208 
GEOLOGY OF THE THIRD DISTRICT. 
The slate at the uplift is not very thick, and shows in the creek and where upturned, two 
or more layers of the Trenton limestone (3) beneath it. At the junction of these rocks with 
the wall, a wedge-shaped mass (2) appears, enlarging downwards. Its color is of a dark 
green when fresh, but becomes earthy or yellowish by exposure. It has the characters and 
composition of an impure serpentine. It contains some crystals of mica of a third of an inch 
in diameter, which have been formed in the mass. Between this and the limestone and slate, 
is the vein of galena first noticed by Mr. Conrad. It is associated with blende and pyrites, 
and with white and brownish-black lamellar carbonate of lime. 
The dyke, as before mentioned, and the vein, enlarge downwards. It was worked but for 
a few feet below the entrance, near the level of the creek, yielding no profitable amount of 
ore in the part excavated. The result is easy to predict, should the ore be derived from the 
visible upturned rocks, for the quantity would be small, not being of great thickness; but 
should the source be independent of these two rocks, proceeding, according to some, from 
something like the fountains of the great deep, the result is not so easily predicted. It is, 
however, one of those points theoretically of the highest interest. It is at the junction of dis¬ 
similar masses, hence electrical results could take place; where different exudations by the 
layers could unite, chemical action would result, and union with the former would produce 
galvanism: these conditions are requisite for the formation of metallic veins, and may here 
have all been realized. As matter of science, the investigation of this point is one of interest. 
It contains ore as a matter of fact. The bottom of the uplifts must extend to the point of 
fluidity; therefore ejections from that part may exist in the fissure, though it is more pro¬ 
bable that it was filled up by lateral infiltration from the masses between which it exists. 
Along the crest of the junction of the slate and the calciferous are some shallow openings, 
from which ochery ore, or hydrate of iron, was thrown out, which evidently was derived from 
the wall or calciferous group, such exudations being common from this group. 
The calciferous, at the south end of the uplift, appears in the bed of the river. Higher up 
in the bank, near the ferry house, is the birdseye; above it, the Trenton limestone; the 
Utica slate forming the range in the rear of the river, and appearing in its usual flat or undis¬ 
turbed position not only there, but in many points between the ferry and the east end of the 
uplift of Little-Falls. 
69- 
No. 1. Gneiss, the base rock of the uplift and the district. 
No. 2. Calciferous sandrock. 
