162 
GEOLOGY OF THE THIRD DISTRICT. 
with oxide of iron, owing to decomposed pyrites ; and certain portions of it also show an 
effloresence of gypsum. 
There are other points of note, such as Gamble’s mill in Otisco; the ravines near Amber; 
those of South Onondaga; the shores of Skaneateles lake, etc. etc. 
In Cayuga county, the most favorable localities are the falls and gulf at Montville; the 
falls of Moravia, and the lake shore from below Levana to the county line of Tompkins ; and 
thence south to Bloom’s lime-kiln, between the mouth of the creek at Ludlowville and the 
head of the lake. The group is largely exposed along the lake shore, and the numerous small 
streams which empty into the lake; some of which, though very small, flow into deep and 
broad gulfs or ravines, exposing from fifty to two hundred and more feet of the group ; such 
are those through the town of Genoa and further north, and also south to Ludlowville creek 
inclusive. 
The group in Cayuga consists of both the fine and the coarse kinds of shale, the former 
being more abundant, and falling into fragments where much exposed ; and the whole of the 
third or sandstone kind is wanting. 
List of Fossils from the Reports, etc. of T. A. Conrad, identified and named to this time, 
which are found in the Hamilton Group. 
Delthyris mucronata. 
— duplicata. 
— audacula. 
— prora. 
— acanthoptera. 
— fimbriata. 
Strophomena syrtalis. 
Avicula flabella. 
— parilis. 
— perobliqua. 
inequistriata. 
carinata. 
demissa. 
pluristriata. 
lineata. 
angustirostra. 
subquadrans. 
boydii. 
erecta. 
cesopus. 
trilobata. 
pleuroptera. 
subfalcata. 
quadrula. 
Orthonata undulata. 
— carinata. 
Nuculites lamellosa. 
— emarginata. 
— triqueter. 
— oblongata. 
— rostellata. 
— radiata. 
— appressa. 
— alta. 
— multilineata. 
Microdon bellastriata. 
Cypricardites elongatus. 
recta. 
mytiloides. 
alta. 
oblonga. 
rugosa. 
— i radiata. 
subulata, 
indenta. 
truncata. 
