104 
GEOLOGY OF THE THIRD DISTRICT. 
common to its layers when hard or solid, to form an arch over the gypsum, which, though not 
regular, is yet well defined. Where this exists, the mass or rock which forms the arch is 
full of cracks, owing to the force exerted by the plaster in its expansion upwards, and shows 
more or less consolidation of that part before the particles of plaster had collected together, 
and assumed the form in which we find them. Where the mass which encloses the gypsum 
is soft or friable, no arching appears, owing no doubt to the particles of the one taking the 
place of the other, both being in a yielding state. 
No. 2, is light-colored, like No. 3, with hopper cavities ; two feet thick. 
No. 3. Thicker layers than No. 4, harder, not so dark colored, with hoppers ; and at its 
intersection with the same, it is porous like the lower vermicular rock : four feet. 
No. 4. Thin layers, brownish, with a few pores or cells, the whole appearing to be altered 
or decomposed : three feet. 
No. 5. Slaty, variegated, grey and blue, striped, etc., with some fossils consisting of fucoids ? 
resembling small spear-grass ; they are charred, or in other words of a black color from coal 
or carbon : also the Lingula limosa, and two or three yet undescribed thin bivalve shells, whose 
character is very obscure, and which are of interest only from their rareness and position. 
Total thickness of this part, about ten feet. 
No. 6. Porous bluish limestone rock (vermicular), the pores or cells larger than usual, and 
slightly compressed ; these cells show that their origin is due to saline or solid, and not to 
gaseous matter as before stated : three feet thick. This terminates the mass, the third or 
upper alluvion of Chittenango covering the whole. 
Not far from Bull’s quarry is Mr. Brown’s, about a mile and a quarter from Clockville, on 
the top of a low hill: the gypsum is very near the surface, and therefore more advantageously 
quarried. It presents a range of detached masses more or less rounded at the top, and with 
a flat surface below, enclosed in the usual thin layers of dark brownish and apparently a much 
altered rock. Above the gypsum are the layers No. 2 and 3 of Bull’s quarry, with hoppers 
and pores. 
The old Sullivan bed, now not worked, and near the turnpike gate, was the first plaster 
mass that was discovered. It no doubt contains all the members at Bull’s, though not so 
prominently developed : it was the first one examined. The lower part is about twenty feet 
thick, being the part where the gypsum was quarried, none of it having been removed when 
visited. Above this was the mass which corresponds with No. 5 of Bull’s quarry ; then a 
bed of an olive color, much altered, two feet thick ; upon which is the vermicular rock, about 
three feet thick, the pores large and numerous. In a quarry further east, the pores are both 
large and small. 
The plaster hills range from east to west through the county, extending south of the turn¬ 
pike from two to four miles. The hills arc more or less round and short, rendering some 
portions of their plaster very accessible, the layers in which the masses exist having but a 
slight inclination. These latter observations apply also to the counties of Onondaga and 
Cayuga. 
In Onondaga county, numerous quarries are opened along its whole range to the south of 
