1821.] Geological Society. 391 



nodules of a calcareous nature and irregular shape are met with, 

 which", on calcination, afford an impure lime ; but throughout 

 the low country, limestone is generally deficient. A small hill at 

 Maniharij in North Bengal, being one of the few instances of 

 detached hills in the midst of this champaigne country, is a rock 

 composed of rounded pebbles and angular nodules imbedded in 

 a cement of hke nature, but different colour. Both effervesce 

 with acids, and the cement leaves the larger insoluble pro- 

 portion. 



In some places, at a considerable depth below the surface ; 

 for instance, at Calcutta, at the depth of 30 to 35 feet, fossil 

 wood not petrified, but more or less rotten and decayed, is 

 found, and sometimes in large blocks. Vegetable petrifactions 

 are also sometimes met with, and in particular silicified wood. 



Except fragments of shells abounding in the fluviatile sand,' 

 no animal exuvise have as yet been found within the limits of 

 the low country of Middle India. 



March 2. — Part of an *' Outline of the Geology of Russia," 

 by the Hon. W. I. H. F. Strangways, MGS. was read. 



Of the Russian empire, the two great divisions, viz. Russia, 

 properly so called, and Siberia, must be considered in a geolo- 

 gical point of view, as perfectly independent of each other, the 

 same bqundary dividing the two countries, and the two tracts of 

 secondary formation belonging to them. The empire contains 

 five principal mining districts ; viz. two in Europe, two in Asia, 

 and one on the confines of Russia and Siberia. Those in Euro- 

 pean Russia are the northern or Finnish district, and the central; 

 the former reaching from the gulf of Bothnia to the lake Onega; 

 the latter stretching across the country, in an obhque direction, 

 from the government of Kulouga to that of Nishegorod. The 

 border, or Oural district, comprehends the Oural mountains as 

 far as they have been explored. The two mining districts that 

 he entirely within the frontier of Siberia are those of Kolyvan, on 

 the west frontier of China, and Nerchinsk, on the frontiers of 

 China and Siberia towards the Pacific Ocean. 



In traversing Russia from north to south, we find a great 

 extent of primitive country comprehending Russia^ Lapland, 

 Old and New Finland, the northern parts of Careha, and part of 

 the governmentofOlonetz, and forming evidently a prolongation 

 of that of Sweden, with which its connection may be traced by 

 the Isles of Aland, on the south by those in the centre of the 

 Gulf of Bothnia, and by the Lapland chain of mountains on the 

 north. Of this district, the northern parts are said to consist 

 principally of trap rocks, the central of gneiss, and other varie- 

 ties of schistose rocks ; whil-e the northern border is compiosed 

 entirely of granite. 



The islands of Pargas in the Gulf of Bothnia, about two miles 

 south of Abo, present in general the same features as the main 

 land, being in fact but continuations of the hills of the continent*. 



