WITH DESCRIPTIONS OF SOME OF ITS ORGANIC REMAINS. 253 



beneath the coal strata. It is characterized by Pentremites, a fossil which has 

 not been, I believe, observed above the carboniferous limestone.* 



Orthocera Humboldtiana. Plate VIII., Fig. 1. 



Testa recta, elongato-conica, suhcylindracea; articulis transversis, subdistantibus. 

 Shell straight, elongately conical, nearly cylindrical; joints transverse, rather distant. 



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



My Cabinet. 



RemarTis. — Unfortunately, I received only an imperfect fragment of this 

 Orthocera. It is important in connexion with these fossils, as it proves them 

 to belong to the lower series of the Oolitic group. De la Beche mentions one 

 only, O. elongatum, as being found in the Oolitic group, and that in its lowest 

 member, the, Lias, while below that, as far down as the Transition Limestone, 

 they are common. I propose the name of the distinguished American traveller 

 for this species. 



Ammonites Tocaimaensis. Plate VIIL, Fig. 2. 



Testa orbiculari; aufractibus planulatis, transversim costulatis; costis planulatis ; periphcerid minute 

 sulcata. 



Shell orhicular ; whorls flattened, transversely ribbed ; ribs flattened ; periphery minutely furrowed. 



Found on the top of a mountain between Tocaima and La Messa, in New 



Granada. Dr. Gibbon. 



My Cabinet. 



* Since the completion of this paper I have received the beautiful work of Von Buch on some of the fos- 

 sils taken to Europe by Humboldt, from New Granada. I owe to the kindness of the author the opportune 

 acquisition of this volume. His Trigonia alaformis may be identical with T. Tocaimaana (nobis.) In 

 other cases the specific forms seem to differ. 



Von Buch takes a different view from Humboldt as regards the age of these organic remains, placing 

 them rather higher, and in the chalk formation. They certainly do not resemble the forms common to our 

 chalk fossils, nor do they seem to me to be allied to those of England, so far as I am acquainted with them. 

 Notwithstanding the arguments deduced by the author, I still am of opinion that the fossils brought by Dr. 

 Gibbon from New Granada, and herein described, are properly members of the Oolitic group. 



VII. — 3 o 



