344 Methods of Stratigraphy. — Winchell. 
allowing the term Lower Cambrian to supply the interval 
covered by it. Another point should be mentioned in con- 
nection with this original idea of the term Huronian, viz : It 
is distinctly avowed '^ that the Huronian embraces the vol- 
canic formations of the shores of lake Superior. These are 
made the parallel to the trap and associated quartzytes of the 
north shore of lake Huron. The geological map that accom- 
panies the French document has the Keweenawan throughout 
the shores of lake Superior, at Thunder bay, and on Isle Royal ^ 
colored to represent the Huronian, the same as the north 
shore of lake Huron. This embraces the traps and conglom- 
erates and the amygdaloids as well as the Animike rocks of 
Thunder bay with their associated greenstones. The Huro- 
nian is said, unqualifiedly, to rest unconformably on the 
Laurentian. This view of the Huronian seems to have con- 
tinued in favor till 1862. 
In the Quarterly Journal of the Geological Society of Lon- 
don (Nov. 19, 1862), appeared a contribution by J. J. Bigsby 
"On the Cambrian and Huronian formations," which has 
played a very important figure in its effect on the literature 
and geology of the Huronian formation. At various times 
Dr. Bigsby had contributed important articles on the 
older rocks of lake Superior and of the region further north- 
west, and his opinion and authority, with English and Cana- 
dian geologists, stood in such high esteem that there was no 
one who would venture to question his conclusions. Still 
they were at variance with those of Logan, Sir Roderick Mur- 
chison, Dana,' and nearly all the geologists who had expressed 
an opinion on the subject, Dr. Dana going so far as to state 
that the true Cambrian formation did not exist in North 
America ; the same interval being covered, as remarked by Dr. 
Bigsby, by the Huronian, "as a substitute in place if not in 
time." Still, after taking a wide survey of the Huronian and 
the Cambrian, in the light of the conceptions which he held 
of them, Dr. Bigsby reached the conclusion that they are not 
the same, but that the Huronian differs markedly from the 
Cambrian. He placed it on the same plane as the "Second 
* Canadian Naturalist, vol. i. 1856. p. 16; Esquisse geologique, 
p. 29. 
^Am. Joar. Sci., N. S., vol. xiv. p. 227; Siluria, 2nd Ed. p. 19; 
A.A.A.S. vol. IX. 1855. Providence meeting, p. 32. 
