No. 161.] 
161 
cover the escarpment, attest the fruitless industry of deluded in- 
dividuals. In many places, vast quantity of debris may be seen, 
consisting of small angular fragments, a mode of disintegration 
common to all the rock in the vicinity of gneiss. These fragments 
appear as if they had been broken up by the hammer, are hard 
and difficult to break, and may be used with advantage in repair- 
ing roads. No better material can be obtained within a moderate 
distance, except perhaps the gneiss of Little-Falls. In many lo- 
calities, the calcareous sandstone alternate with a gray shale, ex- 
tremely friable and full of obscure traces of fossils, among which 
isotelus alone can be recognized: It contains small concretions of 
whitish limestone, about the size of a winter pea, near the village 
of Canajoharie. The sandstone is of a granular texture, passing 
from fine to coarse, and varies much in its composition. In some 
instances, it contains but a small proportion of lime, and is then a 
solid compact rock, and breaks into large square masses. This form 
is finely displayed at the South Nose," on the Erie canal, about 
two miles east of Canajoharie. It here contains small cavities 
filled with anthracite, quartz crystals and brown spar. The rock 
also embraces large irregular masses of dark hornstone, which on 
East Canada creek is remarkable for its small annular markings, 
resembling an organic structure. Along the Erie canal, from Am- 
sterdam to East Canada creek, this rock is of a siliceous texture, 
but generally not so compact as at the Noses. It occurs in nearly 
horizontal strata, and is easily broken out into large masses. 
West of the primary range of Little-Falls, we noticed this rock 
at Middleville and Newport, in the bed of West Canada creek, 
containing in cavities anthracite, brown spar, and very numerous 
and beautiful quartz crystals. In a northwesterly direction from 
the last mentioned places, it is shortly seen to pass under the dark 
blue fossiliferous limestone which forms the lower portion of Tren- 
ton-Falls. On East Canada creek, near Manheim, a very interest- 
ing fault occurs, which the geological student will find well worthy 
of attentive examination. The sandstone at the falls has been 
broken by a downheave, leaving a vertical wall, against which 
the superincumbent slate inclines at a n angle of about 33°, but in 
a short distance gradually recovers its usual slight inclination to 
SW. The southern limit of this fault is the south bank of the 
Erie canal, nearly opposite Manheim, where the slate which has 
been sunk in the downheave was thrown out during the excava- 
tion of the canal. At the northern wall of the fault, where the 
[Assem. No. 161.] 21 
