XIX. 



other fossils derived from the London clay. The presence of remains 

 of terrestial animals furnishes evidence of the close proximity of dry 

 land : and there are authorities who consider that this deposit itself 

 represents an old dry land surface. It may be briefly noted that among- 

 the erratics found in the deposit are some of a nature unknown in the 

 British Isles, which must therefore have been brought from a more- 

 distant land. 



Next in strati graphical order occur the interesting crag deposits^ 

 the older of which is the Coralline, and is found lying on the boxstone 

 deposit ; but where it is absent the Red Crag is then contiguous to that 

 stratum. For a full account of these beds the reader may be referred 

 to the papers of Prof. Prestwich, Ray, Lancaster, of Messrs. S. V. Wood, 

 sen., and jun., the Memoirs of the Geological Survey, and many others. 



The White, Coralline or Bryozoan Crag, is peculiar to the County 

 of Suffolk, and is composed of a mass of calcareous sands mixed with 

 shelly debris but very rich in perfect specimens and many polyzoa 

 It may be divided into three beds, the lowest, about 40ft. thick, consists 

 of shelly sands ; the middle of false-bedded stone, composed of broken 

 shells and polyzoa, in some places hard enough to be used for building 

 stone, about 30f t.,the third,or uppermost bed,which is not always present, 

 has the appearance of being composed of the debris of the lower 

 beds. The whole depth of this deposit may be put down as varying from 

 40 to 60ft. After deposition, the land began to rise, and the Coralline 

 crag was raised above the sea and broken up into islands and reefs by 

 denudation. 



The deposit originally was doubtless continuous from Tattingstone 

 in the S.E., to Aldeburgh in the N., but now consists of a main body 

 outcropping in the valley of the Aide at Orford, Ged grave, Sudbourne, 

 and Aldeburgh, with outliers at Sutton, Ramsholt, and Tattingstone. 

 316 species of fossil mollusca, of which 84 per cent, belong to living 

 species, 140 species of Polyzoa, and 16 species of Echinodermata are found 

 together with some crustacean, fish and mammalian remains. It is con- 

 sidered, from the fauna, that these beds were deposited in from 30 to 40 

 fathoms of water under a somewhat warmer climate than that which, 

 we now enjoy. 



