This ore is very similar to that often associated with coal and coal 
strata, and we find in the south part of the State, and in Pennsylvania^ 
similar ores. The presence of this kind of ore is liot, however, an in- 
dication of the existence of coal in the vicinity, as the situation of the 
stratum under consideration will show. 
The fossils of the iron ore are all of marine origin, consisting of frag- 
ments of Encrinites, Corallines, Producta, &c. 
SECTION IV. 
Calcareous Shale. 
The argillaceous shales and beds of limestone are succeeded by a cal- 
careous shale of a dark colour, extremely soft and fissile below, but be- 
coming harder and more calcareous above, and finally changing into a 
limestone. The lower portions disintegrate readily on exposure to at- 
mosphere and water. After long exposure, this rock becomes a clayey 
marl, forming a fertile soil. Thin seams of green shale, like that below 
are interlaminated with this rock throughout its whole thickness. 
This rock has been called " Calciferous slate," by Prof. Eaton, but he 
has described three or four distinct rocks under the same name, viz. The 
formation of which we are now speaking; the gypseous rocks which are 
separated from this rock by the geodiferous limestone, and the slates of 
Canandaigua and Geneva, which are above the mountain limestone. — 
He also mentions the slates of Otsquago creek as being a part of the 
" Calciferous slate the latter are below the sandstone of the 4th Dis- 
trict. 
The calcareous shale of Rochester may, in its eastern prolongation, 
meet the gypseous rocks at Manlius and other points, by the thinning 
out of the limestone which separates them. Whatever term we choose 
to apply to the shale of Rochester, there will be no difficulty in recog- 
nizing its place in the series of rocks. It is separated from the sand- 
stone below, by the green argillaceous shale and siliceous limestone, and 
it is directly beneath the limestone of Rochester, Lockport and Niagara 
falls. There is no other limestone shale which resembles this till we 
rise above the carboniferous limestone; and after seeing the two, in place, 
no one will be likely to confound them. The gypseous marls and slates 
are very different from these under consideration. The fossils in these 
rocks are a sure guide, where the lithological characters might mislead. 
The calcareous shale extends from the eastern limit of Wayne county, 
to the Niagara river; at this place it is eighty feet thick, and at Lock- 
