12 DE. EOBEET BELL : 



Of late years, some geologists have manifested a great desire to make out a waut of 

 conformity between the Hurouian and Laurentian Systems, and in the absence of any 

 facts as yet discovered in Canada to prove stich an assumption, they eagerly seize upon 

 any expression to be found in the reports of the older investigators which appears to favour 

 it. The only circumstance, as far as I am aware, which seems to point in this direction 

 is a section in the Atlas accompanying the "Greology of Canada" (1863), in which con- 

 torted gneiss is shown under the contact of the Huronian rocks. But this representation 

 of the general contorted character of the Laui'eutian and which may be largely due to 

 the artist, does not justify the notion of a want of conformity, and, even if it did, we 

 shoirld still prefer to appeal to nature for our evidence. Under a note on the " Contact of 

 Laurentian and Huronian rocks," Logan in the "Geology of Canada" (p. 64) says 

 distinctly that they are conformable. Some of those who favor the theory of unconfor- 

 mability, find evidence in the fact that some parts of the Huronian contain fragments of 

 older rocks. But in any geological formation, we might naturally look for the debris of 

 any other older than itself, and this too without proving want of conformity. In any of 

 the Huronian conglomerates we might have expected to find abundance of pebbles of 

 gneiss, but, strangely enough, such pebbles are very rare, while those of other members 

 of the Huronian series itself and of various kinds of granite and syenite, like those 

 occurring in situ within the Huronian areas, are quite abundant. 



The fact that bands of imperfect gneisses and gneissoid strata are occasionally to be 

 found among the Huronian rocks, might be considered a reason in favor of classifying 

 them with the Laurentian, the greater part of which is gneiss, or against recognising 

 them as a separate division of the Archcean. G-neisses, however, are not conspicuous — 

 indeed, they are of rare occurrence in the Huronian, and always appear to present points 

 of difference sufficient, along with the stratigraphy, to distinguish them from those of the 

 Laurentian system. They are generally "imperfect" or more finely-grained, and less 

 completely crystalline than the latter. Another point of difference I have observed, is, 

 that they are slightly calcareous in all the numerous cases which I have tried, while the 

 Laurentian gneisses rarely contain carbonate of lime. In the few examples which I have 

 noticed of more coarsely crystalline bands of gneissoid rocks in the Huronian, the felspar, 

 or a considerable part of it, has been of triclinic species. 



The Huronian is the great metalliferous system of Canada, especially if we consider 

 the Hastings Series, and the altered rocks of the Eastern Townships as belonging to it. 

 The presence of gold has been detected in many localities, and it appears to occur in 

 promising quantities at Jackfish Bay, at the Huronian Mine and elsewhere to the west of 

 Thunder Bay, and in the Township of Denisou north of Lake Huron. Small quantities 

 of silver have been found by assay in veinstones from numerous places, and in larger 

 amount at the 3 A Mine on Thunder Bay. The sulphurets of copper are very generally 

 diffused among these rocks, esiDCcially in the diorites and some of the schists. They have 

 been worked at the Bruce audWellington Mines and recently at several localities near 

 Sudbury. Trials on a smaller scale have been made at various other places. But irou is 

 the metal for which these rocks are more especially noted. The great iron mines of the 

 Marquette district on the south side of Lake Superior are well known. In Canada, west 

 of Lake Superior and between the great lakes and Hudson Bay, iron ores in notable 

 quantities have been found at the following among other localities : — Knee Lake, between 



