and F7-eshwaier Deposits of Eastern Norfolk. 365 



tween the marine craa: and those beds from which freshwater 

 shells have been procured. 



Ci'ag at Runton. — In the patches of marine crag below the 

 freshwater at Runton, the followino; shells have been found 

 and presented to me by Mr. Simons: 1. Fusus striatus. 

 2. Scalaria grcenlandica. 3. Littorina littorea. 4. Natica 

 helicoides, Johnston, (see fig. 12.). 5. Tellma obliqua. 6. T. 

 solidula. 7. Cardium edule, and a fragment of a Helix. 



The shell which I have called 

 N. helicoides is identical with 

 No. 58, in my list of Norwich crag 

 shells published in the Mag. Nat. 

 Hist., vol. iii. new series, 1839, p. 

 313. I have given it there as a new 

 and extmct species, statmg, that it 

 resembled in shupePahidina solida. 

 Say. I afterwards learnt from Mr. Natica helicoides, Johnston ; 

 TT',J.,,„«J T? \ ^u ^ -i. u 1 I from the crag at Runton, near 



iiiuvvard l<orbes that it had been Cromer. 



found recent on our east coast in 



Berwick Bay, and published by Dr. Johnston in the Berwick 

 Transactions, 1835, under the name of A^. helicoides. That 

 gentleman has since sent me the recent shell, which is quite 

 identical with the fossil figured above. The species is remark- 

 able for departing from the normal form of the genus Natica. 

 It seems to have been much more abundant in the sea of the 

 Norwich crag than in our own sea at present. 



Cli^s bet'ween Cromer and Sherringham. — The drift near 

 Cromer and to the north of it includes a much larger quan- 

 tity of chalk rubble than to the southward, and huge frag- 

 ments of chalk itself are sometimes intercalated in a manner 

 which is very difficult of explanation. It is often no easy mat- 

 ter to decide whether the largest of the chalky masses associ- 

 ated with drift have been regenerated or not, in other words 

 whether they have been brought piecemeal or in mass into 

 their present position ; but there are some clear and unequi- 

 vocal exemplifications of both of these modes of transport. 

 Some of the enormous fragments of chalk which are inter- 

 stratified with drift have not only layers of undisturbed flints, 

 but also sandpipes in the middle of them, or cylindrical ca- 

 vities filled with sand and gravel, such as are found pene- 

 trating the chalk at various depths from the surface in the in- 

 terior of Norfolk. These pipes seem to me to imply that such 

 masses of chalk were once at or near the surface of emerged 

 land, but a hasty observer seeing such patches of sand or 

 pebbles in the middle of the chalk might suppose the whole 

 mass to have been broken up and then redeposited, whereas 



