90 
GEOLOGY OF THE THIRD DISTRICT. 
At the mill in the bed of the creek, rising for about eight feet in the bank, is a yellow green 
shale. It contains some fossils, among which is the Broad agnostis, and an Avicula yet 
unnamed; above which are thin layers of limestone composed entirely of Shining orthis 
(Orthis nitens), the same which occurs above the pentamerus limestone in the fourth district. 
The mass is covered with about fifteen feet of alluvion, at the bottom of which were fragments 
of light-colored hard limestone with ore adhering to it, showing that a deposit exists in the 
vicinity. 
The last point in the district where the group was observed, was towards the west of the 
town of Stirling, on the land of Peter P. Van Patten. There one of the ore beds exists near 
the surface, numerous fragments being often ploughed up. 
The same fossiliferous iron ore, so characteristic of this group, is found, according to Dr. 
Locke, in Clinton county, Ohio, near the bottom of the cliff limestone, which is its proper 
position. The peculiar fucoids of the Clinton group (the bilobe and unilobe) are also found 
near Cincinnati in the same position, showing the extent of its range and the value of the fossil 
character. 
11. NIAGARA GROUP. 
Tjockport Group. Upper part of the Protean Group, of the Reports. Geodiferous Limerock 
and Calciferous Slate of Eaton. 
This group consists of limestone of a dark blue or black color, and of dark shale or slate. 
When the limestone is but small in quantity, it is in hemispheric concretions, whose parts 
are more or less concentric to each other, like the coats of an onion. The group is very 
thick in the fourth district, and forms the rocks of Niagara falls; but it thins out to the east, 
leaving not a trace to be seen east of a line passing south through the village of Mohawk in 
Herkimer county. It first appears in Steele’s creek, to the southwest of that village ; then 
in Swift creek, near the road from Sauquoit creek to Paris hill; at Hart’s mill, on the east 
branch of the Oriskany; in the ravine back of Dr. Noyes’ house, near Hamilton college; in 
Skanandea creek at Vernon village ; on the same creek also back of Turkey-street; south of 
Oneida lake ; in the north parts of the towns of Lenox and Sullivan in Madison county; and 
in the towns of Cicero, Clay, Lysander, Ira and Victory in Onondaga and Cayuga counties. 
From the east end of Madison county, it appears generally as a concretionary mass, in one 
or two layers, enclosed in dark blue slate or shale, not hard, the concretions varying in size 
from an inch to two or three feet in diameter. It is there too impure to be used as a lime¬ 
stone, and it is but small in quantity; but in Madison, and particularly in Onondaga and 
