No. 50.] 
427 
Feet. Inches. 
Brought forward, 
4. The same, mostly in thick layers, one being six or 
eight feet thick, highly silicious, with irregular 
cavities, 22 6 
3. The same, in thin, greyish layers, with seams of 
blue marl, 12 
2. Bluish marl, crumbling into irregular angular frag- 
ments, 5 
1 . Greyish and greenish marl, with some portions very 
compact, ten or twelve feet of the lower part fill- 
ed with small cavities or pores, like those in the 
rock covering the gypsum, 19 
65 10 
The drab limestone is not so thick at this place as at some others 
which I have examined. 
This rock forms the northern escarpment of the great limestone ter- 
race, extending from the Genesee to Lake Erie, and also seen in the 
counties east. It passes through the towns of Leroy, Stafford, Bata- 
via, and the south part of Alabama, forming the lower falls on the In- 
dian reservation. I am not aware that it has been used for cement in 
this county, though it is doubtless good for this purpose. 
Onondaga limestone, — This rock occupies the summit of the ter- 
race ; extending from Livingston county westward, it passes, with va- 
riable width, to the north of the village of Leroy, underlies Stafford, 
Morganville, &c. the north part of Batavia and Pembroke. A few feet 
of the lower portion of this rock is in regular courses, with little or no 
hornstone ; the succeeding 40 or 50 feet consists principally of horn- 
stone, being a rough, ragged mass, called the chaived rock^ This, 
in some places, contains large numbers of coralline fossils. 
From Leroy village to the falls, a section of rocks shows the black 
shale, Onondaga limestone, (the Seneca being absent,) the hydraulic 
limestone and the marls below ; there is scarcely a point in this dis- 
tance where the rocks are concealed. The whole thickness, including 
the chaived rock^^^ is less than 100 feet. Along this stream are fine 
opportunities for quarrying, though httle improved. 
