No. 275,] 
267 
The greatest exposition of plaster is along the Nine Mile creek from 
Camillus to a mile or two beyond the great embankment. The plas- 
ter beds were laid open by the grading of the rail-road from Syracuse to 
Auburn. Here the dark coloured mass which encloses the lowest range 
can be well observed for some distance; also the hopper cavities which 
are above that mass; they are followed by gypsum, and lastly the po- 
rous or " vermicular rock," forms the upper part of the whole. This 
latter is four feet thick. 
Throughout the three counties where plaster exists, I have no reason 
to believe that it is more abundant in one part than in another part, the 
difference being merely apparent arising from the greater ease of extrac- 
tion, caused by denudation, which by removing the superincumbent por- 
tions, admitted also of less accumulation of rubbish upon the hill sides. 
Some idea of the quantity of plaster which the region contains, may 
be formed by the report of the engineer of the Syracuse rail-road, Mr. 
Edwin F. Johnson, dated June, 1837. The whole of the plaster was 
obtained from the hill side going from Camillus to Auburn, and to that 
period " about 40,000 tons had been obtained, estimated to be worth, 
in the aggregate, $35,000." Mr. Johnson further remarks, " that the 
location of the rail-road is such, that the gypsum is exposed at various 
points in the excavations for the distance of five or six miles. In some 
places the bed of the rail-road is composed entirely of that material." 
Very little plaster is quarried between Nine Mile creek and Owasco 
river, and no quarry opened in Elbridge or Brutus that I could hear of. 
In the town of Mentz, about one and a half miles below Troopsville 
on the Owasco, is a quarry belonging to Mr. N. Marble, of Port By- 
ron. It belongs to the upper range, and this is the last excavation for 
gypsum before reaching the quarries at Cayuga bridge. 
Gypsum is abundant at Cayuga bridge; but one quarry worked, that 
of Mr. Williard. Mr. Titus has opened a bed a little north of the road, 
but has not proceeded further. 
The beds at the bridge all seem to belong to the upper mass; they are 
wanting in the hoppers, in the " vermicular rock," the want of arching 
in the layers above the plaster, and they are accompanied by a class of 
cavities which I have only observed in those masses which hold the high- 
est geological position in the third deposit. 
South of Cayuga bridge, and about two miles north of Union spring, 
and near the lake shore, are the five plaster quarries of Richardson, Par- 
[Assem. No. 275.] 33 
