REVIEWS BET 
lowa Geological Survey, Annual Report, 1898, Vol. IX. By 
SAMUEL CALVIN, State Geologist; H. F. Barn, Assistant 
State Geologist. 
Statistics of Mineral Production. By S. W. BEYER; Geology o7 
Carroll County, H. F. Bain; Geology of Humboldt County, T 
H. McBripe; Geology of Story County, S. W. BEYER; 
Geology of Muscatine County, J. A. UppDEN; Geology of Scott 
County, W. H. Norton; Artesian Wells of the Belle Plaine 
Area, H. R.Mosnar. Thirteen plates, 56 figures, 14 maps. 
This volume of the reports of the Iowa State Geological Survey 
serves to. corroborate the high opinion already established among the 
geologists of the United States of the work of this organization. The 
record of the Iowa survey has been one of uninterrupted excellence in 
both the theoretical and the economic phases of its work. The list of 
the corps engaged in the work of 1898 is of itself sufficient to invite 
inspection of the report. 
Each of the county reports gives a systematic exposition of the 
physiographic and economic features of the geologic field under con- 
sideration, each being emphasized as the peculiar characteristics of the 
district demand. ‘To many ofthe reports is appended a discussion of 
the forestry of the areas studied. 
In the geology of Carroll county the physiography is of exceptional 
interest, since the tract is bisected diagonally by the edge of the Wis- 
consin drift sheet. Consequently the northeastern and southwestern 
parts of the county display topographic features in admirable contrast 
as the result of these relations. The Middle Coon River follows this 
drift margin in a general way, receiving numerous tributaries with sec- 
ondary and tertiary branches from the area of Kansan drift westward, 
while from the Wisconsin drift there is only one important tributary 
and that without branches. The erasure of post-Kansan drainage by 
the Wisconsin invasion is illustrated by a number of examples. The 
Coon River, flowing across the northeast part of the county has con- 
structed a makeshift course from ‘‘bits of old captured valleys, and 
new trenches which it has cut for itself.” 
The stratigraphy of Carroll county includes an exposure of a Car- 
boniferous limestone, probably of the Des Moines series. The Creta- 
ceous is represented by several exposures of the Dakota sandstones and 
