PRECIOUS METAL MINING IN THE UNITED STATES. 95, 
in harmony with any system of development. To show this the more plainly to 
the eye, we have given two Figs.—1 and 2, exhibiting the times of the appear- 
ance geologically of the various forms, and also the relative periods at which they 
should have appeared according to the system of evolution. 
Fig. 1 is condensed from Dana.* It will be seen from this that four of the 
five sub-kingdoms of animal life—all but the vertebrates—came in together at the 
beginning of the Silurian, when if there was in nature a systematic plan of de- 
velopment, the Protozoans should have appeared first, and the others followed in 
the order of their organic rank. The latter idea we have endeavored to show in 
Fig. 2. We have divided the time nearly equally between the fine sub-kingdoms. 
This may be giving the lower forms more importance than they deserve for they 
are not equally dissimilar in the degree of their organization. But it is usually 
stated by evolutionists, that the lower the type the more slowly is the change of 
advancement. This we think justifies the statement that the time required for 
the Protozoan to become a Radiate would be as long as for the highest Crustacean 
t» become a Vertebrate. Our tables in Fig. 2 may not be entirely accurate, but 
they are certainly so approximately. It is enough to show how entirely antago- 
nistic are the facts of the earth’s early history to the theory of development. The 
great difference of life rank, between the different sub-kingdoms, is admitted by 
all Zodlogists. coh 
Similar tables (see Figs. 11 and 12) in relation to the geological and theoretic 
appearance of vegetration, gives nearly the same results. 
Note.—We have commenced, in our geological history and observations, with the fossils of the Lower Si- 
lurian. The fossils below that age are so few and obscure that they throw little, if any, light on the subject 
under discussion. Whether Eozon Canadense is organic, is an unsettled question in the scientific world. 
Dana in referring to the oldest Silurian fossils has stated that they were not less than fifty millions of years 
old. Weshall use that standard of time, in the following pages, though most European geologists assume a 
much longer period. [See appendix for the Geological Ages and Periods. ] : 
PRECIOUS METAL MINING IN THE UNITED STATES. 
BY N. S. SHALER. 
*k *K *k * *k k *k * *k *k ae * 
The fields of the precious metals in the United States may-be generally di- 
vided into two principal areas, that of the Appalachian and that of the Cordil- 
leran ranges. Besides these there are the smaller regions, which may be termed 
in a similar fashion, from their neighboring mountains, the Laurentian, including 
the region about Lake Superior, and the Ozark region about the mountains of 
that name in Arkansas and Missouri. There are lead ores in several of the 
States of the Mississippi Valley, at great distances from these mountain ranges, 
that contain a small proportion of silver, but in few cases does this silver exceed 
about the four or five thousandth part of the ore; nor is there any chance that 
they will ever produce this metal in quantities of the least commercial importance. 
* Manual, pps. 886 and 589. 
