PRESTWICH — CRAG -BEDS OF SUFFOLK AND NORFOLK. 



343 



with characters somewhat modified. The Coralline-Crag ridge ap- 

 pears to be further prolonged from Aldborough nearly to SizeweU ; 

 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 fresh- 

 water 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 chff ; 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 tricinetum. 



Cardium edule. ConoTuliis pyramidalis. 



interruptum. Nassa incrassata. 



Cyprina islandica. Natica hemiclausa. 



Lucina borealis. Paludina lenta. 



Mactra ovalis. Purpura lapillus. 



Mya arenaria. Trochus Kicksii. 



Mytilus edulis. Turritella communis. 



Nucula Cobboldiie. 



Tellina obliqua. Base of horn of deer, in pre- 



lata, cisely the same condition as 



praatenuis. Eed-Crag specimen. 



together with fragments of CoralUue Crag drilled by boring-shells 

 and Annelids and covered with Balcmi. 



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 



Abra obovahs ? 

 Astarte gracilis. 

 Cardium edule. 

 Corbula striata. 

 Cyprina islandica. 

 Donax trunculus. 

 Lucina borealis. 

 Mactra ovalis. 



arenaria. 

 Mytilus eduhs. 

 Pecten opercularis. 

 Peotunculus glycymeris. 

 Solen siliqua. 

 Tellina lata. 



Thorpe pit, near Aldborough. 



Tellina obliqvia. 



prsetenuis. 



Buceinum undatum. 

 Cerithium tricinetum. 

 Calyptraia 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. 



2b 2 



