234 FOSSIL REPTILES. 



nuation of Mount Jura. This fossil would appear to have been 

 but ill preserved. Its gangue is a grey, schistous, argillaceous 

 earth, and an impression of ammonite is visible in it. The 

 head, breast, anterior limbs, and hinder part of the tail, are 

 wanting. What remains, however, is sufficient to justify the 

 reference of this specimen to the genus of the crocodiles, and 

 M. Cuvier thinks it probable that it is the same species as that 

 last described. The situation of the two along the two borders 

 of the same chain gives additional weight to this conjecture. 



This fragment is forty-five inches and a quarter in length. 

 The two knees are separated three-and-twenty inches and 

 a half. Nothing is very distinct, except five vertebrae of the 

 back, the femora, a part of the leg, and the left foot. But the 

 form of the vertebrae, long, narrow, cut squarely at the two 

 ends, and more contracted in the middle, would suffice to prove 

 it a crocodile, and not a monitor. The vertebrae in the last- 

 mentioned genus would be wider in front, narrower behind, 

 terminated in front by a concave arch, and behind by a con- 

 vex. Other minuter particulars go to establish the resemblance 

 between these remains and those of crocodilus priscus. 



The town of Caen, in Normandy, is surrounded by quarries of 

 a very fine limestone, from which beautiful stones have been 

 supplied for the construction of the city, and for churches and 

 other public edifices throughout the province. It is even said 

 that most of the cathedrals erected in this country, by our 

 Norman princes, were built with stones brought from Caen. 

 The nature of this stone bears some resemblance to that of a 

 hardened chalk, and the geological position of its beds is 

 unquestionably lower than that of the chalk in the neighbour- 

 hood of Paris, which extends very far into Lower Normandy, 

 and occupies all the upper part of that province, as well as 

 Picardy and the opposite coasts of England. 



The whole soil of this country is essentially composed of four 

 kinds of strata. The upper stratum, immediately above the vege- 

 table soil, but which elsewhere passes under the chalk, is a lime- 



