D. Mackintosh— might of Glacial Drift. 401 



seem to show that floating coast-ice is the great glaciator of stones, 

 while land-ice is the great grinder and smoother of solid rocks. 



Clay- and Gravel-Pinnel or Sammel. — I have lately seen upwards 

 of a hundred clean sections of this formation from 134 up to 2800 feet 

 above the sea. It consists of clay, loam, or sand, intermixed with 

 numerous stones from the size of a pin's head up to one foot or 

 sometimes a foot and a half in average diameter, boulders of a larger 

 size being very exceptional. The stones are nearly all more or less 

 blunted, some of them considerably rounded, but most of them sub- 

 angular. The stones chiefly lie or stand at various angles, but not 

 unfrequently exhibit a tendency to a curved linear arrangement. 

 "We almost invariably find the stones less and less rounded the 

 higher we ascend the hill-sides — a fact (as above hinted) not ver}^ 

 easily reconciled with the idea of their having been distributed by 

 the great ice-sheet which ignored hill and valley. In the two kinds 

 of pinnel, the clayey ("waxy") and the sandy or gravelly, the stones 

 are similarly distributed ; and both kinds (but especially the latter) 

 frequently present the appearance of being rudely stratified in the 

 form of a series of curves or arches, occasionally varied by a 

 rough interwedging of beds. The waxy pinnel often contains 

 seams, beds, or pockets of sand. — Pinnel may be found in nearly all 

 positions. It fills up crevices and recesses in the rocks, chokes up 

 brook courses, clings to steep as well as gently-rising hill-slopes, and 

 covers plateaux and broad ridges at various levels ; but the greatest 

 masses are associated with angular or mammillated rocky projec- 

 tions which would appear to have arrested it in its forward move- 

 ment. In such positions it forms undulating terraces, and gently- 

 swelling large oblong knolls which generally run along the sides or 

 middle of the larger valleys, or diversify broad low-level passes. 

 The colour of the pinnel is usually yellowish brown, sometimes 

 grey, especially when dry. 



Pinnel on Helvellyn. — On the W. side of a great part of Helvellyn 

 there is a flat terrace which slopes transversely from about 1900 feet 

 up to 2100 feet. It is more or less covered with drift, the greater 

 part of which, I believe, is true pinnel. West of the top of Hel- 

 vellyn, a steeper slope at a higher level runs ujj to 2800 feet, where 

 a sudden rise of the ground marks its termination. At this point 

 (which is only a few hundred yards from the top of the mountain) 

 I was fortunate in finding a newly-cut drain apparently intended to 

 divert a part of the water of the celebrated Brownrigg well to a 

 mine at a lower level. Under a covering of stony loam I saw a 

 clear section of typical clayey pinnel, and afterwards found pinnel 

 in brook sections lower down, so that the upland extension of this 

 deposit to at least 2800 feet above the sea may be regarded as 

 certain. But as pinnel, especially clayey pinnel, could only have 

 been formed directly or indirectly by ice-action, the former ex- 

 tension of either land or sea-ice (possibly both) to this great altitude 

 can scarcely be doubted. 



Pinnel Hillocks and Surface Blochs. — In inland valleys and upland 

 cwms, on passes between hills, and on cols or depressed parts of 



VOL. IX.— NO. xcix. 2G 



