specimen closely resembles the early goniatites, and is fre- 
quently mistaken for one of them. 
Nautilus lratus and N. buccinum, two species of nau- 
tilus proper, are also found in this limestone. 
Gontatites Vanuxem, the goniatite proper found in 
this group, is quite a handsome specimen. It often at- 
tains a large size, specimens a foot in diameter are not 
rare, but on account of the friable nature of the limestone 
it is not always easy to obtain entire specimens. 
Some of the other fossils found in this group are the 
gasteropods: flcurotomaria regulata, Euomphalus plano- 
discus and Macrochilina Hebe. The cephalopods: Gowm- 
phoceras Conradi, G. Fischeri, G. oviforme; and a ptero- 
pod, Colcolus acicula. A handsome little trilobite, the 
Proetus Haldemant, is also found associated with these 
fossils. These specimens are all found in the Goniatite 
Limestone. 
The Hamilton Group.—As has already been stated, the 
shales composing the upper part of the Marcellus Group 
gradually become harder in texture and lighter in color, 
until they have gradually changed into the dark blue 
shales everywhere recognized as the Hamilton Beds, thus 
leaving little or no line of demarkation between the 
groups. In some places, however, there seems to be a 
more abrupt change, which is noted more especially on 
account of the abundance of fossils that suddenly appear 
than by any distinct change in the rock. In other 
places even the fossils begin in shales which are without 
doubt Marcellus, and gradually become more abundant, 
until at last we find them in the greatest profusion in 
rocks that are clearly Hamilton. Nevertheless, it is im- 
possible to say that at any one point the one group begins 
and the other ends. 
This group, which is quite extensive, includes a variety 
of rocks occurring between the Marcellus Shale and the 
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