1821.] . Geological Society. 233 



between Asiatic and European Russia. An extensive district 

 of red marl, salt, and gypsum, stretches down the course of the 

 Kama, and is probably connected on the south with the salt 

 district of the Volga. On both sides of this salt country, and 

 skirtino - the south and west sides of the Oural mountains, is a 

 vast tract of a dull red or a green sand, commonly called copper- 

 sand, and worked for copper. It extends through great part of 

 the governments of Viatka, Perin, and Orifa. 



Of the Steppe district, the primitive tract may be described as 

 stretching in a direction ESE from the upper part of the river 

 Bu«- to the Berda, and terminating within a short distance of the 

 Black Sea. It is a coarse grained granite, containing garnets, 

 but sometimes passing into trap or syenite. In Volhynia, near 

 the borders of Gallicia, it affords a fine white earthy felspar. 

 A series of calcareous rocks accompany the southern border of 

 the primitive Steppe, in which, towards the frontier of Gallicia, 

 and near Tomaspol, some large grained oolites appear. A 

 shelly limestone resembling that of Purbeck and Portland also 

 occupies a large tract in the vicinity of the last named situation, 

 between the rivers Bug and Dniester. 



The greater part of the interior of the Crimea appears to con- 

 sist of similar strata, the only new formation being the bitumi- 

 nous peninsula of Korch, and at the other end of the Caucasian 

 chain in the promontory of Bacou. The bituminous formation 

 reappears in the Isles of Naphtha, on the eastern shore of the 

 Caspian, and it is said also in Georgia. 



The Salt Steppe lies at an extremely low and generally uniform 

 level, extending between the Black Sea and the Caspian. The 

 lakes and pools which it contains are mostly salt; the rock 

 under the superficial sand, and sometimes left bare, is a hard 

 clay. Its origin is usually referred to a change of level in the 

 waters of the Black Sea, which, having burst a passage through 

 the Straits of Constantinople, left the shallow tract between 

 them and the Caspian perfectly dry. 



The Caucasus is a primitive chain, containing, in many places, 

 columnar trap. On its northern border, the older secondary 

 rocks are a continuation of those which form the highest moun- 

 tains on the south coast of the Crimea, and which are principally 

 composed of slate, with a conglomerate and older limestone. 



A letter was read from Mr. Parkes, concerning the Black 

 Oxide of Manganese found in Warwickshire. 



The specimens which accompanied this paper appear to be of 

 a different character from those obtained from Cornwall, Devon- 

 shire, and Scotland ; and contain more oxygen. They were 

 found at a place called Hartshill, near the towns of Ather- 

 stone and Nuneaton, in the county of Warwick ; occurring in 

 detached pieces of from 1 to 50 or 60 pounds in weight, at 

 the depth of from one foot to six or eight feet, below the surface 

 of the soil, which is chiefly clay. 



