with characters somewhat modified. The Coralline-Crag ridge appears to be further prolonged from Aldborough nearly to Sizewell ; and it is on the northern side of this that we find the marked change in the newer Crag. From this point the characteristic land and freshwater features of the Norwich beds set in, and the typical Red Crag is no longer met with.
Let us therefore see what relation the more northern Crag bears to the Chillesford Clay, and in what the difference in organic remains from the Red Crag consists.
The cliff at Thorpe is now overgrown ; but the Boulder-clay appears in pits a short distance inland. At Sizewell traces of crag may be seen in the cliff ; and a few years since the digging of a well * brought to light additional specimens, of which I collected : —
Fossils from Sizewell Cliff.
Astarte compressa. Cerithium tricinctum.
Cardium edule. Conovulus pyramidalis.
— interruptm. Nassa incrassata.
Cyprina islandica. Natica hemiclausa.
Lucina borealis. Paludina lenta.
Mactra ovalis. Purpura lapillus.
Mya arenaria. Trochus Kicksii.
Mytilus edulis. Turritella communis.
Nueula Cobboldise.
Tellina obliqua. Base of horn of deer, in precisely the same condition as Red-Crag specimen.
— lata.
— praetenuis.
together with fragments of Coralline Crag drilled by boring-shells and Annelids and covered with Balani.
A mile and a half W.S.W. from Sizewell is the well-known pit on Aldringham common, generally known as Thorpe pit. Here, again, no superposition is seen. The Boulder-clay caps the hill between this pit and Sizewell ; and the Chillesford Clay appears on higher ground to the westward. At Sizewell the crag is more or less ferruginous, like the Red Crag ; but here it is light-coloured, like the Norwich Crag. The following is a list of the shells that my friend Mr. Evans and I have collected there on various occasions : —
List of Fossils from near Aldborough.
Abra obovalis ?
Astarte gracilis.
Cardium edule.
Corbula striata.
Cyprina islandica.
Donax trunculus.
Lucina borealis.
Mactra ovalis.
Mya arenaria.
Mytilus edulis.
Pecten opercularis.
Pectunculus glycymeris.
Solen siliqua.
Tellina lata.
Tellina obliqua.
— praetenuis.
Buccinum undatum.
Cerithium tricinctum.
Calyptraea chinensis.
Conovulus pyramidalis.
Littorina littorea.
Natica.
Paludina lenta.
Purpura lapillus.
Scalaria groenlandica.
Trophon antiquum.
Turritella communis.
— incrassata.
- There was 20 feet of unproductive sands above the shell-bed.
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