58 Clement Reid—Glacial Deposits of Cromer. 
and the ice of Greenland advance and retreat short distances without 
any very marked cause.! As yet no fossils are known from this 
horizon, so we are left in doubt as to whether it is marine or fresh- 
water, but the character of the deposit seems lacustrine. 
Above these ‘intermediate beds” there occurs a second deposit of 
unstratified till, clearly distinguishable from the first till by the 
abundance of soft upper chalk that it contains. This bed is so like 
the Great Chalky Boulder-clay, that at Hasbro’, where it caps the 
cliff, it has often been mistaken for that deposit, and it is quite possible 
that some of the Boulder-clays further south commonly referred to 
the Chalky Boulder-clay may, in fact, belong to the ‘“‘ Second Till.” 
Though this “Second Till” seems so different from the first, closer 
examination shows that this difference is more apparent than real, 
consisting only of a change in the relative proportion of the ingre- 
dients. The first till was above described as ‘‘a mixture of about 
equal parts of shelly sand and clay”; the second till is nearly half 
soft chalk and half clay, with a little shelly sand, the other materials 
being the same as in the older deposit. 
At Hasbro’ the intermediate beds under the second till are 
crumpled in the same manner as the pre-glacial beds; but from the 
difficulty of the examination, I have been unable to take the direction 
of the folding. There is, however, no reason for considering that 
the direction of the flow had changed, for the tills only differ in the 
shelly sand being replaced by chalk—a change accounted for on the 
supposition that the first advance of the ice ploughed out most of 
the sand-banks, leaving the second ice only bare chalk to grind up. 
Though these tills are unstratified, they often show a “streak” lke 
that of doughy bread or pie crust. This, I believe, has nothing to do 
with a sedimentary origin, but is simply formed like the flakes in pie 
crust by a sliding pressure from above. Special care is needed in 
the examination of Boulder-clays to avoid being misled by this ap- 
pearance, for ] have sometimes seen it so strongly developed as to be 
a fair example of slaty cleavage, though at first sight no one would 
have hesitated to point to it as evidence of ordinary bedding. 
Sands.—Ahove the second till, and resting on an eroded surface of 
that deposit, or in one or two places on the Pliocene beds, there are 
fine false-bedded sands, always chalky and carbonaceous, and of a 
peculiar pale tint easily recognizable. At Mundesley these sands 
are about 40 feet thick, and they can be traced from Hasbro’ to 
Trimmingham, but at the latter place they are lost. No fauna is yet 
known from them. 
Contorted Drift_—Above the sands we find the irregularly stratified 
and more or less contorted deposit known as the Contorted Drift. 
This, I think, is most likely a true sedimentary Boulder-clay, though 
from the great difficulty of distinguishing between true bedding and 
‘‘streak” produced by pressure, and also the fragmentary character of 
the shells, I cannot feel certain. In a few places it shows small con: 
tortions, such as might be formed by coast-ice, which appear not to 
* Ordinary variations in temperature and in the rate of condensation from year to 
year, are fully sufficient to explain this well-known phenomenon.—Enir. Gzou. Mac. 
