ALASKA. 43 
lation, elevations being determined by vertical angles and barometric 
readings. These determinations enable the topographer to sketch the 
configuration from commanding points by contours spaced at regular 
intervals. 
At the close of the season the parties are disbanded and the geologists 
and topographers return to Washington with maps, notes, and collec- 
ts ns. The topographic material is assembled and adjusted as rapidly 
as possible and maps are prepared for publication. 
The geologist's time is given to assembling and plotting his Held 
notes and studying and comparing the specimens collected, usual 1} T 
by the aid of the microscope. Assays and chemical analyses are made 
by the section of chemistry, and collections of fossils are examined by 
specialists in paleontology. When all the data are in hand the geolo- 
gist prepares a report, which, if possible, is submitted for publication 
during the winter following the field work. The report also con- 
tains valuable information in regard to the timber, game, and fish of 
the region traversed. 
It is the practice in the Alaskan division to prepare preliminary 
statements showing the economic results of all investigations, for 
immediate publication, leaving the strictty scientific data for more 
thorough study. This policy has enabled the Survey to issue much 
timely information in regard to new mining districts. 
In 1899 the Alaskan work occupied 2 geologists and 2 topographers, 
with an additional field force of 12 men. With increased appropria- 
tions and also by greater economy of expenditure, which is the result 
of a closer appreciation of the field conditions, the force has gradually 
been increased. The division now includes a geologist in charge, 7 
geologists, 3 geologic assistants, 2 topographers, 2 topographic assist- 
ants, and a field force of 25 to 30 camp men. During the season of 
1903 this force was divided into seven parties. 
RESULTS. 
It is difficult at the present day to conceive how little was known of 
Alaska previous to 1898. The expeditions of the earlier years had 
resulted in contributions to the knowledge of the Yukon Valley, the 
interior plateau, the St. P^lias Range, and the coast south of that range, 
but most of the country was practically unknown. 
The reconnaissance trips of 1898 added to the map many of the most 
important geographic features lying south of the Yukon River, and 
the trips of each succeeding year have filled many gaps in the earlier 
work and extended it from the Yukon to the Arctic Ocean and from 
the Koyukuk to the coast of Bering Sea. Thus were the broad 
geographic features outlined and the important mountain ranges and 
drainage areas defined. The preceding sketch of the geography of 
Alaska, which embodies all the available data, is based chiefly on the 
