No. 161.] 
165 
Salmon river, at Pulaski, near its junction with Lake Ontario, but 
more especially at the fall in the town of Orwell, about ten miles 
from Pulaski. A vertical section is here presented to the observer 
of 107 feet in height, over which the water falls in an unbroken 
mass, the most grand and imposing of all the minor cataracts in 
the State. The rock is here of excellent quality for architectural 
purposes, being compact and fine grained, of a beautiful uniform 
tint, inclining to green, and w^e can scarcely doubt that it will 
prove more durable and ornamental than any variety of the super- 
incumbent sandstones. Excellent flagging stones may be obtained 
in inexhaustible abundance, and near the fall is a quarry, noted for 
the excellence of the grindstones, which are made of this material, 
and sent to various parts of the Union, as well as into Canada. 
Organic remains are rare in the upper mass; a few indistinct shells 
and fucoids on the surface of one or two layers being all that we 
observed, but in the lower portion of the mass, where it approaches 
the preceding limestone series at Pulaski, layers of limestone alter- 
nate with the shale, both crowded with shells and fucoids. It is 
worthy of notice, that as a groupe, these fossils are very dissimilar 
to those of the Trenton-Falls series of rocks on which they repose; 
and also to those of the superincumbent red or variegated sand- 
stones, which on the received principles of modern geology, obli- 
ges me to separate this formation from those above and below it, 
assigning to it an independent distinctive character, "a local habi- 
tation and a name." Mr. Eaton has termed it second grey- 
wacke," but confounds undpr this head, rocks of very different age 
and character, for which reason we have chosen the simple appel- 
lation of gray sandstone, referring to the locality where it is best 
exposed to observation. Layers of a red color are never seen in 
any part of the series of strata composing the formation. As the 
strata of limestone of Ms formation are the only rocks which can 
be converted into lime, between the Salmon and Niagara rivers, 
and between the Erie canal and Lake Ontario, except in the imme- 
diate vicinity of the canal, they deserve attention; more especial- 
ly as lime would be of essential service to the soils of this region. 
The principal layer we noticed, is just above the level of the river, 
at Pulaski, and measures ten inches in ihickness. Some layers of 
the slaty rock effervesce slightly with acids, others do not; the 
more compact variety is extensively used for buildings in Pulaski. 
The rock is here characterized in some of its layers by a species of 
mytilusy in great numbers, slightly resembling the common sea 
muscle of the coast, {modiola dernissa^) but much broader and flat- 
