Section III., 1885. [ 9 ] Trans. Roy. Soc. Can. 



III. — On some Iron Ores of Central Ontario. 

 By E. J. Chapman, Ph. D., LL.D. 



(Read May 28, 18S5.) 



The series of analyses, embodied in this communication, refer to magnetic and other 

 iron ores — obtained, in almost every instance, by the writer, personally — from mines or 

 exposures in the Counties of Haliburton, Peterborough, and Hastings, in the Province of 

 Ontario. The analyses are accompanied by brief notices of the general character and con- 

 ditions of occurrence of the ore-deposits from which the samples were taken ; but in many 

 cases, it should be observed, the totally undeveloped nature of the ground prevents 

 detailed statements from being given. If thought of sufficient interest to be accorded a 

 place in the Transactions of our Society, these analyses — supplementing those of other ores 

 from this region, already published by Dr. T. Sterry Hunt, Mr. Thoitias Macfarlane, and 

 Dr. B. J. Harrington, — will serve at least to shew the vast abundance of iron ore, for the 

 greater part of pre-eminently good quality, contained within a very limited section of the 

 Province, alone. And it must not be supposed that in the iron ores which form the sub- 

 ject of the present communication we have examples of all, or anything like all, the ore- 

 deposits of the district. Many others are known, and discoveries of additional deposits 

 are constantly being made. "When to these, therefore, are added the known workable 

 deposits of adjacent districts, withovit taking into consideration the valuable iron ores of 

 other Provinces of the Dominion, we may well admit the truth of Sir "William Logan's 

 prediction that Canada is destined to become eventually one of the greatest iron -producing 

 countries in the world. 



The geological horizon of these iron-ore deposits is that of the middle portion of the 

 Laurentian series Avhich occupy that section of Ontario. Briefly, the area is traA'ersed in 

 a general N.E. and S.W. direction by belts of elevated, rocky land, consisting of unstrati- 

 fied, probably eruptive, syenites or syenitic granites of a prevailing red colour. Between 

 these belts lie rugged tracts, of essentially synclinal structure, occupied in ascending 

 order by strata of red and grey gneiss, poor in mica, and by some crystalline graphitic lime- 

 stones ; succeeded more or less irregularly by dark green amphibolic and pyroxenic rocks 

 with which the iron ores are chiefly associated ; whilst these again are followed by 

 micaceous and slaty beds, crystalline limestones, quartzites, and conglomerates, — the entire 

 series being overlaid, here and there, by outlying patches of Lower Silurian limestone. 



In the following analyses, where the ferrous and ferric oxide has been separately deter- 

 mined, the latter, it will be seen, is nearly always slightly in excess of what it should be 

 to form, with the amount of ferrous oxide, pure Fe'^O'. This arises from the ore, as a rule, 

 being more or less peroxidized, especially when taken in unl)roken ground from near the 

 surface. The localities of the ores, and their general conditions of occurrence, are given 

 in the notes following the table. 



Sec. III., 1885. 2. 



