G. F. Eaton — Prehistoric Fauna of Block Island. 159 



Conclusion. 



Such is the brief account of the exploration of the prehis- 

 toric shell-heaps of Block Island, together with a statement of 

 their contents, which were found to include a great variety of 

 primitive implements and the remains of many species of ver- 

 tebrate and invertebrate animals. The bones of the land ani- 

 mals seem at first to be strangely out of place upon a small 

 island several miles out at sea ; and the necessity is immediately 

 felt for some explanation of their occurrence there. In view 

 of the number of modifying factors which must have affected 

 the distribution of the fauna over this interesting region, it is 

 difficult to formulate a theory which shall satisfactorily explain 

 the way in which the land animals came there. Still, in many 

 cases, it is possible to arrive at conclusions which are supported 

 by the weight of strong probability, and certainly all the 

 known conditions of the problem are satisfied by the hypothesis 

 which has been advanced; namely, that the area of land now 

 represented by Block Island already possessed a considerable 

 "mainland fauna" at the time of its separation from the conti- 

 nent. AVhether this supposition is correct or not may be 

 determined by future investigation ; and it is to be hoped that 

 this will lead to further discoveries tending to throw light 

 upon this subject, as well as upon questions connected with 

 the history of the Indian tribe which the English colonists 

 supplanted. 



Yale University, New Haven. Conn., June 1. 1808. 



Explanation of Plates. 

 Plate II. — Outline map of Block Island, showing location of Shell-heaps. 

 Plate III. — Outline of Southern New Ens-land Coast. 



