WITH DESCRIPTIONS OF SOME OF ITS ORGANIC REMAINS. 255 



Found in the Province of Velez, New Granada. Dr. Gibbon. 



My Cabinet. 



Remarks. — A small species with numerous ribs, which are alternately dupli- 

 cated on the outer part of the whorl. It is destitute of a carina and furrow. 

 I name it after my friend Professor Vanuxem, the distinguished geologist. 



Ammonites Americanus. Plate VIII., Fig. 6. 



Testa orhiculari ; aufractibus subplanis, oblique costulatis ; periphcerid sulcata. 

 Shell orbicular; whorls somewhat flattened, obliquely ribbed; periphery furrowed. 



Found on the mountains between Tocaima and La Messa, in New Gra- 

 nada. Dr. Gibbon. 



My Cabinet. 



Remarks. — A portion only of a single whorl of this species is before me, and 

 the description is necessarily imperfect. It is distinct from the other species 

 which accompanied it, in being furrowed. The furrow is not very distinct, 

 and an imperfect carina seems to be connected with it. 



Trigonia GiBBONiANA. Plate IX., Fig. 7. 



Testa, ovato-trigona, mullicostata ; costis transversis, sub tuberculato-asperis ; area, carinata. 



Shell ovately triangular, many ribbed ; ribs transverse, somewhat roughly tuberculate ; posterior slope 

 carinate. 



Province of Velez, New Granada. Dr. Gibbon. 



My Cabinet. 

 Diam. 1.5, Length 2, Breadth 2 inches. 



Remarks. — In outline and size this species resembles Parkinson's figure of 

 T. spinosa, (Vol. III., PL XII., Fig. 7,) which is described by Lamarck as T. 

 scahra. Neither of the two specimens in my possession are very perfect. The 

 tubercles on the ribs of the larger and broken specimen are more observable. 

 In these tubercles it has some resemblance to T. doedalcEa, Sow. and Park. 



