562 Prof. T. Stern/ Hunt — On Cambrian and Silurian. 



the probable equivalent of the Obolus or Ungulite grit of St. Petersburg. Thus 

 Emmons, in 1842, asserted, on lithological and stratigraphical grounds, the 

 existence, beneath the base of the New York system, of a lower and unconform- 

 able series of rocks, in which, in 1844, he announced the discovery of a distinctive 

 fauna. Hall, on his part, asserted in 1842, and more fully in 1847, that the New 

 York system itself held an older fauna than that hitherto known in the British 

 rocks. 



It is not necessary to recall in this place the details of the long and unfortunate 

 Taconic controversy, which I have recently discussed in my address before the 

 American Association for the Advancement of Science, in August, 1871. It is 

 however to be remarked that Hall, in common with all other American geologists, 

 followed Henry D. Rogers in opposing the views of Emmons, whose Taconic system 

 was supposed to represent either the whole or a part of the Champlain division of 

 the New York system ; which included, as is well known, all of the fossiliferous 

 rocks up to the base of the Oneida conglomerate (and also this latter, according to 

 Emmons) ; thus comprehending both the first and the second Palseozoic fauna ; as 

 shown in the Table on page 510. 



So early as 1827 Dr. Bigsby, to whom North American geology owes so much, 

 had given us (Trans. Geol. Soc, 2nd series, vol. i. p. 37) a careful description of the 

 geology of Quebec and its vicinity. He there found resting directly upon the 

 ancient gneiss, a nearly horizontal dark-coloured conchiferous limestone, having 

 sometimes at its base a calcareous conglomerate, and well displayed on the north 

 shore of the St. Lawrence at Montmorenci and Beauport. He distinguished 

 moreover a third group of rocks, described by him as a "slaty series composed of 

 shale and greywacke, occasionally passing into a brown limestone, and alternating 

 with a calcareous conglomerate in beds, some of them charged with fossils .... 

 derived from the conchiferous limestone." (This fossiliferous conglomerate con- 

 tained also fragments of clay-slate.) From all these circumstances Bigsby con- 

 cluded that the flat conchiferous limestones were older than the highly inclined 

 greywacke series ; which latter was described as forming the ridge on which 

 Quebec stands, the north shore to Cape Rouge, the Island of Orleans, and the 

 southern or Point- Levis shore of the St. Lawrence ; where, besides Trilobites, and the 

 fossils in the conglomerates, he noticed what he called vegetable impressions, 

 supposed to be fucoids. These were the Graptolites which, nearly thirty years 

 later, were studied, described, and figured for the Geological Survey of Canada 

 by Prof. James Hall ; who has shown that two of the species from this locality 

 were described and figured under the name of fucoids by Ad. Brongniart, in 1828. 

 (Geol. Surv. Canada, Decade ii. p. 60.) Bigsby, in 1827, conceived that the lime- 

 stones of the north shore might belong to the Carboniferous period, and noted the 

 existence of what were called small seams of coal in the greywacke series of the 

 south shore, v^hich substance I have since described in the Geology of Canada 

 (page 525). 



In 1842, the Geological Survey of Canada was begun by Sir William Logan, 

 ■who, in a preliminary report to the Government in that year (p. 19), says, "Of the 

 relative age of the contorted rocks of Point Levis, opposite Quebec, I have not 

 any good evidence, though I am inclined to the opinion that they come out from 

 below the flat limestones of the St. Lawrence." He however subsequently adds, in 

 a footnote, ' ' The accumulation of evidence points to the conclusion that the Point 

 Levis rocks are superior to the St. Lawrence limestones." [The views of Bay- 

 field are here discussed, also the later observations of Logan.] 



The concurrent evidence deduced from stratigraphy, from geographical dis- 

 tribution, from lithological and from palseontological characters, thus led Logan, 

 from the first, to adopt the views expressed by Bigsby, Emmons and Bayfield, 

 and to assign the whole of the Palaeozoic rocks of the south-east shore of the St. 

 Lawrence, below Montreal, to a position in the New York system above the 

 Trenton limestone. While thus, as he says, founding his opinion on the strati- 

 graphical evidence obtained in Eastern Canada, Logan was also influenced by the 

 consideration that the rocks in question were continuous with those in western 

 Vermont. Part of the rocks of this region had, as we have seen, originally been 

 placed by Emmons at this horizon ; while the others, referred by him to his 

 Taconic system, were maintained by Henry D. Rogers to belong to the Pludson- 

 River group ; a view which was adopted by Mather and by Hall, and strongly 



