36 
GEOLOGY OF THE FOURTH DISTRICT. 
1. Red marl, and marly or shaly sandstone, sometimes banded and spotted with green; the bands hori¬ 
zontal, or parallel to the strata, and vertical. 
2. Grey quartzose sandstone, entirely distinct from the mass below. 
3. The lower part is merely a repetition of No. 1; gradually passing into a more sandy form in the 
western portion of the district, while in the eastern portion the whole of this division is more 
siliceous, the central mass (No. 2) not appearing. 
4. The grey or greenish grey terminal portion of the mass, which in the Third district is considered 
a distinct rock, forming the Oneida or Shawangunk conglomerate. In the Fourth district, it 
always appears more or less as a part of the Medina sandstone, possessing the same lithological 
features. 
l. Red Marly or Shall' Sandstone. 
Throughout the counties of Niagara, Orleans and Monroe, the lower part of this rock is a 
soft red shale or marl, with but a small admixture of siliceous matter. It coheres but slightly 
where weathered, and readily decomposes to a loamy clay. When exposed in the banks of 
ravines and streams, it presents a cracked and crumbling appearance; the surface crossed in 
every direction by seams, separating the whole into small angular fragments, which are con¬ 
stantly softened and detached by the weather, exposing a fresh surface which in turn undergoes 
the like changes. The first appearance, after being broken down in this manner, is that of 
cubical or angular fragments, which are easily crushed in the hand, mixed with a smaller 
proportion of soft clay. The process of disintegration goes on till the whole is reduced to a 
clayey soil of a brick-red or brownish color. These changes may be witnessed on the banks 
of the Niagara at Lewiston, the banks of the Genesee below Rochester landing, and in nearly 
all the small streams crossing the Ridge road between the Genesee and Niagara rivers. 
In Wayne county, the lower division of this rock can scarcely be said to exist, though that 
portion near the level of the lake possesses in a considerable degree the same characters. The 
color of the decomposing rock has been communicated, often in a high degree, to the soil above. 
This is more particularly seen where the covering of transported materials is light, as through¬ 
out all that portion of the country between the Ridge road and Lake Ontario. The same color 
prevails in a less degree much farther south, where the materials derived from the destruction 
of this rock form a large proportion of the drift or transported matter, producing the soil of the 
district. This brownish color of the soil will not be confounded with the deep red color pro¬ 
duced by the destruction of the red k shale of the Onondaga-salt group, which is seen to a great 
extent farther east, but which has had little influence in the Fourth district. 
The uniform texture of this part of the rock, is the cause of the very even surface of the 
country bordering Lake Ontario between the Genesee and Niagara rivers. The same cha¬ 
racter is presented in some degree east of the Genesee, except where interrupted by hills of 
drift. When penetrated to some distance, it appears compact, and is readily quarried into 
large blocks, but it does not withstand the effects of weathering. This has been tested by the 
experience of many years; and the quarries in this division of the rock are now, I believe, 
generally abandoned. 
