202 



CORALLINE CRAG. 



[Ch. XIII, 



Fig. 150. 



Fossils characteristic of the Bed Crag. 



Fig. 151. Fig- 152. 



JS T assa granulata. 

 Fig. 153. 



Fusus contrarius. 



Purpura tetragona. Cyprcea europcea. 



150 half nat. size ; the others nat. size. 



Among the bones and teeth of fishes are those of large sharks 

 ( Carcharodon), and a gigantic state of the extinct genus Myliobates, 

 and many other forms, some common to our seas, and many foreign 

 to them. It is questionable, however, whether all these can really be 

 ascribed to the era of the Red Crag. Not a few of them may possi- 

 bly have been derived from older strata, especially from those Lower 

 Miocene formations to be described in the next chapter, which are 

 largely developed in Belgium, and of which a fragment only (the 

 Hempstead beds of Forbes) escaped denudation in England. 



Many of the fossils found in the Red Crag have been washed out 

 of older Tertiary strata, especially out of the London Clay. This is 

 particularly the case in one of the lower beds, which has of late been 

 much used in agriculture for manure, as containing nodules of phos- 

 phate of lime. These nodules often include crabs and fishes like 

 those of the London Clay, and thus clearly betray the date of their 

 origin. With the nodules (in which there is nearly 60 per cent, of 

 phosphate of lime), occur rolled flint pebbles, and others of sand- 

 stone, containing casts of crag-shells and many ear-bones of whales. 



Some teeth of the Mastodon arver- 

 Fi °- 1M - nensis, and of a rhinoceros and tapir, 



have also been found in the same bed, 

 which has been worked near Felixstow 

 among other places. As to the ear- 

 bones of cetacea, Professor Henslow 

 found those of two or three distinct 



Tympanic hone of Balcena emarginata, . . , . .. . . . .. _ .. 



Owen ; Bed Crag, Felixstow. species in this detrital bed at h elixstow. 

 They belong, according to Professor 

 Owen, to true whales of the family Balcenidce (fig. 154). Mr. "Wood 

 is of opinion that they are of the age of the Red Crag, or if not, that 

 they may be derived from the destruction of beds of Coralline Crag. 

 White or Coralline Crag. — The lower or Coralline Crag is of very 

 limited extent, ranging over an area about 20 miles in length, and 3 



