Mr. Murchison on the Salt Steppe south of Orenburg. 357 



and chloride ; the anhydrous salt is Cd I + KI. It is very 

 soluble in water. 



Cadmio-chloride of sodium does not crystallize in a regular 

 form, but in verrucose crystals. The formula is Cd CI + 

 Na CI + 3 aq. 100 parts of water at 60 dissolve — 71*32. 



Cadmio-chloride of ammonium crystallizes like the potassium 

 salt in two forms ; the large crystals are anhydrous. 



All these salts are somewhat soluble in alcohol and wood- 

 spirit, but not so much so as the simple chloride, iodide and 

 bromide. 



The analyses of these, as well as some other salts of cad- 

 mium, will be published in a second paper. 



LXVI. On the Salt Steppe south of Orenburg, and on a re- 

 markable Freezing Cavern. By Roderick Impey Mur- 

 chison, Esq., Pres. G.S.* 



HPHIS salt steppe is distinguished from many of those which are 

 ■*■ interposed between the Ouralsk and the Volga or are situated 

 on the Siberian side of the Ural Mountains, by consisting not of 

 an uniform flat resembling the bed of a dried-up sea, but of wide 

 undulations and distantly separated low ridges ; nevertheless it is, 

 Mr. Murchison states, a true steppe, being devoid of trees and little 

 irrigated by streams. The surface consists of gypseous marls and 

 sands, considered by the author to be of the age of the zechsteinf, 

 and it is pierced in the neighbourhood of the imperial establishment 

 of Uletzkaya Zatchita by small pyramids of rock-salt. These pro- 

 truding masses attracted the attention of the Kirghiss long before 

 the country was colonized by the Russians, but it is only during a 

 short period that the great subjacent bed has been extensively 

 worked. The principal quarries, exposed to open day, are situated 

 immediately south of the establishment, and have a length of 300 

 paces, with a breadth of 200 and a depth of 40 feet. The mass of 

 salt thus exposed, is of great purity, the only extraneous ingredient 

 being gypsum, distantly distributed in minute filaments. At first 

 sight the salt seems to be horizontally stratified, but this apparent 

 structure, Mr. Murchison states, is owing to the mineral being ex- 

 tracted in large parallelopipedal blocks twelve feet long, three feet 

 deep and three wide. On the side where the quarry was first 

 worked, the cuttings presented, in consequence of the action of the 

 weather, a vertical face as smooth as glass, but at its base there 

 was a black cavern formed by the water which accumulates at cer- 

 tain periods of the year, and froni its roof were saline stalactites. 



* From the Proceedings of the Geological Society, vol. ii. part 2; ha- 

 ving been read March 9, 1842. 



j- His extensive surveys of Russia have convinced Mr. Murchison that 

 rock-salt and salt springs occur in all the lower sedimentary rocks of that 

 empire, from great depths below the Devonian or old red sandstone system 

 to the zechstein and the overlying marls and sandstones. 



