302 Proceedings of Societies. 
appearances at two different levels, there were occasionally intermediate 
levels and deposits of gravel even higher than St Acheul. It would be 
difficult to suppose that it was always strictly at two levels that these 
gravel beds occurred; but there was a prevalence of them at a higher 
level and at a lower level, that lower level being necessarily higher than 
that of the present Somme. He therefore had no objection to suppose 
that, after the country had been for some time in that state at which the 
gravels and sand were formed, there was some movement or elevation 
during which the river was able to cut the land down, and then form the 
inferior or lower level gravels ; and it did not appear to him that if that 
view were adopted it made any very essential difference. Professor Phillips 
thought it made this difference—that the time would be much shorter if 
there were such a movement, and certainly it would; but he could hardly 
conceive any movement would enable the river to destroy so much older 
strata, as it must have destroyed to produce such reiterated river beds. 
If Professor Phillips could bring evidence of such a movement it would be 
a great assistance; but that would not alter at all any views at which Mr 
Prestwich and himself had arrived with regard to the manner in which the 
higher and the lower levels were formed. There were other proofs besides 
the fresh-water shells and the absence of marine animals of the fluviatile 
origin of the St Acheul gravels. The gravel in the Somme, the Seine, 
and their tributaries was composed of rock that belonged to the hydro- 
graphical beds of those rivers. In addition there was the presence of 
fluviatile shells as well as of land animals. He could receive the views 
of Mr Prestwich that these gravels were remains of an old river; and 
he could admit that there might have been such a movement as Professor 
Phillips had supposed. Mr Austen, in speaking of the Bedford section, 
had endeavoured to do away with the argument in favour of the antiquity 
of man by supposing that the remains of extinct lions, rhinoceroses, and 
other animals, taken out of the gravel, which was about thirty feet above 
the level of the sea, were derived from an older gravel. He supposed 
some pre-existing formation, out of which the bones were taken, and then 
deposited in the present, so that that formation which contained the flint 
instruments would not be proof of the co-existence of man with those 
extinct mammalia, and that the mammalia existed before and were washed 
out into the beds containing the flint instruments. Such an objection 
might be made to almost every river bed, because rivers were constantly 
ploughing up their channels—doing and undoing. Therefore, if any animal 
remains had sunk in the channel, the chances were that they would be 
torn out again and rolled on before they got to their final resting-place. 
It was perfectly true that in some of our valleys, such as the Severn, the 
old drift containing distinct animals will be undermined, and occasionally 
bones in a state of integrity will be thrown down into the new river bed. 
There were such cases, and they were guarded with respect to them ; but as 
a general rule, if they found remains buried in gravel, the inference was 
that they were formed during that long period when that ancient growth was 
deposited, bed after bed, and sometimes partly destroyed and re-deposited. 
If a geologist wished to draw a contrary conclusion, he was bound to show, 
first of all where was the old formation out of which these extinct bones 
were derived. To make out his theory, he would be bound to show that 
such a formation was under the drift of that country ; which, however, 
was not the case. Under the circumstances, the hypothesis seemed a 
violent one, formed to get rid of a violent conclusion, to suppose that 
these bones had been derived from some other formation that existed in 
the neighbourhood, without a shadow of evidence of there having been 
such a one, and with all the existing evidence against it. He hoped the 
