214 PIViIst ONS Of THE SretTe rot. 
In a large portion of this district, south of latitude 46° 47’ 10”, and east of longi- 
tude 92° 40’, more detailed examinations have either been made by yourself, or 
reported to you by other members of the corps, since my reconnoissance in 1847. I 
shall, therefore, devote most of this Report to that part of the Chippewa Land Dis- 
trict, which is bounded on the south by a line drawn easterly from the mouth of 
Rum River to St. Croix River, in latitude 45° 15’, and including all the country 
north of it within the boundaries before mentioned. At the same time, I shall 
incorporate as much of the Report of 1847 into this, as may be necessary to illus- 
trate the geology of such portions of the country examined that year, as have not 
been since more fully explored. 
As might be expected of such an extent of territory, there is very great diversity 
in its physical features, so great, indeed, as to produce a variety in productions and 
climate seldom found in countries destitute of high mountain ranges, or, at least, of 
plateaus greatly elevated above the level of the sea. It is divided by nature into 
five well-defined districts, which, while they differ materially in their geology, pre- 
sent also considerable modifications of climate, the result of local influences peculiar 
to each division. 
The first division, or that bordering on the Mississippi, extends through two 
degrees of latitude, in a direction nearly northwest from the mouth of the Wisconsin 
River. It is narrow, having an average breadth of only fifteen to twenty miles, 
except near its northern and southern terminations, where it is deflected east 
between Prairie du Chien and the mouth of Bad Axe River, and north between 
the middle of Lake Pepin and the Falls of St. Anthony. 
The second division, which has an average breadth of thirty to forty miles, crosses 
Wisconsin River between Whitney’s Rapids and Winnebago Portage, and extends 
in a northwesterly direction along the line of the first division. Its northeastern 
boundary crosses the large tributaries of the Mississippi a short distance below the 
falls of those rivers, and is continued until it reaches the head-waters of Rush 
River, when it turns directly north, and terminates somewhere between the sources 
of Red Cedar and Shell Rivers, and the dividing ridge, on the east side of the St. 
Croix, and crossing to the west side of that stream, between the mouths of Wolf 
Creek and Shell River, extends up the valleys of Snake and Kettle Rivers. 
The third division includes all the country between the northeastern boundary 
line of the second division and the shores of Lake Superior, embracing all the 
northern chain of highlands and the sources of all the great streams east of the St. 
Croix and Bois Brulé Rivers; and also a broad strip of country stretching in a south- 
westerly direction from the southwestern bend of St. Louis River, through the 
Mille Lacs region, to the Mississippi, and crossing that stream between the mouths 
of Clear-water and Omoshkos Rivers. 
The fourth division embraces all the country lying northwest of a line drawn 
from the mouth of Crow Wing River, through the Sandy Lake country to Savanna 
Portage, and extends to Red Lake, and the sources of some of the tributaries of 
Rainy Lake River. This district includes, also, the lake region about the sources 
of the Mississippi. 
The fifth division comprehends all the country bounded by St. Louis and Ver- 
