THE FOUNDING OF THE " QUEBEC GROUP." 455 



the presence, at many points, of great numbers of fossils, principally grap- 

 tolites. Large collections were made by Logan, Richardson, and others, 

 which were submitted to Professor James Hall, of Albany, and upon exam- 

 ination were found to be in many respects unlike those from the recognized 

 Utica or Lorraine of New York; but they were at the time regarded as 

 probably representing the Hudson River division of the Champlain group. 



Hunt's Studies. — Hitherto the views as to the Hudson River age of many 

 of these rocks were held to be firmly established by the stratigraphical suc- 

 cession of the beds; since there appeared to be a regularly ascending series 

 from the well-defined Trenton on the north side of the St. Lawrence to the 

 summit of the fossiliferous shales of Levis. Further collections of fossils 

 were, however, made from the rocks opposite Quebec, and in 1856 Dr. T. 

 S. Hunt succeeded in finding in the limestone beds of Levis the imperfect 

 remains of a trilobite which appeared to be new. Stimulated by this dis- 

 covery, a vigorous search was at once commenced in the calcareous beds of 

 that place, and many of these were found to be richly fossiliferous — so much 

 so that in a short time nearly 170 species were obtained, not including the 

 graptolites. These were handed for determination to Mr. E. Billings, who 

 found that of this number five were peculiar to the Chazy and twelve to 

 the Calciferous, while yet others had a true Potsdam aspect, and none were 

 observed which indicated a Utica or Hudson River horizon. 



This somewhat startling discovery at once overturned the conclusions so 

 long held as to the Hudson River age of the strata at Levis and vicinity, 

 and led to the reversal of their positions from the top to the base of the 

 Champlain division. 



The Founding of the "Quebec Group." — After a careful examination of the 

 evidences obtained by Billings, Sir William Logan, in a letter to Barrande, 

 dated December, 1860, and made public in March, 1861, in the American 

 Journal of Science, expressed the opinion that these rocks represented a great 

 development of strata about the horizon of the Chazy and Calciferous, 

 brought to the surface by an overturned anticlinal fold, with a crack and 

 a great dislocation running along the summit, by which the rocks in ques- 

 tion were brought to overlap the Hudson River formation. At the same 

 time he stated that "from the physical structure alone no person would sus- 

 pect the break that must exist in the vicinity of Quebec, and without the 

 evidence of the fossils every one would be authorized to deny it." To these 

 rocks the name "Quebec group" was now for the first time applied. 



With the light thus thrown upon their structure by the determination of 

 the great series of fossils from the Levis beds, the new " Quebec group " 

 now entered upon an entirely distinct stage of discussion. It was soon divided 

 into two portions, styled the Levis and the Sillery, of which the former was 

 again subdivided into seventeen parts, representing a total thickness of 5,025 



