1869.] MACKINTOSH LANCASHIRE AND CUMBERLAND DRIFTS. 429 



a new village has lately sprung up) I noticed a considerable spread 

 of decided Upper Boulder-clay. At the top of the eminence, in a 

 quarry, a deposit of stratified sand and gravel rests immediately on 

 the smoothly shaved-off edges of incKned beds or laminae of slate. 



7. Direction and Derivation of the Flow of Granitic Drift 

 IN N.W. Lancashire. 



A line running from about Bootle in a south-easterly direction 

 across Morecambe Bay, and along the north-eastern side of the 

 drift plain between Preston and Longridge, would jDerhaps roughly 

 indicate the north-eastern border of the granitic drift of JSTorth-Avest 

 Lancashire*. In the Furness and Whicham areas I have traced it 

 as far N.E. as A\'Tiicham Hall (as already stated), Holborn Hill, the 

 neighbourhood of Soutergate, and Stainton Green. The north- 

 eastern border of the ice-laden current which carried the granite 

 would appear to have been more or less mnding. The current 

 must have set in before the close of the period of deposition of the 

 Blackpool Lower Boulder- clay, if not earlier, and must have con- 

 tinued to flow till the close of the Upper Boulder-clay period. The 

 same current may have supplied the granitic drift of the Cheshire 

 and Shropshire plains, a great part of Staffordshire, a part of Wor- 

 cestershire, &c. But if so, it seems unreasonable to look to the limited 

 sea-coast area which Eskdale could have furnished (even admitting 

 a series of different levels) as the sole or even the principal source 

 of the granitic drift f. A current could not have flowed from the 

 north over the high ground at the head of Eskdale into and along 

 the course of the valley at the time when its granitic slopes were 

 above water. A great current passing by the mouth of the valley, 

 would not be likely to become loaded to a greater extent with the 

 granite of the valley than with the rocks impinging on the pre- 

 vious and following parts of its course. If so, it appears difficult to 

 explain the great pre]3onderance of granitic boulders in many parts 

 of the extensive drift-area just mentioned by appealing solely or 

 even principally to Eskdale in Cumberland ; and such being the 

 case, where are we to look for the other source or sources of the 

 granitic drift so widely distributed over the west of England ? To 

 the south of Scotland, or to some part of Ireland ? Without wish- 

 ing to support the theory of the Irish derivation of any paj-t of the 

 granite, I may state : — that the Eev. Maxwell H. Close is of opinion 

 that chalk flints found in the drift of Shropshire came from Ireland ; 

 that I have seen chalk flints in the drift of west Cheshii-e nearer to 

 Ireland ; and that a chalk flint has been found at an altitude of 

 nearly 1000 feet above the sea, on Holcombe Hill, near Man- 

 chester |. These remarks, made perhaps partly in ignorance of 



* Boulders of granite from Shap Fell may possibly be found in the drift to 

 the north of this line. 



t I have been informed that Shap granite may be found on the west coast of 

 Lancashire ; but this would merely show that granite may have been floated 

 from the Shap Fells into the course of the great N.W. and S.E. current. 



I Mr. Aitken, Trans. Greol. Soc. Man. vol. vii. 



2g2 



