No. 275.] 
199 
8lh avenue near 15th- street, a distance of two miles in a SSW direc- 
tion 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 in different localities. Sometimes they are the finest scratches, not 
more than a line in diameter horizontally, and of the smallest apprecia- 
ble depth; from this they increase to grooves 4 inches deep and 18 
inches in horizontal diameter. In a few cases, they are furrows, or ra- 
ther troughs, more than 2 feet wide and 6 or 8 inches deep. A case of 
the latter kind occurs on 8th avenue, between 79th and 8lst-streets; 
and one of the former on the west side of the island, on the very banks 
of the Hudson, 500 yards north of Mr. John H. Rowland's country 
seat, (near 97th-street.) 
Convenient places for examining the Diluvial Furrows. The nearest 
places to the city for examining the furrows are at the junction of 22d- 
street and 1st avenue, south of the alms-house yard; and again about 
half a mile northward at Kip's bay, at the junction of 1st avenue and 
35th-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 8th avenue from Bloomingdale road at or near 60th- 
street to Harlem and Manhattan ville valley, at lOSth-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 600 yards northwest of Burnham's hotel. 
The interest excited by this locality arises from the fact, that the fur- 
rows ascend from beneath the lowest tide water up an elevation of 70 
feet in 300 or 400 feet distance, requiring a force greater than that of 
any current with which we of modern days are acquainted. 
Respectfully submitted, 
L. D. GALE, 
^ssisH Geologist First District JV. F. 
