CONTENTS OF A BONE CAVE. 27 



man, is a question which must be left for future investigators. Of one point we 

 may be assured, namely, that the deposit inclosing the Amblyrhiza is of late geo- 

 logical age. This may be derived from the close affinity which exists between that 

 genus and existing ones, and also from some species of shells which I found im- 

 bedded in the matrix inclosed in the intercondylar fissure of the femur of the 

 Amblyrhiza latidens. I sent these to my friend Thomas Bland of New York, whose 

 knowledge of West Indian land-shells is exhaustive, and he informed me that they 

 belong to a species of Tudora so nearly allied to the existing species T. pupce- 

 formis as to make it difficult for him to characterize it as distinct. I would not 

 place the age of the Amblyrhiza earlier than the Pliocene. 



The island of Anguilla, now embracing but thirty square miles, could not readily 

 have supported a fauna of which these huge rodents formed a part. Such large 

 animals have no doubt ranged over a more extended territory. This, and other 

 facts mentioned by Pomel, lend probability to the hypothesis of the latter author, 

 that the submergence of the ranges connecting many of the islands of the Antilles 

 has taken place subsequent to Pliocene times. 



