Vol. 62.] GLACIAL PERIOD IX ABERDEENSHIRE, ETC. 17 



totally-different quarter, when the Glacier of the Dee had apparently 

 retreated still farther back. 



In the old clay-pit on the north side of the river opposite Torry, 

 the section was very similar, 1 but the beds were deeper, the Red 

 Clay being 17 feet thick. This pit is now closed, and those at 

 Torry also. 



The Red Clay 7 and sand, however, attain their greatest development 

 to the north of Aberdeen, in the neighbourhood of Ellon, and in the 

 coast-parishes of Slains, Cruden, Peterhead, and St. Fergus, which 

 lie to the north of the River Ythan. On the lands of Ardiffery, 

 near the parish-church of Cruden, the depth reaches 100 or 150 feet, 

 and may be even more. Here a large proportion of the mass 

 •consists of sand, much of it very fine-grained and free from stones ; 

 varying in colour from reddish to pale-grey. Other portions 

 are coarser and more pebbly, with some small debris of yellow and 

 grey limestone. Crumbs and dust of Crag-shells 2 can generally 

 be detected where this limestone-debris occurs in the sand and 

 gravel. Beds of Red Clay are met with in any part, both above and 

 below the sand, while seams of the two are often interstratified. 



The character of the surface here is very inoundy — large swelling- 

 mounds, but these do not run in long narrow lines like eskers. The 

 stratification in their interior is generally undulating and irregular. 

 The sand and gravel looks as if it had been shot down in great 

 heaps. Much of it is well washed and free from muddy sediment, 

 and there is a marked absence of big stones and boulders in the 

 interior of these sand-beds ; but a few big stones seem to occur 

 on the surface in all parts of the district. It seems to me that the 

 explanation of this heavy mass of material being lodged here, may be 

 that great streams of water flowed off from the glacier at this place, 

 washing out the mud, sand, and mineral-debris embedded in the ice. 

 Farther off from where the border of the glacier seems to have 

 existed, we find the deposit to be more of a clayey nature, lying in 

 flatter widespread sheets ; whereas, along what had been the margin 

 of the ice, the surface is moundy, the accumulations much deeper, 

 and the stuff consists mostly of washed gravel and sand, sometimes 

 •of very pebbly gravel, with occasional masses of coarse mud or 

 Boulder-Clay. 



In one of the railway- cuttings at Port Errol, in the parish of 

 Cruden, there was a bed of Red Clay from 30 to 40 feet thick, having 

 much the same composition from top to bottom. It showed no 

 distinct stratification or lamination, and contained some small stones 

 dispersed through it. 



At Belscamphie, which forms the north-western boundary of the 

 pebbly gravel that contains the debris of Crag-shells (loc. cit.) and 

 Secondary limestone, the section was as follows. At the bottom was 

 -a mass of Boulder-Clay of a very dark indigo colour, containing small 

 fragments of crystalline schist and granite. This rests upon the 

 schistose rocks of the district, which crop out a little farther on in the 



1 Quart. Journ. Geol. Soc. vol. xiv (1858) p 510. 



2 Ibid. vol. xxxviii (1882) p. 145. 



Q. J. G. S. ]STo. 245.. c 



