FOSSIL REMAINS OF EXTINCT .MAMMALIA. 115 



a soft flattened margin; a modification of structure 



enabling these animals to conceal themselves in 

 the mud at the bottoms of rivers and lakes, and 

 seize the mollusca which constitute their principal 

 food.* 



The only vestige of any other order of reptiles 

 observed in these strata, is a tooth of the croco- 

 dilian type, apparently of the Alligator Hantonien- 

 sis ; a fossil species described by Mr. Searles 

 Wood, from a splendid specimen of the lower 

 jaw and teeth, &c, found in the freshwater beds 

 at Hordwell Cliff, on the Hampshire coast.f 



FOSSIL REMAINS OF EXTINCT MAMMALIA. 



From the general correspondence between the 

 tertiary formations of Hampshire and Paris, it 

 is probable that these strata were deposited con- 

 temporaneously, and under very similar con- 

 ditions ; their respective basins being connected 

 with the same sea, and alike characterised by 

 alternations of marine and fluviatile sedimentary 

 detritus. When, therefore, the attention of 



* I very much regret my inability to give a correct representation of the 

 entire carapace; but having been promised the refusal of the specimen by 

 the dealer, I contented myself with the sketch of the part here figured ; the 

 form of the bones, and the sculpturing of the surface, are correctly shown in 

 the lignograph. 



t Of this most interesting specimen a beautiful representation is given in 

 the first number of the new periodical,, called " The London Geological 

 Journal, or Record of Discoveries in British and Foreign Palaeontology ." 

 published by Churchill. 



