At Coltishall, 8 miles N. of Norwich, the relation of the Crag to the Chillesford Clay is again clearly shown in the pit at the lime-kiln (fig. 29).
Fig. 29.— Chalk-pit, Coltishall.
feet.
8. Boulder-clay (traces of).
5. Ochreous and ferruginous sand and shingle 12 to 15
3. Grey clay, with a few fragments of wood and a seam of pebbles (Chillesford Clay) 6 to 8
2'. White sand and fine gravel, with patches of shells and large flints at base (Norwich Crag) 4 to 6
The shells collected by Mr. Reeve* and by myself in bed 2' are: —
Astarte borealis.
— compressa.
Cardium edule.
Corbula nucleus.
Cyprina islandica.
Mactra — ?
Mya arenaria.
Mytilus edulis.
Pecten opercularis.
Tellina obliqua.
— praetenuis.
Littorina littorea.
— rudis.
Purpura lapillus.
Scalaria groenlandica.
Turritella incrassata.
Natica catena.
Helix hispida.
Limnaea palustris.
Planorbis complanatus.
Teeth and bones of the Mastodon are occasionally found at the base of the same bed. One of the workmen informed me that he had also found bones above the clay (3).
In the closely adjacent pits at Horstead the Chillesford Clay may be seen holding the same position. But in one pit (the old water- channel) the sand bed (2') under the clay is not fossiliferous, whereas the one above it (5) is ; whilst at the farmyard- pit, close by, the lower bed (2') is fossiliferous and 5 is not. An entire skeleton of Mastodon is said to have been discovered in 2' some years since.
Thence we pass to the coast at Cromer without meeting any more Crag-pits†. At Cromer traces of the Crag were found lying on the chalk in digging the foundations of the jetty ; but no section of it is seen until we reach Runton Cliff. At a short distance west of the Gap a ferruginous pebbly mass of crag, 2 feet thick,
- In addition to these, Mr. Reeve has found in the same bed at Wroxham,
two and a half miles S.S.E. of Coltishall pit, Nucula Cobboldiae, N. tenuis, Leda Limatula, Lucina borealis, Mactra subtruncata, M. solida, Tellina lata, Anomia ephippium, Trophon antiquum, and Pecten tigrinus, but no freshwater shells, no Turritella, and no Astarte borealis.
† My friend the Rev. J. Gunn has this summer been with me to the pits at Burgh, between Coltishall and Weybourne. The Chillesford Clay is again well exposed there, and overlies a foot or two of pebbly sand, which contains in places a few Norwich-Crag shells.
