34-8 Mr. Lyell on the Boulder Formation^ 
I have seen no kind of deposit now in progress precisely sh 
milar in character to the till, except one, namely, the terminal 
moraines of glaciers. These, as Charpentier has justly re- 
marked, are entirely devoid of stratification, because the ac- 
cumulation has taken place without the influence of any cur- 
rents of water by which the materials would be sorted and 
arranged according to their relative weight and size. Year 
after year the ice, as it melts at the extremity of a glacier, adds 
fresh mud, together with fine and coarse sand, gravel, and 
huge blocks, to the moraine, all being carried to the same 
distance^, without the least reference to the volume or specific 
gravity of the component particles or masses. 
There can be no doubt that similar accumulations must 
take place in those parts of every sea, where drift ice, into 
which mud, sand, and blocks have been frozen, melts in still 
w'ater, and allows the denser matter to fall tranquilly to the 
bottom. The occasional intercalation of a layer of stratified 
matter in the till, or the superposition or juxtaposition of the 
same, may be explained by the existence or non-existence of 
currents, during the melting of the ice, w’hether successively 
in the same place or simultaneously in different places. 
It is, I believe, a common error of those who are not un- 
willing to admit the agency of ice in reference to the larger 
fragments of transported rock, to forget that what carries 
heavier masses from place to place must unavoidably convey 
a much larger volume of lighter and finer materials. 
Having offered these preliminary remarks, I shall proceed 
to describe in detail some of the appearances which present 
themselves to one who travels along the coast from Has- 
borough to Weybourne. The section of the mud cliffs begins 
at the more southern of the two lighthouses about a mile and 
a half south of Hasborough. The cliffs here, w’^hich are be- 
tween sixteen and tw’enty feet in height, are composed generally 
of a mass of blue clay covered with yellow sand, the clay and 
sand being both stratified in some places wnth great regularity, 
but in others the clay or mud is quite unstratified. Included 
in this till I found pieces of unrounded white chalk, angular 
chalk flints, fragments of argillaceous limestone (lias ?), blocks 
of dark greenstone, and other rocks. There are also inter- 
spersed pieces of shells, apparently belonging to Cyprina, Car- 
dium^ Mactra, and Tellina, such as might have been derived 
from the denudation of the Norwich ‘crag. At some points 
where stratified clay reposes on the till, the surface of the latter 
is very uneven, and was evidently so when the superior de- 
posit was thrown down upon it. Examples of intercalation ol 
* Ann. dcs Mines, tom. viii. 
