261 
or in the sea — such as is found in masses at the mouth of the 
Mississippi and other large rivers. Indeed, it seems hardly safe 
to infer submergence on the simple evidence of the bed itself, 
unless you find the stools of the trees in situ , with their roots 
penetrating the underlying soil, and also find the bed passing 
beneath low-water mark. 
De la Beche, Henwood, and others have described the sub- 
merged forests along the southern coasts. In the Quart. Journ. 
Geol. Soc.* is a paper by Mr. Smith, of Jordan-hill, “ On recent 
depressions in the land,” in which he gives many legends and 
traditions probably founded on the obvious marks of changes 
of level along the coasts of the channel. He also records, on 
the authority of Capt. White, R.N., who, under the direction 
of the Admiralty, surveyed parts of the coast, that there were 
stumps of trees in situ not less than 60 feet below high-water 
in the Bay of Cancale, where the tide rises and falls about 
50 feet. 
There are many sources of error when we regard the evi- 
dence of submergence or of elevation, but when we have got 
rid of these there still remain plenty of well-authenticated 
cases of raised beaches and submerged forests to show that 
movements always have been going on, now up, now down, 
and therefore we must allow for the acceleration or retarda- 
tion in the rate of waste in all the valleys within the area so 
affected. As we trace these movements north to the borders 
of the mountains, we find evidence of greater sinking and 
greater elevation, perhaps because we have there the moun- 
tains as our gauge on which are marked the various depths by 
nature in terraces and banks of shells, but more as I believe 
because along the mountain chains the movements were always 
greater. This point is clear, that after Glacial times the land 
went down in places, probably at least 2,000 feet below the 
sea, and then the ice was lifted and melted off. After that the 
land began to rise, and by this time the sea was warmer and 
the forms of life less arctic, as seen at Moel Tryfaen, Maccles- 
field, and later on the Vale of Clwyd and Kelsea Hill. And 
now destruction of all softer beds went on, whether by the sea 
eating along the coast, or streams tearing the mountain-sides 
and flanks of hills, or larger rivers undermining as they flowed 
along banks of old glacial drift. In all the earlier deposits 
resulting from these agencies we see the great preponderance 
of glacial drift used up by denudation, as compared with the 
proportion found in the later beds, when the covering of drift 
* Vol. iii. (1847), p. 234. 
T 
VOL. XIV. 
