1821.] Geological Society. 151 



When ravines occur, as on the banks of the Oca and Volga, near 

 Nishroy Novgorod, they exhibit only horizontal strata of red and 

 white marl, with occasional alternations of red sandstone. 



Near Pechersk, the colour of this sandstone varies from a 

 pale-red to a dusky-green, and is marked by irregular concre- 

 tions, and a sort of globular structure like that of Borovichy 

 and the Pepovca. At the bottom of this cliff, along the shore, 

 it is a thick bed of a very compact tufa, of which the cavities 

 are often filled with brown sulphate of lime disposed stalactiti- 

 cally, and capable of taking a fine polish. Freshwater shells 

 are sometimes found in this tufa. A similar formation exists in 

 the Oca, near the salt magazine. 



Among the most remarkable natural curiosities of the govern- 

 ment of Nishroy Novgorod are the rocks and cavern of Barnou- 

 cova, which are situated near the western extremity of a ridge 

 of hills that bound the northern bank of the river Piana, and are 

 distinguished by their romantic beauty and resplendent purity of 

 the alabaster of which they are composed. It is indistinctly 

 stratified in large beds, and contains starry crystallizations of 

 selenite. The neighbouring country is wholly of red rock marl, 

 in which the alabaster forms subordinate beds. 



At the village of Troitska, 1 1 versts further up the Piana, a 

 fibrous gypsum, which has been mistaken for the mineral called 

 rock leather, is found in continuous layers between the beds of 

 marl, and may be pulled out with care in sheets of several square 

 feet. 



At Simberck, the upper part of the hills in the Volga contains 

 jjreat quantities of a very white marl (kreide-mergel) ; and the 

 limestone of Cazan appears to belong to the same formation. It 

 is of a greyish colour, usually very distinctly oolitic, and at the 

 same time much harder and more compact than the rocks 

 which form the oolitic series in England. At the former 

 place also a black clay containing pyrites and green sand, and 

 usually full of organic remains, is found. It appears also at 

 Polymnia, a little higher up the river ; at Mourzikha, on the 

 Soura ; at Vixa, and in some parts of the neighbourhood of 

 Moscow. The apparent situation of this rock is beneath the 

 sand. 



At Tatuski, 24 versts west of Moscow, a pinkish-white silice- 

 ous sandstone is found in large slabs with irregularly curved 

 surfaces. It is used for foundations and for millstones. 



