288 PEocEEDiNGS OP THE GEOLOGICAL SOCIETY. [March 11, 



March 11, 1868. 



John Piggot, Esq., The Elms, Ulting, Maiden, Essex, was elected 

 a Fellow. 



The following communication was read : — - 



Oil the Steuctttee of the Crag-beds of I^foRFOLE: aoid Suffolk, 

 with some observations on their Organic Eemaixs. — Part I. Coral- 

 LixE Crag. By Joseph Prestwich, Esq., F.E.S., E.G.S., &c. 

 [The publication of this paper is deferred.] 

 (Abstract.) 



The history of the division of the several crag-deposits into three 

 formations (the Mammaliferous, Eed, and Coralline Crags) having 

 been recounted, the author states that for the last thirty years the 

 evidence of their sequence has remained unaltered, the distinction 

 between the Mammaliferous and Red Crags being still purely palse- 

 ontological, not a single case of superposition having been discovered. 

 Mr. Prestwich then proceeds to the special object of this paper, 

 which is to describe more fully the physical structure of the several 

 crags, and to determine, if possible, the exact relation which the 

 Suffolk Crags bear to the Crag of IS'orfoLk. 



Commencing with the Coralline Crag, the author states that the 

 well-known outlier at Sutton furnishes a base-line and the best clue 

 to its structure and dimensions, showing also the depth to which it 

 has been denuded and rej)laced by the Eed Crag. The Coralline 

 Crag is generally described as consisting of two divisions : — an upper 

 one, formed chiefly of the remains of Bryozoa ; and a lower one, of 

 light- coloured sands with a profusion of shells : and the author now 

 gives their exact dimensions and his proposed subdivisions, as 

 follows : — 



Character and Thickness. Localities. 



■B ^. I ^- Sand and comminuted shells, 6 ft. Sudbourne and Gredgrave. 



^ c§ J ^- Comminuted shells and remains of Bry- Sutton, Sudbovirne, Gred- 



^ -r t ozoa, forming a soft building-stone, grave, Iken, Aldboro'. 



&.I 30 ft. , 



P «= I 



ff. Comminuted shells, with numerous entire Sutton, Iken, Orford, High 

 small shells, 5 ft. Gredgrave. 



Sands with numerous Bryozoa, and some Sutton, Broom Hill. 



small shells and Echini, 12 ft. 

 Comminuted shells, large, entire, and Sutton, Broom Hill, Sud- 

 double shells, and bands of limestone, bourne. 

 15 ft. 

 Marly beds, with numerous well-preserved Sutton, E-amsholt. 

 and double shells, 10 ft. 

 ^ b. Comminuted shells and Cetacean remains, Sutton. 

 3 4 ft. 



Phosphatic nodules and Mammalian re- Sutton, 

 l^ mains, 1 ft. 



Mr. Prestwich then states the localities at which these subdivi- 

 sions of the Coralline Crag are exposed, and proceeds to discuss the 



