THE ARCHEAN. 171 
be among the raetamorphic rocks of later times. You thus see 
that I have no scheme of my own to advocate. I advocate only 
the general principle that the science accept what is proved, and 
allow the rest to remain in doubt until doubts are removed ; that 
a geological map should not call crystalline schists Archean with- 
out first definite evidence that they are Pre-Cambrian, etc." 
The plain interpretation of this is, that, after a sufficient amount 
of work has been done on the geological column to enable one to 
express any opinion at all as to what the various groups, systems, 
and series show, it is permissible to state, if such be the result of 
examination, that this or that group, system, or series contains 
certain rocks found in no other. Provided, that this be consid- 
ered, as all results of inductive science must be, a working hypo- 
thesis or theory ready to be promptly abandoned as soon as the 
first fact inconsistent with it be ascertained. 
Limited and qualified as above, then, the proposition contained 
in the question under review has the support of Profs. Dana, N. 
H. Winchell, Irving, Le Conte, Emerson, Hitchcock, Sir Wil- 
liam Dawson and A. Winchell, Capt. Dutton, Drs. Hunt and 
Emmons (eleven of those asked). 
Mr. Walcott and Prof. Wadsworth reject it absolutely. 
Prof. Geo. H. Williams rejects it with a certain reservation 
for its employment " in a broad way." 
More than three-fourths of those who express opinions at all, 
while they do not accept it without many restrictions, refuse to 
reject it entirely : and leave it to the future. 
J. Are the lower stratified crystallines (1.) or aque- 
ous origin metamorphosed partly or wholly by 
igneous action ; OR (2.) of igneous origin metamor- 
phosed in part or in whole by subsequent agencies; 
OR (3.) sometimes one and sometimes the other?* 
Prof. Dana holds that there is no general rule. Each rock 
should have its origin and nature ascertained by special study. 
Sir J. W. Dawson thinks it would require a treatise in ex- 
planation. 
Dr, Hunt says: "The lower stratified crystalline rocks are 
indigenous rocks of aqueous or crenitic origin and not meta- 
morphic in the Huttonian sense." 
* As sent out this question read "partly" for "sometimes." — Eep. 
