. 
700 Notes on Classification and Nomenclature, [Aug 
be assigned to the Taconic and the second to the Cambrian. 
This will, of course, require the restriction of the term Silurian 
to the rocks of the ¿ird fauna, or to as much of it as was a | 
first covered by that term, as argued by Hunt, Marcou, Rogers, 
Dawson, Jukes, and others, 
The weight of authority and of usage has been in favor of 
covering the rocks in dispute between Murchison and Sedgwick, 
so far as they both claim strata holding the second fauna, by the 
Murchisonian term. Of the merits of this controversy I have 
nothing to say. It may fairly be left to the English geologists 
to decide. It would be an easy adjustment of all the conflicting 
claims, however, to assign, pro honoris causa, the first fauna to | 
Emmons, the second to Sedgwick, and the third to Murchison. — 
Tue ArcH@an.—lt is my individual opinion that no sub- 
divisions of the Archean can be made, with an approach to 
probable acceptance and long-continued usefulness, at the pres 
enttime. It would be judicious to introduce some indeterminate 
non-descriptive terms, such as Archean No. r and Archean No. 46 
or Archean No. 3, which could be interpreted by each locality, | 
and applied by the geologists of each country, according t0 
individual preference. In the Northwest, including Wisconstt, 
Minnesota, and Manitoba, much is. now being done on the: 
tematic study in the field of these rocks, and, without say! 
that the recognized, usual subdivision into Huronian and Lae 
rentian is not valid in very large areas, it is true that, as a ge 
eral scheme, this simple nomenclature is not applicable. 1 sp 
of these rocks as “ Archean” because of the general use of 
designation. The terms azoic and cozoic may have prior rights, 
and, perhaps, ought to be used instead. 
i 
