8 
on the quaternary period, the publication of which commenced 
in the Journal of the Geological Society, vol. xxiv. p. 103, 
and was continued in another paper, read May 6th, 1868. He 
advances the following important considerations : — 
1. The contour of the river-bed is such as could only have 
resulted from pluvial and fluvial action. 
2. After the heaviest rainfall in recent times there is not 
sufficient force of water to remove the vegetation so as 
to make any change in the present surface. 
3. There is therefore evidence of an enormous rainfall at the 
commencement and close of the second period. 
4. The materials show that floods brought down from the 
uplands heavy materials into the valleys. 
He adds : — “We are able to correlate the gravel of the river 
Aire, containing remains of hippopotami, with that of a number 
of rivers which appear to have risen in times of floods from 40 
to 80 feet above the present ordinary level, in that part of the 
second period which I term the ‘ pluvial period.’ ” All the 
observers now, in England, Belgium, and France concur in 
this. Then we have from Mr. Godwin-Austen’s researches in 
1850-1851 proofs of a vast river and delta system having 
existed in what is now the English Channel ; valleys occupying 
lines of depression in the line of existing rivers. The Somme, 
Seine, Thames, and others were valleys deepened by the great 
waters which occupied them. Beds of thick sand and silt were 
deposited by the action of vast floods. 
Now all these witnesses are experts of the first class, and 
write fx’om personal observation. Professor Dawson of 
Montreal, surely a competent witness from observation in both 
continents, says : — “ Slow and gradual movement, even if 
interrupted, could not have produced these sharply-defined 
terraces.” . . . “ When we stand by the grassy and tree-clad 
slopes of a river valley, and consider that they have been just 
as they are during all the centuries of history, it is difficult to 
resist the prejudice that they must always have been so, and 
that vast periods have been required for their excavation at the 
slow rate now observed ; but if we carry ourselves in imagi- 
nation to the time when a plain was raised out of the sea, bare 
and bald, and a river began to run in it, we at once see our 
error. The river so running, and beginning to cut a channel, 
must in a few years execute a stupendous work of erosion, 
almost diluvial in its character; but in the course of centuries 
its work becomes completed, a state of equilibrium succeeds, 
