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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 15, 



the river. From this point, then, the drift stretches up the slope of 

 the mountain in one thick continuous mass to an altitude, exposed by 

 the section, of nearly 1200 feet above the sea, but does not thin en- 

 tirely out until it reaches an elevation of about 1550 feet. Two small 

 streams descending the hill have laid open its structure. The north- 

 ernmost of these ravines is by far the most satisfactory, giving a clean 

 section down to the subjacent rock and extending through a vertical 



Fig. 9. — Section of Drift on Meal Uaine. Depth of a-b, 130 feet. 



1. Coarse stony stratum. 



2. The stratified drift. 3, 3. The surface of rock with striae. 



height of 500 feet, — showing the mass to be regularly stratified in an 

 almost horizontal manner, with occasional undulations; while its 

 composition is seen to be much the same from top to bottom, consist- 

 ing of numerous beds of the finest laminated silt, alternating with 

 others, coarser and more stony, that show hardly any stratification - 

 lines : large boulders from 4 to 5 feet in length are scattered through 

 the whole. I also ascertained that it rested in all its extent on a 

 rock-surface of gneiss, mica-slate, and quartz, which was grooved 

 and polished as if by the passage of a glacier, while multitudes of 

 both the small stones and large boulders imbedded in it were similarly 

 marked. 



In the channel of the rivulet were great numbers of blocks, that 

 had, apparently, been derived from the waste of this bank of drift ; 

 some of them were from 8 to 14 feet in diameter, and many were 

 grooved and furrowed. 



The horizontal arrangement of the beds in this section would seem 

 to indicate that they had originally occupied the whole width of the 

 valley, in which case the thickness must have amounted to several 

 hundred feet. It has been evidently all accumulated under water; 

 and the great number of seams of fine laminated silt would seem to 

 show that its deposition had been very gradual and had occupied a 

 great lapse of time. These loamy layers are rather more numerous 



