RED AND NORWICH CRAGS. 
129 
The Chalk itself in this neighbourhood has been eroded so as 
hardly to present any actual exposure in the low line of hills 
bordering the river. This pit has yielded a considerable number 
of species of mollusca, all of which, except the thin-shelled 
Thracia papyracea occur also in the Weybourn Crag of the const. 
One of the best sections of the Crag in the Bure Valley is that 
seen a little to the south-east of Coltishall Railway Station. 
Fig. 31. 
Section at Coltishall. 
(H. B. Woodward.) 
4. False-bedded pebble gravel and sand - - - 9 to 12 
2. Laminated clay with bed of sand (3j - - - 6 to 
1. False-bedded sand, gravel, and shell-beds (s) with 
seams of clay and clay-pebbles - » - 5 
A. Chalk, with flints and paramoudras, about 12 feet 
exposed. 
A bed made up of specimens of Mytilus edulis occurs from 1 
to 2 feet above the Chalk ; a similar bed occurs at Wroxham. 
At one time the shell-bed abruptly terminated in a mass of buff 
unfossiliferous sand. One conspicuous feature was a tongue of 
sand, which divided up the laminated clay in the part of the pit 
worked, and whose lower junction with the clay would, if isolated, 
have been taken for an unconformity between the “ Chillesford 
Clay ” and overlying sand. The gravel above also rested in one 
place on an eroded surface of the clay beneath ; an erosion which 
may have been caused by springs in recent times. The cla}^ itself 
becomes more and more interbedded with sand, until in one place 
it passes into a merely subordinate feature. In this pit Tellina, 
haltliica. is not found, but another section near the Anchor Inn 
yields that shell in abundance, though the relation of the shelly 
Crag to the clay cannot there be made out. 
On the opposite side of the river, in the parish of Horstead, 
the Crag has been largely opened up, on account of the numerous 
excavations for Chalk. The last working was closed in 1877, 
the ground being sloped and planted with fir trees, but the 
discovery of a skeleton of Mastodon in 1820 must always render 
the locality of interest. Mr. H. B. Woodward has given a full 
account of the discovery,"^ and inclines to the opinion that a 
* Geology of the Country around Norwich (Memoirs of the Geological Survey)^ 
pp. 57, 58. 
E 60798. I 
