308 MORLEY E. WILSON 
The regional correlation of pre-Cambrian rocks from the nature 
of the evidence upon which it is based must always be to a degree 
hypothetical, but so long as it is logically inferred from a reasonable 
number of facts and its hypothetical character is kept in mind by 
geologists, it serves a useful purpose in the progress of our science. 
In the report of the Special Committee on the Lake Superior region, 
certain sedimentary rocks included in the basement complex to 
the north of Lake Superior were called Huronian, and thus tacitly 
correlated with the Huronian rocks occurring in the region south 
of Lake Superior and on the north shore of Lake Huron. The 
purpose of the present paper has been to point out that from a 
careful consideration of the facts now at hand, it must be concluded 
that the evidence on the whole is equally in favor of an alternative 
hypothesis, that these ancient sediments are a part of the older 
complex which underlies the Huronian, and are pre-Huronian in age. 
