1870. | DE RANCE—-GLACIAL PHENOMENA. 64 
Co 
GuactaL Deposits or WesteRN CHESHIRE AND LANCASHIRE. 
Lower Boulder-clay.—This bed, in North Cheshire, between Liver- 
pool and Southport, and between that town and Preston, is a soft 
rather loose clay, of a reddish-brown colour, containing many erratic 
boulders and pebbles, nearly all of which are ice-scratched, but 
rounded by marine action. It occasionally contains seams of sand 
and beds of marl, the latter being much used for marling the moss 
lands near Halsall, Crosby, Formby, and Southport. 
When the Lower and Upper Boulder-clays are seen in the same 
section in the districts mentioned above, as at Kgremont, in Wirral, 
and near Preston, the two clays are found to be apparently identical, 
both as regards physical aspect and the character of the included frag- 
ments. But in the Lower Boulder-clay of Blackpool, and to a greater 
extent in that of the Furness district, known as “ pinel,” a slight 
change of character takes place: the stones are more closely packed, 
each individual stone is scratched in every possible direction, and the 
percentage of granites and Lake-district Silurian erratics increases. 
These clays lie in boss-shaped masses beneath the Middle-drift sand 
and gravel, as if shot down in the water by a moving body from 
above; the pebbles in the clay, though so intensely scratched, are 
nearly all waterworn; and fragments of the rocks beneath the drift 
at Blackpool are absolutely never found. It therefore appears pro- 
bable that a fringe of coast-ice skirted the foot of the Lake moun- 
tains, which, lifted daily by the tides of the glacial sea, scratched the 
pebbles of the beach (formed by the sea before the coast-ice came 
into existence), in every possible direction, and that these, when the 
ice was carried out into the more open sea by tidal currents, were 
deposited in the tumultuous heaps of packed silt which we observe in 
various parts of the Lancashire lowlands. I may here mention that 
I found shells of the species of Tellina balthica and Turritella com- 
munis in tolerably good condition in the Lower Boulder-clay of the 
Blackpool section. 
In a railway-cutting made last year between Chorley and Black- 
burn, the Upper Boulder-clay and Middle Drift were seen resting on 
a stiff clay of a bluish-black colour, containing rather angular blocks 
of comparatively local origin, the clay being of such extreme hard- 
ness as to seriously affect the cost of the work, damaging the 
tools of the men, and withstanding the action of blasting. Since 
examining this section, to which I have had the pleasure of directing 
the attention of Mr. Eecles, F.G.S., and my colleague Mr. Tiddeman, 
F.G.8., I have found other examples of this peculiar type of Lower 
Boulder-clay ; and in some cases the ordinary marie Lower Boulder- 
clay is seen resting on an eroded surface of the stiff blue clay beneath, 
which I believe to have been formed by land-ice, probably in the 
form of an ice-sheet. I have never yet found in it either Lake-dis- 
trict erratics, granite boulders, or marine shells; and from a careful 
examination of the drift-deposits of the Lake-district, I believe this 
terrestrial Lower Boulder-clay ” to have been formed contempora- 
neously with the Lower Moraine Drift of that area, and that both are 
in great measure older deposits than the marine Lower Boulder-clay. 
