Winslow —The Mapping of Missouri. 89 
surveys, we reach the end of what we may term the period of 
explorations, when the work was of the nature of a reconnois- 
sance, when determinations were confessedly of only very 
approximate nature and little or no detail was attempted. 
During the next decade the war and the succeeding years of 
reorganization prevented any further progress of geographic 
work. Not until after the year 1870 was such resumed and 
we then pass into what may be called the period of exact and 
detailed mapping. 
The work of the U. 8S. Coast & Geodetic Survey. — 
The beginning of precise and detailed geographic work 
was the extension of the trans-continental chain of tri- 
angles by the U. S. Coast and Geodetic Survey from Illinois 
into Missouri. This was started in the year 1871, when a 
base line was measured in the Missouri bottoms and several 
stations were selected. During the year 1873 triangulating 
was resumed and was extended 32 miles west of St. Louis; 
during the years 1874 and 1875 it was extended to the Gas- 
conade river and during the years 1879 to 1886 the work was 
continued uninterruptedly and the triangles were carried en- 
tirely across the State into Kansas. The position of this 
chain of triangles in the State is clearly shown in the dia- 
gram on page 90. Following this belt of triangles, precise- 
leveling has now also been completed across the State by the 
Coast and Geodetic Survey. This work was carried from St. 
Louis to New Haven in the year 1882; from New Haven to 
Jefferson City in 1888 and from Jefferson City to Kansas City 
in 1891. 
The Mississippi River Commission was organized in the year 
1879. At this date only about 18 miles of the river from 
Cairo down, had been mapped. Since that time, according 
to data kindly furnished by Capt. Carl F. Palfrey, the present 
secretary of the Commission, their operations have been as 
follows, up to 1891: — 
' Under the appropriations of 1881-82, in the working 
seasons of 1881-—2-3, this work was carried southwards beyond 
the limits of Missouri. Also triangulation was carried north- 
wards to Keokuk, Iowa, covering the Missouri front. Under 
the appropriation of August 11th, 1888, in what remained of 
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