188 
GEOLOGY OF THE THIRD DISTRICT. 
more solid or hard rock succeeding, often accompanied by red sandstone or red shale, and the 
grey sandstone sometimes accompanied by thin beds of cornstone, which readily attracts the 
eye, when long exposed to the weather, from its cellular appearance and dark umber color; 
the former caused by the removal of accretions, etc. of limestone, and the latter by the oxida¬ 
tion of iron and manganese associated with the calcareous material. Above all these, and 
usually capping the whole, was the complex structured sandstone, of which the wood-cut is 
intended to give some idea. 
The fossils which have been observed in this group in this State so far, are but few in 
number, the group being very barren; and so also in Pennsylvania, where the rock has con¬ 
siderable surface distribution and great thickness. In this State, the only ones which with 
certainty could be referred to it, are the two shells figured at the head of the group, from 
Richmond’s quarry, above Mount Upton on the Unadilla. The half probably of a third species 
was also found at this quarry, but no other fossils, except vegetable remains of the smoother 
sort, or rather the kind without marks or configurations, having simple lanceolate forms. 
No. 1. Catskill cypricardite (C. catskillensis). This species is the most numerous, appearing to exist 
in great numbers at the quarry; besides its greater width, it is distinguished from the next species 
by the circle on the sides, curving at a higher point on the back. 
No. 2. Narrow cypricardite. (C. angustata), exhibiting the back and side. They have very much the 
appearance of fresh-water shells. They are considered by Mr. Conrad to belong to the genus 
named, but the generic character is wholly obscure. The circles with which the sides are marked 
as above mentioned, curve at a lower level than in those of the preceding species. 
In this group, both in England and in Pennsylvania, are the remains of a peculiar class of 
fish, which show the value of the fossil character, since the position of the rock is well esta¬ 
blished ; holding the place of base to those of the coal in both countries ; being above the De¬ 
vonian system according to some geologists, or forming its upper member according to others, 
just as it may be included in or excluded from that system. These remains have been found 
in many places in Pennsylvania, and some of them are described by Mr. Hall. As yet but 
small fragments only have been seen in this State. They exist in the cornstone near Oneonta, 
and in the same mass near Oxford, and no doubt will generally be found in that fragmentary 
portion. The small fragments in the cornstone show that besides containing accretions of lime¬ 
stone or carbonate of lime, it also contains those which have been subjected to a mechanical 
action, which has rounded some of its particles. 
Though shells and bones are rare in this group, plants appear to be much more numerous ; 
accumulations existing similar to those of the Ithaca and Chemung groups, but in greater 
number and frequency, and giving rise to thin seams of coal; none of which, however, ex¬ 
ceeded a foot in length or breadth, and an inch in thickness ; and they were generally found 
in the grey sandstone rock. These accumulations are rarely unaccompanied by pyrites, the 
decomposition of which stains the rock of an ochery color. The sandstone, coal and ochery 
appearance, being three of the common characters of the coal in its proper series, is the reason 
