248 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
1. Zone of Diplograptus amplexicaulis, Corynoides calicularts, ete. 
As one goes further west the limestone at the base of the section 
becomes thicker and it is found that the graptolites characteristic of 
the lower part of the shale at Canajoharie are not present, but the 
lowest of the shale beds, resting on the limestone, contain species 
which first appear high in the section at Canajoharie. 
At Dolgeville, half way between Canajoharie and Utica, where the 
lower 200 feet of the Trenton is limestone, the first shale bed contains 
Glossograptus quadrimucronatus, Climacograptus typicalis, and Lasio- 
graptus eucharis, which is interpreted by Ruedemann as being a fauna 
younger than that of zone 2 above, since Climacograptus typicalis is 
best developed in the still higher Utica shales. 
In the typical Trenton at Trenton Falls, Diplograptus amplexicaulis 
is arather common graptolite in the lower part of the formation, where 
it is found in limestone. (See Fig. 1, p. 257). 
THE TYPICAL UTICA, OR ZONE OF PLEUROGRAPTUS LINEARIS. 
At Holland Patent and South Trenton, New York, where the black 
shale of the typical Utica rests upon the top of the Trenton limestone 
not far from the type-locality, the following fauna has been found: — 
Callograptus compactus (Walcott), Dicranograptus nicholsoni Hop- 
Climacograptus typicalis Hall, kinson, 
C. putillus (Hall), Glossograptus quadrimucronatus 
Mastigograptus simplex (Wal- Hall. var. 
cott), Lasiograptus eucharis also occurs 
M. tenuiramosus (Walcott), nearby and in beds a little 
Pleurograptus linearis (Carruth- higher in the section. 
ers), L. bimucronatus timidus Ruede- 
Leptograptus annectans (Walcott), mann. 
This may be taken as the typical Utica fauna, but it may be re- 
marked that it has not been found in its entirety, at any other locality. 
Associated with these graptolites one finds also Triarthrus becki and 
Cryptolithus tessellatus. It will be noted that in the above fauna there 
are certain graptolites which are found at a lower horizon, such as 
Climacograptus typicalis, Glossograptus quadrimucronatus, and Lasio- 
graptus eucharis. Mastigograptus simplex has until recently been 
found only at Holland Patent and the immediate vicinity. Lasio- 
graptus bimucronatus timidus, Leptograptus annectans, and Mastigo- 
aS ee ee eer ee 
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