184 THE FORMATION OF MAGNESIAN LIMESTONES. 



ON THE rOEMATION OE MAGNESIAN LIMESTONES. 



BY T. STEEBT HUNT, 



OF THE GEOIiOGICAL SUKTEY OF CANADA. 



At a meeting of tlie Canadian Institute, held on April 10th, 1 858, 

 Professor Chapman produced, and deposited with the Institute, a' 

 sealed packet containing a notice of certain investigations and demon- 

 strative experiments then in progress, by Mr. T. Sterry Hunt, of 

 the Canadian G-eological Survey. Mr. Hunt's investigations having 

 now been sufficiently advanced to admit of the publication of his 

 views, the sealed packet has been opened, by his directions, and 

 is herewith appended to the communication, which sets forth the 

 special views he claims to have adopted at the annexed date. — Ed. 

 Can. Jour. 



NOTE ON THE ORIGIN OF DOLOMITES. BY T. STERRY HUNT. 



The results of a long series of investigations and experiments 

 relative to the formation of dolomites or magnesian limestones, have 

 led me to reject the idea of their metamorphic origin from the alter- 

 ation of limestones in the manner generally understood. I conceive 

 that dolomites have been formed in sea basins, from which the solu- 

 ble salts of lime have been completely separated, as sulphate or as 

 carbonate by the agency of allialine carbonates, which afterwards 

 give rise to carbonate of magnesia. This carbonate appears capable, 

 under certain conditions, of slowly combining with carbonate of 

 lime, and forming with it a double carbonate, which is dolomite. 



The experiments required for the complete demonstration of this 

 theory are as yet unfinished, but I wish by this note to take priority 

 in the solution of a difficult and hitherto unresolved problem in 

 Chemical G-eology. 



Montreal, March 30, 1858. 



The mode in which magnesian limestones occur, often interstrati- 

 fied with beds of pure carbonate of lime, has induced some recent 

 observers to reject the notion which supposes dolomite to have been 

 formed by the alteration of beds of limestone, whether by magne- 

 sian vapours, as supposed by Von Buch, or by the intervention of 

 magnesian solution, as conjectured by Haidinger and Von Morlot. 



