446 NEW YORK STATE MUSEUM 



as also occurring in Ireland. Hall found it in considerable number in the 

 Normanskill shale at the Normanskill. The writer has observed it in nearly 

 all of the many outcrops of the Normanskill shale (Dicellograptus zone) in 

 the slate belt of New York, often in profusion, especially so at Glenmont, 

 south of Albany ; at Mt Moreno near Hudson and in localities in Wash- 

 ington county ; and in a mutation [see below] also in beds transitional from 

 the Trenton to the Utica shale at Van Schaick island below Cohoes, in 

 association with Utica fossils (Climacograptus putillus, L e p t o - 

 bolus i n s i g n i s , Schizocrania f i 1 o s a) . In Canada Ami has 

 found it in Normanskill beds at Point Levis near Quebec and Lapworth 

 has recognized it in collections from the Upper Trenton zone at Quebec. 

 Lately Ami has also announced its occurrence in New Brunswick. Gurley 

 cites it further from the beds at Mystic and Magog in Canada. In the west 

 of the continent it occurs, according to Lapworth, in beds at the Kicking 

 Horse pass, and at Dease river, British Columbia. Gurley has reported it 

 from the " Upper Calciferous zones" of Arkansas and Nevada. T. S. Hall 

 has this year described it from Victoria, Australia, and Perner has identified 

 a form from d \y in Bohemia with Carruthers's species. 



It is evident from these citations that this small peculiar graptolite 

 possessed not only a considerable range and ma}' have extended from the 

 Chazy formation to the base of the Utica, but was also well established in 

 Trenton time in both the Atlantic and Pacific oceanic basins, and their 

 border seas, as the Appalachian and Bohemian-Mediterranean basins. I have 

 not seen it cited from the Baltic basin, but doubt that it was absent there. 



Remarks. This most remarkable graptolite has baffled the attempts 

 of paleontologists to elaborate its obscure structure and led to the erection 

 of various species, until Lapworth succeeded in unraveling the mystery 

 and described the true form of the thecae. 1 We can do no better than copy 

 his description [1880, p. 173 f] here: 



1 A peculiar variety {see fig. 411,416] characterized by thinner rhabdosome and 

 somewhat < loser arrangement of the thecae (12-13 thecae in 10 mm) lias been observed in 

 an outi rop of Normanskill shale near Speigletown north of Troy, 



