculiar chemical condi- 

 tions conducive to the production of magnesian lime- 

 stones and gypsum are not favourable to animal life, 

 though no doubt compatible with its existence. Hence 

 the rich fauna of the Carboniferous seas died out in the 

 Permian, and was not renewed ; and the Atlantic areas 

 of the period are unknown to us. They were, how- 

 ever, probably very deep and abrupt in slope, and not 

 rich in life. This would be especially the case if they 

 were desolated by cold ice-laden currents. 



During the Permian period there was in each of 

 our continental areas a somewhat extensive inland sea. 

 That of Western America was a northward extension 

 of the Gulf of Mexico. That of Eastern Europe 

 was a northward extension of the Euxine and Caspian. 

 In both, the deposits formed were very similar — mag- 

 nesian limestones, sandstones, conglomerates, marls, 

 and gypsums. In both, these alternate in such a way 

 as to show that there were frequent oscillations of 

 level, producing alternately shallow and deep waters. 

 In both, the animal remains are of similar species, in 

 many instances even identical. But in the areas inter- 

 vening between these sea basins and the Atlantic the 

 conditions were somewhat different. In Europe the 

 land was interrupted by considerable water areas, not 

 lakes, but inland sea basins ; sometimes probably con- 

 nected with the open sea, sometimes isolated. In these 

 were deposited the magnesian limestone and its 

 associated beds in England, and the Zechstein and 

 Kotheliegende with their associates in Germany. In 



