THE AECHEAN. 159 
D. Do YOU APPROVE THE PLAN OP SUBDIVIDING THE 
AeCHEAN PETROGRAPHICALLY, and of omitting COR- 
RESPONDING CHRONOLOGICAL DIVISIONS AND NAMES ? 
In the last session of the Congress, after its silent refusal to 
attempt a division of the Archean, Prof. T, McKenny Hughes 
proposed that where these rocks occurred the geologist studying 
them might express their petrological characters, and omit all 
attempts to give a chronological succession. To this Prof. Rene- 
ViER, of Switzerland, agreed. This plan was temjwrarily to take 
the place of the ordinary classification. 
Sir J. W. Dawson thinks that like other formations the 
Eozoic should be divided stratigraphically and the qualities of 
its rocks should be used merely as characterizing subordinate 
series. This is especially necessary, he thinks, in a group where 
we may have in one series crystalline and non-crystalline rocks, 
or rocks so different as gneisses, quartzites, and limestones. 
Dr. Selwyn thinks the Archean should be dealt with petro- 
graphically like other systems. 
Prof. J. L. Le Conte approves the plan for local distinc- 
tions. 
Prof. Irving holds this view, provided the plan be not ex- 
tended beyond local description. 
Mr. Arnold Hague thinks the whole tendency of modern 
research in this direction, but sharp lines cannot be drawn. 
Prof. G. H. Williams thinks that petrographical classifica- 
tion is the only safe one, aside from the two-fold division of 
Laurentian and Huronian.* 
Prof. C. H. Hitchcock would use petrological, or chrono- 
logical, or geographical division as might be most conven- 
ient. 
Mr. T. Macfarlane approves of it, but would rather 
leave it to the national committees. 
Prof. B. K. Emerson would use petrological division only 
for local and temporary use. 
Dr. Robert Bell approves of it. 
* In a late note, Prof. G. H. Williams modifies his view, first given, of the 
advisability of this two-fold division, and prefers to omit it for the present. — 
Kep. 
