1870. | DE RANCE—GLACIAL PHENOMENA. 651 
‘Edinburgh Philosophical Magazine,’ with which I was unfortu- 
nately unacquainted when I wrote. 
General Observations.—Two beds of Boulder-clay have been 
shown to occur over the whole of Western Lancashire, divided by a 
stratum of sand and gravel, often 60 feet thick, but sometimes thin- 
ning out so as to cause the two clays to coalesce. The thinning 
out appears to have been caused, as pointed out by Mr. Hull, by 
the denudation of the Middle Drift’ before the deposition of the 
Upper Boulder-clay, which thus unconformably overlaps the Middle 
and Lower Drifts. This denudation appears to have been partly ma- 
rine, and partly possibly subaerial. Mr. Binney, however, still appears 
to consider the two clays to be one deposit, with an occasionally 
wedge-shaped mass of sand and gravel intercalated in its midst, 
absent in places merely because it was not. universally deposited over 
the country. Thus, in his admirable description of the Blackpool 
cliffs of Glacial Drift, he gives the following classification :— 
brown clay, mixed wath stones ci4+ le os tee 4to 5 
2. Brownish-coloured clay, used for “ Till,” containing 
much lime, often replaced by stratified beds of 
SUA RAU OGRA UCL wert Nea el hale crenata nes 80 
3. Silt, lightish brown, with a few pebbles ........ 2 
4, Brownish-coloured Till, with stones to the extent of 
one-third of the mass exposed .............. 30 
In the section accompanying this paper (from Rossall to Black- 
pool), he represents two masses of sand and gravel disconnected 
from each other, the northern mass stopping abruptly near the top 
of the cliff under the Boulder-clay, and the southern mass near 
the “‘ Royal Edward” (now Bailey’s Hotel) also stopping abruptly 
in the midst of the Boulder-clay occurring all around it. I have 
now, from time to time, for more than a year, examined this sec- 
tion after heavy storms, and especially when the embankment was 
in great measure washed away in the spring of last year. I then 
became convinced that the thin bed of sand under Bailey’s Hotel 
can be continuously traced behind the embankment under the Im- 
perial Hotel until it connects itself with the great mass of sand, 
with occasional beds of gravel, which, commencing at the little 
brook called the Gynn, extends to Bispham. Between these two 
points the Middle Drift is about 60 feet thick, its base being, for the 
most part, but little above the base of the cliff; but here and there 
the Lower Boulder-clay rises in the form of a boss or dome. The 
chief of these occurs near Bispham, where the clay is densely 
packed with stones, nearly all of which are scratched. The clay 
forms a low arch, the crown of which is about 22 feet above the 
base of the cliff; it isseparated from the overlying sand by a bed of 
silt or sandy clay, which is also arched, dipping under the beach at 
either end, and about 14 inches in thickness. It is the third bed of 
Mr. Binney’s Table and Sections. He has also described an arch of 
silt covering a boss of Lower Boulder-clay under Bailey’s Hotel ;. 
