214 Proceedings of Philosophical Societies. [Sept. 



which forms the highest parts of the provinces of Ingiia and 

 Esthonia, and afterwards cuts down to the blue clay which lies 

 below : between the limestone and the blue clay a stratum of 

 dark-green schist is interposed, which is of course divided by 

 the channel. Soon after the river has left the second lake, it 

 runs through a narrow defile, with a winding course ; and it is 

 here that it passes from the lime into the blue clay ; but its 

 banks in this place are covered with alarge accumulation of gravel, 

 which prevents the junction of the strata from being accurately 

 observed. The heights on the west side of the valley are formed 

 of the limestone, and are intersected by some small streams, 

 which pass through deep ravines, the sides of which afford a 

 good opportunity of examining the nature of the rock which 

 composes them, and especially of the manner in which the lower 

 beds of the limestone pass into the upper strata of the green 

 schist on which they rest. As the successive strata of the 

 limestone approach the schist, they acquire a green colour ; 

 while the schist itself below the limestone soon becomes almost 

 perfectly black. This schist contains large masses of bitumi- 

 nous limestone, or stinkstone ; these masses, when examined 

 internally, are found to possess a radiated structure, and are 

 white at the centre. The fossils of the limestone are principally 

 orthoceratites and trilobites : the orthoceratites are very large 

 and numerous. The hills on the east side of the valley, although 

 of equal elevation with those on the west, are less steep, and 

 their sides are more covered, and have no chasms in them ; the 

 limestone is only to be seen at their insulated summits. These 

 summits consist of the uppermost beds of the limestone, which 

 composes an elevated table land, that surrounds the valley on 

 eveiy side except the N. This limestone does not present the 

 same diversity of colours with that on the river Pulcovca, which 

 was described in Mr. Strangway's former paper : it is more 

 argillaceous, and has probably, from this cause, preserved its 

 organic remains in a greater state of perfection. Its colour is of 

 a yellowish-grey, with spots of green earth. 



An extract from a letter from Mr. D. Scott was then read. It 

 contains an account of some marine remains, consisting of 

 cockles and other shells that have been laid bare by the river 

 Bramaputra, near the north-east frontier of Bengal. The circum- 

 stance that is chiefly worthy of notice is, that the bed of shells 

 appears to extend under the adjoining hills, which of course 

 must have been of subsequent formation. The Garton hills, 

 which are in the vicinity of Bramaputra, are of two formations : 

 the first, which occasionally rise to the height of from 2000 to 

 3000 feet, consist of granite, with veins of quartz and felspar ; 

 the second, which rest upon these, seem to have been deposited 

 from water, as their strata are nearly horizontal : it is under or 

 through one of these latter that the bed of shells appears to 

 extend. These hills are seldom more than 150 or 200 feet in 

 height, and consist of clay, sand, and small stones. 



