PHENOMENA OF KEUKA AND SENECA VALLEYS 41 



is thought to correlate with tlie Bath outlet and to have been formed 

 during seasons of high water before the Wa^nie outlet was cut and low- 

 ered sufficiently to carr}^ all the overflow. 



The ancient land stream deltas are excellently displayed upon the 

 slopes of the Keuka valley, and the elevation of benches have been meas- 

 ured by aneroid at Hammondsport and Urbana upon the west side and 

 at Eglestons glen upon the east side. The terraces about the southern 

 end of the valley correspond closely and fall into four distinct levels, 

 which may be generalized as follows, taking the lake surface as 709 feet 

 in August, 1897: 



Summit plateaus in south end of vallej' ],145 =b feet. 



Higher gravel lidges and bars 1,115 to 1,140 " 



Main terraces 950 to 965 " 



Lower tei'races 825 to 865 ' ' 



The 1,145 ± plateaus are found only in the upjjer end of the valley 

 and correlate Avith the Bath outlet, making allowance for differential 

 uplift. Somewhat lower are found the embankments and frontal bars 

 on terraces which mark the later level of the waters with the Wayne 

 outlet. Ttiese correlate with the lower beach on the slope back of Grove 

 Spring. 



The main terraces are clearly those of the NewberrjMvaters, which, to 

 judge b}^ the relative development of the benches, must have existed 

 longer in the valley tlian the earlier lakes; the lower terraces as those 

 of the Warren waters, 



Seneca Valley 



in general 



The topographic features of this central valley of the Finger lakes were 

 described in the former paper with an account of the lacustrine phe- 

 nomena at Horseheads and Watkins. It is now desirable to record with 

 more detail the shore phenomena and to determine the lake succession 

 in this most important valley of the central New York series. 



SOUTH END OF SENECA VALLEY 



No observations are to be added to the description of the Watkins- 

 Newberry outlet at Horseheads, but shoreline phenomena have been 

 studied at Montour Falls (Havana), in the southern part of the valley. 

 This is the most southerl}^ point at which any observations have been 

 niade of glacial lake shorelines in New York. 



On the western slope of the valley, above the village and on the 

 north side of the ravine, occur gravel bars of the Watkins and Newberry 



