GENERAL HISTORY OF ICE OCCUPATION 217 



to turn the ice at a high angle from its general direction, certainly more 

 than 45 degrees. The deflective influence proved by these striae was, 

 however, that exerted during the closing stages of the ice stand in the 

 region, when the general ice sheet was thin at this point and tongues 

 projected into the major valleys. The direction of earlier ice motion in 

 these valleys can not now be determined, since the records were erased 

 by the latest stands. 



General History of Ice Occupation 



Leaving out of consideration earlier ice advances, of which no direct 

 evidence has been found in this region, and events connected with the 

 advance of the last ice sheet, of which little evidence has been dis- 

 covered, it may be stated that during the occupation by the Wisconsin 

 ice sheet the entire area of the Watkins Glen quadrangle was covered 

 by an ice sheet which overspread the highest hills. The outermost ter- 

 minal moraine of this ice sheet is in Pennsylvania, from 45 to 50 miles 

 south of the southern edge of the quadrangle. Although the ice stood 

 at this outermost position long enough to build a distinct terminal mo- 

 raine, its erosive activity was not sufficient to remove the decayed rock 

 from the hills of a large part of the southern half of the quadrangle.* 



From the terminal moraine northward to the New York-Pennsylvania 

 state line the glacial deposits have not been mapped, so that it is not 

 now certain whether the ice sheet halted during its withdrawal ; but the 

 fact that so far no moraine bands have been discovered indicates that if 

 there were any halts they were brief. The New York-Pennsylvania 

 state line is almost on the southern boundary of the Watkins Glen 

 quadrangle, and from this line northward to the northern edge of the 

 quadrangle the mapping has been in sufficient detail to warrant inter- 

 pretation of the main events ip. the ice withdrawal. 



This mapping of the glacial deposits proves that the disappearance of 

 the ice across the southern half of the quadrangle was rapid, with no 

 pronounced halts. No traceable moraine bands have been discovered 

 there, and such scattered morainic deposits as are found were evidently 

 associated in origin either with very brief halts or else with stagnant ice- 

 block conditions. Such deposits are recognized in the Chemung valley 

 and some of its larger tributaries.f 



In the north-south Cayuga and Seneca valleys, on the other hand, 

 there are clear records of a series of halts, together making extensive 

 morainic deposits, often very complex in character and distribution. 

 Between the two valleys, where the ice fronts of the several stands swung 



* R. S. Tarr in Journal of Geology, vol. xiii, 1905, p. 160. 

 f These are described in the text of the Watkins Glen Folio 



