130 M. Kupff'er's Account of the Russian Steppes, 



we see a change in the aspect of this rock and of its contained 

 fossils : Sometimes it is very compact and of a grey colour, 

 whereas the rock containing the Cytherese, when devoid of 

 shells, is always very white, and generally so soft that it is 

 often friable : Sometimes it becomes a little more porous, and 

 contains some fossils of the family of the Helices. It is with 

 this limestone rock that the country begins to present an un- 

 dulated surface, so that we perceive that the mountains are ap- 

 proaching. In quitting Stavropol, we descend into a wide 

 plain, at the extremity of which is situated the village of Na- 

 deja, twenty versts from Stavropol. This limestone (which I 

 shall call the helical limestone, to distinguish it from the 

 cythereal limestone,) extends to Kalinova ; and it is between 

 this village and the small town of Alexandrovsk that we ob- 

 serve on the right, in descending a hill, some insulated rocks 

 of sandstone, and, at the same time, the snowy top of Elbrouz 

 (or Chad,) and a part of the central chain of Caucasus presents 

 itself for the first time. 



This sandstone is distinguished by a particular bivalve shell, 

 with which it is filled, and of which M. Pander (who has 

 thrice visited the shores of the Black Sea,) has formed the new 

 genus Hypania. The sandstone is of a yellow colour, it 

 slightly resists the blow of a hammer, and sometimes becomes 

 even friable ; it is liable to perpendicular cleavages, and to form 

 enormous blocks with salient angles, and of a grotesque form ; 

 it effervesces strongly with acids, even at places which contain 

 no fossils ; and there are grains of sand enveloped in a calca- 

 reous mass, which is sometimes deposited in separate beds. 



A phenomenon deserving of notice is the great fertility of 

 this soil. It appears that the sandstone, being more porous 

 than the calcareous rock, the subterranean waters circulate in 

 it with more facility, and distribute themselves more uniform- 

 ly, so that plants whose roots are almost constantly moistened 

 resist better the burning heat of the sun in the steppes. At 

 some points the country loses entirely the character of a steppe. 

 We meet with trees, cultivated fields and lakes, habitations 

 multiply, the means of subsistence increase, whereas every- 

 thing in the steppe languishes. 



Behind Alexandrovsk, the view of the chain of the Caucasus 



