16 MR. T. F. JAMIESON" OX THE [Feb. I906, 



In Strathspey, which has a comparatively slight rainfall, a similarly - 

 early shrinkage took place, as we know from the phenomena of the 

 Parallel Roads of Glen Roy, and other facts which I shall mention 

 farther on. In proof of the state of matters at the month of the 

 Dee, we have excellent evidence in the clay-pits at Aberdeen. 

 These were formerly worked on both sides of the river, but of late 

 only on the south side at Torry, where the clay has long been dug 

 for the manufacture of drainpipes and bricks. I have visited the 

 excavations at intervals for the last forty years or more, and am 

 consequently well acquainted with the varying nature of the sections 

 displayed there. 



The river at Torry is bordered on the south side by a ridge about 

 150 feet high, which consists of granite and gneiss covered by Glacial 

 Drift. The bed of fine clay, used for industrial purposes, occupies 

 a sort of hollow nestling in the northern flank of this ridge, and 

 thins out at an altitude of about 50 or 60 feet above the sea-level. 

 It rests upon a grey Boulder-Clay which is rarely exposed to view, 

 owing to the rise of water in the bottom of the pits. The lowermost 

 portion lying immediately on the top of this Boulder-Clay is of a 

 similar grey colour, and contains some irregular masses of sand and 

 gravel of a like hue. The thickness of this grey portion, when best 

 displayed, I found to be about 14 feet. This grey clay is delicately 

 laminated by the interposition of films of mica between the leaves 

 of clay. Above it comes a mass of red clay of a stiffer and more 

 waxy nature than the grey, owing to the much smaller proportion 

 of fine sand which it contains. This red clay at Torry attains 

 in some places a depth of 14 feet, thinning out towards the ridge 

 and thickening towards the river. Where it meets the subjacent 

 grey clay, the two are generally interstratified for some distance. 

 Above the red there is a few feet of grey clay, similar in colour 

 to that which lies beneath, but of coarser texture and without 

 appearance of lamination. This upper grey clay is often altogether 

 absent, owing to the denudation which the top of the beds has 

 undergone. A mass of ferruginous pebbly gravel of later origin, 

 from 4 to 7 feet thick, lies upon the denuded top of the clay. The 

 red and grey clays at the bottom are remarkably free from stones ; 

 often not a pebble of any kind is to be seen, but now and then a 

 stone or two does occur, generally of no great size. No shells 

 have ever been found in this Torry Clay, so far as I know. Prom 

 the red clay I have, by washing and sifting, extracted one or two 

 specimens of foraminifera, but they seem to be rare, and I did not 

 meet with any ostracoda. In the grey clay I found no organisms 

 of any kind. 



These clays at Torry have all the appearance of having been 

 deposited in very tranquil water, after the Glacier of the Dee had 

 retreated some distance up the valley. The stillness of the water 

 may have been caused by a thick covering of ice, which would 

 account also for the absence of stones. The grey bottom-clay was 

 probably formed from the fine mud proceeding from the end of the 

 Dee Glacier, but the red clay marks the incoming of sediment from a 



