356 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Crags with those of England after treating of the Norwich Crag. 

 On the latter subject we must make a few observations in reference 

 to that portion of it which extends into Suffolk. T have shown 

 that the Ked Crag S. and S.W. of Sudbourne and Iken is sepa- 

 rated from that to the northward by a ridge of Coralline Crag, and 

 that the fossils of the Red Crag take then a more littoral character 

 and already present at Aldborough a somewhat intermediate type — 

 the rich fauna of Sutton and Walton having gradually become 

 poorer, though the shells are still all Red-Crag species, and that 

 species of Mactra, Mya, Mytilius, and Gardium have become more 

 common. After passing Aldborough the Crag puts on another type ; 

 the littoral shells, especially Littorina littorea, Mya, and Mactra, 

 largely predominate ; but still, out of 44 species I have found in the 

 pits between Aldborough and Southwold, there are only two which are 

 not found in the Red Crag : — the one, Paludina lenta, being a fresh- 

 water and therefore a local shell * ; the other, Astarte horealis, being 

 a shell of northern type, which here first makes its appearance, and 

 whose range may have been restricted by the Thorpe ridge of Coral- 

 line Crag. 



The Mammalian remains found at Thorpe and Southwold cannot 

 be compared with Red-Crag fossils, which are mostly extraneous. 

 At the same time I would call attention to the occurrence of the 

 teeth of Mastodon in the Coralline Crag of Sutton, in the Red Crag 

 of the same district, and in the Crag at Southwold. 



Further the stratigraphical relation of the beds is alike in the 

 two districts. At Chillesford and Iken we find the Chillesford 

 clays and sands overlying the Red Crag ; and in the same way we 

 find at Southwold a crag, which is probably the equivalent of the 

 upper division of the Red Crag, immediately underlying clays which 

 contain similar fossils to those in the Chillesford district. It is pos- 

 sible, also, that in the northern area, as well as in the southern, 

 there are two subdivisions, of which the beds at Wangford and 

 Thorpe may be the lower, whilst those at Bulchamp or Southwold 

 may represent the upper. 



In my next communication, I propose tracing the same horizon of 

 the Chillesford Clay into Norfolk, and to show its relation to the 

 Crag-beds of that district and their relation to the Crags of Suffolk. 



* Mr. A. Bell has since found this shell in the Eed Crag at Waldringfield. 



