72 TRANSACTIONS OF THE [pEc. 16, 
and part of Montgomery counties. The rock is here chiefly a 
fissile slate, but as it passes to the north it assumes, as at Tren- 
ton Falls, the character of a dark blue, very hard foetid lime- 
stone, crowded with organic exuvie, chiefly bivalve shells and 
fragments of trilobites. The rock has here been cut through 
by a branch of West Canada Creek, which thus, in a suc- 
cession of beautiful cascades, leaps through a deep gorge 
through perpendicular black walls.* * * North of Trenton Falls 
there is a capping of gray crinoidal limestone, but we are as yet 
ignorant of its precise character and limits.’’ In the reports of 
several succeeding years by the various survey geologists the 
limestone of Trenton Falls is alluded to, and in 1838 Con- 
rad enumerated a few of the fossils from there in his “Sixth 
group.”* Eaton in 1830 applied the name “shelly metalliferous 
limerock,”} and the formation was “ No 2” of the Pennsylvania 
Survey. The term Trenton Limestone was first applied by 
Vanuxem in 1838,} and a few of its characteristic fossils men- 
tioned, but the type section was not defined so as to establish it 
until his report on the Third District appeared in 1842.§ 
He says.‘ At Trenton Falls, there are two distinct varieties : 
The first is a dark or black’ coiored fine-grained limestone in 
thin layers, separated by black shale or slate, and which forms 
the great mass through which the creek has worn its channel 
and in which are all the falls. The second is a gray coarse- 
grained limestone in thick layers, which forms the top of the 
mass. Fossils are extremely numerous in the dark colored part, 
but are less numerous in the upper or gray part: this latter kind 
is quite crystalline.” Seventeen typical fossils are then de- 
scribed or figured. 
The type section of the Trenton, as thus defined, then extends 
from the bridge just below the milldam at Trenton Falls village 
to the bridge at Prospect, about two and a quarter miles along 
the gorge of West Canada creek, more fittingly known by the 
original Indian name “ Kauya Hoora” (Laughing waters). In 
the course of this two and one quarter miles the river makes a 
total fall of over three hundred and twelve feet. The dip of 
the strata is in the direction of the current, and although locally 
variable, averages less than 10°, so that the path along the can- 
yon ascending with the dip rises at about the same rate as the 
creek level, except at the falls. Hence the thickness of the beds 
traversed is greater than it at first seems to be. 
* Second Annual Rept. N. Y. State Geol. Survey, p. 115. 
+ Geological Text-book, p. 38. 
t Second Annual Rept. on 4th Geol. Dist. of N. Y., pp. 275-276. 
¢ Geology of New York, Part 3, pp. 45-56. 
