214 PROCEEDINGS OP THE AMERICAN ACADEMY 



In May, 18G3, Sir "William E. Logan published his " Geology of 

 Canada, 1863. — Geological Survey of Canada; Report of Progress 

 from its Commencement to 1803 ; accompanied by an Atlas of Maps 

 and Sections." A large volume of more than 900 pages (Montreal, 

 8vo). 



Let us notice first the contradiction between the text and the geo- 

 logical map. 



'' The Quebec Group," or Chapter XL, is placed in the description of 

 the stratigrapliic series between Chapter X., "• The Utica and Hudson 

 Kiver Formations," and Chapter XIL, "The Auticosti Group and the 

 Guelph Formations"; that is, between the second and third fauna?. 

 But in the text (p. 225) Logan says: "Although from their geo- 

 graphical position apparently superior to the Hudson River formations, 

 these rocks belong in reality to an older group, which is developed 

 to a great extent in Eastern Canada, and presents somewhat different 

 characters in the various parts of its distribution. The rocks of this 

 series are still under examination, and the descriptions now given may 

 hereafter require to be somewhat modilied." 



Thus, in 1863, Logan reconsiders the opinions expressed in Ins letter 

 to Barrande, of 1861, and his acquiescence in the opinions long main- 

 tained by Emmons. Li the Geological IMap of Canada, instead of 

 placing the Quebec group above the Hudson River, as he does in the 

 text, he places it below the Birdseye and Black River group ; and 

 even more, he identifies it with the Chazy limestone and the Calcif- 

 erous group, an error as glaring as putting the Georgia slates with 

 Olenellus, above the Utica and Lorrain groups. 



In Chapter II., " Geological Nomenclature," (p. 20.) the Quebec 

 group represents the Calciferous and the Chazy, and, further, the Cal- 

 eiferous is identified with the Levis, and the Chazy with the Sillery; 

 two errors as incomprehensible as the position of the OleneUus schists 

 of Georgia at the top of the second fauna. Towards the close of the 

 volume (p. 836), the supplementary Chapter XXII. gives the results 

 of his researches in 1862 and 1863. The Quebec group is again de- 

 scribed at length, from pages 844 to 880. In the Atlas accompanying, 

 sections are given, and a geological map on a large scale, with the 

 title, "Map showing the Distribution of Rocks belonging to the Pots- 

 dam, Quebec, and Trenton Group on the east side of Lake Cli:\mplain 

 in the Neighborhood of the Line between Canada East and Vermont." 

 In the explanation of the colors, there are only three divisions, the 

 Trenton, the Quebec, and the Potsdam, arranged in their supposed 

 order of superposition. 



