PRCM^EEDINGS ^ 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



Vol. II. 1837. No. 51. 



March 22. — Arthur Capel, Esq., of Charles-street, Berkeley- 

 square ; John B. Boileau, Esq., of Upper Brook-street, Grosvenor- 

 square ; Henry Still, Esq., employed on the Ordnance Survey ; John 

 David Day, Esq., A.B., Brazen Nose College, Oxford ; John G. 

 Malcolmson, Esq., Surgeon in the Hon. East India Company's Ser- 

 vice ; and the Right Hon.T. Frankland Lewis ; were elected Fellows 

 of this Society. 



A paper "On the Ancient State of the North American Continent;" 

 by Thomas Roy, Esq., Civil Engineer, Toronto, Upper Canada, and 

 communicated by Charles Lyell, Esq., F.G.S., was read in part. 



April 5. — ^The reading of Mr. Roy's paper was concluded. 



The author having in the course of his professional duties, disco- 

 vered in the lake district of Upper Canada terraces or level ridges 

 which agreed in elevation at considerable horizontal distances, he 

 was induced to extend his inquiries and ascertain how far similar 

 phaenomena have been observed in other parts of North America, — 

 what may have been the probable extent of the lake or sea by which 

 the ridges were formed,' — and by what operations the waters were 

 drained off, leaving only the present detached Canadian lakes. 



With a view to ascertain the probable extent of the sea, Mr. Roy 

 traced upwards from Lake Ontario the successive ridges or terraces*, 

 and ascertained that their greatest height was 762 feet above the 

 lake, or 996 feet above the ocean ; he therefore assumed, that the 

 boundary of the ancient sea must have had an elevation of at least 

 1 000 feet, and in consequence, that it must have been formed on the 

 west by the rocks and mountains ranging from the table-land of 

 Mexico to the parallel of 47° of latitude ; on the north by the barrier 

 which separates the head-waters of the lakes from those of the Arctic 

 rivers, and extending to CapeTourmente below Quebec ; on the east 

 by the hills stretching through the United States to the Gulf of 

 Mexico ; and on the south by a mountain ridge which has been de- 

 stroyed. The area thus circumscribed is calculated to be 960,000 

 square miles. 



* These parallel ridges were exhibited on a section extending obliquely 

 from the mouth of the Niagara to the south of Lake Ontario, and over the 

 ridge north of that lake, to Lake Simcoe. 



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