494 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 25, 
though no strata represent this Diestien period, yet the Cetaceans, 
Sharks, and shell-containing Sandstone-nodules of the Suffolk bone- 
bed, are the fragments rescued to us from the destruction of a vast 
extent of a once existing close equivalent of the Black “Crag” of 
Antwerp. Such remains were long confounded with those belong- 
ing to the true Crag epoch. ‘They can now no longer be so. The 
term “Crag” is not applicable to the Cetaceans of the Diestien 
period, nor to the other contents of the Suffolk bone-bed. 
The observation of the occurrence of the Suffolk bone-bed below 
both Coralline and Red Crags, and the recognition of the Diestien 
age of a large portion of its contents, first published by me in 1865, 
and the similar conclusion of the Rev. John Gunn with regard to 
the Mastodon and Hlephas supposed to belong to the Norwich Crag 
proper (but which he has shown to be confined to a basement bed, 
the Norfolk stone-bed), have facilitated very considerably the com- 
parison of the Norfolk and Suffolk shell-bearing strata. Mr. Prest- 
wich, after detailed study of the stratigraphical and paleontological 
evidence, has recorded his opinion that the Norwich Crag is the true 
continuation northwards of the Red Crag of Suffolk. At the same 
time, he assigns an earlier age to the Coralline Crag, and points out 
a lower undisturbed and an upper disturbed portion of both Red and 
Coralline Crags in the Suffolk area. 
The remarkably confused condition of the Red Crag in Suffolk 
tells a history which enables us to understand in some measure its 
agreement with and its differences from the Norfolk Crag. Many 
remarkable species of Mollusca, such as Voluta Lamberti, Cassidaria 
bicatenaia, Pleurotoma intorta, &c., occur in the Red Crag, but do 
not appear in the so-called Norwich Crag; and no valid evidence 
has been adduced to support the view that they are derived 
from the Coralline Crag when found in the Red. At the same 
time, the more boreal fauna of the Norwich beds is present in the 
Red Crag. It is well known to collectors of the mollusca of the 
Red Crag in Suffolk that, superficially, they may only expect to 
obtain the shells belonging to the Norwich-Crag fauna, and that for 
the rarer forms, such as those mentioned above, they must seek in 
the deeper parts of the deposit and in the low-lying areas. Thus, 
at Waldringfield, and in the immediate neighbourhood of Wood- 
bridge, lying on the river Deben, those species of the Red-Crag Mol- 
lusea are to be obtained which do not occur in the Norwich deposit; 
moreover, in these localities the valves of Lamellibranchiates are 
frequently found in apposition *, and small specimens of a well- 
marked variety of Terebratula spondylodes (differing from the Coral- 
line-Crag variety), with united valves, are not uncommon. From this: 
we may infer that the Red Crag is a deposit representing a consider- 
able stretch of time, and that its earliest deposited beds contained a 
fauna differing from that which occupied the sea which at later’ 
periods, again and again, turned over and added to the accumulation. 
At the earlier period the Red-Crag sea contained a fauna not very 
different from that exhibited in the Coralline Crag, still retaining 
‘* See a paper by Mr. Alfred Bell, Brit. Assoc. Rep. 1868, ; 
