LOWER PALEOZOIC. 
219 
when its vertical or geographic connection with other faunas is 
not preserved. The three divisions of the table have been rec- 
ognized to a greater or less extent in all the sections of Cambrian 
strata studied in North America, and all the observed Cambrian 
faunas come within their limits. 
The second column in the table gives local names that have 
been applied within certain geologic provinces, where the fauna 
and the sedimentation indicate a greater uniformity of conditions 
than existed throughout the larger areas outlined by the tirst 
three divisions. The right-hand column gives the names of local 
subdivisions where the conditions of sedimentation and of life 
were still more restricted. 
Upper 
Cambrian. 
Lower 
Calciferous. 
Lower portion of the Calciferous formation of 
New York and Canada. Lower Magne- 
sian of Wisconsin, Missouri, etc. 
Potsdam. 
Knox. 
Tonto. 
Potsdam of New York, Canada, Wisconsin, 
Texas, Wyoming, Montana, and Nevada; 
Tonto of Arizona ; Knox shales of Tennes- 
see, Georgia, and Alabama. The Alabama 
section may extend down into the Middle 
Cambrian. 
Middle 
Cambrian. 
Georgia. 
L'Anse au 
Loup. 
Prospect. 
Georgia and "Granular Quartz" formations of 
Vermont, Canada, New York, and Massa- 
chusetts. 
Limestones of L'Anse an Loup, Labrador. 
Lower part of Cambrian section of Eureka and 
Highland Range, Nevada. Upper portion 
of Big Cottonwood Canon, Cambrian section, 
Utah. 
Lower 
Cambrian. 
St. John. 
Bra in tree. 
Newfound- 
land. 
Uinta? 
Paradoxides beds of Braintree, Mass., St. John, 
New Brunswick, St. John's area of New- 
foundland ; Lower Portion of Big Cotton- 
wood Canon, Cambrian section, Utah. 
Uinta? (The Ocoee conglomerate and 
slates of East Tennessee are doubtfully in- 
cluded.) 
The table is a correlation of the various sections described in 
the introduction to U. S. Geological Survey Bulletin No. 30, 
and hence is tentative. It is the expression of my present 
knowledge and opinion. All who use it in geologic work 
should refer to the data given in that Bulletin, and decide indi- 
vidually upon the value of the correlations made in the table. 
C. D. WALCOTT. 
