210 
GEOLOGY OF THE FIRST DISTRICT. 
tion is north forty-five degrees west. Hence it appears, that the diluvial current which once 
swept over this island from northwest to southeast, on reaching the western shore, was de¬ 
flected southward, as by the action of some force at a right or some other angle to its course; 
and that the same current, before it reached the middle of the island, again assumed a south¬ 
easterly direction, but was again diverted southerly on approaching the eastern shore. That 
some portion of the current was diverted southerly on reaching the western shore of the island, 
is evident, not only from the diluvial furrows, but from the boulders of anthophyllite found in 
large numbers in the lower part of the Eighth avenue near Fifteenth-street, a distance of two 
miles in a south-southwest direction from the only locality whence they could have proceeded. 
Again, the white limestone of Kingsbridge has been distributed along the eastern shore of 
the island, in a direction almost due south of the only locality in the vicinity where it is found 
in place ; whereas had they been carried in the general direction of the current, they would 
have been deposited eastward in Westchester county, as before stated. 
“ Magnitude of the furrows. The size of the furrows varies in the same and different locali¬ 
ties. Sometimes they are the finest scratches, not more than a line in diameter horizontally, 
and of the smallest appreciable depth; from this they increase to grooves four inches deep 
and eighteen inches in horizontal diameter. In a few cases, they are furrows, or rather 
troughs, more than two feet wide and six or eight inches deep. A case of the latter kind 
occurs on Eighth avenue, between Seventy-ninth and Eighty-first-streets; and one of the former 
on the west side of the island, on the very banks of the Hudson, five hundred yards north of 
Mr. John H. Howland’s country seat (near Ninety-seventh-street). 
“ Convenient places for examining the diluvial furrows. The nearest places to the city for 
examining the furrows are at the junction of Twenty-second-street and First avenue, south of 
the Alms-house yard ; and again about half a mile northward at Kip’s bay, at the junction of 
First avenue and Thirty-fifth-street. Both of these localities will soon be destroyed by grading 
the streets. Some of the most interesting localities have been made known by cutting through 
Eighth avenue, from Bloomingdale road, at or near Sixtieth-street, to Harlem and Manhat- 
tanville valley at 105th-street; these localities are on both sides of the avenue, and very 
conspicuous. Another, equally interesting in many respects, is on the banks of the Hudson, 
west of the Bloomingdale road, about six miles from the city, and about six hundred yards 
northwest of Burnham’s hotel. The interest excited by this locality arises from the fact, that 
the furrows ascend from beneath the lowest tide water, up to an elevation of seventy feet in 
three hundred or four hundred feet distance.”* 
It will be seen by referring to the tables, that the scratches on the east side of the Hudson 
and Champlain valley, on the mountain tops, are mostly directed northwest and southeast, 
as their general direction; those of the west side of that valley, from northeast and east, to 
southwest and west, as common directions ; those of the high range of land along the divide 
of the waters of the St. Lawrence valley, of the Great lakes, and the waters of the Dela- 
Geological Report of New-York, 1839, pp. 197, 199. 
