112 



PALEONTOLOGY 



proportion to the body of the fish, this must have been 



about sixty feet in 

 length* Teeth of 

 Carcharodon have been 

 obtained from the Eed 

 Crag of Suffolk, mea- 

 suring upwards of six 

 inches in length. The 

 microscopic structure 

 of the teeth in sharks 

 is illustrated by the 

 longitudinal section of 

 a fossil from Sheppy, 

 showing the outer hard 

 layer of "vitrodentine," 

 and the "vaso-dentine" 

 forming the body of 

 the tooth. With these 

 fossil teeth of sharks 

 are found, though 



nm 



Fig. 3G a. 



Magn. section of a tooth of a 

 fossil Shark ( Lamna). 



Kg. 37. 



Side view and back view of 

 the body of a vertebra of a 



Shark, Lam nam (hlonlaspis. 

 (London clay, Sheppy.) 



sparingly, in both the cretaceous and tertiary beds, petrified 



* See the Author's Catalogue of Fossil Reptilia and Pisces, in Mus. R. 

 Coll. of Surgeons. Lond. 4to, 1854, p. 124. 



