252 H. L. Fairchild — Glacial Lakes in Central New York. 



Lake Dana is a stage of the waters having their level deter- 

 mined by the outlet channel east of Marcellus, elevation 691 

 feet, with which the Dana shoreline terminates. 



The several rock channels cut by the east-flowing waters in 

 their escape to the Mohawk-Hudson lie so near together that 

 they cannot be well represented on the larger map (Plate VI),. 

 but they are more clearly shown on the smaller map, p. 251. 



The small circles on the larger map indicate cities or villages, 

 the names of -which are omitted to save confusion. On the 

 smaller map the names are given. 



The heavy broken line indicates the post-glacial divide 

 between Laurentian and south-flowing waters. Bars drawn 

 transverse to the water-parting indicate the location of outlets 

 of the primitive local glacial lakes ; those elsewhere on the 

 map represent later outlets of secondary waters. 



Numerals give elevations, in feet, above ocean level. 



Physiography of the District. 



The territory in general which includes the glacial lake phe- 

 nomena described in this paper is that part of S~ew York State 

 known as the region of the " Finger " Lakes. Its more pre- 

 cise limitations are, on the west, the valley of Honeoye Lake 

 and on the east a line somewhat beyond Syracuse. Those 

 north and south valleys lying to the west of Honeoye, namely, 

 Canadice, Conesus and the Genesee, were never related to the 

 Newberry waters. 



The accompanying map shows the hydrography of the present 

 time. The topography will be sufficiently described, with the 

 help of elevations given on the map, by stating that the area 

 between Lake Ontario and the northern ends of the Finger 

 Lakes is a plain of 400 to 600 feet elevation, while the north 

 and south u Finger" Lake and intermediate valleys are pre- 

 glacial trenches in an elevated tract of more enduring rocks. 

 As far as the waning ice sheet upon the north left the land 

 exposed, the northern and lower plain was covered by the 

 Warren and Dana waters, which extended southward in a series 

 of deep narrow bays up the valleys into the higher plateau. 

 To the work of these lakes, with the subsequent Iroquois, is 

 due the heavy silt deposits and the subdued topography of the 

 lower part of this plain. 



^ The ice movement, in the closing phase, followed the direc- 

 tion of the lake valleys, thus having a" radial or spreading flow ; 

 and local lobes of the ice, or stream glaciers, protruded beyond 

 the general ice front up each of the valleys, leaving in each 

 valley a heavy moraine, which now constitutes the head of the 

 present drainage, or the divide between north and south flow. 



