The Hon. Mr. Strangways on the Geology of Russia. 83 



In some parts of the district are chalybeate, and in others sulphureous 

 springs, at which buildings are erected as hospitals for the establishment. In 

 digging for these were found the fragments of the black rock with ammo- 

 nites, and also of the siliceous rocks containing shells. 



Central Limestone District. 



There extends across the middle of Russia a tract of limestone of a very 

 well-defined character. It is generally of a very pure white, completely 

 filled with broken encrinites, large terebratulites, caryophyllites, pectinites, 

 and the exuviae of other marine animals. Its extent may be taken from 

 the reach of Samara on the Volga to the country between Smolensk and 

 Moscow : it is easily recognised under the characters above stated. Near 

 Moscow it is quarried at Machcova, where the earthy varieties nearly re- 

 semble chalk, and have sometimes a pale yellow colour. There are also in 

 that part of Russia two species of marble, which should be noticed here, as 

 they are probably members of the same formation. One is the yellow mar- 

 ble of Serponkhof and Colomna, both on the Oca, near which places it is 

 quarried, to be used in Moscow for ornamental purposes. It contains frag- 

 ments of encrini, and a very large species of terebratulite with a spiral hinge, 

 found also in the mountain lime of Derbyshire. It is very frequently covered 

 with dendrites. The other marble is found near Aleshina, between Moscow 

 and Colomna, and is of a dull reddish-brown colour, and is sometimes used 

 for tables. It contains large specimens of the Anomites productus, like those 

 of Borovichy*. 



This white limestonef occurs also in great quantity on that part of the Oca 

 above Mourom, where the governments of Nishney Novgorod and Tambof 

 join those of Vladimir and Rezan. At Ounsha near Yelatom, one of the 

 iron works dependent on that of Vixa, and at Gelat in the same neighbour- 

 hood, it is quarried for the use of the smelting-houses. It contains its usual 



* A mineral called Ratofkite is found lining the surface of siliceous layers in marl, on the river 

 Ratofka near Moscow. Professor Fischer has published an account of it : Mem. de V Universitc 

 de Mogcou, torn, 5. 



t A limestone with flints is stated by Bray to occur on the Diina, where it enters Livonia ; but 

 it is doubtful whether it is a prolongation of the limestone of the Valday, or of that of Central 

 Russia. 



A white entrochal limestone occurs in Scania, but its exact geological relations are not known ; 

 it much resembles that of Machcova. 



VOL. VI. p 



