324 THE CANADIAN NATURALIST. [Vol. vi. 



the Geological Section of the British Association, at Manchester, 

 Sept. 1^^61 " :— 



'•'In an able review of this subject, Mr, Sterry Hunt thus expresses 

 liimself: — "We regard the whole Quebec group, with its underlying 

 primordial shales, as the greatly developed representatives of the 

 Potsdam and Calciferous groups (with part of that of Chazy), and the 

 true base of the Silurian system." "The Quebec group, with its 

 underlying shales," this author adds (and he expresses the opinion of 

 Sir W. Logan), " is no other than the Taconic system of Emmons ;" 

 which is thus, by these authors, as well as Mr, James Hall, shown to 

 be the natural base of the Silurian rocks in America, as Barrande and 

 De Verneuil have proved it to be on the continent of Europe," 



The meaning of the above is i^iuiply this : that the age of the 

 Quebec group was determined by Sir W. E. Logan, as physical 

 geologist; Prof. Hall, as palaeontologist, and by Dr. T. S. 

 Hunt, as chemist and mineralogist, an arrangement very satisfac- 

 tory to the latter two gentlemen, but not so to myself. Upon 

 reading the address, I resolved to publish same remarks upon it, 

 but on speaking to Sir W. E. Logan, he thought it best that the 

 matter should be rectified by himself. Accordingly he addressed 

 the following letter to the Editors of the Amer. Jour. Science : 



^^ Letter from Sir Wm. E. Logan, Director of tJie Canadian 

 Geological Survey, on Sir Roderick Murcliison s reference to 

 the determination of the age of the Quebec Rochs. 



Montreal, November 27, 186L 

 " To the Editors of the American Journal of Science : 



Dear Sirs, — In his address to the Geological Section of the last meet' 

 ing of the British Association, Sir Roderick Murchison has placed the 

 name of my friend Prof, Hall in such a relation to the Quebec group 

 of rocks, as might lead to the inference that to him was due the credit 

 of having determined its horizon, as adopted by the Geological Survey 

 of Canada. Nothing I am persuaded can he farther from the mind of 

 this distinguished paleontologist than a wish to put forward any claim 

 of this description, as the credit is wholly due to Mr. Billings the 

 Palaeontologist of the Canadian Survey. 



In 1848 ana 1849, founding myself upon the apparent superposition 

 in Eastern Canada of what we now call the Quebec group, I enuncia- 

 ted the opinion that the whole series belonged to the Hudson River 

 group and its immediately succeeding formation ; a Leptsena very like 

 L. sericea, and an Orthis very like 0. testudijiaria, and taken by me to 

 be these species being then the only fossils found in the Canadian rocks 

 in question. This view supported Professor Hall in placing, as he had 

 already done, the Olenus rocks of New York in the Hudson River 



