THE ARCHEAN. 175 
Europe, does not meet with general favor in the United States, 
and will not be accepted for general use in its present form, at 
least without strong opposition. It should be observed, however, 
that of those who have most devoted themselves to petrology in 
the above list, and whose authority on that branch of science is 
highest, one accepts the system unreservedly, and several others 
do not express any opinion, 
M. Should Serpentines constitute one class of 
ERUPT! VES ?* 
Prof. Dana answers : " No." 
Sir J. W. Dawson : " Certainly not." 
Dr. Hunt : " No Serpentine is ever truly eruptive or plu- 
tonic." 
Prof. Le Conte : "If eruptive origin is undoubted, it should 
be made a distinct class, because its appearance, both in the field 
and in hand-specimens, is very distinct."t 
Prof. Irving : " No." 
Dr. Emmons : " No." 
Prof. G. H. Williams : " No." 
Prof. Hitchcock : " Serpentine is an altered rock, one-fourth 
water." [Answer, presumably, "No." — Rep.] 
Prof. N. H. Winchell : " No." 
Prof. Wadsworth : " Serpentine, so far as I have studied it, 
when not a veinstone, is an altered condition of a peridotite, and 
comes as a variety under that eruptive rock. (See ray Litho- 
logical Studies, pp. 189-192 for more fully expressed views,)" 
Prof. Emerson: "No." 
Capt. Dutton: "I know of a great many serpentines which 
I think can be demonstrated to be altered peridotites. Regard- 
ing others, I await further research. I see no reason to dispute the 
* [In Prof. Lossen's sclieme the eruptives are arranged in seven groups, one 
of the separate divisions of each being selected to represent the group. The 
first group is "Granites, Syenites, etc."; the second, " Porphyries"; the third 
"Trachytes, Phonolites, etc." ; the fourth, " Melaphyres, etc." ; the fifth, "Ser- 
pentines, etc." ; the sixth, " Basalts, Dolerites, etc." ; the seventh, " Present 
Eruptions." — Rep.] 
t Prof. Le Conte's answer to the next question is that Serpentine is " always 
an alteration product." Fi'om this it would seem that liis answer to this must 
be "No." 
