244 CRUISE OF THE NEPTUNE 



dominates and incloses lenses of hematite, while where the 

 hematite is most plentiful it incloses similar lenses of jasper. 

 The detailed description of these rocks shows that the 

 measures of this division contain an immense amount of 

 hematite. The rocks of the division do not occur on all the 

 islands, being wanting on Flint, Belanger and Eoss. On 

 Anderson they are represented by a few thin beds not rich in 

 ore, while on Clarke they form the summit of the section with 

 a thickness of eighty feet. They reach their maximum develop- 

 ment on Gillies and Taylor, where their ores are richest and 

 most concentrated. Farther northward they become thinner 

 and poorer in ore, being twenty feet thick on Davieau and only 

 eight feet thick on McTavish, where they die out. No trace of 

 these measures is found underlying the upper rocks on the 

 islands south of the ISTastapoka group. 



The fourth division, consisting of red jaspilites, is an 

 arbitrary one, of use only as a subdivision of the iron-bearing 

 rocks. Wherever the jaspilites are well developed the richer 

 beds are underlain with leaner measures, unfit for working, and 

 these poorer ores constitute this division. On Clarke island 

 these beds are twenty feet thick ; on Gillies they vary from ten 

 to twenty feet in thickness, on Taylor they are ten feet, while 

 to the northward they merge into the overlying division, all 

 poor in iron ores. 



The richest ores are found in division III, where extensive 

 beds several feet in thickness are found containing ore practi- 

 cally free from jasper, and ranging in iron values from thirty 

 per cent to sixty per cent. Most of these ores, however, would 

 require separation from the bands and lenses of jasper before 

 becoming sufficiently rich to be economically treated in the 

 furnace. The position of the ores on the islands separated from 

 the mainland by a sound varying from a mile to four miles in 

 width, with excellent, almost tideless, harbours, constitute ideal 

 conditions for shipment. The mining of the ores would also be 



