Description of the Head of a Fossil Crocodile. 267 



only those genera which have elongated beaks in formations an- 

 terior to, and including the chalk ; whilst true crocodiles, with a 

 short and broad snout, like that of the cayman and alligator, ap- 

 pear for the first time in strata of the tertiary periods, in which 

 the remains of mammalia abound."* 



This observation would seem to differ in a geological sense, 

 from that of Dr. Harlan, as just quoted, because his description 

 and figure correspond to those of a true crocodile ; while the C. 

 clavirostris seems, as we have remarked, to possess an interme- 

 diate organic structure. 



M. Geoffrey St. Hiliare has divided the fossil Gavials into two 

 genera, viz. Teleosaurus and Steneosaurus, which chiefly differ 

 from each other in the position and form of the anterior termina- 

 tion of the nasal canal. As the terminal portion of the snout of the 

 present specimen has not been discovered, we cannot avail om- 

 selves of this generic distinction ; and this uncertainty must con- 

 tinue until the recovery of the deficient portion may enable us 

 to decide the question. 



The following list embraces all the organic remains hitherto 

 discovered in New Jersey, in the same strata with the Crocodilus 

 clavirostris : they are mostly described in the sixth and eighth 

 volumes of the Society's Journal. 



Sq,ualus, several species; Belemnites ? ambiguus, (M.) ; 

 Planularia cimeata, (M.) ; Nautilus Dekayi ? (M.); Scalaria 

 annulata, (M.) ; Cirrus crotaloides, (M.) ; Vermetus rotula, (M.) ; 

 Grypheea vomer, (M.); Gryphsea convexa, (Say); Pinna rostri- 

 formis, (M.); Teredo tibialis, (M.); Cidarites diatretum, (M.); 

 Cidaretes armiger, (M.) ; Nucleolites crucifer, (M.) ; Ananchytes 

 cinctus, (M.) ; Ananchytes fimbriatus, (M.); Escharina sagena, 



(M.); Eschara digitata, (M.); Retepora , fragments; An- 



thophyllum (Montivaltia) atlanticum, (M.) ; Alveolites cepularis, 



(M.) ; Alcyonium , Idmonea contortilis, (Lonsdale) ; Alecto 



fascicularis, {Lonsdale) ; and Cellepora tubulata, (Lam.) 



* Bridgewater Treatise, Vol. I, p. 251, and Penny Cyclop., Art. Crocodile. 



