the Hudson and its Tributaries. 



315 



Annsville cove just north of Peekskill. Along this line is the 

 crucial area in the interpretation of the geology of the High- 

 lands, as has already been discussed by C. P. Berkey.* 



The crossing is about three miles from the Hudson, in a 

 narrow and rather steep-sided valley. Archean gneiss forms 

 the hills, but after a concealed strip on each side the drill 



Fig. 10. 



US0+ 



1400% 



Fig. 10. The Sprout Brook Crossing. Sedimentary gneiss on the west ; 

 marble in the valley ; granite gneiss on the east. 



revealed white marble in the bottom, beneath 125 ft. and less 

 of drift. The bottom of the buried channel was caught at —8, 

 as shown in fig. 10. This is less than the last two, but the 

 stream is hardly as large. The stream evidently selected the 

 easily eroded limestone in preference to the harder gneisses. 



Fig. 11. 



P E E K S K I L 



Fig. 11. The Peekskill Brook Crossing. 



Peekskill Creek.— -East of a steep divide from Sprout Brook 

 lies the valley of Peekskill Creek, a somewhat larger stream 

 and one in a broader valley. On the north side is the Hudson 

 Elver slate at a steep angle and in an abrupt hillside. The 

 present creek flows upon drift at its foot. Thence to the south 

 for over a mile there are no exposures and the geology must 



* Structural and Stratigraphic Features of the Basal Gneisses of the High- 

 lands, Bulletin 107, N. Y. State Museum, 361, 1907. 



