No. 2.] DAWSON — IRON ORES OF NOVA SCOTIA. 13T 



smaller concretionary or " gravel" ore. In some places the ore 

 of iron is associated with concretions or crystalline masses of 

 Pyrolusite and Manganite. 



Denuding agencies in the Post-pliocene period have removed 

 portions of the vein and its wells, and have deeply covered the 

 surface in many places with debris. Hence the outcrop of the 

 vein was originally marked by a line of masses of the ore too 

 heavy to be removed by water. From the analogy of the other 

 veins to be mentioned in the sequel, I was led to believe that the 

 source of these masses would be found in the Lower Carbonifer- 

 ous rocks, and so stated the matter in the first edition of Acadian 

 Geology (1855). Subsequently, however, the vein h :ving been 

 exposed in situ, and one wall proving to consist of metamorphic 

 slate, it was described by Dr. Honeyman and by Mr. Hartley of 

 the G-eological Survey as a vein in the Silurian rocks. Still 

 more recently exploratory works conducted by Mr. Gr. M. Daw- 

 son, with the aid of Mr. D. Fraser, have clearly proved that the 

 vein follows the junction of the two formations. The ore of this 

 vein is of the finest quality, affording from 62 to 65 per cent, of 

 metallic iron. The more productive portions of this vein, as 

 well as of the specular vein in its vicinity, are in the hands of 

 the parties already referred to, in connection with the Hematite 

 Ibed. 



(8) Limonite of Shuhenacadie, Old Barns and Broohfield. 

 At the mouth of the Shuhenacadie Eiver, the lowest Carbon- 

 iferous bed seen is a dark-coloured laminated limestone, in all 

 probability the equivalent of the Manganesian limestone already 

 referred to, as well as of the Manganiferous limestone of Walton, 

 the Plumbiferous limestone of the Stewiacke, and the lower 

 black limestone of Plaister Cove, Cape Breton.'^^ This limestone 

 and the sandstones and marls overlying it, are traversed by large 

 fissure veins, holding a confused aggregation of iron ores and 

 other minerals, as Limonite, Hematite, Gothite, Sulphate of 

 Barium, Calcite, &c., some of which appear sufficiently large and 

 rich for profitable exploration. In the same formations, further 

 to the eastward, at Old Barns, similar veins are found to be 

 largely developed, and at Brookfield, fifty miles east of the Shu- 

 henacadie, and apparently near the junction of the Lower Car- 

 boniferous with older rocks, large surface masses of Limonite 



* See Acadian Geology 



