252 
GEOLOGY OF THE FOURTH DISTRICT. 
generally, however, there is a tinge of green or olive pervading these strata. Towards the 
upper part of the group, in many places, there is a tendency to conglomerate ; and in a few 
localities the mass becomes a well-characterized puddingstone, still retaining the fossils of the 
shales and sandstones. This conglomerate nowhere attains sufficient thickness or importance 
to merit a distinct description; but in hasty observations it may sometimes lead to erroneous 
inferences, since it resembles in many respects the distinct and well-defined conglomerate 
which rests upon this group in the western part of the State, but which is totally distinct from 
the same. 
Many of the shaly sandstones and shales of this group are highly micaceous ; and towards 
the upper part of the whole, the shales are reddish, coarse and fissile, with much mica in 
small glimmering scales. There is also in these shales a slight change in the character of 
the prevailing organic forms. 
From being well developed along the Chemung river at numerous localities, and particularly 
at the point represented in the woodcut at the head of the group, this name has been adopted 
for its designation. 
These strata rise to the south from the Portage group, forming the higher elevations of the 
southern counties, and covering nearly the whole surface of the same. The greatest elevation 
of these hills is about 2500 feet above tide water, and from 600 to 1000 feet above the deepest 
valleys of the surrounding country. 
The outline section crossing this part of the State from east to west (PI. 12), will give an 
idea of the general contour of the surface. The deep valleys are bounded by abrupt hills, 
while the surface between them is, for the most part, but moderately undulating. This feature 
of the surface is entirely due to denudation, the valleys being all produced by this cause, and 
the slight undulations in the strata have scarcely affected the surface in any perceptible man¬ 
ner. The evidence of the denuding action is often plainly visible in some of the harder strata, 
but the perishable nature of most of them has obliterated all traces of this kind. An inspec¬ 
tion of the sections crossing these counties in a north and south direction (Plates 9, 10, 11 
and 12, as well as the outline section), where the comparative elevations are given, will suffice 
to give an impression of the vast amount of material removed. The outliers of conglomerate 
resting on some of the higher hills of this group also prove the same fact, and show how 
powerfully and effectually this agency has operated. An inspection of the map also shows 
numerous points of the same, often with broad and deep valleys between them. In the val¬ 
leys in this group are some of the highest lakes in the country; these will be noticed in 
another place, with their elevations. 
The numberless natural sections along the deep ravines and river channels afford good 
opportunities of studying this group in all its various developments throughout the district. 
In many situations, its relations to the groups below can be distinctly traced in an almost 
continual line of section from the Hamilton group upwards. Its relations with the rocks 
above it are not so clearly seen in many localities within the State, but they are sufficiently 
so for satisfactory investigation, and localities beyond the limits of the State present the same 
order in the most conclusive manner. 
