22 NEW YORK STATE MUSEUM 



P. pumila Ulrich 

 Stictoporella cf. angularis Ulrich 

 S. exigua Ulrich 

 Phaenopora incipiens Ulrich 

 Dalmanella futilis (Sardeson) var. 

 Rhynchotrema increbescens (Hall) 

 Eurychilina subradiata Ulrich var. 

 Calymmene senaria Conrad 

 Pterygometopus callicephalus (Hall) 

 Trinucleus concentricus (Eaton) 



The shaly intercalations have afforded us: 



Rafmesquina alternata (Emmons) (c) 



Leptobolus insignis Hall (c) 



Lingula curta (Conrad) (c) 



Dalmanites (Pterygometopus) callicephalus Hall (r) 



Diplograptus amplexicaulis Hall (cc) 



Diplograptus (Mesogr.) mohawkensis (c) 



Corynoides calicularis Nicholson (r) 



Ctenodonta cf. nuculiformis Hall (r) 



Ulrichia ? bivertex Ulrich (c) 



Primitiella unicornis Ulrich (r) 

 Small ostracods of Primitia type 



It will be noted that the shaly intercalations of the Trenton 

 limestone contain two of the most characteristic graptolites cited 

 above from the basal " Utica " shale in the neighborhood of Amster- 

 dam. Likewise it will be seen that also in the Canajoharie section 

 these graptolites and all the other fossils observed in these shaly 

 intercalations go up into the black " Utica " shales. 



The fauna of both the limestone and the shaly intercalations is 

 of earliest or basal Trenton age. 



This belt of basal Trenton limestone with the underlying Amster- 

 dam limestone can be traced by outcrops, rather widely separated 

 through the faulting of the region, around the southeast side of the 

 Adirondacks to Saratoga and Glens Falls. Since these beds are 

 lower than any exposed at Trenton Falls, their reference to the 

 Trenton is likely to lead to confusion and they should be recognized 

 by a distinct name. For a time we have termed them the Jackson- 

 burg limestone, but since the latter unit, recognized in New Jersey 

 (title 59), also comprises beds of Amsterdam and Lowville age, it 

 is not properly applicable to the limestone in question. As the 

 latter is best exposed at Glens Falls with the underlying Amsterdam 

 (Black Marble) limestone and overlying Canajoharie shale, we pro- 

 pose for it the term Glens Falls limestone. 



