Correspondence. 339 
Michael L4vy ; The Archaean geology of the region northwest of lake 
Superior, A. C. Lawson ; On the crystalline schists of the United 
States and their relations, Powell, Irving, Chamberlin, Van Hise, 
Becker, Dutton ; Einige Fragen zur Losung des Problems der krystal- 
linischen Schiefer, nebst Beitragen zur deren Beantwortung aus den 
Palaozoicum, K. A. Lossen. 
CORRESPONDENCE. 
"Two Systems Confounded in the Huronian," is the title of aletter 
by professor Alexander Winchell in the American Geologist, vol. iii, 
No 3.— Yes : but then arises the question, by whom? and my reply to 
this is : by those who would attempt to include the Animikie silver- 
bearing formation of Thunder bay in the Huronian, with which it has, 
as I have pointed out since I first examined it in 1883, no similarity or 
correspondence whatever. 
The relations of the Huronian, Archaean, and the Animikie Cam- 
brian are so plain and unmistakable, that it seems to me most extra- 
ordinary that any one who has examined them in the field could pos- 
sibly confound these silver-bearing Animikie rocks with any part of the 
copper-bearing Huronian as known in Canada. 
Prof. Winchell refers, page 213 to " the great Plummer Argillites"— 
a name by the way I have no recollection of having met with before in 
Canadian geology — "or slate conglomerates of Logan," and a few lines 
further he says " I do not regard, therefore, as Huronian the series of 
rocks succeeding the Plummer argillites (Animikie slates) down- 
wards, though the Canadian geologists may so regard them." I must 
confess I do not understand what the foregoing paragraph means. 
Are the Plummer argillites the same as Logan's slate conglomerates, 
or are they the same as the Animikie slates ? and if so what are the 
rocks succeeding the " Plummer argillites downwards," that are not re- 
garded as Huronian ? 
If not Huronian, what does professor Winchell consider them to be? 
This we are not told, neither is there any reason given why they are 
not Huronian. The only reason seems to be personal conviction. 
Professor Winchell is certainly not very complimentary to the intel- 
ligence of Canadian geologists. But, evidently we are not wise, and 
are unable to recognize our own children though we have lived with 
them all our lives, as well as the stranger who has only recently be- 
come acquainted with them. 
Professor Bonney's conclusions a. b. and c, referred to by Professor 
Winchell, may be all perfectly correct, but do not therefore in any 
way affect the validity of the Huronian system, as such. a. is a very 
natural result of metamorphic action on a mixed series of clastic, pyro- 
clastic and igneous rocks, as varied in composition as they are in 
origin, h. Great thickness has always been recognized, and conse- 
quently long time. The alternative c, to which professor Bonney is 
