148 O. Fisher—On the Cromer Cliffs. 
Ihave thought that glacial geology in a mountainous country, 
like Scotland or Wales, is a different matter from the like subject 
treated in connexion with obviously marine beds, as many of the 
beds in Norfolk are proved to be by the fossils they contain. It is 
therefore extremely gratifying to study a paper by a writer who, 
like Mr. Clement Reid, has made the latter branch of glacial geology 
his special study. For one is assured that he is writing on what he 
has intimate acquaintance with. On that account he will be the 
better able to explain any difficulties which his paper suggests, and 
also to appreciate any clue, which another observer may have de- 
tected, but which has since probably been obliterated. 
Iam now alluding to certain cavities, which I saw, many years 
ago, in the eastern flank of the curious chalk bluff at Trimmingham. 
I mentioned these in the paper that I read before the British 
Association at Norwich, in 1868, to which Mr. Reid has so cour- 
teously referred. And I am very pleased that he thinks I struck 
the right key for explaining the formation of this bluff. JI think 
these cavities ought to throw some light upon the mode of accumu- 
lation of the Boulder-clay which envelopes the bluff; for when I saw 
them, they had been apparently exposed to view by its removal. 
They must therefore have been formed and filled in the interval 
between the formation of the bluff and its envelopment in Boulder- 
clay. But there remains the difficulty, that the glacial deposits 
which rest on the top of the bluff were evidently lifted up along 
with it. Ido not venture to explain the matter; but I wish to draw 
Mr. Reid’s attention to it. 
a Chalky Clay. 
6 Sand. 
e Boulder-clay. 
d Sand. : 
e ** Laminated beds.” 
f Chalk with cavities. 
Fic. 1.—Eastern face of Trimmingham Chalk Bluff with caverns, as seen 
July 8, 1868. 
