GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 99 



The above-given numerals and description were taken from Pro- 

 fessor Kemp's paper. The general conclusions to be drawn from 

 these facts to which Professor Kemp has called attention, are that 

 the Hudson river occupied a deep gorge at the close of the Tertiary 

 period and that its tributaries emptied into it from hanging valleys. 

 Unless a deep gorge exists at the Pegg's Point crossing, as discussed 

 above, a rather large gradient between this point and Storm King 

 would have to be assumed. 



The borings south of Fishkill Village suggest that this creek 

 •deepened its gorge some distance back from the Hudson during late 

 Tertiary time. The other tributaries probably did the same to an 

 extent commensurate with their size and erosive power. All the 

 tributaries, however, occupied hanging valleys with reference to the 

 bed of the main stream. 



The boring records also show that much glacial stuff now lies in 

 these buried channels. 



GLACIAL GEOLOGY 



Erosion. The elevation of the land at the close of the Tertiary 

 is believed by many to have ushered in the glacial epoch. The 

 passage of the ice sheet over this region is marked by grooves and 

 ■striae and characteristic deposits of surface material. The ice sheet 

 may have assisted in gouging out the channel of the Hudson. 



The following is a summary of observations by the writer on the 

 direction of glacial striae and grooves in different parts of the 

 quadrangle. West of the Hudson about two miles northwest of 

 Highland, along the road to Lloyd, a deep glacial groove was noted 

 with bearing true s. 15° w. One and a half miles west of Milton 

 another fine groove gave a reading of true s. 9° w. Fine roches 

 moutonnees occur to the west of " Illinois mountain " south of 

 Lloyd. 



East of the Hudson in the eastern part of the city of Pough- 

 keepsie, near the driving park, striae were noted with bearing true s. 

 about 14° w. and farther east, just west of the central strip of the 

 Wappinger belt along the Hackensack road, a reading of true 

 s. 1° w. was taken. Near the Central New England Railroad at 

 Poughkeepsie the striae had a bearing of true s. about 26° w. ; north 

 ■of Poughkeepsie near quadrangle boundary, east of Fallkill creek, 

 true s. 11° w. ; one mile north of New Hackensack, n. 21° w. ; near 

 the Hudson, north of Fishkill Landing, true s. 33° w. 



Some of the strike fault scarps, as, for instance, those of Bald 

 liill. Mount Honness and Shenandoah mountain of the Highland 



