CROCODILEANS. 103 



had been called into existence, the important ofRce of con- 

 trolling the excessive increase of the aquatic herbivora ap- 

 pears to have been consigned to the Crocodiles, whose 

 habits fitted them, in a peculiar degree, for such a service. 

 Thus, the past history of the Crocodilean tribe presents 

 another example of the well regulated workings of a con- 

 sistent plan in the economy of animated nature, under which 

 each individual, whilst following its own instinct, and pur- 

 suing its own good, is instrumental in promoting the general 

 welfare of the whole family of its contemporaries. 



Cuvier observes, that the presence of Crocodilean reptiles, 

 which are usually inhabitants of fresh-water, in various beds, 

 loaded with the remains of other reptiles and shells that are 

 decidedly marine, and the farther fact of their being, in many 

 cases, accompanied by fresh-water Tortoises, shows that there 

 must have existed dry land, watered by rivers, in the early 

 periods when these strata were deposited, and long before 

 the formation of the lacustrine tertiary strata of the neigh- 

 bourhood of Paris.* The living species of the Crocodile 

 family are twelve in number, namely, one Giaval, eight 

 true Crocodiles, and three Alligators. There are also many 

 fossil species: no less than six of these have been made out 

 by Cuvier, and several others, from the secondary and ter- 

 tiary formations in England remain to be described.! 



* M. Gcoffroy St. Hilairc has arranp^ed the fossil Saurians with long and 

 narrow beaks, like that of the Gavial, under the two new g-cnera, Teleosau- 

 rus and Steneosaurus. In the Teleosaurus, (PI. 25', Fig. 2.) the nostrils 

 form almost a vertical section of the anterior extremity of the beak ; in the 

 Steneosaurus, (PI. 25', Fig 3.) this anterior termination of the nasal canal 

 had nearly the same arrangement as in the Gavial, opening upwards, and 

 being almost semicircular on each side. — Rccherches sur les grands Saufi- 

 ens, 1831. 



t One of the finest specimens of fossil Tclcosauri yet discovered, (see 

 PI. 25, Fig. 1,) was found in the year 1824, in the alum shale of the lias 

 formation at Sajtwick, near Whitby, and is engraved in Young and Bird's 

 Geological Survey of the Yorkshire Coast, 2d Ed. 1828: its entire length 

 is about eighteen feet, the breadth of the head twelve inches, the snout 

 VOL. I. — 17 



