m Nortvay and in Canada, 12§ 



liar character ; III. The prevalence of copper ores, of a high per- 

 centage, unmixed with iron pyrites ; the veinstone accompanying 

 them being quartzose, and therefore diflScultly fusible ; IV. The 

 presence of iron glance in the few deposits of iron ore occurring 

 in the group. 



The equivalent of these rocks in Canada appears to be the 

 Huronian formation. In support of this view I shall avail 

 myself of the minute descriptions of the latter to be found in the 

 Reports of the Geological Survey, and particularly in Sir W. E. 

 Logan's Report on the north shore of Lake Huron. The rocks of 

 the Huronian formation are, by these authorities, described as fol- 

 lows: 



" The quartzites have sometimes the aspect of sandstones, but 

 at other times lose their granular texture, and become a vit- 

 reous quartz. Not unfrequently the quartzite is thin bedded, and 

 even schistose in its structure, and it sometimes holds a Uttle 

 mica, passing into a variety of mica schist; 



** These quartzites often become conglomerate, enclosing pebbles 

 of quartz and various coloured jaspers. These pebbles are some- 

 times arranged in thin layers among fine grained beds. At other 

 times, the conglomerates form thicker beds, which swell into moun- 

 tain masses; including great portions which contain blood-red 

 jaspers in a white matrix, constituting a very beautiful rock. 



" In addition to these, there are conglomerates of a distinctly 

 diflferent character, belonging to this formation. They are somposed 

 chiefly of syenitic pebbles, held in a grey argillo-arenaceous ce- 

 ment,which is more frequently of a greenish color, from the presence 

 of chlorite. The pebbles, which are of reddish and grey colors, 

 vary greatly in size, being sometimes no larger than swan shot, 

 and at others, boulders rather than pebbles, measuring upwards 

 of a foot in diameter. 



" The quantities in which they are aggregated vary much. 

 They sometimes constitute nearly the whole mass of the rock, 

 leaving but few interstices for a matrix, and sometimes on the 

 contrary, they are so sparingly disseminated through con- 

 siderable portions, as to leave spaces of several feet between 

 neighboring pebbles ; which are still, in such cases, often several 

 inches in diameter. With the syenitic pebbles, are occasionally 

 associated some of diflferent colored jaspers. The matrix ap- 

 pears often to pass on the one hand, into the grey quartz rock, by 

 an increased proportion of the arenaceous particles ; and on the 

 other, into a thin bedded greenish fine grained slate, which is 



