184 EEPORT OF THE AMERICAN COMMITTEE. 
selection of Serpentine as the type of the fifth division of the 
eruptive rocks, which is inadmissible because — 
N. Serpentine is all but universally regarded as a product 
of alteration either of Peridotite (the commonest view) or of that 
and other eruptives, or even of sedimentary rocks. 
O. It is better that the word Taconic as a term of Archean 
classification, be dropped altogether. But if employed it has 
been proposed by Dr. Hunt for the place of the uppermost division 
of the Archean, where this division can be made out. 
It is recommended that the American Committee use every 
proper means before the next Congress : 
1st. To have the word 'Group' of the Committee on Nomen- 
clature substituted by Realm for the most comprehensive strati- 
graphical division. 
2d. To have it officially declared that neither the color-scheme 
for the proposed map of Europe, nor the classification of erup- 
tives of Prof. Lossen, provisionally adopted by the map-committee 
in order to bring out the map, are other than tentative schemes, 
subject to alteration when their application to the map shall have 
shown to what extent they are deficient. 
3d. To cause it to be understood that American geologists will 
acquiesce in the recommendations of the Congress by sacrificing 
individual opinions to a reasonable degree, provided that these 
recommendations do not hamper the efforts of research by re- 
quiring more correlation of beds between the two continents than 
observation can justify. 
Note I. 
In this connection it would be impossible to pass over a work 
which displays on this subject great erudition,* written chiefly, as 
its title indicates, to establish the claim of one of its authors to 
priority in the name of Azoic as applied to the Pre-Carabrian 
rocks, and to vindicate the appropriateness of this designation. 
The following very condensed summary of the argument in the 
Resume it is hoped does this work no injustice. The term 
Azoic was used by Murchison in 1845, for the crystalline masses 
in Scandinavia which he found underlying those beds which he 
deemed to be the exact equivalents of the Lower Silurian of 
* The Azoic System and its proposed Subdivisions. 
