212 a Reviews— Glacial Lake-basins. 
Guide-book, when we see the following localities mentioned as having 
been walked over, and talked over, and written on, by good ob- 
servers, with open eyes and mutual good-will, giving and taking 
information on nearly all points of interest. Ellesmere, Llanhraiadr, 
the Breidden, Treflach, Meifod, Llangollen, Wroxeter, Glyn Ceiriog, 
Corndon Hill, Coed-y-gaer, Llansaintffraid, Wenlock, Chirk, and the 
Onney River, are amongst the places visited; and very pleasantly the 
trips are described, and often with humour. The Conversazione at 
Oswestry, last December, appears to have been very successful, and 
four or five good papers were then read, Mr. D. C. Davies’s popular 
account of the Drift-gravel of Oswestry (p. 102, &c.) being a good 
Geological contribution on that occasion. 
GLACIAL LAKE-BASINS. 
N the Philosophical Magazine for April, Prof. Ramsay, criticising 
Sir Charles Lyell’s remarks (in his ‘ Elements of Geology’) on 
the improbability of glaciers having scooped out large lake-basins, 
and on the probability of such hollows having been due to unequal 
movements of upheaval and subsidence, observes as follows :— 
1. Glacier-ice, widening out on the flats near the mouths of moun- 
tain-valleys, must be still pushed forward from behind, and its per- 
pendicular pressure on the ground must-be even greater than when 
it was on a slope: further, that, thinning at its outer margin, the 
waste of underlying matter by erosion would decrease towards what 
are now the mouths of the lake-basins.—2. Cup-shaped cavities are 
not worn by existing glaciers, because these are too petty, neither 
are they working over plains.—38. Local obstacles, in the course of a 
glacier or a river, may exist without being regarded as indestructible. 
—4. In the ‘Elements’ it is stated that lakes have been present in ail 
ages on the earth, and have been probably connected with upheavals 
and subsidences. Mr. Ramsay, asking for the evidences of Silurian, 
Devonian, Carboniferous, Permian, Triassic, Jurassic, and Cretaceous 
‘lakes,’ reminds us that several of the great conglomerates have 
been, or may be, likened to accumulations of ice-carried boulders,— 
such as the Lower Silurian Conglomerate of Wigtonshire, the Old 
Red Conglomerate, the Permian Breccia, the Rothliegende, &c. ;— 
and hence the agency of ice has not been lost sight of in connection 
with several geological epochs, as also special phenomena in the New 
Red Sandstone, Oolite, Chalk, and Miocene beds show; and it may 
therefore be referred to as having been an actual agent, as well as 
oscillatory crust-movements.—5. As to changes of level in valleys, 
converting parts of them into lakes, Prof. Ramsay argues, and shows 
by diagram, that to make the Lago Maggiore basin out of the old 
valley, the Central Alps must, before the hypothetical depression, 
have had a height of at least 30,000 feet! Also, that the glaciated 
undulations of North America cannot come under the hypothesis 
proposed; nor the Scandinavian and Swedish lakes; nor those of 
Cumberland, radiating from a centre; as well as others which do 
not conform to the proposed hypothesis of subterranean movements, 
