[COLEMAN] CLASSIFICATION OF THE ARCHÆAN 147 
pages; though at one point on Lake Temiscaming, and perhaps also 
on Lake Huron, the granite and gneiss seem older than the upper 
Huronian; so that possibly both arrangements may be right at differ- 
ent points, the first, however, being the prevalent one. 
With regard to the break between the Keewatin and the Coutchi- 
ching, my own observations have not shown it to be important, though 
Lawson’s detailed work in the region should give his opinion on the 
subject far more weight than mine. I thoroughly agree with him, 
however, that a series of gray mica schists and gneisses of sedimentary 
origin can be separated from the prevailingly eruptive Keewatin rocks 
in many localities. 
The iron range rocks, which form the upper part of the lower 
Huronian in many places, if not all, have not been provided for in 
his subdivisions, since the Keewatin group is defined as mainly or 
entirely of eruptive origin. ‘Though they are not usually of great 
thickness, they form an easily recognized horizon and are of great 
practical importance. On Grassy Portage bay of Rainy lake and near 
Wabigoon to the north, rocks of the iron range are associated with 
characteristic Coutchiching schists, while at other points, as at Michi- 
picoton, the associated rocks are sheared eruptives and pyroclastics 
which may properly be called Keewatin. 
Is it not possible that the Coutchiching, is the true lower Huronian 
and that the Keewatin series, being eruptive, is accidental in its 
occurrence, sometimes lying above the Coutchiching, sometimes inter- 
calated with it, and sometimes replacing it altogether? 
The name Ontarian to include the Keewatin and Coutchiching 
seems very suitable, since the province of Ontario contains the best 
examples of these rocks; but there are two objections to it, perhaps, 
however, of little importance. The name, I am informed, has been 
given to a fossiliferous formation in the United States, though whether 
it has priority or not, I cannot say, not having a copy of the report 
in which it was described. The other objection is that the name was 
not published in the reports on the areas where the Keewatin and 
Coutchiching were first described, so that the two latter terms, espe- 
cially Keewatin, already hold the field in the literature. Both in 
Ontario and Minnesota the term Keewatin has often been used to 
replace lower Huronian and is now found on many of the maps of 
the Archean. It might. therefore, be better to use Keewatin as 
the general term including the whole lower Huronian instead of 
Ontarian, and to give a fresh designation to the eruptives and pyro- 
clastics. 
While the propriety of separating the lower part of the Archæan 
from the Huronian as Keewatin or Ontarian is quite clear in view 
