o3 
At any rate we may look at the chalk and clay near Ely as a 
single mass, and whatever accounts for the presence of one will 
equally account for the other. In short they are a large mass of 
eretaceous beds in a nearly vertical position, with boulder clay 
abutting upon them. The curved lines of junction as seen in 
the section are nothing more than the curves formed by the in- 
tersection of the surface of the workings with a nearly plane 
surface of junction between the chalk and the gault, dipping at 
a very high angle towards the north. 
Now there are two ways of accounting for the presence of 
this cretaceous mass. It is either brought up by a fault with 
reference to the boulder clay, but down with reference to the 
Kammeridge, or else it isa huge boulder, forming as much an 
integral part of the boulder clay as any block of oolite or flint 
which it contains. 
Mr Seeley appears to consider its presence best accounted 
for by a fault, but I think I shall be able to show that the other 
is the more probable explanation. 
And to clear away any possible a priorz objection drawn from 
the magnitude of the mass, I would beg to remind you that chalk 
boulders occur in the Norfolk drift so large that quarries and 
limekilns are worked in them. 
Extract from a letter by the Rev. John Gunn :— 
IRSTEAD, 
Dec. 10, 1866. 
“ Of the masses of chalk you enquire about, that near Castle 
Rising is now exhausted and used for top-dressing land. Only 
the large flints remain to prove that the mass belonged to the 
upper chalk which does not remain anywhere in that part of 
West Norfolk. ; 
“The largest detached mass I know of is between Cromer 
and Overstrand. I do not know the precise boundary of the 
