Geological Survey. | 197 
twenty to thirty miles broad. a ds generally from twelve 
to twenty inches thick. 
Ina slate rock, which may "he called secondary gray- 
wacke, or calciferous slate. Numerous beds of gypsum of 
vast.extent. It is found in no other situation in beds; but 
is every where confined to this slate rock in the state of 
New-York. It is found in geodes, however, in swinestone, 
&c. In thisslate we find shell limestone, water limestone, 
epsom salts, copperas, and alum, in numerous localities. 
This rock underlies all the country over which the stage 
road passes from Oneida Creek to near Genesee River; 
parallel to the canal, and from halfa mile to twenty miles 
south of it. 
In swinestone, or it may be called geodiferous lime rock. 
This rock abounds in geodes, which contain beautiful 
crystals of sulphate of strontian, limpid cubic crystals of 
fluor spar, transparent waxy zinc blende, immense quanti- 
ties of dog-tooth spar and pearl spar, selenite and snowy 
gypsum, arragonite, though rare, and numerous quartz 
crystals. It contains many petrifactions also; such as 
those of the coral family, asterites, and numercus bivalves. 
This rock extends from Genesee River to a considerable 
distance west of Niagara River. It forms most of Niagara 
Falls. The canal at Lock Port is cut thirty feet deep into 
it for two miles. East of Genesee River it is cut through 
this rock about half a mile. 
In pyritous shale of English Geologists; or it may be 
called pyritiferous rock, as it is not always slaty. ‘thin 
horizontal layers of bituminous coal, alum, copperas, ep- 
som salts, and immense quantities of iron pyrites. I saw 
thousands of petrifactions in it. on the south shore of Lake 
Erie, eighteen miles from Buffalo, which consist wholly 
of iron pyrites. This rock extends from a considerable 
distance east of the south end of Cayuga Lake to Lake 
Erie, and many tases along the south shore of the latter 
lake. 
It may be proper to mention, that the sulphuretted hy- 
drogen gas which issues through water at the foot of the 
bank a mile above Niagara Falls, and near the head of 
Otsquago Creek, in Herkimer county, manifestly proceeds 
from pyritous shale. The gas burns with a flame equal in 
extent to that of balf'a dozen candles, at both places. But 
