140 GEORGE C. MATSON 



south of Ithaca. The stream occupies a broad, mature valley 

 with gently sloping sides. This valley divides at Danby, the 

 branches becoming narrower and the walls steeper for some dis- 

 tance beyond the village. While Ten Mile Creek now rises at 

 Danby, there is evidence that the preglacial divide was farther 

 south. Danby Creek, which rises near the east branch of Ten 

 Mile Creek, flows southward through a valley which gradually 

 narrows for a distance of three miles and then widens again. 

 Michigan Creek, which heads near the west branch, flows through 

 a similar valley; but in this case the narrowest part of the val- 

 ley is only about two miles from the source of the stream. The 

 narrowing of these mature valleys cannot be explained on the 

 ground of rock texture, for the rocks here are of uniform charac- 

 ter. The narrowing may be explained by supposing that the 

 narrowest part represents the divide between these streams at the 

 time the broad valleys were being formed. The divide hypothe- 

 sis is strengthened by the fact that the highest hills are on either 

 side of the narrowest parts of the valleys; and by the additional 

 fact that the present divides are clearly of constructional origin, 

 being composed of low drift ridges. The drift ridges are within 

 the limxits of the region covered .by the last ice-sheet ; and the 

 present location of the divides was determined by the material 

 deposited at the ice-front.' 



About a mile from the Inlet, Ten Mile Creek enters a narrow 

 postglacial gorge ; and in less than a mile it falls, by a series of 

 rapids and cascades, through a vertical distance of about 420 feet. 

 The highest falls are the two cascades near the edge of the inlet, 

 which together measure 190 feet. Running nearly parallel to 

 this gorge is a drift-filled gorge, which is much broader and 

 deeper than the postglacial gorge, as shown by sections i and 2. 

 The buried gorge is now occupied by a small stream which has 

 removed the drift down to 520 feet A. T., but has not reached 

 the rock bottom. The width of this gorge is 250 yards ; its depth 

 is not known, but the north wall rides 156 feet above the drift 

 which forms the bed of the present stream. The lower end of 

 this stream is through a small postglacial gorge, cut in the north 



^For location of the divides, see Map I. 



