the Hudson and its Tributaries. 317 



The buried channel was found at —20, while the present 

 Croton flowed at 4-50, leaving 70 ft. of drift, mostly of bowl- 

 der clay, between. The section is two miles from the Hudson. 

 Summary. — From this tabulation it is evident that consider- 

 ing the distances of the crossings from the Hudson, the Esopus 

 at Hurley (or perhaps the Pliocene Kripplebush), and the Wall- 

 kill at Springtown A, have cut deepest. The bed-rock at their 

 mouths must be relatively far down. For those near the river 

 Casper Creek is strikingly low for a stream that is decidedly 

 smaller to-day than the modern Wappinger. Fishkill Creek 

 with —40 at six miles back may well be much deeper at its 

 Pliocene mouth, but its location has not been established, much 

 less explored. Even giving all possible latitude to these depths, 

 it still remains true, that as compared with the gorge of the 

 Hudson, now demonstrated at the Storm King crossing, all 

 these tributaries entered in the last stages of erosion, either just 

 preceding or during the Glacial epoch, by hanging valleys of 

 500 ft. or more above the bottom of the main stream. 



The Hudson Crossings. 



The borings which cross this great river furnish naturally 

 the most interesting data of all, and, as will appear, they show 

 a surprising depth to bed-rock. The crossings begin about 

 eight miles north of Newburg or seven miles south of the 

 Poughkeepsie bridge. They are somewhat irregularly distrib- 

 uted, but extend at the extreme limit, about two miles south of 

 West Point. The one of greatest interest is the Storm King cross- 

 ing, between Storm King mountain on the west and Break- 

 neck mountain on the east. Of this we have the completest 

 data, but there are core-borings available at Peggs Point, next 

 to the most northerly crossing, and at Little Stony Point, 

 although they are not numerous. All the rest are based on 

 wash-borings, which, as already stated, are only of value in 

 showing that the bed-rock is lower yet. In some of the 

 wash-borings an artesian flow of fresh water was encountered 

 which spurted above the decks of the lighters carrying the 

 drills, deluging the drillers with water and sand. There is 

 thus a connection with the hills on the banks and beneath the 

 silt. A few little shells have been yielded from beds forty feet 

 below the bottom of the river. 



The Tuff Crossing. — This is situated a half-mile above Peggs 

 Point, where the next crossing south was located, and runs 

 diagonally across the river in a direction about N. 63 W. Its 

 profile is shown in fig. 12. Hudson River slates are on the 

 west bank, and the heavily bedded Wappinger limestone of the 

 Clinton Point quarries on the east. The geological relations are 

 presumably like those at Peggs Point, of which we have much 



Am. Jour. Sci.— Fourth Series, Vol. XXVI, No. 154.— October, 1908. 

 23 



