5© NEW YORK STATE MUSEUM 



York lake, that now occupy a considerable portion of the outwash 

 plains. Part of Crooked lake of the Tully group is shown in plate 

 15; Little York lake appears in plate 20. As in the case of the 

 kettles in the kanie section of the Tully moraine these lake basins are 

 the result of the melting out of buried ice blocks and the subsequent 

 settling down of the superimposed material. Here the blocks seem 

 to have been tabular in form, though irregular in outline, probably 

 wide thin wedge-ends of the ice very quickly and deeply covered by 

 the morainic and outwash accumulation. That such deductions are 

 not wholly theoretical will appear on inspection of plate 16, where 

 pitted plain lakes are actually in process of formation on a diminu- 

 tive scale at the front of an Alaskan glacier. If one will recall how 

 easy it is to store ice through the summer vmder only a thin cover of 

 sawdust, it will be understood how ice blocks, detached from the 

 glacier front, might persist for long periods under deep deposits of 

 earthy material. In fact, experiments made on the surface of 

 glaciers show that under even a slight rock cover the ice melts down 

 only about two-thirds as fast as it does where freely exposed, a con- 

 dition which gives rise to the phenomenon of glacier tables on many 

 glaciers. These consist of an ice pedestal supporting a tabular frag- 

 ment of rock which has protected the ice below from melting down as 

 rapidly as the surrounding area. 



The lakes in the Tully outwash plain are all shallow, as might be 

 expected, but they have steep, though low shores. While the shores 

 have not persisted through postglacial times in the perfection prob- 

 ably given them originally by the faultlike breaking down exhibited 

 along the edges of such lakes in the Alaskan instance, the feature is 

 still noticeable and is another point in support of this theory of their 

 origin. 



The several lakes are scenic features of much charm and in years 

 before the vogue of motor travel were summer resorts that attracted 

 numerous cottagers. While they continue to function in this way lai 

 some degree the upper ones now also serve another economic purpose- 

 Water is piped from them through the Tully moraine and on the 

 lower slopes of the moraine flowed into wells which have been 

 drilled down to the salt strata in the bedrock. As saturated brine 

 the water is pumped out of the wells and then conveyed by gravity 

 flow to the notable chemical industries of Syracuse adjacent to 

 Onondaga lake. This brine is the basic raw material for these indus- 

 tries. The continuous gravity movement of the liquids that the 

 topographic relations make possible is a geographic factor of more 

 than small importance in the success of the industry. 



