[October, 
614 Analyses of Books . 
the so-called “ territories.” The diligence of Wisconsin in this 
important task will be more fully appreciated if we remark that 
the volume before us — the third of the “ final report ” of its 
survey — extends to 763 large and very closely-printed pages, 
abundantly illustrated with maps, plans, sections, views of cha- 
racteristic scenery, &c. 
The Report comprises, in its main divisions, the General Geo- 
logy of the Lake Superior Region, by R. D. Irving ; the 
Lithology of the Keweenawan or Cupriferous System, by 
Raphael Pumpelly ; the Geology of the Eastern Lake Superior 
District, by R. D. Irving ; the Huronian Series west of Penokee 
Gap, by C. E. Wright ; the Geology of the Western Lake Supe- 
rior District, by E. T. Sweet ; the Upper St. Croix District, by 
the late Moses Strong ; the Menominee Region, by T. B. 
Brooks ; and the Economic Resources of the Menominee Iron 
Region. 
The entire extent of Wisconsin presents much that is highly 
interesting to the geologist. The series of strata measure about 
100,000 feet in thickness, and include four great systems, — the 
Laurentian, the Huronian, the Keweenawan, and the Lower 
Silurian, each uncomformable to its predecessors. 
Concerning existing theories on the origin and age of these 
formations, and of the structure of the trough of Lake Supe- 
rior, the author regards most of them as hasty. The Keween- 
awan is characterised as the “ copper-bearing ” system. Copper, 
indeed, constantly accompanies these rocks throughout their 
entire extent in Michigan and Wisconsin, and is associated with 
silver, though in small quantities. The Menominee region, on 
the other hand, contains abundance of iron in the Huronian 
system. It appears that an earlier survey of this region, exe- 
cuted under the orders of the Federal Government, is not merely 
“ entirely inaccurate, but absolutely fraudulent and false.” A 
certain “ Spread Eagle Lake ” was not only never surveyed, but 
apparently was seen only in part by the Deputy Surveyor, who 
swore to having traversed and mapped it according to his 
contraCl. 
We find some interesting observations on the climatology of 
the Lake Superior country. The mean annual temperature at 
the lake shore is 38° F. — certainly low for the latitude. The 
spring months show a mean temperature of 34 0 , summer 62°, 
autumn 40°, and winter 15 0 . Winter sets in about the end of 
October. It is mentioned that in 1877, though an early season, 
the snow was all gone by the 1st of May, though “ ice was found 
in the swamps two or three weeks later.” Strawberries ripen on 
the south slope about the 1st of August, and on the north slope 
from the middle to the end of August. In the main body of 
Lake Superior the water, which is of exceptional purity, never 
exceeds the temperature of 46° F. 
Concerning the fauna and flora of the region we find but little 
