12 



J. F. Kemp — Buried Channels Beneath 



source must either have been passed or 

 else it still lies beneath the drift farther 

 west than it was necessary to bore. 



The Moodna Crossing. — Having 

 passed the Wallkill valley by a siphon, 

 the aqueduct reaches sufficiently elevated 

 ground to make a long course to the 

 south at grade. Its first depression is at 

 Moodna creek, which enters the Hudson 

 just north of Cornwall. The Moodna 

 proper comes in from the west, but it 

 receives an important tributary, Wood- 

 bury creek, which drains the valley be- 

 tween Schunemunk mountain and the 

 Highlands. In the three miles before it 

 discharges into the Hudson the Moodna 

 has cut a deep gorge in exceedingly 

 heavy drift, with huge bowlders of very 

 impressive size and extremely trouble- 

 some to penetrate with either the calyx 

 or the diamond drills. 



The details of the Moodna crossing 

 are shown in tig. 6. The present creek 

 is in the drift but very near the southern 

 emergence of slates, and at about the 

 100 ft. contour. For a half mile to the 

 west the drills have shown a very even 

 floor with a maximum depression at 

 minus 59'2 beneath 360 ft. of drift. A 

 divide then rises of sharp outline, beyond 

 which is another old channel reaching 

 minus 10. The surprising thing about 

 this section lies in the fact that two or 

 three miles away is the gorge of the 

 Hudson with a depth below of minus 

 600 ft. We have therefore been slow 

 to admit that there is not somewhere in 

 this section an incised notch through 

 which the ancient drainage of the country 

 to the southwest must have been poured 

 without leaving a hanging valley 550 ft. 

 above its master depression. Still, care- 

 ful search and fairly close-set holes have 

 failed to locate it. Somewhat the same 

 relationships with the Hudson gorge are 

 shown by other tributaries, such as the 

 Wappinger, and Fishkill and the Croton, 

 as will be later brought out. 



