136 PROFESSOR JAMES GEIKIE ON THE 



The beds overlying the boulder-clay are evidently of lacustrine origin. The fine clay 

 (No. 2), according to Mr Williams, is simply reconstructed boulder- clay. After the 

 disappearance of the mer de glace the land would for some time be practically destitute 

 of any vegetable covering, and rain would thus be enabled to wash down the finer 

 ingredients of the boulder-clay that covered the adjacent slopes, and sweep them into the 

 lake. The clay formed in this way is described as attaining a considerable thickness near 

 the centre of the old lake, but thins off towards the sides. The succeeding bed (No. 3) 

 consists so largely of vegetable debris that it can hardly be called a clay. Mr Williams 

 describes it as a " bed of pure vegetable remains that has been ages under pressure." He 

 notes that there is a total absence in this bed of any tenacious clay like that of the under- 

 lying stratum, and infers, therefore, that the rainfall during the growth of the lacustrine 

 vegetation was not so great as when the subjacent clay was being accumulated. Eemains 

 of Megaceros occur resting on the surface of the plant-bed and at various levels in the 

 overlying brownish clay, which attains a thickness of 3 to 4 feet. The latter is a true 

 lacustrine sediment, containing a considerable proportion of vegetable matter, inter- 

 stratified with seams of clay and fine quartz-sand. According to Mr Williams, it was 

 accumulated under genial or temperate climatic conditions like the present. Between 

 this bed and the overlying greyish clay (30 inches to 3 feet thick) there is always in all 

 the bog deposits examined by Mr Williams a strongly-marked line of separation. The 

 greyish clay consists exclusively of mineral matter, and has evidently been derived from 

 the disintegration of the adjacent granitic hills. Mr Williams is of opinion that this 

 clay is of aqueo-glacial formation. This he infers from its nature and texture, and from 

 its abundance. " Why," he asks, " did not this mineral matter come down in like 

 quantity all the time of the deposit of the brown clay which underlies it ? Simply 

 because, during the genial conditions which then existed, the hills were everywhere 

 covered with vegetation ; when the rain fell it soaked into the soil, and the clay being 

 bound together by the roots of the grasses, was not washed down, just as at the present 

 time, when there is hardly any degradation of these hills taking place." He mentions, 

 further, that in the grey clay he obtained the antler of a reindeer, and that in one case 

 the antlers of a Megaceros, found embedded in the upper surface of the brown clay, 

 immediately under the grey clay, were scored like a striated boulder, while the under 

 side showed no markings. Mr Williams also emphasizes the fact that the antlers of 

 Megaceros frequently occur in a broken state — those near the surface of the brown clay 

 being most broken, while those at greater depths are much less so. He shows that this 

 could not be the result of tumultuous river-action — the elevation of the valley precluding 

 the possibility of its receiving a river capable of producing such effects. Moreover, the 

 remains show no trace of having been water-worn, the edges of the teeth of the great 

 deer being as sharp as if the animal had died but yesterday. Mr Williams thinks that 

 the broken state of the antlers is due to the " pressure of great masses of ice on the 

 surface of the clay in which they were embedded, the wide expanse of the palms of the 

 aDtlers exposing them to pressure and liability to breakage ; and even, in many instances, 



