1872.] LANE POX PALEOLITHIC IMPLEMENTS. 463 



an implement-bearing bed, which may turn out to be more produc- 

 tive hereafter. 



It may perhaps be expected that, in concluding this paper, I should 

 offer some conjectures of my own upon the unsettled question of the 

 age and mode of deposition of the river-gravels. I confess, however, 

 that the evidence which I have been able to collect does not appear 

 to me to warrant any fresh hypothesis. There are, however, one or 

 two fragments of archaeological evidence, proving the great antiquity 

 of the present bed of the Thames, which appear to me to have some 

 bearing on the question of the erosion of the Thames valley. Near 

 the town of Dorchester, at the junction of the Isis with the Thame 

 stream, are the ancient earthworks known as the Dorchester Dykes, 

 attention to which has unfortunately been drawn by their recent 

 destruction. These works consist of a nearly straight line of en- 

 trenchment in the bottom of the valley, running from the Isis on 

 one side to the Thame stream on the other, and enclosing the flat 

 salient promontory formed by the bend of the river. The flanks of 

 the entrenchment rest upon the stream on both sides. The require- 

 ments of defence demanded that they should rest upon the stream at 

 the time they were constructed ; there is evidence, therefore, that 

 the river must have run in its present course through the flat bot- 

 tom of the valley at that time. Nor could the conditions of its flow 

 have been materially different from what they are at present ; for the 

 river still floods a considerable portion of the enclosed space, and, if it 

 had habitually risen only a few feet higher, it would have rendered 

 the spot unsuitable as the site of an encampment. Now the associ- 

 ated relics prove that this entrenchment is the work of pre- Roman 

 times. All the works of art discovered within the area of the en- 

 trenchment are of flint or bronze ; and notwithstanding the existence 

 of a Roman station at Dorchester close by, nothing Roman is found 

 in this place. We have evidence, therefore that the Thames ran in 

 its present course, and under nearly the same conditions as at present, 

 ever since the bronze period of England ; and how much longer, we 

 cannot tell. But we have facts of the same kind within the district 

 represented upon our map *. Prom Ham to Petersham the river runs 

 northward, by Richmond to Kew, where it bends to the south, run- 

 ning to East Sheen, and then turns again northward, running by 

 Barnes to Hammersmith ; again turning to the south, it flows by 

 Putney and Wandsworth, turning north again, in the direction of 

 Battersea and Chelsea, thus making four bends between Ham and 

 Chelsea in the comparatively flat bottom of the vaUey. Throughout 

 the whole extent of this winding course, almost wherever the dredging 

 machine is put into operation, relics of the bronze and stone age are 

 turned up at various depths, extending to 10 feet below the existing 

 bed of the river. Mr. T. Layton, P.S.A., of Kew, to whom I am 

 indebted for information on this subject, has collected nearly one 

 hundred specimens of the prehistoric age, many of which are bronze 

 leaf-shaped swords, together with a number of stone and bronze celts 

 from diiferent parts of the river. 



* Eeferenee is here made to the larger map exhibited to the Meeting. 



