MAGANESE ORBS OF NOVA SCOTIA. 13 



uess of the two being abotit eight inches. The ore also occvirs in this vicinity as len- 

 ticular pockets and irregular nests in conglomerate, etc., and sometimes forms the 

 cementing material. This latter mode of occurrence is similar to that shown by the red 

 hematites (sometimes highly mangauiferous) found at various ^joints in the lower Carbo- 

 niferous conglomerates of the island near their junction with older strata. The analysis 

 of the overlying limestone has already been given. The ore from this locality is 

 generally a pyrolusite, soft, fine-grained, and sometimes sirb-crystalliue. It is at some 

 openings mixed with manganite, and the latter ore is abundant at several places in the 

 grits. The minerals associated with the ore are calcspar, barite, films of selenite, and 

 limestone. Analyses by Mr. Hofi"mau, of the Canadian G-eological Survey, show that the 

 ores run as high as 88'9 per cent, of binoxide, and contain an admixture of ferric oxide as 

 low as two-tenths of one per cent. On the Magdalen Islands, the manganese ores are 

 found, according to Mr. Richardson ( Geological Survey Report, 1879-80 ) associated with 

 sand, clay, gypsum, and doleritic rocks of Lower Carboniferous age. From Mr. Hoffman's 

 report, {ibid.) the ore is a purely crystalline manganite, yielding on analysis 4561 of 

 binoxide. I have, however, seen samples of pure pyrolusite from these islands. There do 

 not seem to be any limestones directly connected with these ores, as surveyed by Mr. 

 Richardson, and the locality appears to form an exception to the rule which, so far as my 

 information goes, governs the presence of manganese ores in the Carboniferous of Nova 

 Scotia, viz., the presence of limestone. Possibly in the case of these Magdalen Island 

 ores they may have been derived directly from the dolerite. 



From the preceding notes, which cover, I think, all the localities known to yield 

 manganese in this province, it may be inferred that in Nova Scotia there appears to be 

 ground for referring the principal deposits of the ores of manganese to an horizon low 

 down in the Carboniferous marine limestones, and certainly, in most cases, underlying the 

 lowest gypsum beds, and that limestones, magnesian and sometimes also mangauiferous, 

 appear to be associated with them. I am not prepared to attempt any outline of the pro- 

 cess which, in Nova Scotia, appears at some points to have deiwsited in these strata iron 

 ores, sometimes mangauiferous, and at other points ores of manganese frequently very free 

 from iron. The source of the manganese may be looked for in the older strata bordering 

 the Carboniferous sea, or, as Dr. Dawson suggests, its presence in these limestones may be 

 due to the decomposition of volcanic debris proceeding from the contemporaneous igneous 

 Agents which produced the Carboniferous traps. Both the older bordering strata, and 

 the limestones and associated strata may have been drawn upon for the deposits of this 

 interesting and useful mineral. The action of magnesian thermal springs may have led to 

 the alteration of the limestones more particularly referred to in the preceding notes. Such 

 an action might lead to the deposition of manganese and iron oxides, as well as of lead and 

 copper ores, all of which are frequently found in them. 



