Winslow —The Mapping of Missouri. 91 
the season of 1888 and in that of 1889, topographical work 
was completed from Cairo to Alton, Ill. The section of pre- 
cise levels from Illinois river to Cairo was run in 1880; that 
northward from Illinois river in 1883. Even if there should 
be no appropriation at this session of Congress, the topography 
will reach the northern boundary of Missouri during the 
working season of this year. The reduction and publication 
of maps has followed the same course as the field work. Ten 
sheets, scale 1:20000, from Cairo to the southern boundary of 
Missouri were published in 1888-89; 14 sheets, from Cairo to 
Carondelet, have been published in 1890-91. Unless there is 
an appropriation at this session it is not probable that publi- 
cation can be continued at present.’’ 
The area mapped by the Commission is shown on the 
diagram opposite page. 
The published maps of the Mississippi river Commission are 
on two scales. One series consists of large sheets 22 inches by 
36 inches, on ascale of about 31 inches to the mile. These 
show all detail of importance to the navigator, such as the 
shore line, the positions of bars, and the depths of the water ; 
the topography on each side of the alluvial plain is shown in 
five foot contours, timbered and open country are distin- 
guished and many other recognizable land marks are intro- 
duced. The second series of maps are not much more than 
reductions of the larger maps and include less detail. They 
are issued on a scale of one mile to the inch, in sheets 12 by 
22 inches. 
The work of the Missouri River Commission was begun in 
1878. Their mapping is similar to that of the Mississippi river 
Commission and in the words of their reports, embraces ‘* an 
accurate delineation of the shore line, islands and sand bars,’’ 
the general topographical features of the valley and the line 
of bluff bordering the same, the whole checked by a system 
of triangulation carried along the river banks.’’ Soundings 
were also made along lines normal to the current and from 
500 to 1500 feet apart. The survey commenced in 1878 at 
the town of Weston and was extended thence to Boonville 
during that year; a line of unchecked levels was carried 
along with it. During 1879 the survey and line of unchecked 
