504 PROCEEDINGS OF NEW YORK MEETING. 



a half miles. It i- thus known that the region of the Saguenay formerly stood at least 

 about a thousand feet higher than now. 



Scarcely less grand is the gorge through which the Hudson pierces the mountain- 

 Archean 1 « « - 1 1 between Newburgh and Haverstraw; and if there should be a 

 depression of the land, faster in its rnt<' than the filling of the valley with sediment, 

 the tidal portion <>f tins river, from Albany t" New fork, would become a fiord. 

 But the former channel and fiord of the Hudson, which were a continuation of the 

 present valley but are now submerged beneath the bob outside the NarrowB, arc of 

 greater interest in our present inquiries, as they Bupply most important testimony 

 concerning the geologic time and conditions of the erosion of the North American 

 fiords and the preceding uplift and succeeding subsidence of the northern part of 

 this continent. 



Soundings of the Bea approaches to New York, made in 1842 and 1844 by the United 

 Sta- I : Survey, were long agosbown by Professor Dana to afford evidence of a 

 submarine continuation of tin. Hudson river valley; and during the year- 1880 to 

 1884 minute hydrographic surveys of this part of the submerged Atlantic Blope of 

 the continent supplemented what was before known, obtaining very significant ob- 

 servations. A report of this work, written by A. Lindenkohl of the United States 

 I ast and Geodetic Survey, and read at the meeting of the National Academy of 

 Sciences April 22, 1885, by J. E. Hilgard, was published in the American Journal 

 of Science for June of that year. The submarine valley or channel begins to be 

 noticeable ten miles east by Bouth off Sandy Hook, al a depth of 19 fathom-, and ex- 

 tends first southerly about ten miles; thence, after bending eastward in the next five 

 miles, it maintain- a straight course, S. 60° E., to its bar, which is eighty miles from 

 Sandy Hook. The soundings to the top of the channel'- banks and the submarine 

 plain on each side along the first ten miles, to the bend, are 18 to 20 fathoms; and 

 the depth of the channel, from the top to the bottom of it- hank-, increases from one 

 or two fathoms to 1"> fathoms, or 90 feet. Onward for the next twenty mile- the 

 depth of the channel continues a1 16 fathoms; hut the soundings to the top of its 

 banks and the adjacent plain increase to '-'7 fathoms. Along the next ten miles the 

 channel decreases in depth to 11 fathoms, in ten miles more to only 7 fathoms, and 

 then in ten miles t,> 5 fathoms. At five miles farther, or seventy-five mile- from 



Sandy Hook, it- depth i- two fathom-, and it eea-e- within the nexl five mile-. 



Through the forty miles in which the depth of the channel decreases, the soundings 

 to the top of its hank- increase from 27 to 18 fathom-, or 258 f< 



The average -lope of the hank- i- one degree, and the width of the included chan- 

 nel from three-quarters of a mile to one mile ; but in the bend the -lope i- increased 



to three degrees and the width contracted to an eighth of a mile. S| imens of the 



bottom brought up by the lead from the bed and hank- of the channel are sandy 



clay, evidently the continuation, as believed by Mr. Lindenkohl, ol the Tertiary 



indy clay strata " found occupying the southeastern part of New Jersey by the 



logical survey of that -tnic. The adjacent plain differs from the channel in being 



overspread with -and and gravel, which appear to be of Quaternary age and th n 



tinuation of the expanse of modified drift that form- the Bouth side of Long island, 

 Bloping down from the front of the terminal moraine. 



ond the bar of fine sand which terminate, thi* channel, a submarine fiord Is 

 found in the line of it- continuation, extending about twenty-five miles, with a width 



of three miles, to th Ige of the steep continental Blope at a distance of about one 



hundred and ii\e mile from Sandy Hook. The adjacenl flal sen bottom descends 



