R. D. [rving—Divisibility of the Archean. 247 
should extend the term Cambrian from the fossiliferous Pots- 
da ownward over two great unconformities and two enor- 
strong an advocate as any of the indivisibility of the Archzean. 
Not that I would maintain the certain absence of unconformities 
seems very improbable that this generally accepted reference 
of the iron-bearing series to the Archean can ever be proved 
erroneous in any other save one way, viz: by the discovery 
in them of fossils. This is, of course, a discovery that may be 
made at any time. The rocks are, in the main, less alter 
than many of later date carrying fossil remains. Until this 
discovery is made, however, we must, I think, continue to call 
them Archean. 
The question next arises as to the names we shall use for 
these two divisions of the Lake Superior Archzan. 
It is now many years since Sir William Logan, after an ex- 
Still, there are certain points in it with regard to which I feel confident that he is 
mistaken. The most important of these points, in the present connection, is the 
north shore of Lake Huron a mica ist or micaceous quartzyte whi has 
always be pped Canadians as Huronian and which may represent 
the mica-schist of Winchell’s Group II. But I have never designed, in parallel- 
n, e n uronian with that of the nd Penokee regions, to 
indicate my belief that it covers exactly the same range as they. it is equiva- 
lent to any part of, or to more than all of, the Marquette and Penokee iron- 
series, inasmuch as in these series there is no evidence whatever of any 
discordances or separations, we are justified in speaking of the two latter series 
a8 Huronian. 
. 
