248 bulletin: museum of comparative zoology. 



1. Zone of Diplograptus amplexicaulis, Corynoides caUcularis, etc. 



As one goes further west the Umestone at the base of the section 

 becomes thicker and it is found that the graptoHtes 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 

 Glossographis quadrhnucronatus, Climacograptus typicalis, and Lasio- 

 graptus cucharis, wdiich is interpreted by Ruedemann as being a fauna 

 younger than that of zone 2 above, since CUmacograptus typicalis is' 

 best developed in the still higher Utica shales. 



In the typical Trenton at Trenton Falls, Diplograptus amplexicaulis 

 is a rather 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 : — 



C allog raptus compactus (\\a\cott), . Dicranograptus nicholsoni Hop- 



Cliniacograpfus typicalis Hall, kinson, 



G. putillus (Hall), ^Glossograptus quadrimucronatus 



Mastigograptus simplex (Wal- Hall. var. 



cott), Lasiograptus eucharis also occvirs 



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 graptoHtes one finds also Triarthrus becki and 

 Cryptolitlms tessellatus.^ It will be noted that in the above fauna there 

 are certain graptoHtes which are found at a lower horizon, such as 

 Climacograptus typicalis, Glossograptus quadrimucronatus, and Lasio- 

 graptus eucharis. Mastigograptus simplex has until recently been 

 foimd only at Holland Patent and the immediate vicinity. Lasio- 

 graptus bimucronatus timidus, Leptograptus annectans, and Mastigo- 



