336 The American Geologist. December, 1895 
I doubt not the genera would have a greater vertical range, and at cer- 
tain horizons also intermediate forms would be found. 
The succession of these three sub-faunal zones has been 
well established in America. But the cause of the changes 
from one to the other has been problematical. As indicated 
by Dr. Hicks, such cause can be seen in the nature of the sed- 
iments, where the strata are conformable, but where they are 
entirely non-conformable at definite horizons it can be seen, 
especially in the Lake Superior region, in the succession of 
eruptive epochs whose activity is attested not only by the 
faunal changes but by the presence of the eruptive masses in 
great volume. 
The writer has been compelled to limit the present discus- 
sion to the rocks that lie above the great non-conformity at 
the base of the Taconic. To fully review the classification of 
the "Correlation papers" would require another series devoted 
to the Archean, in respect of which are inconsistencies and 
assumptions, in the publications here reviewed, which can 
only be considered detrimental to the progress of geology. 
These chiefly center in and revolve about the introduction, 
the definition and the application of the term Algonkian, the 
whole constituting, in brief, one of the greatest mistakes of 
American official geolog3^ With this brief expression of 
opinion, the writer is comi)elled to forego the discussion of 
this portion of the subject. 
Minneapolis, Ajiril 2, 1895. 
Supplementary Note. In writing of the Canadian localities of the 
Taconic eruptives (vol. xv, p. 356, June, 1895j, by an unfortunate over- 
sight the earliest mention of the rocks of Mt. Stephen, and the erup- 
tives found therein, was omitted by the writer. 
The first announcement of Cambrian fossils from this region was 
made by Mr. H. H. Winwood (on the authority of Dr. Hicks) in the 
London Geological Magazine, May. 1885. The first discovery of such 
fossils was made by Dr. G. M. Dawson, in August, 1884. These, as 
well as those afterwards collected during Mr. Win wood's visit (at the 
time of the British Association excursion), were examined by Mr. C. 
D. Walcott, who recognized Olenelliis gilberfi and luywelli and Olen- 
oicles Iceius. Publication occurred shortly afterward in the Annual 
Report Geol. Sur. Can., 1885, (pp. 119B, 139B). Mr. McConnell, there- 
fore, who collected later and more fully from the same place, knowing 
this earlier announcement, was in no haste to place his discoveries on 
record . 
