88 MINERALS AND GEOLOGY 



or sub-metallic lustre. Rhombic in crystallization, but occurring 

 chiefly in fibrous masses. H=3.5 4.0; sp. gr. 4.3 4.4. B.B 

 infusible. Yields water by ignition in the bulb-tube, and forms a 

 " turquoise enamel " with carb.-soda (see Part I., p. 39). Composi- 

 tion, if pure : sesquioxide of manganese 89.8, water 10.2. 



Said to occur in a broad vein, with quartz, calc spar and fluor 

 spar, traversing trap rocks, on the south shore of Bachewahnung 

 Bay, Lake Superior, but no examples have yet come under the 

 author's observation. 



36. Earthy Manganese Ore (Wad, Bog-Manganese, Manganese 

 Ochre) : Black or blackish-brown, in dull, earthy and often nodular 

 masses. Very soft. BB, infusible. Yields water in the bulb-tube, 

 and forms with carb.-soda a " turquoise enamel," green whilst hot, 

 greenish-blue and opaque when cold. Composition, essentially, hy- 

 drated oxide of manganese, but always mixed with earthy matters, 

 and often with iron ochre. Some varieties contain baryta, others 

 oxide of cobalt, copper, &c. The manganese is usually present both 

 as protoxide and sesquioxide. 



This substance occurs principally in recent deposits throughout 

 the district south of the St. Lawrence, as, more especially, in Cleve- 

 land, Bolton, Stanstead, Tring, Aubert Grallion, Ste. Marie (Beauce), 

 St. Sylvester, Lauzun, &c. Deposits of this ochre have also been 

 found on the north shore, as in Seigniories of Ste. Anne and Cacouna, 

 and in the immediate vicinity of Quebec. In Ontario, it has only 

 been observed, as yet, in the Township of Madoc ; and. in admixture 

 with iron ochre, on the north-east shore of Thunder Bay, Lake 

 Superior. A sample from the latter locality, yielded the author : 



Sesquioxide of Iron 33.68 



Sesquioxide manganese 16.54 



Protoxide manganese 5.08 



Lime 0.81 



Carbonic Acid 3. 78 



Sulphuric acid trace only 



Phosphoric acid . . very slight trace 



Water 3.82 



Silicious rock matter 36.12 



99.83* 



I Carbonate manganese .. 8.23 

 I Carbonate of lime. . . .1.44 



* The small amount of water held by this ochre is somewhat remarkable. As regards the 

 Dominion of Canada, workable amounts of Pyrolusite or Black Ore of Manganese appear to 

 occur only in the Lower Carboniferous strata of Albert and King's Counties, New Brnnswick. 



