358 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 15, 



rather abruptly at the head of a long narrow meadow about 300 to 

 500 yards wide that stretches down the glen for a mile or two, 

 bounded on either side by bare hill-slopes destitute of any mounds. 

 The upper limit of the mounds at the head of the glen is several 

 hundred feet higher than the point where they cease at the top of 

 this long meadow. At their termination here, they form a series of 

 rough heathery hillocks 20 to 40 feet high, with many granite blocks 

 upon their surface, through which the stream pursues a devious 

 course. 



At this point it had cut into some of them, exposing the internal 

 structure and showing the upper part to consist for the most part of 

 fine stratified sand (in many places almost as fine as sea-sand), 

 derived from the disintegrated granite, of which some large boulders 

 were imbedded in various parts of the mass as well as strewn more 

 thickly on the surface. Small fragments of quartz-rock and a few of 

 hornblende also were noticed. 



Another section showed the base of one of these mounds to con- 

 Pig. 7. — Section of a Mound in Glen Berry. 



4, 4. Blocks of granite. 



sist of a stratum of the finest laminated silt, of which a thickness of 

 four feet was exposed, the laminse being partly of fine sand and 

 partly of clay capped by a bed of stratified sand with boulders inter- 

 spersed, above which lay a stratum of peat with remains of decayed 

 fir-trees. As these sections therefore showed the mounds to be 

 evidently of watery origin, I concluded that they were not glacier- 

 moraines, but the denuded relics of an aqueous deposit that had over- 

 spread the whole bottom of the glen from side to side, and that the 

 greater frequency of the boulders on their surface arose from the 

 washing away of a portion of the gravelly mass, concentrating these 

 above them ; while the termination of the deposit at the head of the 

 flat meadow seems to indicate that it had been formed at the extre- 

 mity of a lake whose waters had once extended to the top of the 

 glen, and into which the mountain-torrent descending from Loch 

 Etichan had washed down the debris. 



Whether this former lake was fresh water or an arm of the sea 

 may be questioned; but the great height of the mounds, the absence 

 of any barrier below, and the fact that the upper limit of the deposit 

 seemed to be higher than the watershed that divides the head 

 of this glen from that of the Alt-Dhu-Lochan, whose waters de- 

 scend into the basin of the Spey, seem all adverse to the idea of a 

 fresh- water lake ; while the circumstance of similar accumulations 

 being general in all the glens of the district, together with the pre- 



