REPORT OF THE DIRECTOR I919 I15 



Stromatocerium sp. 



Lasiograptus eucharis (Hall) 



Arthrostylus cf. obliquus Ulrich (fide Ulrich) 



Leptobolus insignis Hall 



Schizocrania filosa Hall 



Dalmanella rogata Sardeson 



Conularia trentonensis Hall 



Isotelus cf. latus Raymond (pygidium & pleurae) 



This faunule, small as it is, suggests a lower and middle Trenton 

 age of the beds, as before inferred by Ulrich. It is then probable 

 that these slaty limestones are in part at least equivalent to the Cana- 

 joharie shale. They represent, however, lithologically and faun- 

 istically, a different facies, and were clearly deposited under different 

 conditions, if not in a separate basin, and should for that reason be 

 distinguished by a name of their own. 



The " Utica " shale forms a broad belt in Vermont from the Cana- 

 dian boundary line southward over the islands of the lake, especially 

 North Hero and Grand Isle (see Perkins 1904, p. 103) and attains 

 there a considerable thickness. This shale is described by the Ver- 

 mont geologists as being remarkably barren of fossils, T r i a r - 

 thrus becki and " Diplograptus" being the only 

 fossils mentioned as common in places. This combination of 

 Triarthrus becki and Glossograptus quad- 

 rimucronatus (the "Diplograptus pristis" 

 of the earlier authors) , as well as Climacograptus typi- 

 cal i s which the writer has collected on Grand Isle, indicate that 

 the Stony Point shale reaches, on the Vermont side, in pretty strong 

 development to the middle of the Champlain basin. 



There is, however, little doubt that the Canajoharie shale which 

 reaches such great thickness along the Panton shore, only 30 miles 

 south of South Hero, is also still represented in the lower part of the 

 black shale mass of the island "' and its fauna is still recognizable in 

 the shaly limestone at Alburg, close to the Canadian boundary. 



The black Ordovician, so-called " Utica " shales of the Champlain 

 basin consist then in the south entirely of Canajoharie shale, in the 

 north prevailingly of the Stony Point shale. In the middle they may 

 meet; the Stony Point shale resting upon the Canajoharie shale on 

 Grand Isle and in the Vermont portion of the northern part of the 

 basin; while on the New York side the Canajoharie shale is replaced 

 by the peculiar facies of the Cumberland Head shale, the latter plac- 



' The U. S. National Museum, for instance, contains specimens (no. 15244). 

 of Lingula (Palaeo gloiSisa) trentonensis (Conrad) 

 from the " Utica " of Grand Isle, Lake Champlain. 



