TRANSACTIONS OF SECTION C. 031 



systematlsed. In this volume, after stating that Hail's nomenclature of the 

 Paljeozoic rocks in the State of New York had been adopted unchanged for the 

 adjacent Canadian territory, 'in the interests of unity of plan for future 

 researches,' Logan writes : — * To the Azoic rocks no local names have yet been 

 applied in any part of America except in Canada,' and adds : — ' The names of the 

 Laureutian and Huronian systems or series, which we have been accustomed to 

 apply to them, are allowed to remain unchanged, particularly as they have been 

 recognised abroad, and have been made by other geologists a standard of com- 

 parison both in America and Europe.' 



In Chapter V. of this volume the ' Upper Copper-bearing Rocks of Lake 

 Superior ' are separately treated, and are recognised as comprising two groups 

 which are stated to overlie the Huronian unconformably. These groups are those 

 now known as the Animikie and Keweenawan. 



There can be no doubt about the classification intended at this time, and the 

 rocks are correctly laid down on the atlas pre])ared to accompany the volume, but 

 in consequence of an unfortunate error in the geographical description of the 

 distribution of the Huronian about Thunder Bay, that arose in 1846 and was 

 repeated in 1863, several later investigators have been led to regard the rocks of 

 the ' Upper Copper-bearing Series ' as those of Logan's typical Huronian, and to 

 suppose that when examining these rocks they were dealing with those intended 

 to be classed as Huronian. Irving, Winchell, and others have adopted this mistaken 

 view, which it is particularly necessary to refer to here, as it has been the chief 

 cause of all subsequent misapprehension in regard to the ' Original Huronian.' * 



The temporary grouping of the Huronian proper with the ' Upper Copper- 

 bearing Series ' (Animikie and Keweenawan), on the grounds already explained, 

 as ' Huronian or Cambrian,' together with the employment (proper enough at the 

 date) of the term ' .slates ' for rocks that would now be named schists, further 

 assisted in giving colour to the erroneous view just referred to. 



In a second geological sketch of Canada, printed in Paris at the time of the 

 International Exhibition of 1867, the same classification is maintained, but to it 

 is added the Upper Laurentian or Labradorian. This sketch was actually written 

 by Hunt, but it was an official publication, correctly representing the views held 



' As already stated, the relations of the principal rock-series of the vicinity of 

 Thunder Bay had been correctly outlined in 18i0, although the series had not at that 

 time been named. The Kaministiquia Kiver section had been examined by Murray, 

 who also correctly described the distribution of the series there, stating that the 

 ' granite, syenite, gneiss, micaceous and chloritic schist ' (Laurentian and Huronian) 

 find their southern limit on a line running from the falls on that river to the ' head 

 of Thunder Bay,' while the ' Upper Slates (Animikie) rest upon them and occupy the 

 country between such a line and Lake Superior' {Ileport of Progress, 1846-47, p. 51). 

 In combining his own results with those of Murray, Logan describes the southern 

 line of the granite, gneiss, and chloritic slates as ' commencing in the vicinity of 

 Fort William,' or at the mouth of the Kaministiquia, although the falls, at which 

 this line had been determined by Murray, are some twenty miles up the river. Pro- 

 ceeding (pp. cit. p. 25) to describe the extent of the ' superior trappean formations ' 

 (Animikie and Keweenawan), he then reverts to the line previously stated, making 

 these rocks to terminate locally where he had said the older rocks began. In 

 recasting the earlier observations for the volume of 1863 (no further work having 

 meanwhile been done at this place), Logan is thus naturally led to state that the 

 Huronian (i.e. the 'Chloritic Slates') occupies the coast east of the Ka^ninistiquia, 

 whereas this coast, for ten or eleven miles, is actually occupied by Animikie rocks. 

 Subsequent investigators, inspecting this coast-Une with the volume of 1863 as a 

 guide, very naturally thus assumed that they were examining Logan's 'typical 

 Huronian,' or a part of it. It is in consequence only of a too consistent adhesion to 

 this misunderstanding, that it has been found necessary to speak of an 'Upper 

 Huronian,' and refer to an ' inter-Huronian ' unconformity. The so-called Upper 

 Huronian is no part of the system as understood by the Canadian Survey. One 

 cannot fail to note, in reading much that has been written on this subject, that the 

 importance of the great unconformity at the base of the Animikie was realised only 

 after a new classification had been adopted, in which it bad practically been ignored. 



