26 GEOLOGICAL SURVEY OF WISCONSIN. 



which are to be connected, and made the basis of a system of triangu- 

 lation, covering all the ground to be surveyed. 



The engineer department of the United States army have in charge 

 the survey of the lakes, which reaches into this state along the shores 

 of Lake Superior, Lake Michigan and Green Bay, and also otlier mili- 

 tary and geographical surveys in the west. The work of the lake sur- 

 vey will be available, so far as it goes, for the purposes of the state 

 survey, and it is exceedingly desirable that it should be extended so as 

 to embrace a larger portion of the interior. At my suggestion Gen. 

 Humphrey, chief of engineers, has authorized the determination of 

 the position of points on the base line of the land survey (the south- 

 ern boundary of the state) and others on the fourth principal meridi- 

 an, and on the "correction lines;" these being the governing lines 

 of the public land surveys, their exact determination becomes of the 

 greatest importance. Should the congressional appropriation for these 

 objects be continued, other work of the same kind will be done. 



If such a survey could be extended over the state of Wisconsin, and 

 properlj' connected with the land surveys, it would accomplish all that 

 could be desired in this direction. It was found that congress, while 

 making provision for extending the coast survey across the continent, 

 so as to form a geodetic connection between the Atlantic and Pacific 

 coasts, required also the determination of points in each state in the 

 Union, which shall make requisite provision for its own topographical 

 and geological surveys. Under this authority, the oflScers of the coast 

 survey have already taken observations for determining the position 

 of Madison and La Crosse, and arrangements have been made for the 

 further prosecution of the work, which will be in charge of Prof. J. 

 E. Davies, of the University of Wisconsin. In addition to the general 

 benefits of that survey, it will be the means of training a number of 

 young men in the methods of this important kind of work, thus mak- 

 ing it the source of educational advantages. 



Other importanl surveys have been made by the general govern- 

 ment within our state. Among them, perhaps the most valuable are 

 those made a few years ago under the direction of Gen. G. K. Warren, 

 of several of the larger rivers, including the Mississippi so far as it 

 forms our western boundary, and portions of the St. Croix, Chippewa, 

 Black, Wisconsin and Fox rivers. Of these, maps were constructed 

 on a scale of two inches to one mile (same as the plats of the govern- 

 ment land surveys), showing not only the margins of the rivers, with 

 the islands and sand bars, but also the boundaries of the bottom lands 

 and the position of the adjacent bluffs. Copies of these detailed and 

 costly maps have been furnished for the use of the state survey, and 



