1850.] DAWSON METAMORPHIC ROCKS OF NOVA SCOTIA. 355 



tliem in relation to the mode of their formation and the changes of 

 the containing rocks. 



The first of these deposits to which I shall refer is a vein' of iron 

 ore and ferruginous limestone, extending along the south slope of the 

 Cobequid hills ; and which has been most carefully explored in the 

 vicinity of the Folly and Great Village rivers. This deposit appears 

 to have been noticed as early as the time when the land on which 

 it occurs was granted by the Crown ; and it received some attention 

 from Mr. Duncan and other gentlemen in Truro, nearly twenty years 

 ago. No steps were however taken toward its scientific exploration 

 until 1845. In the summer of that year I received a specimen of the 

 ore for examination, and in October of the same year I visited and 

 reported on the deposit. In the same autumn it was examined by 

 Dr. Gesner. In 1846 I again visited it, and reported on it to C. D. 

 Archibald, Esq., of London, and other gentlemen associated with 

 him ; and in the summer of 1849 I had the pleasure of again going 

 over the ground and examining the vein at some new points, in com- 

 pany with J. L. Hayes, Esq., of Portsmouth, U. S. Since 1845, the 

 extent and economical capabilities of the deposit have been discussed 

 by several writers, both in this province and in Great Britain. In 

 the following remarks I shall confine myself as far as possible to its 

 geological relations, and facts bearing on its origin*. 



I shall begin by describing the vein as it occurs on the west branch 

 of the Great Village River, at the site chosen by C. D. Archibald, 

 Esq., for the furnace and buildings of the " Acadia Mine." In the 

 western bank of this stream, at the junction of the carboniferous and 

 metamorphic series, a thick series of grey and brown sandstones and 

 shales, dipping to the south at angles of 65° and 70°, meet black and 

 ohve slates, having a nearly vertical position, and with a strike N. 

 55° E. The dip of these slates, where apparent, is to the southward, 

 and the strike of the slaty cleavage and of the bedding appear to co- 

 incide. Near the Falls of the river, a short distance northward of the 

 junction just noticed, the slates give place to grey quartzite, which, 

 with some beds of olive slate, occupies the river-section to, and for 

 some distance beyond, the iron vein. 



The vein is well seen in the bed of the stream, and also in excava- 

 tions in the western bank, which rises abruptly to the height of 327 

 feet above the river bed. In the bottom of the stream it presents 

 the appearance of a complicated network of fissures, penetrating the 

 quartzite and slate, and filled with a ciystalline compound of the car- 

 bonates of lime, iron, and magnesia, which, for reasons to be stated 

 in the sequel, I refer to the species Ankerite. With this mineral 

 there is a smaller quantity of red ochrey iron ore, and of micaceous 

 specular iron ore. 



In ascending the western bank of the stream, the vein appears to 

 increase in width and in the quantity of the ores of iron. In one 

 place, where a trench was cut across it, its breadth was 120 feet. 



* The localities referred to in the following paragraphs will be found in the 

 map of the New Red Sandstone district of Nova Scotia, 1847, Quart. Journ. Geol. 

 Soc. vol. iv. p. 50, pi. 5. 



