Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/303

1870.] WILSON — RUGBY SURFACE-DEPOSITS. 195 in the Ballast-pits. The cliff to the west exposes a fine section of the prevailing flinty drift overlying this sand. The edge of a terrace visible there is the same steep slope of Lias that was spoken of above. Masses of clay still lie about the ballast-pits. These formerly overlay the sand in detached spots. They are re-formations of Lias containing pebbles of lias, oolite, and chalk, with many flints and much quartzite ; some of the pebbles are striated. There was one heap of clay, a yard or so across, which yielded totally different specimens, and perplexed me much. I found afterwards that it had been brought for some reason from beyond Blisworth.

The sand here frequently exhibits diagonal stratification ; it contains small pebbles of flint, oolite, chalk, quartzite, and rolled Lias fossils. I have been informed that Mr. Searles Wood found Ostrea edulis here. Many of my pupils and I have spent hours here; and no shells or bones have ever been discovered by us, or noticed by any workmen, as far as I can ascertain.

From Rugby to Lowmorton there is generally 13 feet of gravel lying on clayey sand. Towards the northern edge of the plateau the gravel thins out ; and here a cutting of the London and North- western offers a magnificent section of the clays below the gravel and sand. The cutting is 50 feet in depth, and exposes a re-formation of Lias clay containing scratched stones. I have met with well-striated blocks of liassic limestone, of chalk, and flint. The clay is wholly unstratified, very soft and wet. The whole depth, except a few feet of gravel and sand at the top, appears to be of the same nature.

The deposit disappears before we come to the station, which rests on Lias. Higher up the slope of the hill is found a bed of sand which rests on the Lias, and extends up to the gas-works, where the gravel begins.

We now come to Rugby itself, which is on an arm of the plateau at first described. It illustrates very well the singular varieties in the distribution of the sand and gravel. Along the Hillmorton road is gravel, varying in depth from 7 to 13 feet, generally mixed with sand. The School-close is of the same nature ; so also is the eastern side of the town down to the George Hotel, where, however, the gravel is thin, and water is obtained from a well 60 feet deep, reaching the rock. In the slope towards the station the gravel becomes thinner. Towards the west of the town we find sand. Billington's is on sand 23 feet thick, St. Matthew's church on sand 20 feet thick ; by the side of the road to Newbold the hill is capped with deep sands, the lower part of which is saturated with water. Generally on the south of the Bilton road there is sand ; but at several houses on the north there are gravel and clay. There are many curious varieties in the town within a few yards of one another.

Continuing on the edge of the plateau we meet with a sand-pit on the way to Newbold (fig. 1). Much of the sand is now removed. There used to be exposed a face of sand of precisely the same character as that at Hillmorton — sugary, dirty, stratified partially, containing few (if any) pebbles, and marked with a few black scams. It was covered with a foot or two of the usual flinty drift. Lower down the slope