150 THE CAMBRIAN. [inxuSl. 



scribes Palwophycus rectus (p. 862), Buthotrephis (?) asteroides (p. 8G3), 

 Helminthoidichnites tenuis (p. $66), from the slates now referred to the 

 Lower Cambrian. Me also mentions Palwophycus virgatus Hall, Butlio- 

 trephis (?) flexuosus Emmons (p. 862), and Gordia marina of Emmons 

 as Helminthoidichnites marina (p. 868). 



The fauna of the " Red sandrock" of Vermont was first discovered 

 by Prof. C. B. Adams in 1847, 1 who sent the specimens to Prof. James 

 Hall. The latter identified Oonocephalus, but did not refer the fossils 

 to any geological horizon. Prof. Adams in 1848 2 mentions the Oono- 

 cephalus and also an Atrypa, like Atrypa hemispherica (equivalent to 

 Camerella f antiquata Billings). 



Mr. E. Billings, as paleontologist to the Geological Survey of Canada, 

 took up the study and correlation of the older paleozoic faunas, and 

 was the first to assign the fossils described by Prof. Hall to a pre-Pots- 

 dam horizon and to correlate the strata containing them with the 

 Upper Primal sandstones of Pennsylvania, and the limestones of the 

 Straits of Belle Isle. 3 



In 1861 he described a number of Lower Silurian fossils from the 

 " Potsdam group " of Vermont and assigned the following species to the 

 horizon of Paradoxides thompsoni of Hall : Palwophycus congregaUis, P, 

 incipieriSj Obolella (Kutorgina) cingulata, Orthisina fcstinata, Camerella 

 antiquata ,Gonocephalites adamsi, C. teucer, C.vulcanus, C.arenosus. 



A little later he published a note on the u Red sandrock w formation 

 of Vermont, 4 in which he refers the formation to the base of the Lower 

 Silurian somewhere within the horizon of the Potsdam and identifies 

 Couocephalites from the formation. In reprinting in 1865 the article 

 published in 186 1 5 he correlates the primordial fauna of the u Red sand- 

 rock " of Vermont with that of Newfoundland and Labrador, and refers 

 them to the Potsdam group, stating that there is no paleontological 

 evidence of precise similarity of age, but the general affinities and scope 

 of the fossils and the physical relations of the rocks prove that there 

 can be no great difference. 



Under the title " On some new species of fossils from the limestone 

 near Point Levi, opposite Quebec." 6 Mr. Billings described the fauna 

 collected by the Geological Survey of Canada from the limestone con- 

 glomerate. He designated the rocks simply as Limestone JSos. 1, 2, 3, 

 and 4, not recognizing at the time that the bowlders were transported 

 and imbedded in a secondary deposit; and that the fossils in the bow 1- 



1 3d Annual Report on the geology of the State of Vermont. Burlington, 1847, pp. 31. 



2 On the Taconic rocks. Am. Jour. Sci., 2d ser., vol. 5, 1848, p. 109. 



3 Paleozoic fossils, vol. 1. Containing descriptions and figures of now or little known species of or- 

 ganic remains from the Silurian rocks. 1860-1865. Montreal, 1865, pp. 1, 2. 



4 Billings, E. : On the age of the Red sandstone formation of Vermont. Am. Jour. Sci., 2d ser., vol. 

 32, 1861, p. 232. 



6 Billings, E. : Palezoic Fossils, vol. 1, 1865, p. 371. 



* On some new species of fossils from the limestone near Point Levi, opposite Quebec Canadian 

 Nat., voL 5, 1860, pp. 301-324. 



