138 ROYAL SOCIETY OF CANADA 
represent the basal conglomerate of the upper Huronian as found 
in other localities; and it is doubtful if the lower division occurs in 
the portion studied by Murray, though silica banded with iron ore 
belonging to the iron range has been found nine miles northeast of 
the Sault Ste. Marie and near Batchewana bay.’ The slight break 
between the upper and lower divisions of the Huronian, as mapped by 
Murray, is not of much significance, the two conglomerates which 
he separates being closely alike in every respect; and almost the whole 
of the so-called typical Huronian may be classed as consisting of the 
basal conglomerate of the upper Huronian or the quartzites and 
arkoses rising above it. 
In the other regions described by Logan as Huronian, however, 
there are well defined members of both the upper and lower divisions. 
In the Temiscaming country we have jasper-bearing conglomerates of 
the upper division and banded jaspers of the lower; and the same is 
true of the Michipicoton area; so that the conclusion is unavoidable 
that in his Huronian, Logan included rocks both above and below the 
important unconformity described on a former page. As much of 
the lower division consists of schistose volcanic materials and sheared 
eruptives, while the upper conglomerate in many cases contains great 
quantities of materials derived as pebbles and boulders from the lower 
rocks, the whole rolled out and rendered finely schistose by squeezing 
and shearing, so that the pebbles may be entirely indistinguishable, 
it is not surprising that the two should have been confounded in 
reconnaissance work. In fact, hand specimens of schists from the 
two divisions at Michipicoton could not be separated even by men 
who had been at field work in that region, so closely alike are they. 
When we add to this that the two divisions have undergone the 
same folding, squeezing and recrystallization, so that they are now 
everywhere in parallel position as to strike and dip, the reason will 
be clear why rocks really separated by a great lapse of time should 
have been thrown together as Huronian. 
That the so-called typical Huronian, as mapped by Murray, is 
far from being typical is well known to all Canadian geologists who 
have worked in the region. If the different areas described as Huron- 
ian by Logan are examined it will be found that all the others contain 
a larger amount of eruptive material, have a more schistose and 
crystalline character, and have undergone a far greater amount of 
tilting and folding than the region mapped by Murray. In fact, the 
region specially mapped is quite exceptional in its gentle dips and 
slight metamorphism. The very same rocks may be followed a few 

* Bur. Mines, 1901, pp. 189 and 201. 
