Lake Superior Stratigraphy. — Law-son. 321 
dividing line between Archaean and post- Archaean in the lake Su- 
perior region, which seems to me to be fraught with confusion to 
this branch of geological inquiry and to be based upon an under- 
valuation of some important conditions which obtain generally in 
the region. The new information given us by Prof. Van Hise is 
of the most interesting character and will do much to harmonize 
some seemingly conflicting views ; it is therefore to be regretted 
that the approximation to harmony which he seeks to establish 
should be marred by an utterance which is not only out of ac- 
cord with the very commonly accepted view as to the upper limit 
of the Archaean, but is in startling discord with the significance of 
facts which have been well authenticated. 
It is with much reluctance that I offer this criticism. For the 
most part Prof. Van Hise and myself are, or at least have been, 
in agreement as to the interpretation of the main facts of lake 
Superior geology which have come under nry notice ; and if the 
new view now advanced by him involved simply a matter of ex- 
pediency or nomenclature I should abstain from adverse criticism, 
so that our general agreement might not be confounded with a 
disagreement on a minor point. It appears to me, however, that 
this new suggestion involves a bad principle which it would be un- 
wise to pass unchallenged. I am constrained, therefore, to ven- 
tilate the subject, feeling confident that I shall suffer no con- 
demnation at Prof. Van Hise's hands should I succeed in showing 
that he has overlooked, or is not cognizant of, considerations 
which if placed in evidence must logically force him to modify his 
present judgment. 
During the time that I have been at work northwest of lake Su- 
perior, no general truth has been brought home to me more im- 
pressively than the fact of the individuality, so to speak, of the 
Archaean complex. By the latter term is meant, in accordance 
with the usage of nearly all previous writers on this field, the com- 
plex of rocks upon the profoundly denuded remains of which the 
Animikie strata of Thunder bay rest in strongly marked un- 
conformity. It includes all the rocks which existed as geological 
formations prior to that epoch of denudation which produced the 
truncation of the pre-palseozoic continent and prepared the floor 
upon which the Animikie ami its equivalents rest. How great 
was that epoch, how stupendous is the evidence of its duration. 
and how important it is as a geological base line I have attempted 
