164 PEOCEEDINGS OF THE GEOLOGICAL SOCIETT. [Jan. 11, 



glacial period. In other places, however, it lies in undisturbed 

 strata, as in the base of the sea-cliif at Collieston Preventive Station 

 (vrhere it consists of a great thickness of fine soft sand), and along 

 the coast from that to the old castle of Slains *. 



There are also some other spots in this low north-eastern part of 

 Aberdeenshire that seem to have escaped the erosive action of the 

 ice, to which I ascribe the denudation of the older superficial 

 deposits of Korth Britain. The extensive bed of chalk-flints cover- 

 ing the top of a low moory ridge for six or seven miles near Peter- 

 headf, with its associated patch of Greensand at Moreseat, is the 

 most notable of these. The remarkable bank of quartz -shingle, on 

 the top of the Windyhills^:, near Tyvie, is perhaps another; large 

 flints abound in it, in some of which I have detected chalk-fossils. 

 On the top of a ridge near Delgaty Castle, and about two miles 

 north-east of the town of Turriff, there is a bed of similar pebbles, 

 aU finely water-worn, and resting on the slaty rocks of the district. 

 Here again are flints; but I also observed another circumstance 

 which seemed to me of importance. This bed of shingle containing 

 the flints is covered in some places by a mass of glacier-mud full of 

 ice-scratched stones; and as this is on the top of a hill about 

 400 feet above the sea, with no height in the neighbourhood 

 whence there could have been a slip, it seemed to me to establish 

 a very old date for the formation of the shingle. The flint-pebbles 

 at Windyhills and near Peterhead also lie on the top of a set of 

 low hills of similar elevation. 



In addition to the above there are indications of the Mammoth, 

 or large fossil Elephant, having inhabited Scotland before the 

 glacial period. These consist of a few instances of its tusks having 

 been found imbedded in the Boulder-clay. Now the condition of 

 Scotland during the glacial period, as I shall presently endeavour 

 to show, seems to have been such as would be incompatible with 

 the existence of the Elephant in that country ; I therefore consider 

 that the animals whose remains we find imbedded in our old 

 Boulder-clay must have lived at an earlier time, when the climate 

 and state of the surface were more favourable. 



§ 3. Pebiod oe Land-ice. 



a. Glaciation of the Rocky Surface. — The next condition of which 

 we have any clear evidence is that indicated by the mark of the ice 

 upon the rocky framework of the country. This we find here and 

 there over the length and breadth of the land, from Aberdeen to the 

 Hebrides, from the south of Scotland even to Orkney, Shetland, 

 and the Faroe Islands, and from the tops of high hUls in the centre 

 of the country to the sea-shore down to low- water mark and further, 

 as far as the eye can penetrate. The frequency, however, of these 



* See Quart. Journ. Geol. Soc. vol. xiv. p. 515, where a sketch of the section 

 is given, showing a deep mass of Crag-sand covered by glacial clay. In this 

 sand I got Nucvla Cobboldiee. 



t Ibid. p. 528. J Ibid. p. 530. 



