MEDINA SANDSTONE. 
37 
This is one of the most uniform masses in the whole district, the only change in its whole 
extent being the gradual increase of argillaceous matter in a westerly direction. Its uniform 
reddish brown color is but slightly relieved by the occasional spots and bands of green, and 
the absence of fossils renders it a very uninteresting rock to the geological observer. 
2. Grey Quartzose Sandstone. 
In the western part of the district, the lower division is succeeded by a grey quartzose 
sandstone, exhibiting a sudden contrast in the material and coloring matter. This mass, which 
is twenty-five feet thick on the Niagara river, extends through Niagara and Orleans counties, 
but is not seen in Monroe or Wayne, either from having thinned out, or from passing beneath 
the lake; the former is more probable, as there is no evidence of the latter. From Medina 
westward it exhibits a prominent line, rising abruptly from the softer rocks below, and jutting 
out beyond those above, forming a terrace, which runs a little to the north of the great lime¬ 
stone terrace or mountain ridge. It appears as a projecting band in the banks of the Niagara 
river, extending from Lewiston as far as the Whirlpool, where it disappears beneath the level 
of the water. 
The mass is mostly composed of thin layers, from the thickness of one-eighth of an inch to 
six inches. Near the Niagara river the layers are generally thicker, the deposition apparently 
having been more rapid. At a quarry one mile north of Lockport, the layers are often ex¬ 
ceedingly thin, not more than one-eighth to one-fourth of an inch, and perfectly separable from 
each other, the planes in many instances presenting a partial coating of the oxide of manganese. 
The surfaces are exceedingly smooth, as if washed by water before the deposition of the suc¬ 
ceeding layers; in other cases they are covered with the separated valves of Lingula, and 
marked with numerous wave-lines. 
This mass, which is light grey or nearly white on the Niagara river, becomes slightly tinged 
with red on going eastward, and at Medina some thin layers are strongly colored; it, how¬ 
ever, maintains its general uniformity, the grey color and quartzose character every where 
predominating. East of Medina it is seen in but few places, and in these not well developed. 
In lithological character, this mass bears a very close analogy to the sandstone forming the 
terminal member of the Clinton group in Herkimer county, as it appears on the south side of 
the Mohawk in several places. The peculiar fossils are wanting, however, and the association 
is entirely unlike. 
The range of the grey sandstone from Lewiston eastward is, for several miles along the base 
of the escarpment, formed by the Niagara limestone; afterwards it extends a little farther 
northward, and becomes from thence a distinct elevation from half a mile to one mile north of 
the principal terrace, and nearly parallel with it. The descent over its outcropping edge is 
a rapid slope, covered with fragments of the sandstone broken up and mingled with the soil. 
After passing a few miles to the east of Lockport, the elevation produced by this rock merges 
in the general level of the country; and thence eastward, exhibits upon the surface no evidence 
of its existence. 
