ERIE COUNTY. 471 
place. Care is required iu selecting the rock as it is quarried, thin seams of shaly matter 
intervening between the thicker masses, which only are fit for cement. 
The next place west of Williamsville where this rock is exposed to any great degree, is in the 
Skajockety creek, about four miles from Buffalo. Here there are about twenty feet of the rock 
visible, extending for half a mile north of the road. The upper portions abound with cavities, 
many of them containing sulphate of strontian, but principally emply, and showing the re¬ 
mains of a small coral which has been partially removed. Below this the mass is quarried 
for rough building stone, in blocks from four to eight inches thick; thin layers are often quar¬ 
ried for flag-stones and door steps. The rock has all the external characters of the water lime¬ 
stone of Williamsville and Falkirk, and is probably as good for cement. 
Between the place just mentioned and Black-Rock, the hydraulic limestone appears in 
several places; the most prominent, however, is on the land of Mr. Arms, a mile and a half 
east of Black-Rock, where large quantities can be easily obtained. The burning of the rock 
at this place has been heretofore attempted, but unsuccessfully. 
At Black-Rock and the vicinity, the water-lime appears in several places. At the quarries 
near the ferry, the rock is visible to a depth of eight feet, underlying the blue limestone. 
Here, as at other places, the upper portion of the mass is too calcareous, and it is only the 
ash-colored and striped layers beneath that are fit for use as a cement. The situation at this 
place is very favorable ; but where covered by the other rocks, it cannot be profitably brought 
into use. By pursuing examinations to the northeast of the village, the same mass may be 
found covered only by the soil, and consequently much more easily obtained. 
In many places, and for the greater part of the breadth of this county, the Onondaga lime¬ 
stone forms a very thin mass, or the limestone above rests immediately on the hydraulic 
limestone. It is owing to the resisting nature of these two limestones, and to the soft nature 
of the rock on the north, that a terrace is formed, leaving the valley of the Tonawanda ex¬ 
cavated from the rocks below. The undulating outline of the terrace is also caused by the 
greater or less thickness of the limestone. Sometimes we find it jutting out to the north a 
mile beyond the general line, and again falling below or south of the general direction nearly 
as far ; the latter appearance usually occurs where the terrace is cut through by streams run¬ 
ning to the north. 
At Black-Rock, the Onondaga limestone is only from six to fourteen inches thick; it is of 
a greyish color, crystalline, and containing few fossils. This mass has been quarried, pro¬ 
ducing excellent stone for fine building or foundations. Some of it has been sawed and 
polished, being sufficiently compact to form a good marble ; the colors, however, are dull. 
The Corniferous limestone is extensively quarried at Black-Rock for the public piers, break¬ 
waters, etc., and serves a very good purpose where rough stones are required. From its posi¬ 
tion, and its vicinity to the public works and canal, it becomes invaluable to the State. 
The hornstone portion is largely quarried for use on the Macadam road, and is an excellent 
material for this purpose; the hornstone, from cracks and fissures, readily falling to pieces by the 
action of frost, produces a bed of angular fragments little affected by the changes of weather. 
