286 
GEOLOGY OF THE FOURTH DISTRICT. 
district, must be regarded as evidence of the former existence of the rock at these points, or 
farther to the north.* 
In some places where this rock is a sandstone, the marks of furrows and striae are still 
clearly preserved upon its surface; showing the influence of that denuding agency which 
removed the greater part of the rock, and probably the same which excavated the deep valleys 
crossing this part of the country from north to south, as well as many lesser ones in other 
directions.t The prominent outliers of this rock upon the high and distant hills furnish good 
landmarks for showing the extensive denudation which this part of the country has suffered. 
From its great extent northward, it appears very probable that originally some of the lower 
beds of the Pennsylvania coal-fields extended into New-York, and that being of more de¬ 
structible materials than the conglomerate, they have been entirely swept off. This may 
appear more reasonable, when it is stated, that about six miles south of the State line, on a 
high ridge of land between the Allegany river and the Connewango creek, a bed of coal lies 
upon the conglomerate, which latter extends thence northward into New-York, its broken 
outliers appearing for ten or fifteen miles north of the State line4 
133. 
Diagonal lamination .— The diago¬ 
nally laminated structure is often beau¬ 
tifully presented in the broken cliffs and 
large fragments of this rock, and this is 
one of the most obvious characters. 
The illustration No. 133 is of a quarry 
at “Burned hill,” in the south part of 
Allegany county. The alternation of 
horizontally laminated strata shows the 
varying conditions of deposition. The 
stratum below the upper one shows an 
undulated structure very much like the 
rippled surfaces, but not so well defined. 
* I am frequently reminded that these huge fragments, scattered upon the hills in this manner, are the loads deposited by 
immense icebergs, which have here stranded, and subsequently melted away. But however plausible this argument may he, I 
prefer another solution of the phenomena, which appears more in accordance with facts here given. Allhough this would show 
a former extension of the conglomerate to points twenty miles north of where it is now known in place, the inference seems 
unavoidable, and well substantiated. 
f The points where these striae and furrows occur are on some of the highest hills in Chautauque county, and nearly two 
thousand feet higher than similar markings along the borders of Lake Ontario. 
$ There is another conglomerate in Chautauque county, and in some places in Allegany county, which was briefly noticed under 
the Chemung group. This, however, is a thin mass, and wherever it has been found in place, is associated with fine grained 
compact sandstones, and frequently contains the fossils of the Chemung group. In the northern part of Chautauque county, l 
found some loose masses of this conglomerate, containing lossils known to belong to the Chemung group, and by this they were 
chiefly identified. The aspect of the rock is also somewhat different; the pebbles smaller, more round, and not of the same white 
quartz which occurs in the higher rock. 
Diagonal lamination in sandstone. 
