6 DE. EGBERT BELL : 



"typical" and "so-called." A Set of rocks does not become typical of anything but itself, 

 simply because some one chooses to say it is so; and the term "so-called," with which 

 some geological controversies are so thick interlarded, is unnecessary and disrespectful to 

 those from whom authors may see fit to differ. 



The misconceptions which grow out of Prof. Irving's arguments, in the paper referred 

 to, are largely due to his starting on wrong premises. He fights a phantom. He insists 

 on defining his own ideal type as that which should be the Huronian, instead of accepting 

 the definition of the system which had been well established for thirty years before he 

 began his work, and then endeavours to demolish every view which may not agree with 

 his own. I do not propose to try to controvert any facts which he may state, but only 

 what appear to me to be misconceptions, and I think if he were to give the whole subject 

 an impartial consideration, regardless of any theories whatever, there would be no great 

 disagreement between us. 



The north shore of Lake Huron is so easily accessible, compared with the vast regions 

 into which the Huronian rocks extend northward and elsewhere, that the rocks of the 

 the classes under discussion were most easily studied there at the time when the first 

 attempts were being made to obtain a knowledge of the geology of Upper Canada, and 

 owing to the still greater facilities whiili now exist for reaching this district, it continues 

 to be the ground most visited by geologists who liaA^e interested themselves in these rocks. 

 Great stress is laid by such visitors on matters of small local detail, which they happen to 

 observe there, and on unimportant circumstances which are of almost no account, when 

 we look at the vast extent and thickness of these rocks and take a broad view of the 

 whole question. 



The comparatively undisturbed or little folded condition, which is sometimes 

 observed near Lake Huron and elsewhere, is not the rule in the Huronian strata, but is 

 confined to limited districts ; and instances of similar areas may occasionally be found 

 among the Laurentian gneisses which are generally so much contorted. The rocks 

 originally described by Murray, in the Reports of Progress of the Svirvey (whose descrip- 

 tions were afterwards condensed by Logan in the "Geology of Canada"), near the north 

 shore of Lake Huron, and which have been selected by Prof. Irving as what he thinks 

 should be the type of the Huronian System, happen to be comparatively little disturbed 

 in some parts of this district, but the same rocks are elsewhere highly inclined. In fact 

 this is the rule even in the " typical " Hiirouiau area. The examinations of Murray only 

 extended to an average distance of about ten miles inland from the north shore of Lake 

 Huron ; while those of the writer, who by the way, worked with Murray in this region, 

 have since extended by degrees to about fifteen hundred miles in the same direction. 

 Murray paid most attention to the rocks which formed ridges, or were from any cause 

 conspicuous ; quartzites and "slate-conglomerates" were his favorites. He does not even 

 mention numerous varieties of rocks which exist in the district he ma^îped out. As a 

 matter of fact, crystalline schists, such as those which prevail among the Hiirouiau rocks 

 of Lake Superior, are largely associated with the qviartzites and slate-conglomerates of the 

 Lake Huron region. The intrusions of greenstones or diabases which form prominent 

 hills and bluffs and obtrude themselves along rivers, received a good deal of attention, but 

 the greywackes or volcanic ashes, which are much more extensive, but generally occupy 

 lower ground, are scarcely referred to. 



