mi Geology of Portion of Provinc* of Quebec. 105 



Bret notice <>t* tin 1 rocks in tbe vicinity of Quebec, in 1 S2 7, by 

 Dr. J. Bigsby, to Professor Jules Blarcou'a essay in 1S88. 

 From the study of the Literature and of all the original area of 

 the "Quebec (iron])," including the mapping or the entire 

 area, Dr. Ells concludes that : 



"The name 'Quebec Group,' which lias for so many years 

 ti applied to much of the rocks of this portion of the prov- 

 ince of Quebec, has become so misleading and unintelligible in 

 view of the many new facts brought to liffht concerning its 



composition and structure, by the study of the past fifteen years 

 and the many changes rendered necessary in consequence, that its 

 further use appears not only undesirable but to a certain extent 

 objectionable. It was applied by Sir \V. Logan to a great series 

 of sediments which were deemed to lie somewhere about the 

 horizon of the Calciferous and Chazy formations. Dr. Selwyn 

 and others have, however, since 1S70, pointed out that it has 

 been found to embrace rocks ranging from the Pre-Cambrian to 

 the Hudson River or Lorraine, both inclusive. An almost entirely 

 new arrangement of the different formations which make up the 

 group is therefore imperative. In the case of such portions of 

 the original group, the horizon of which lias been definitely 

 determined, the proper name of the formation can be readily 

 applied, while in the case of such portions, either distinctly fossil- 

 iferous, or closely related areas the exact position of which in the 

 Geological scale may be doubtful, the terms Levis or Sillery, 

 with their system classification, may be retained" (p. 6K). 



The author then proceeds to give, after the brief historical 

 sketch, a description of the rocks referred to the " Quebec 

 Group'' by Sir Wm. E. Logan. 



In the historical review it is stated that the first notice of 

 the rocks of the " Quebec Group " by Sir William Logan, was 

 published in 1845. He then expressed the view that u the 

 r<>cks on Point Levis come out from beneath the limestone of 

 the St. Lawrence, and belong to an apparently older horizon f 

 but in a foot note it is stated : " The bulk of evidence points to 

 their superior position, which would make them the equiva- 

 lents of the Hudson River and Lorraine shale formation/' 



In the report of progress for 1849, it is stated "that another 

 formation, contemporaneous with the Hudson River of Xew 

 York, superior to the Trenton limestone, but also far beneath 

 the same Carboniferous deposits, extended from Point Levis 

 to Cape Rosier." 



In the Esquisse Geologique of 1855, by Logan and Hunt, 

 the rocks which form the cliffs of Quebec and Point Levis are 

 referred to the Hudson River group, and the series of sand- 

 stones and shales, named the Sillery group, are considered 

 equivalent to the Shawangunk or Oneida conglomerate of the 

 Xew York section. 



