and the workmen had the appearance of flint flakes and implements explained to them by showing them specimens from other localities; rewards were also offered, to induce them to preserve any similar implements they might find during the excavations; but nothing of the sort was found in any of the pits. .... Passing westwards along the Uxbridge road, I found that some excavations were being made for the foundations of houses in the high-terrace gravel in Churchfield, east of the village of Acton. The lay of the ground in this place corresponds so closely with that of the implement-bearing gravels of the Somme and the Ouse, that I determined to watch the diggings closely, and repeated my visits to this spot almost every day for some months. [Pitt Rivers 1872: 453]
Pitt Rivers describes some finds of implements at East Acton villas and Alfred Road:
In Alfred Road, .... a small oval-shaped implement was found at a depth of 7 feet, resting on the actual surface of the London Clay ... The surface of this implement is very much rolled; I saw it a few moments after it was taken out, and I have preserved a piece of the London Clay taken from immediately below the spot. [Pitt Rivers 1872: 454]
and
Section G, at the top of Lorne Terrace, surface 83 feet, furnished the largest and best-formed implement discovered in this place. It is triangular, 8 inches long and 4 inches at the base; the natural surface of the flint is left at the butt end. It was found beneath several deposits of sand, gravel, and brick-earth, at a depth of 13 feet 6 inches from the surface. The upper surface of the London Clay was here seen to slope gently upward towards the north.
Section H. ..., shows the position of a number of flakes remarkable 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...; the posiition 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 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 ... 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 are exhibited). [Pitt Rivers, 1872: 456-7]
That is, Pitt Rivers brought some of the latter flakes to the meeting of the Geological Society where he read the paper for other members to see.
Pitt Rivers' survey area was quite large, in the next paragraph he mentions two tools that he found at Ealing Dean, two miles west of Acton, where a sewer was being constructed, later he mentions an area north of the Great Western Railway between Hanwell and Ealing (circa W13) and later an area about a mile and a half south of the first area near Churchfield, in an area between Acton Green and the Brentford Road [Pitt Rivers, 1872: 457, 458 ] His work also spread to the other side of the River Thames, to Wandsworth and Battersea Rise. [Pitt Rivers, 1872: 462]
Although Pitt Rivers was reliant upon his workmen informants, he seems to have been suspicious of them:
I was aware that there is a natural tendency amongst workmen to say that what they find is "right down at the very bottom" ... 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. [[Pitt Rivers, 1872: 457]
and
'Shortly after I commenced my visits to Acton, some rather ingenious attempts at forgery were foisted upon me, by chipping, varnishing, and, when dry, burying the flints thus prepared in the ground; but upon my pointing out at once to the workmen the precise manner in which each chip had been made, the recent character of the whole, the varnishing, the burying, and the economy of time and labour which might be effected by looking for the real implements when at work in the gravel, instead of wasting so much time over very imperfect imitations, they at once saw that it was impossible to deceive me, and I never afterwards found any attempt made to impose upon me. [Pitt Rivers, 1872: 458-9]
Apparently, Pitt Rivers and his workmen discovered a total of 22 implements and 160 flakes in the gravels at Acton and Ealing.
When Pitt Rivers read his paper to the meeting it was discussed by the members of the Geological Society who were present, including Mr Prestwich, Mr Evans (presumably Sir John Evans), Mr Flower (John Wickham Flower), Mr Busk and Professor Ramsay amongst others.
Note that although the records and biographies suggest that Pitt Rivers only worked round this area in 1869, there are a number of stone tools in the founding collection that are dated 1870 and 1871, he may either have carried on collecting stone tools as they were found, or he may have been passed them by a third party who knew of his interests, only items which seem clearly to relate to his paper have been discussed.
Find out more about the artefacts collected in Acton in 1869
Further Reading
http://en.wikipedia.org/wiki/Acton%2C_London
Pitt Rivers/ Lane Fox A.H. 1869 ‘On the Discovery of Flint Implements of Palaeolithic type in the gravel of the Thames Valley at Acton and Ealing’ Report of the British Association of the Advancement of Science [1869] 130-2
Pitt Rivers/ Lane Fox A.H. 1872 ‘On the discovery of Palaeolithic Implements, in connection with Elephas primigenius, in the gravels of the Thames Valley at Acton’ Journal of the Geological Society of London 28 [1872] 449-66