34 Sketch of the Geology of Northern Russia. 



The salt steppe is a remarkable region Ijdng at an extremely low 

 and uniform level, occasioned it is believed, by a change in the level 

 of the Black Sea. Pallas, and others who have examined the geolo- 

 gy of this tract, conjecture that the waters of the Black Sea, at some 

 remote period, burst a passage through the straits of Constantinople, 

 and receding from this shallow tract, left it dry, from its present mar- 

 gin to the shores of the Caspian. This supposition is rendered highly 

 probable, from the extreme want of fresh water through the whole 

 extent of the steppe, and the fact of its being covered with sand, and 

 and recent shells like those now found in the neighboring seas, v^th 

 no other herbage upon its whole surface, than an occasional tuft of 

 such plants as grow only on the sea shore. Lakes and pools are 

 found in its different sections and an efflorescence of salt, resembling 

 hoar frost is said to cover some parts of the dry ground. The rock 

 under the sandy superficies is a hard black clay slate, sometimes 

 bare and totally sterile. The whole steppe is a tract of barren desert 

 without inhabitants. 



In the centre of this steppe, alabaster, which is said to belong t6 

 the salt formation, rises in the insulated hills of limestone, accompa- 

 nied with gypsum and salt. 



The Caucasian chain consists chiefly of primitive rocks, but in 

 many parts of columnar trap. The secondary rocks resting on its 

 northern border, are a continuation of the mountains of the Crimea, 

 and consist principally of slates and limestone, with chalk and flints. 

 On the south part of this secondary tract is a soft shelly yellowish 

 limestone, extending along the shores of the Black Sea, tlirough a 

 rich and productive, although woodless, country. The secondary 

 strata, being probably a continuation of these limestones, form the 

 high steppe of Pallas, between the lower Volga and the Don. 



VIII. Miscellaneous Notices of Siberia. 



Geological inquiry has made but little progress m tlie nortliern re- 

 gions of Asia, but a miscellaneous notice of Siberia, is subjoined, 

 enumerating such mineral and metallic substances, as are known to 

 occur, although their positions in situ are not ascertained, nor in 

 every instance their localities. This immense territory extending 

 from the Ural Mountains on the west, to the Pacific Ocean on the 

 east, and from the borders of China and Kalmuck Tartary on the 

 south, to the Frozen Ocean, presents a scene of great interest to the 



