12 EDWIN GILPIN ON THE 



shales. At several points in this vicinity the limonite ores, found along the line of junc- 

 tion of the Upper and Lower Silurian vfith the Lower Carboniferous marine limestone 

 are lieaA^ly charged with manganese. The ore is dull brownish-black in colour, with a 

 black streak, and softer than the normal limonite. The percentage of manganese present 

 in the iron ore varies. The general character of this ore, however, will appear from the 

 following analyses by the writer : — 



1:2 -530 



L IL 



Water of composition — ■> 



Moisture 1 .450 I 



Insoluble residue 2-731 25-130 



Alumina 2-S80 trace 



Iron sesquioxide 10-848 48-223 



Manganese sesquioxide 62 • 950 — 



^Manganese jieroxide — 14-410 



Magnesia 1-630 — 



Lime 7-280 -015 



Baryta. •670 — 



Carbonic acid — — 



Sulphur — -480 



Phosphorus — -020 



90-439 100-808 



In Antigonishe County similar ferriferous manganese ores have been found in drift 

 at several places. 



In Cape Breton deposits of economic value occur only in the western part of the 

 county of the same name. Here, at the head waters of the Salmon Eiver, the lower 

 members of the Carboniferous are met in a valley between the felsites of the Mira and 

 East Bay hills. The space is generally occupied by the millstone grit, beneath the edges 

 of which the marine limestones occasionally crop out, or the latter are excluded by the 

 basal conglomerates. The following notes are from a visit to the Moseley (iron) mine, and 

 from information kindly furnished by Mr. Fletcher, of the Canadian Greological Survey. 



The felsites of the Mira Hills form a series of bays along which are exposed carbon- 

 iferous limestones, conglomerates, shales, and grits as they were accumulated subject to 

 the varying conditions of the winds and currents of the period iruder consideration. At 

 some points, the limestones rest on the felsites ; at other localities, grits and shales inter- 

 vene ; elsewhere, the basal conglomerates are covered directly by the millstone grit. The 

 manganese ores were discovered two years ago in one of these recesses where the felsites 

 were succeeded by shales and grits, and finally by limestones, the latter apparently 

 extending from point to point of the ancient bay. The ores at the western mine are found 

 in irregular bedded layers in a soft arenaceous reddish-coloured shale, which is in some 

 places calcareous and coated with films of manganese oxide. The layers vary in thick- 

 ness up to eighteen inches, and are frequently connected by cross stringers of ore. The 

 shales when weathered present the ore in small nodules, and the disintegration of the 

 former by water probably indicates the source of the beds of gravel manganese ore found 

 lying on them. The ore at the eastern mine occurs as a bed immediately underlying a 

 layer of black mauganiferous limestone, with red and greenish shales and coarse grit. 

 The thickness of the ore and limestone varies from two to eight inches, the average thick- 



