G. F. Eaton — Prehistoric Fauna of Block Island. 139 



clear, but it is probably due, not to any failure of the glacial 

 deposits to be formed in this space or in any considerable 

 degree to their erosion, but rather, it is likely, to the fact that 

 the floor on which they rest was originally lower in this part 

 of the coast than elsewhere. This is indicated by the circum- 

 stance that from the western end of Martha's Vineyard there 

 is a shoal that extends to Block Island and thence to Long 

 Island. This shoal seems to be a continuation under water of 

 the glacial mass to which Long Island and Martha's Vineyard 

 belong." In the same report (p. 34-9), he expresses the belief 

 that Martha's Vineyard has been connected with the mainland 

 since the close of the glacial period, and adds that the animals 

 and plants of the island are in no way peculiar, there being a 

 few species existing on the mainland which are not found on 

 the island, but none on the island which are altogether limited 

 to it. He also makes the following statement : " We can 

 hardly believe that several large-seeded plants and many of the 

 land animals have found their way across the five miles of 

 water which separates the Vineyard from the continent." 



Turning to the United States coast charts, it will be seen 

 that it is eight nautical miles from Block Island to the nearest 

 part of the mainland, the maximum depth of water in the 

 intervening channel being twenty-two fathoms. The straight 

 course from Block Island to Montauk Point is twelve nautical 

 miles, but here the soundings are far less than those taken in 

 the waters to the north and east of the Island, doubtless 

 because of extensive shoals formed by the tidal currents. 

 These shoals stretch from the Island and from Montauk Point 

 toward the middle of the intervening channel, at which point 

 there is apparently a sudden increase in depth to between 

 thirteen and sixteen fathoms. The character of the bottom 

 over these shoals is hard, with occasional rocky localities. In 

 fact, it is essentially the same as that of the bars underlying 

 Plum Gut and the channels east and west of Great Gull 

 Island. 



In this Journal (vol. xl, No. 24:0), appeared an article 

 by Prof. J. D. Dana entitled "Long Island Sound in 

 the Quaternary Era, with Observations on the Submarine 

 Hudson Biver Channel." The theories there set forth were 

 the result of close inspection of soundings taken between the 

 years 1878 and 1883. Apparently the author did not trace the 

 former course of the Connecticut Biver with perfect confi- 

 dence, for he took up and dismissed the subject in the follow- 

 ing paragraph : 



" As regards the existence of a submarine Connecticut chan- 

 nel the evidence referred to is certainly unsatisfactory. The 

 bend in the bathy metric lines on the accompanying map be- 



