Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/314

206 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 12, drifts of Worcestershire and "Warwickshire into three classes, viz. " (1) Erratic gravel without chalk-flints, (2) Erratic gravel with chalk-flints, (3) Local or non-erratic gravel ;" from which it appears that he was not aware of the existence of the Boulder-clay in those counties, although he mentions the occurrence of a stiff clay, containing fragments of chalk, near Princethorpe, in Warwickshire.

Description of the Drifts of the Upper Series. — Referring to the accurate descriptions of the several classes of drift and their geographical distribution, contained in the papers of Strickland previously mentioned, I shall confine myself to some observations bearing on the extension of the subject which I have had the opportunity of making.

A (1). This deposit of quartzose flinty gravel and sand is found overlying the Boulder-clay in the neighbourhood of Rugby ; in some places it rests immediately upon the basement rock, as at Kenilworth, where it shows signs of stratification, the sand being laminated in the middle bed. A small rounded boulder of grey-coloured porphyritic granite was observed lying in the upper gravel-pit adjoining.

B (2). The area covered by the Lower Lias clay defines pretty accurately the boundary of the purple-coloured Boulder-clay in the north-east part of Warwickshire. The deposit is irregularly distributed over the surface of the high ground, whence it descends into portions of the valleys, attaining a considerable thickness in both situations.

B (2), F. After leaving the district of the Lias, and passing downwards to the region of the New Red Marls, we find a change in the composition and colour of the unstratified beds. Although I have separated them into two classes B (2) and F, — their characteristic features are so much alike, that I believe they both belong to the " General Quartzose Drift " of Strickland, or " Northern Drift " of Sir R. I. Murchison. The composition of the beds in the district in question has been described in general terms by Strickland. With regard to the occurrence of flints in them, my observations have led me to conclude that these are distributed through the beds in a persistent manner, although the relative proportion of them to the other components is small. Seams of carbonaceous matter and lumps of drifted coal are not unfrequently met with. In a sand-pit on the north-west side of Cracombe Hill I observed a peculiarly contorted arrangement of the beds. Narrow seams of finely laminated sand of a red colour were seen interbedded between layers of fine sandy gravel. On the right-hand side of the section appeared a thin seam of light-coloured marl following a curved direction. The longer axes of the pebbles and the sand-seams were inclined at an angle of about 70° N.W. At Sheriff's Lench and in the quartzose flinty gravel at Bredon I have observed somewhat similar phenomena. The liver-coloured and greyish pebbles of quartzite, so abundant in these beds, are commonly found broken in half, having their fractured edges slightly rounded ; their surfaces exhibit small hollows of a lightish colour, due probably to disintegration. The pebbles