Page:Quarterly Journal of the Geological Society of London, vol. 28.djvu/553

1872.] for the sharpness of their edges, all the others being blunted by contact with the other stones of the gravel. These were found in seams of white sandy clay, 9 feet from the surface, beneath deposits of gravel and brick-earth: the position of these flakes is of interest, on account of the edges of the whole of them being as sharp as when they were flaked off from their cores, proving that, whilst the majority of the flakes and implements in this place were carried down by the water, and rolled in the gravel, especially that referred to in Section B, these, on the contrary, must have been flaked off on the spot, and dropped into the soft sandy bottom of the river in this place, after which the deposits of gravel and brick-earth must have accumulated over them. Although I did not myself discover these flakes in situ, I satisfied myself of the correctness of the accounts given me by finding some of these sharp flakes in the excavated material with the soft, sandy, clay-deposit adhering to them. [Some of these were exhibited.]

At Mill Hill, on the other side of the ravine of the Acton brook, about half a mile to the westward, a very large flake was found in a seam of sand, 7 feet 3 inches from the surface, beneath stratified gravel interspersed with seams of yellow sand, the surface being 80 feet above the datum.

At Ealing Dean, two miles to the westward of Acton, in some gravel excavated for the construction of a sewer, the surface being 92 feet above the datum, I found two implements, one of which is an exceedingly fine specimen; it has a slender point, and is 5 inches in length and 2{{smaller|$3⁄4$ broad, rounded at the butt-end. It is worthy of notice that, although I watched this place for some months, examining the cuttings in the gravel for the foundations of houses along the very same piece of road in which the implements were found, and although the workmen were expressly instructed what to look for, I never afterwards found so much as a single flake in this gravel. Upon inquiry, I found that the cuttings for the sewer were carried much deeper than the foundations of the houses; and the implements must therefore have been brought up from the very bottom of the gravel bed, thus confirming in a remarkable manner the experience derived not only from Acton, but from other similar deposits of drift-gravel, in which the implements are all found to lie almost invariably at the bottom of the gravel. I was particular in examining into this question, because I am aware that there is a natural tendency amongst workmen to say that what they find is "right down at the very bottom;" as, however, the cuttings at Acton were made in steps, and the several levels were in most cases excavated upon different days, it was easy to test the truth of their statements; and I found that in every instance the implements came out of the lowest stratum of the gravel. Here the largest flint stones lie, and with them the implements, mostly of the dimensions of the larger stones, so that it was common for the more experienced workmen to say that they should find no implements till they got down into the coarse gravel; the smaller flakes, however, were not so invariably at the bottom.

To the north of the Great Western Railway, between Hanwell and