254 NOTICE OF THE OOLITIC FORMATION IN AMERICA, 



Remarks. — A small portion only of a whorl of this species was received. It 

 differs from A. Gibhonianus in being more flattened, and in having a very mi- 

 nute furrow, being little more than a mere impressed line. 



Ammonites Gibbonianus. Plate YIIL, Fig. 3. 



Testa orbiculari; aufractihus compressis ; costis elevatis, carinatis, remotiusculis ad periphariam. 

 Shell orbicular ; whorls compressed ; ribs elevated, carinate, somewhat distant at the periphery. 



Found between Tocaima and La Messa, New Granada. Dr. Gibbon. 



My Cabinet. 



Remarks. — A small section only of this large species was brought by Dr. 

 Gibbon, after whom it is named. The few characters which can be seized in 

 such a specimen render a description very meager and doubtful. 



Ammonites occidentalis. Plate VIII., Fig. 4. 



Testa orbiculari, utrinque umbilicatd ; aufractibus rotundatis, transversim costulatis; peripharia ro- 

 tunda, sulco circulari destitutd. 



Shell orbicular, umbilicate on both sides ; whorls round, transversely ribbed ; periphery round, being' 

 destitute of a circular furrow. 



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



My Cabinet. 



Remarks. — A single imperfect specimen only was brought by Dr. Gibbon. 

 One of the chambers has been removed without injury to the other parts. It 

 is destitute of a carina and furrow. 



Ammonites Yandxemensis. Plate VIII., Fig. 5. 



Testa orbiculari, utrinque umbilicatd; aufractibus convexo-cylindricis, transversim crebrissimeque 

 costulatis ; periphoerid rotundd, sulco circulari destitutd. 



Shell orbicular, umbilicate on both sides ; whorls convexly cylindrical, transversely and thickly ribbed : 

 periphery round, being destitute of a circular furrow. 



