Correspondence. 91 



stratification on either side of it. But I do not perceive that Mr. Wood 

 attributes this efi"ect to the supposed faults, either at Bulchamp or at 

 Hitchin. — I am, yours faithfully, 



0. FiSHEB. 

 EtMsiEAD Rectory, Colchestek. 



ARE THE CORALLINE CRAG OF SUFFOLK AND THE BLACK CRAG 

 OF BELGIUM CONTEMPORANEOUS DEPOSITS? 



To ike Editor of the Geological Magazine. 



Dear Sir, — In 1864 I communicated a short paper to your excel- 

 lent Magazine on the Crags of Suffolk and Belgium. I was led from 

 a comparison of the lists of MoUusca, mainly, I confess, by the " per- 

 centage method," to associate the Eed and Coralline Crags of Suffolk 

 with the YeUow Crag of Antwerp, regarding the Grey Crag and 

 Black Crag as anterior deposits. Mr. Godwin-Austen, in a most 

 instructive memoir published in the Quart. Journ. Geol. Soc. No. 87, 

 August, 1866, deals with the question of the Crags in a comprehensive 

 and philosophical manner, rejecting conclusions derived from per- 

 centage calculations, and regarding rather the conditions and rela- 

 tions indicated by the nature of the deposits and general aspect of 

 the fauna, which he has lately examined himself in Belgium. I 

 have read this memoir with great pleasure and profit, and am quite 

 prepared to regard the Grey Crag of Belgium as owing its apparent 

 distinctness from the Yellow Crag to the presence of redeposited 

 Black Crag fossils. But there is one point on which I would ask 

 for further elucidation. Mr. Godwin-Austen says (p. 238), " The cor- 

 responding conditions on the English and Belgian areas of the Crag 

 sea are the Eed Crag and the Scaldesien (Yellow and Grey Crags) ; 

 both are ' remanie ' accumulations." " The Eed Crag was from the 

 break up of a neighbouring Bryozoan sea-zone, the Scaldesien from 

 ooze depths. Any comparison of the fossil contents of the ' Coral- 

 line Crag' and of the 'Crag noir' must be subject to the considera- 

 tion of differences which result from depth and condition of sea-bed." 

 From this I gather that the Coralline Crag in Suffolk is considered 

 to represent the Black Crag of Belgium, and to be contemporaneous 

 with it. If this is the case (apart from the objection that the fauna 

 of the Black Crag has an aspect so distinct from that of the three 

 other Crags — explained by Mr. Godwin-Austen as the result of 

 differences of depth), how is the occurrence of the teeth of species of 

 sharks and Cetacea in a " remanie " condition in hotli of our Crags to 

 be accounted for ? Specimens of the teeth of Carcharodon megalodon 

 and Bhinoceros in a worn condition have been obtained from the hase 

 of the Coralline Crag. No specimens of fish or Cetacean remains 

 occur in our Coralline Crag in an unworn, unrolled condition as they 

 do in the Black Crag. "Whence, then, did the abundant " remanie " 

 Cetacean and shark fauna of our Eed Crag come ? from what de- 

 posits are they derived? The answer which 1 have before sug- 

 gested to these questions, which I do not think are considered by 



