s north of the Wrekin; also to a boulder on the summit of the
eminence (774 feet above sea-level), "probably the same as that noticed
many years ago by Mr. Darwin." In a later paper, "On the Correlation
of the Drift-Deposits of the North-West of England with those of the
Midland and Eastern Counties" ("Quart. Journ. Geol. Soc." Volume XXXVI.,
page 178, 1880) Mackintosh mentions a letter received from Darwin, "who
was the first to elucidate the boulder-transporting agency of floating
ice," containing an account of the great Ashley Heath boulder, which
he was the first to discover and expose,...so as to find that the block
rested on fragments of New Red Sandstone, one of which was split into
two and deeply scored...The facts mentioned in the letter from Mr.
Darwin would seem to show that the boulder must have fallen through
water from floating ice with a force sufficient to split the underlying
lump of sandstone, but not sufficient to crush it.") which I had
undermined on the summit of Ashley Heath, 720 (?) feet above the sea,
rested on clean blocks of the underlying red sandstone. I was also
greatly interested by your long discussion on the Loss (514/4. For an
account of the Loss of German geologists--"a fine-grained, more or less
homogeneous, consistent, non-plastic loam, consisting of an intimate
admixture of clay and carbonate of lime," see J. Geikie, loc. cit., page
144 et seq.); but I do not feel satisfied that all has been made
out about it. I saw much brick-earth near Southampton in some manner
connected with the angular gravel, but had not strength enough to
make out relations. It might be worth your while to bear in mind the
possibility of fine sediment washed over and interstratified with thick
beds of frozen snow, and therefore ultimately dropped irrespective of
the present contour of the country.

I remember as a boy that it was said that the floods of the Severn were
more muddy when the floods were caused by melting snow than from the
heaviest rains; but why this should be I cannot see.

Another subject has interested me much--viz. the sliding and travelling
of angular debris. Ever since seeing the "streams of stones" at the
Falkland Islands (514/5. "Geological Observations on South America"
(1846), page 19 et seq.), I have felt uneasy in my mind on this subject.
I wish Mr. Kerr's notion could be fully elucidated about frozen snow.
Some one ought to observe the movements of the fields of snow which
supply t