60 On the Minerals of Canada. 



inctes. The prevailing colors of the ochres are red and yellow, 

 but there occurs also in some parts a beautiful purple tinge, and 

 in others a blackish-brown. At the Industrial Exhibition which 

 took place in Montreal, in October 1850, some of the ochres of 

 this locality presented to the public view by Mr. D. G. Labarre, 

 attracted the attention of persons acquainted with the commercial 

 value of such products, and arrangements were subsequently made 

 with the proprietors of the land, by Messrs. H. A. Munroe & Co., 

 of New York, for the purpose of entering upon such a preparation of 

 the crude material as should fit it for sale. With this view, a couple 

 of furnaces have been erected in the vicinity of the ochre bed, 

 and an agent established to carry out the details of the manufac- 

 ture, and attend to the forwarding of the article to New York, 

 where the sale of it is effected. I was given to understand by the 

 agent, that 400 barrels of the ochre had been disposed of at five 

 dollars each, and that as many as twelve barrels had occasionally 

 been prepared in a day. From the few natural colors that have 

 been mentioned, eight tints are said to be prepared. The deposit 

 being but little mixed with sand, the chief impurity to be got rid 

 of consists of the roots of those plants which have been growing 

 on the surface, some of which penetrate to a considerable depth. 

 Two modes are resorted to for this purpose ; one is by dry sifting, 

 which is used where the natural colors of the ochres are to be 

 preserved, as in the case of the yellow variety, of the purple, and 

 of the blackish brown. The yellow is a hydrated peroxyd of iron, 

 the purple also is probably in some peculiar state of hydration, 

 but the red is the anhydrous peroxyd. By exposure to a sufficient 

 heat in the furnace, the water of combination is driven off from 

 the yellow and purple, and both becoming anhydrous peroxyd, 

 assume the tint of the natural red ochre, from which, as from the 

 other two, the vegetable matter in this operation is burnt out. 

 The blackish-brown variety is scarcer than the others, and affords 

 colors of a more valuable description ; purified from roots without 

 fire, it is sold under the name of raw sienna ; it is admirably adapt- 

 ed for graining, and brings in retail, I am informed, so much as 

 a shilling the pound. When subjected to fire, it assumes brown 

 of less intensity, and it is sold as burnt sienna. As it does not 

 turn red from burning, it is probable that there may be in this 

 •ochre, an admixture of manganese." 



In the St. Malo range of the Seigneury of Cap-de-la-Madeleine 

 a great deposit of ochre occurs. The area occupies upwards of 



