570 Geological Society. 
Channel, thus separating Wales and Siluria on one side, from En- 
gland on the other. Having shown that the Welsh and Silurian 
mountains were partly raised at an earlier period, he points out the 
Abberley and Malvern Hills, as constituting the western side of a 
strait of the sea, the eastern shore of which was the Cotteswold Hills. 
He deduces the principal proof of the preexistence of this eastern 
coast from the observations of Mr. H. Strickland, which show the 
transport from the east and north-east of fluviatile and land shells 
mixed with the remains of extinct quadrupeds in banks of coarse 
gravel, following the drainage of the Avon near to where that river 
empties itself into the Severn; and he asserts, that the terrace-like 
deposits of Cropthorne are exactly those which would have been ac- 
cumulated at the mouth of a river, if the materials had been carried 
onwards beneath the waters of the adjoining strait of the sea, illus- 
trating his views by the analogies of other rivers and estuaries. He 
therefore presumes that the deposit of Cropthorne may have been 
coeval with that of the northern drift. After an explanation of the 
theories hitherto proposed to account for the transport of large boul- 
ders to distant points, the author states that the evidences in question 
seem to him to be subversive of the diluvial hypothesis which imagines 
that. the blocks were carried over the land, it being proved that here, 
at least, they were accumulated under the sea. He does not think we 
have yet been furnished with a full explanation of any method by 
which such blocks can have been transported to distances of 100 
miles: for supposing them to have been derived from the shores 
of Cumberland, and that they extended in a delta from thence, it 
would appear that assuming the slightest degree of inclination, viz. 
3°,—which could give adequate momentum to the ordinary power of 
running water acting upon these loose materials,—the southern part 
of the delta (even at a distance of 50 miles from Cumberland, ) must, 
as suggested by Mr. Lonsdale, have lain at the vast depth of i3,000 
feet beneath the sea, in which case all Wales would have been equally 
submerged ; though we have proof that the mountains of that country 
had risen to acertain height previous to the accumulation of the 
northern drift. It is further submitted that under the physical features 
of the region when this drift was formed, i, e. when a great arm and 
strait of the sea separated England from Wales, submarine currents 
alone could not have been powerful enough to propel these large 
blocks, though the question is one which ought to be more completely 
disposed of by those versed in the laws of dynamics. Mr. Murchison 
next takes into consideration the theory of the transport by ice. After 
allusion to the views of Esmarck, De l’Arrivi¢re, Haussman, &c., it is 
shown that Mr. Lyell has thrown great additional light on this subject 
by his observations on Sweden and the Alps, by which it really ap- 
pears that under certain limitations ‘ice floes” may have been “‘ vere 
cause” in the transport of large blocks, depositing them under seas 
and lakes at great distances from the source of their origin. In the 
Salopian case, however, though it is possible such means may also 
have been employed, there are many arguments which weaken the 
application of the hypothesis, such as the rounded and worn exterior 
