and Freshwater Deposits of Eastern Norfolk, 
365 
Natica helicoides, Johnston ; 
from the crag at Runton, near 
Cromer. 
tween the marine crag and those beds from which freshwater 
shells have been procured. 
Crag at Runton, — In the patches of marine crag below the 
freshwater at Runton, the following 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. F'ellina obliqtia, 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 extinct species, stating, that it 
resembled in shapeP«Mz><7 solida,, 
Say. I afterwards learnt from Mr. 
Edward Forbes that it had been 
found recent on our east coast in 
Berwick Bay, and published by Dr. Johnston in the Berwick 
Transactions, 1835, under the name of N. helicoides. That 
gentleman has since sent me the recent shell, which is quite 
identical with the fossil figured above. The species is remark- 
able lor 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 owm sea at present. 
Clijfs between 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 
