THE ARCHEAN. 16.*^ 
only three who have expressed themselves in favor of classing 
eruptives with the Archean under any conditions. Dr. Hunt, 
Dr. Selwyn, Prof. Jos. L. Le Conte, Prof. R. D. Irving, 
Mr. Arnold Hague, Dr. S. F. Emmons, Prof, W. P. Blake, 
Prof. C. H. Hitchcock, Prof. N. H. Winchell, Mr. Thos. 
Macfarlane, Prof. Heil'prin, Prof. M. E. AVadsworth, 
Capt. Dutton and Prof. A. Winchell are opposed to classi- 
fying the eruptives with their including strata. 
F. Which, if any, of the following terms is applica- 
ble IN American Geology, and how applied ? He- 
BRIDIAN, DiMETIAN, ArVONIAN ?* 
Without attempting to decide whether or not lithological de- 
scriptions enable one to classify two igneous rocks in different 
parts of the world in the same system, the description of the 
occurrence of the English Pre-Cambrian rocks, in Appendix II, 
of this Report, taken from the report of the English Committee 
to the Berlin Congress, is given in order to facilitate a comparison 
between these rocks and our own. 
In answer to the question. Sir J. W. Dawson says : " There 
are good European equivalents for our Laurentian and Huronian." 
Prof. J. L. Le Conte does not believe that any of these 
names can, in the present condition of knowledge, be safely 
applied to American rocks. 
Prof. Roland D. Irving does not think that any one of these 
terms should be used in American geology. 
Dr. S. F. Emmons does not think the use of any of these terms 
advisable. 
Prof. C. H. Hitchcock thinks that the European terms of 
" Hebridian," " Dimetian," "Arvonian," and " Pebidian," should 
be carefully excluded from American geology. If priority of 
suggestion is to be observed, the Europeans must borrow our 
names for these rock-masses.f 
Prof. N. H. Winchell says : " I do not know anything about 
the foreign terms, except that I am satisfied that the Arvonian is 
a metamorphic condition of some of the sediments (perhaps of 
* See Note 2, p. 187. 
f Tliere is an implication here that the rock-masses on both sides of the 
Atlantic can be correlated. 
