PEESIDENTIAL ADDEESS. 9 



shore «ouglomerates which I have anywhere seen among Huronian rocks arc those 

 associated with crystalline schists, etc., at Red Lake, lying north-eastward of Lake of the 

 Woods. 



The geologist whom I have already or often quoted, contends that in northern 

 Michigan, the Huronian rocks may be divided into two distinct classes similar to those 

 which he would establish on th(^ Canadian side of the lakes notwithstanding the " one 

 geological basin" above referred to. "The proofs of this distinctness," he says, "are 

 analogous to those which establish the separations of the type Huronian of Lake 

 Huron from the adjoining crystalline schists, viz. : — (1) a general lithological contrast 

 between the two series concerned, the one being mainly but little altered, the other 

 highly crystalline and schistose ; (2) visible discordances in a few places on the con- 

 tacts of the two sets of rocks ; (3) the penetration of the lower strata by granite veins 

 and masses which fail to penetrate the higher detrital rocks, but on the contrary have 

 yielded fragments to them ; (4) the development of true basal conglomerates at the con- 

 tacts of the two series ; and (5) the fact that the detrital rocks are in contact with diiFerent 

 members of the lower series." The fifth of these arguments appears to be merely a 

 repetition of the second. After laying down these "proofs" of the distinctness contended 

 for. Prof. Irving admits that most of them are very dou.btiul. For example, he says : — 

 " Nevertheless there are presented here some differences from the conditions observable 

 on the north shore of Lake Huron, which seem to obscure the true relations of the different 

 rocks. The placing together of all the stratiform rocks of the Marquette belt by most 

 geologists is not at all to be wondered at," etc. " Thus the evidence under the first of the 

 heads just named is in part obscured," etc. " A more important obscuration of original 

 conditions applies to the evidence under the second head." "This apparent obliteration 

 of unconformity is yet more marked in some of the districts subsequently to be noted. 

 To render the case still more difficult of comprehension, the denudation which has so 

 deeply truncated the region, has occasionally brought to light within the area occupied by 

 the newer detrital strata, patches of the older schistose basement," etc. 



We see here a laboured effort to show that although appearances and conditions or, 

 rather let us say, facts, are all against the supposition that there are two distinct sets of 

 rocks, and in faA^our of the old A^ew that the rocks of his " typical Huronian " and the 

 crystalline schists constitute but one system, yet, notwithstanding all this evidence of both 

 positive and negative character, we are to come to an opposite conclusion— that "things 

 are not what they seem," as it were, so far as the Huronian rocks are concerned. In the 

 third part of the paper referred to, the author concludes that "there must be cases, however, 

 where it will long remain very difficult, if not impossible, to separate the Huronian from 

 the older schists, or to determine if any Huronian be present." It does not appear to 

 have occurred to Prof Irving that by far the simplest exi)lanation of the whole matter 

 is to admit what is manifest, namely, that these rocks are really what they seem to be — 

 all one series — the Huronian, as it has always been described by the Greological Survey 

 of Canada. 



I would not, however, deny, as I have said already, that it may some day be possible 

 to define certain divisions which it may be desirable to make hereafter, but I think it advisa- 

 ble to wait till we shall have accumulated more facts. It is likely that, locally, at any rate, 

 we may be able to draw a line between the Upper and Lower Huronian, and that these 



Sec. IV, 1888. 2. 



