380 
[Assembly 
Marcellus to Skaneateles, we find in ascending the shales, that fossils 
begin to appear, the first is an orthis; a new species appearing here for 
the first time, and continues with many interruptions through several 
groups, if there be but one species of it. Still higher we find the 
shales of Skaneateles, which cover the north end of both sides of the 
Lake of its name, and which at present we consider as a mass, or 
series distinct from those above or below. 
Skaneateles shales. These are highly fossiliferous, but the fossils 
do not differ from those of the Moscow shales that I am at present aware 
of. The great thickness of rock between the two masses is the reason 
why we at this time separate them. 
Hamilton group. In this group we have shales and sandstone, the 
former dark blue, olive, &c. West Hamilton is the locality where it is 
well characterized, also Cazenovia, Pompey Hill, &c. being one of 
the south rocks whose range is uninterrupted through the district, cover- 
ing considerable ground south and north. In this rock we find the 
Dipleura, DeKayi, Orthoceris constrictum, Cyrtoceras maximum, Po- 
sidonia lirata, Goniatites punctatum, Conularia , a large Orbicula, 
with abundance of Aviculae, Pterenea, &cc. with a re-appearance of the 
Fucoides cauda galli, should the species be the same. In this group 
we find many layers suitable for building purposes, and quarries are 
numerous along its range, being the best stone either north or south, 
for some distance. Near to Cayuga lake this group is separated from 
the next one by an encrinal limestone, which is not observable toward 
Madison. 
Moscoiv shales. These shales are various as to hardness, smooth- 
ness, &c. They are found at Tully Four-Corners, under the lim.estone ; 
Ludlowville, below the falls, under the same limestone ; at Moravia, 
Montville, near Sherburne, New-Berlin, Otsego lake, &c. &c., the 
range occurring south or above the former group. This is also a highly 
fossiliferous mass, having plants, with Testaceous and Criistaceous re- 
mains in great abundance ; among them we find the same fucoid last 
mentioned, Delthyris undulatus, D. granulosa, D. distans, Orthis con- 
centrica, Strophomena lineata, S. carinata, Crypheus Greenii, C. cal- 
liteles, &:c. Many fossils are common to the last three divisions, the 
whole together making a mass which cannot be less than from six to 
eight hundred feet where the thickness is greatest. 
