152 O. F. Eaton — Prehistoric Fauna of Block Island. 



though it is, that a river bed implies the existence of land on 

 both sides to form the banks, and therefore it seems probable 

 that at the time when the Connecticut River was scouring out 

 its deep channel across the continental margin, there was a 

 land connection of Block Island with the mainland. Just 

 when the destruction of this land connection could have taken 

 place is not clear; but some light upon this important ques- 

 tion may be obtained from the evidence that at a compara- 

 tively recent time Block Island has undergone a submergence 

 of several feet. 



In a paper entitled " On Pleistocene Changes of Level in 

 Eastern North America," by Baron Gerard De Geer (Proc. 

 Boston Soc. Nat. Hist., 1892), is to be found much informa- 

 tion regarding submergence along the southern New England 

 coast. After reviewing the . condition of the west shore of 

 New Haven harbor, the writer says : " These facts seem to be 

 in accordance with the assumption that this coast is slowly 

 sinking, and I failed to find any proofs that since the ice age 

 the land was ever more deeply submerged than it is now." 

 Of Martha's Vineyard, De Geer makes this statement : " On 

 Martha's Vineyard, where I had the advantage of Prof. N. S. 

 Shaler's guidance, I could only confirm his observation that no 

 raised beaches of any kind were to be seen." 



Block Island nowhere exhibits raised sea-beaches indicating 

 recent emergence ; but, on the contrary, in certain places, 

 former pond bottoms are exposed in the shelving bluffs only a 

 few feet above the level of high tide, and according to Mr. 

 Livermore, from whose history several quotations have already 

 been made, " three [peat] beds of considerable known size, 

 that may be larger than known to be, one on the east side of 

 the Island, and two on the west, extend a considerable distance 

 from the shore into the ocean." No specimens of peat from 

 these beds are obtainable for examination at this time of writ- 

 ing; yet, judging from their description, they present many 

 points of similarity to the submarine peat beds of Nantucket, 

 of which Prof. Shaler, in concluding his discussion of the fos- 

 siliferous deposits of Nantucket (Geol. of Nantucket, 1889), 

 writes : " So far as I am informed this is perhaps the clearest 

 evidence which has been obtained showing recent subsidence 

 along this part of the New England coast. As to the date of 

 the subsidence no evidence seems obtainable from this locality. 

 The peaty matter has a very fresh and unconsolidated aspect. 

 The roots of the rushes which it contains are singularly recent 

 looking ; they are little decayed, and indeed seem to retain 

 some part of their color and odor." 



The eastern part of Long Island is being slowly submerged, 

 for similar peat-beds below high water mark are also reported 



