Fisher — Roswell Hill Clay-pity Ely. 409 



And to clear away any possible a priori objection drawn from 

 the magnitude of the mass, I would beg to remind you that Chalk 

 boulders occ^r in the Norfolk drift so large that quarries and lime- 

 kilns are worked in them. 



The following is an extract from a letter by the Eev. 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 parishes. 

 It has been for years used for lime and a kiln is on the premises. 

 Mr. Prestwich as well as myself noticed a layer of sand beneath it. 

 ( Ohs. They evidently looked for proof that the mass was not in 

 situ, showing how nearly it simulated a natural bed of Chalk.) In 

 several places north of Cromer, from that place to Sherringham, are 

 large masses of bouldered Chalk, proved to be so by the underlying 

 beds. On the south side also, at Barton and Happisburgh, there 

 were some, but they have been all washed away. In North Walsham, 

 Worstead, and Witton, large bouldered masses have from time to time 

 been worked, either for making lime or for top-dressing. A tooth 

 of Elephas primigeyiius was obtained by me at Witton in connection 

 with one. The large masses at Trimmingham, figured in Lyell's 

 Elements, are part of the fundamental Chalk, remnants of an upper 

 bed, from which the gravel of East Norfolk is derived." 



These instances show that the mere size of the mass of Cretaceous 

 strata at Ely is no argument against its having been carried thither 

 by ice, and the fact of its consisting of portions of two distinct beds 

 is a mere accident. 



There is nothing singular in so large a block of Chalk becoming 

 detached from its parent bed. For some miles along the coast, west 

 of Lyme Regis, landslips on a large scale have occurred, where masses 

 of Chalk and Green-sand, fully equalling in bulk the mass at Ely, 

 have fallen from the cliff. The last of these falls occurred not many 

 years ago. The lower portion of the disengaged strata consisted of 

 a sandy loam, the upper of Chalk. 



If we could conceive such circumstances under a glacial climate 

 that this mass could have been floated away, as for instance by snow 

 blowing over the top of the cliff and being frozen on to its face, we 

 should have all the conditions necessary for the deposition of an im- 

 mense boulder like that at Ely ; and on this supposition we mio-ht 

 expect it to have been dropped in a similar position of verticality, 

 for the float would have been attached to its edge. But without 

 making such a supposition, knowing how frequently icebero-s roll 

 over in the process of thawing, we may expect them to drop their 

 loads indifferently in all positions. 



I was originally disposed to think this mass a boulder, when I 

 saw it ten years ago. It was then much less exposed than it is at 



VOL. V. — NO. LI. 27 



