356 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 13, 



Thougli its walls are very irregular, it has a distinct underhe to the 

 south, apparently coinciding with the dip of the containing rocks. 

 As might have been anticipated from its appearance in the river-bed, 

 it presents the aspect of a wide and very irregular vein, including large 

 angular fragments of quartzite, and of an ohvaceous slate with gUsten- 

 ing surfaces. These fragments are especially large and abundant in 

 the central part of the vein, where they form a large irregular and in- 

 terrupted rocky partition. 



The ankerite should evidently be considered the veinstone, as it 

 surrounds and includes all the other contents of the vein, and greatly 

 exceeds them in quantity. Where not exposed, it is white and 

 coarsely crystalhne. On exposure it becomes yellowish ; and near 

 the surface, as well as on the sides of fissures, it is decomposed, 

 leaving a residue of yellow ochrey hydrous peroxide of iron. In some 

 parts of the vein, the ankerite is intimately mixed with crystals and 

 veinlets of yellowish spathose iron. The red ochrey iron ore occurs 

 in minor veins and irregular masses dispersed in the ankerite. Some 

 of these veins are two yards in thickness ; and the shapeless masses 

 are often of much larger dimensions. Specular iron ore also occurs 

 in small irregular veins, and in disseminated crystals and nests. At 

 one part of the bank there appears to be a considerable mass of mag- 

 netic iron ore, mixed with specular ore ; this mass was not, however, 

 uncovered till after I had left the ground. 



The whole aspect of the vein as it appears in the excavations in the 

 river bank is extremely irregular and comphcated. This arises not 

 only from the broken character of the walls, the included rocky frag- 

 ments, and the confused intermixture of the materials of the vein ; 

 but also from the occurrence of numerous transverse fissures, which 

 appear to have shghtly shifted the vein, and whose surfaces usually 

 display the appearance named " slickenside," and are often coated 

 with comminuted slate or iron ore. In some places these are so nu- 

 merous as to give an appearance of transverse stratification. One of 

 them was observed to be filled with flesh-coloured sulphate of barytes, 

 forming a httle subordinate vein about an inch in thickness. 



The general course of the vein, deduced from observations made by 

 Mr. Hayes and myself at the Acadia Mine and further to the east- 

 ward, is S. 98° W. magnetic, the variation being 21° west. At the 

 Acadia Mine this course deviates about 33° from that of the containing 

 rocks. In other localities, however, the deviation is much smaller ; 

 and in general there is an approach to parallelism between the course 

 of the vein and that of the rock formation of the hills, as well as that 

 of the junction of the carboniferous and metamorphic systems. The 

 vein for a space of seven miles along the hills is always found at 

 distances of from 300 yards to one-third of a mile northward of the 

 last carboniferous beds, and always in the same band of slate and 

 quartzite. 



"Westward of the Acadia Mine, the course of the vein over the high 

 ground is marked by the colour of the soil, as far as Cook's Brook, 

 about a mile distant. The outcrop of the ore is not exposed in this 

 brook, but large fragments of specular ore have been found in its bed. 



