642 NEW YORK STATE MUSEUM 



a deposit which is ahuost evorywiiere in its extent more massive 

 than the outer moraine. 



The writer is led by his observations of the two moraines on Long 

 Island to dissent from this long accepted opinion, aiid to regard the 

 inner moraine as continuous westward of Port Jefferson to the vicinity 

 of Cokispring and Syosset, wliere the two moraines nearly coalesce. 

 They maintain their relative positions with some distinctness to the 

 vicinity of Roslyn, where the inner moraine crosses the outer 

 moraine, the latter disappearing beneath the later one, which con- 

 tinues onward to the western end of the island and becomes the 

 terminal moraine of the mainland. The tracing of the two moraines 

 made in the fall of 1900 by J. E. Woodman served to show the 

 extension of the inner moraine to tlie southwest of Port Jefferson 

 on to the eastern limits of the Oyster Bay quadrangle. 



This interpretation of the westward extension of the two moraines 

 is quite in line with the observed tendency of the ice front along the 

 southern coast from the easternmost point in Massachusetts to the 

 Hudson river. On the east the moraines of Nantucket and Cai>e 

 Cod are at the outer margin of these two lobes more than 25 miles 

 apart. In the region of Vineyard sound they are from 5 to 10 

 miles apart ; they are quite 10 miles apart in the meridian of Block 

 island ; when they reappear on Long Island, they approach each 

 other. West of Roslyn, the second moraine crosses the lirst. From 

 this it is concluded that the inner moraine is not so much a reces- 

 sional moraine as a frontal moraine l)uiit after a retreat from the 

 position of the first moraine, followed by an advance to the position 

 of the second moraine, accompanied in the Hudson valley by a 

 greater outrun of the ice sheet than in the first advance. This 

 overlapping of moraines is a well attested phenomenon in the region 

 south of the great lakes. 



The ice front which rested against the north coast of Long Island 

 in the vicinity of Port Washington can not well be the same as that 

 wliose m<jniine caps the cliffs east of Port Jefferson. In the first 

 place, at Port Washington the morainal accumulations are very 

 blight indeed and do not rise in mounds ; in the second place, the 

 ice sheet halted there for a brief time oidy, as is witnessed by the 

 small amount of outuMs!. in the sand plain at that locality. This 



