154 REPORT OF THE AMERICAN COMMITTEE. 
ronian beds are almost the first which show the existence of 
sedimentation. 
Dr. G. M. Dawson thinks our knowledge of the rocks here 
collectively referred to is not yet sufficient to admit of more 
definite subdivision. 
Prof. A. Winchell says " the Archean is an assemblage of 
clastic rocks taking rank with Paleozoic, Mesozoic, etc. I even 
suspect that more complete knowledge will show it to possess 
magnitude and diversification of history equal to all the succeed- 
ing formations. It is certainly not permissible to set it down in 
the rank of a 'system.' It admits of the following systemic 
divisions : 
iOttertall (white) andThessalon (red) Quartzites. "| With associated 
Plummer (conglomeratic) Argillite-Animike. v eruptives. 
Missisaugui (vitreous) Quartzite. J In Canada. 
IArgillites, chlorite and hydromica schists, quartz- "| In Michigan. 
ites, conglomerates and great beds of hematite, J- Minnesota, 
with heavy intercalations of eruptives. J Wisconsin. 
, T • ( Crystalline Schists. 1 t„ nTi„„„„„*„ 
J. Laukentian < ^ . , ^ . . , ^ . I In Minnesota. 
I Gneisses and Granitoid Gneisses. f 
In this exhibit the term ' Marquettian ' is used simply for a 
provisional designation, and it is not intended to propose it as a 
name of a systemic division. Nor do I here present the equiva- 
lences of the subdivisions, nor the evidences on which I rest. I 
do not here include the so-called ' Keweenawan,' because I in- 
cline to the opinion that its equivalents fall within the Paleozoic 
'group.'" 
Sir J. W. Dawson, Dr. T. Sterry Hunt, Dr. Selwyn, 
Mr. Thomas Macfarlane, Dr. Robt. Bell, Prof. C. H. 
Hitchcock (provisionally) and Dr. G. M. Dawson favor the 
retention of Laurentian and Huronian as divisions of the Archean. 
The latter thinks Huronian more doubtful, as the rocks may 
prove " relatively local," but would retain it. Mr, Macfar- 
lane adds Taconian to these two as the upper limit of the 
Archean, but would be willing to substitute for Laurentian, Hu- 
ronian, and Taconian; Gneissose, Schistose, and Phyllitic. Dr. 
Hunt regards at least six divisions as established, to wit : Lau- 
rentian, Norian, Arvonian, Huronian, Montalban, and Taconian 
and adds that perhaps there should be another division made by 
dividing the first or Laurentian. 
So far as these views can be taken as representing the sentiment 
of those American geologists who think for themselves, there is 
