4 Jackson, Facetted Pebbles with Glacial Deposits. 



The most noteworthy feature of these deposits is the occurrence 

 of large numbers of beautifully facetted and wind-worn pebbles in 

 the sand-bed immediately below the soil-cap. These occurred in 

 situ in a somewhat discontinuous layer, sometimes in nests or 

 pockets, at a depth of some 3 or 4 feet from the original land surface. 

 They were first noticed in the weathered talus of the section, but 

 were ultimately located in the sand-bed below the soil-cap, and 

 found to be strictly confined to that horizon. During the last two 

 years I have collected several hundreds of these wind-worn pebbles 

 from this zone as the exposure was cut back and the sand carted 

 away for building and other purposes. They can still be obtained 

 in numbers from the portions of the section still standing. They 

 are not entirely restricted to the northern section, as I have obtained 

 several characteristic examples from the sand occupying the gully 

 in the surface of the clay of the southern section mentioned 

 previously (p. 3). 



The general field relations strongly suggest that the sand of the 

 facetted pebble zone is definitely a post-Glacial deposit, probably 

 the result of redistribution by wind before a soil-cap with vegetation 

 began to form, and that the contained pebbles were worn by sand- 

 blast in post-Glacial times. The close association of this bed with 

 the underlying Glacial Drift would seem to imply that no great 

 interval of time can have intervened between the deposition of the 

 two series. 



The sand in the facetted pebble zone, in its natural condition, 

 is somewhat dark in colour, but noticeably fighter than the over- 

 lying soil : it adheres strongly to the pebbles when damp. On dry- 

 ing it becomes very much lighter. On microscopic examination it 

 is seen to consist largely of yellowish-coloured quartz in rounded 

 and sub-angular grains, mixed with smaller grains of quartz and of 

 various drift rocks. 



The pebbles showing wind action are typical of the North- 

 western Drift, consisting of slate, granite (Eskdale and others), 

 Ennerdale granophyre, Borrowdale volcanic tuffs and ashes, 

 porphyries, quartzites.. millstone grit, sandstones, chalk flints, 

 carboniferous chert and other rocks. 



The largest facetted pebble so far found measures nf S^ 

 inches, and is 7 inches high. Others are of varying dimensions 

 down to half-an-inch in diameter. Without exception, all the pebbles 

 collected from this zone, whether facetted or not, show evidence of 

 wind action on their surfaces. 



A close examination of these pebbles reveals several interesting 

 features. They show all stages towards the formation of typical 

 dreikanter, or three-edged stones. The most remarkable feature, 

 however, is the large percentage of stones which have been fractured 

 or split. In some cases large stones, both igneous and sedimentary, 

 have been split in half ; in others quite a third of the original pebble 

 has been broken off ; and in each case the fractured face exhibits 

 most definite evidences of modification by blowing sand. In a few 

 cases the rounded unsplit pebbles show traces of facetting ; but the 



