28 NEW YORK STATE MUSEUM 



This is the characteristic fauna of the base of the typical Utica. 

 It is the Mastigograptus fauna of Schuchert (1910, p. 529). 

 Lasiogr. eucharis appears in great numbers nearby (at 

 Floyd and Marcy) and a little higher up. 



In the Dolgeville and Jacksonburgh sections which lie halfway 

 between Utica and Canajoharie, the base of the " Utica " shale 

 (above the Dolgeville transition beds) shows no trace yet of the 

 Canajoharie faunule, but contains: 



Glossograptus quadrimucronatus 

 Climacograptus typicalis 

 Lasiograptus eucharis 

 Lingula curta 

 Schizocrania filosa 



The dominant Climacograptus typicalis of the 

 true Utica is found but sparingly, and Leptograptus a n - 

 nectans, P 1 e u r o g r a p t u s linearis, Dicrano- 

 graptus nicholsoni and the Mastigograpti are not ob- 

 served at all in the bed. It is therefore probable that the basal 

 " Utica " at Dolgeville- Jacksonburgh and that at Utica do not 

 represent the same horizons, and if so, the former is probably older 

 than the latter. 



From the assemblage of the facts here presented, we infer that 

 at Canajoharie the two lower zones surely and the others most 

 probably lie below the base of the true Utica and correspond in 

 age to some part of the Trenton. For this older black shale of the 

 Mohawk valley we propose the term Canajoharie shale. This stage 

 is characterized by the following species: 



Corynoides calicularis 

 Diplograptus amplexicaulis 

 Diplogr. (Mesogr.) mohawkensis 

 Glossograptus quadrimucronatus var. cornutus 

 Pterinea (Prolobella) trentonensis 

 P. insueta 

 Ulrichia? bivertex 

 Primitiella unicornis 



All these are unknown to us from the Utica shale. A number of 

 forms as Lasiogr. eucharis, Diplogr. putillus, 

 Triarthrus becki, appear in the Canajoharie beds rarely, 

 but become dominant forms in the Utica shale, and others, as the 

 shale brachiopods Lepto bolus insignis and Lingula 

 curta, are equally common to both. The true C 1 i m a c o - 



