Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/313

1870. LLOYD AVON AND SEVERN VALLEYS. 205 A (1). Quartzose flinty gravel and sand (usually stratified). "General Flinty Drift " of Strickland.

B (2). Boulder-clay. A stiff, compact mass of sandy unstratified clay or earth, varying from a slaty blue to a purple colour, full of grooved and striated boulders of blue Lias limestone, white Chalk, and white Lias limestone, smoothed and polished pebbles of quartzite, showing fine striae on their surfaces, scratched subangular flints, and subangular blocks of syenite. In places there are thin seams and lenticular masses of quartzose sand imbedded in it.

B (2). A light-red, sandy, unstratified clay, compact and hard, containing quartzose pebbles and a few boulders, which occasionally exhibit traces of glacial action. In places the colour of the clay changes to a dark brown or chocolate tint.

C (3). Laminated clay of brown and green colours.

D (4). Laminated sand of a light red colour.

E (5). Clean, quartzose flinty gravel and sharp sand, containing gryphites much water- worn, and other derivative fossils (unstratified).

F. " General quartzose Drift " of Strickland, or " Northern Drift " of Sir R. I. Murchison. It consists, as far as I have been able to ascertain, of a red compact loam, and light-red quartzose sand, which contain quartzite pebbles and fragments of other rocks (mainly unstratified), viz. of white quartz, felstone, flints, &c.

Lower Series, ranging from 300 feet to 50 feet above the level of the sea: —

G. "General Flinty Drift" of Strickland. Beds of quartzose flinty gravel, generally unstratified, but occasionally showing a stratified arrangement in the lowest and uppermost beds.

H. " Local Drift " of Strickland, principally composed of detritus from the Oolitic rocks in its immediate vicinity, with a small proportion of quartzose pebbles, sand, and flints. The beds are stratified, and contain in places marine shells and mammalian remains.

Freshwater Deposits, ranging from about 290 feet near Rugby to somewhat near 30 feet above the level of the sea : —

Quartzose flinty gravel and sand, with occasional seams of clay. Light-red loam or brick-earth. Peat. Modern alluvium.

Land and freshwater shells and mammalian remains.

The above classification may appear to many needlessly detailed ; but I have adopted it after a good deal of consideration, as being one which, I think, is best adapted for excluding all theoretical assumptions regarding the relative connexion and sequence in point of time of the different classes into which I have divided the drifted deposits. In some cases the apparent absence of certain beds and the non-occurrence of marine shells and mammalian remains rest entirely on negative evidence, which future investigations may modify.

The late Professor Strickland divided what he called the marine