CORNIFEROUS LIMESTONE. 
163 
took place in the condition of the ocean, when from a sea teeming with organic forms like the 
corals and crinoidea, it became one in which few of these forms existed, and shells almost 
alone tenanted the deep. It appears to have been the commencement of a change by which 
the sea grew deeper, finally to the depth beyond which corals flourish, and these were all 
covered by the calcareous mud derived from previously existing masses. 
This rock first appears in the district in the eastern part of Seneca county, having the same 
characters as in the quarries near Springport on the eastern side of Cayuga lake. The rock 
is exposed at numerous points, nearly all presenting the same characters ; being in regular 
courses of from six to eighteen inches thick, usually separated by layers of hornstone, and 
sometimes embracing flattened nodules of the same, which have a striated surface, as if from 
the crystallization of some mineral in the space between the two rocks. A mile or two west of 
Waterloo it approaches the Seneca outlet, and is quarried on the margin of the stream ; some 
of the upper strata are of a greyish blue color, weathering to a light grey or ashen, and con. 
taining some argillaceous matter. These strata are often marked by the presence of a Cyr- 
toceras, which often attains a large size. The greater part of the rock is fine grained, bluish 
in color, embracing an irregular strata of hornstone. In one quarry I noticed a separation of 
the higher and lower strata by a “ wayboard ,” or seam of clay about four inches thick. 
This clay is exceedingly fine like the softest talc, and has a laminated structure and yel¬ 
lowish color; it differs greatly from the usual shaly matter separating the strata, and on this 
account is noticed. The rock at these quarries is readily worked, being crossed by vertical 
joints in two directions, which often separate the stone into blocks of convenient size, and 
leave a good back wall to the quarry. 
The effect of these joints, and the manner of working the rock where they occur, is well 
illustrated in the view of a quarry south of Waterloo, which stands at the head of the section. 
The salient and reentering angles, the lines of which bound the quarry, mark the two direc¬ 
tions of these joints, one of which is nearly E. and W., and the other varying from N. 10° E. 
and S. 10° W. to N.E. and S.W. 
About three miles south of Seneca-Falls village it comes to the surface in several places, 
and from always presenting the same strata above ground it appears to have been undermined, 
or from some other cause to have been broken into faults. The surface being level does not 
admit of an actual inspection of the condition of the rock, but judging from what is seen it 
holds the following position. 
65 . 
This dislocation of the strata is probably caused by the removal of the soft gypseous rocks 
from beneath, allowing the higher strata to fall down. From that side next to Cayuga lake 
21 * 
