24 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 



12 feet, and with a total length of 12 miles. Beyond its western end 

 the sand dunes stretched continuously for about 5 miles. The South 

 Beach was half a mile in width and had an almost continuous line of 

 dunes 50 feet in height. In 1808, Superintendent James Morris 

 writes of this channel, " It is completely shut, and it is difficult to 

 trace where it has been." In 1828, Superintendent Edward Hodg- 

 son refers to this obliterated channel, urging that it be reopened. 

 Some years afterward a terrific storm made a breach in the South 

 Beach, again opening the salt pond to the sea, and making it available 

 as a harbor for small vessels. In 1836, during a severe storm two 

 American fishermen ran into this protected harbor for shelter, but the 

 storm completely blocked up the channel, imprisoning the vessels, 

 whose weathered timbers now lie on the shores of Wallace Lake. One 

 of the gales in the winter of 1881 opened a gulch toward the eastern 

 end, which so drained the lake as to reduce it to 8 miles in length, and 

 rendered it so shallow as to be no longer useful in transporting ma- 

 terials from one Life Saving Station to another. This gulch is now 

 closed, and all the dunes beyond the western end of the lake have been 

 washed away, only a narrow beach now separating the lake at this 

 point from the sea. The waves have eaten off almost all of the South 

 Beach, all of the line of dunes is gone except a small remnant near the 

 eastern end, and the beach itself is so narrow now, that waves break 

 over it in heavy weather. It is no longer possible to maintain a Life 

 Saving Station on this South Beach. There is usually an opening, 

 now through one or another part of the narrow South Beach. The 

 wind has drifted sand across and filled up a strip, a mile wide in 1913, 

 dividing Wallace Lake into two unequal parts. 



If we look back over this evidence and draw a contrast, it is a very 

 striking one, for from various surveys of 1766-67, 1768, 1770, and 

 1801, the island was about 30 miles long, 1 to 2 miles broad, with hills 

 150 to 200 feet high; whereas now it is but 20 miles long, hardly 1 

 mile broad, and the highest hill does not even attain 100 feet. 



If the determination of the location of the island in the earlier sur- 

 veys was correct, the whole island has been moving slowly eastward. 

 The prevailing winds are westerly; the western end of the island is the 

 lower and has suffered all of the severe erosion by wind and storm; 

 and the eastern end is broader, with higher hills, and more drifting 

 unanchored sand. As the bare undercut western side of the cross- 

 ridges of dunes testifies the prevailing westerly winds are the dom- 



