CROCODILE IN LONDON CLAY. 223 



Spencer, Esq. of Highgate, in the London clay in the Isle of Shep- 

 pey, of which the annexed cuts give a correct representation. The 



first is an outline, being a side view of the upper jaw and teeth. The 

 second represents a front view of the head, with the two small cavi- 



ties for the lobes of the brain, and the larger cavities for the orbits of 

 the eyes. The length of the head, when entire, and clothed with 

 scales and muscles, must have been about one foot ; hence we may 

 infer, that the entire length of the animal was about six feet. Wheth- 

 er this was the head of a young animal, or of an adult of a small spe- 

 cies, cannot, perhaps, be determined. From the rare occurrence of 

 the bones of saurian animals in the tertiary strata, we may infer that 

 these animals whose remains are so abundant, and of such large mag- 

 nitude, in the secondary strata, had nearly disappeared in northern 

 latitudes, at the epoch when the tertiary strata were deposited. 



The teeth and tusks of elephants have been discovered in many 

 situations, in what is supposed to have been London clay, but which 

 may have been a covering of diluvial clay ; for the patches of dilu- 

 vial gravel that are spread over many parts of the Vale of Thames, 

 frequently contain the remains of elephants.* Ammonites and belem- 



* In clearing away the bed of gravel on the north side of the Regent's Park, 

 the tusks of elephants were found, but in a mouldering state, in 181S. 



