SECTION IV., 1902 [135 j Trans. R.S. C. 
VI. The Classification of the Archean. 
By Prorsssor A. P. Coteman, M.A., Px.D. 
(Read May 27, 1902.) 
The literature on the Archean of America is so immense and 
so scattered that a mere reference to the more important papers would 
demand a large amount of space. Fortunately, the older writings 
on the subject have been admirably discussed and summarized by 
Professor Van Hise, in his correlation paper on the Archean and 
Algonkian,! an indispensable work for the student of these ancient 
and complicated formations, so that in general no reference need 
be made to them here. The views held by the various writers are 
so different and conflicting that no good purpose would be served 
in reviving the old controversies. Of late, however, there are signs 
that the two opposing schools on the north and on the south sides 
of the Great Lakes, as they come together in their field work in Minne- 
sota, are also to some extent coming together in their opinions, giving 
hope of a final satisfactory solution of the difficulties. 
It will be remembered that the earliest work on these formations 
was done north of the lakes by Logan and his assistant, Murray, while 
the workers on the American side, starting from a different standpoint, 
reached conclusions which did not harmonize with those formed by 
Logan and his successors. As a starting point one naturally takes 
the views of Sir William Logan as summed up in the Geology of 
Canada in 1863, dividing the Archean, or Azoic as it was then called, 
into a lower system, the Laurentian, and an upper, the Huronian. 
Following the ideas of the time, the gneisses which form the 
greater part of the rocks of the Laurentian were looked on as met- 
amorphosed sediments. Above them came the Grenville. series, 
characterized especially by crystalline limestones, the Hastings series, 
and the Anorthosites, all largely schistose and, therefore, considered 
metamorphic rocks. 
The Huronian was not found in contact with the Grenville or 
Hastings series, but was considered later than any of the Laurentian 
rocks, largely because it is in part more evidently sedimentary and 
usually less crystalline. 
It will not be necessary to discuss in detail the changes of view 
which have been caused by later studies of the Laurentian and Huron- 
1on regions; but we may hold with Dr. Adams that the Lower Lau- 

+ Bull. U.S. Geol. Sur., No. 86, 1892. 
