TOPOGRAPHIC FEATURES OF THE DESERT BASINS. 3 
and where these were avaiable other data have seldom been Stet. 
For areas as yet unsurveyed by the Geological Survey, use has been 
made of the maps of the Wheeler and King surveys, of the maps 
and notes of the General Land Office surveys, of railway surveys and 
profiles, of various special maps and reports published by the Geo- 
logical Survey and by the early Government surveys, of the maps 
and journals of the early explorers, of many private maps, both 
published and unpublished, of maps and articles in the technical 
press, etc. These data have been supplemented by about 25,000 
tiles of personal travel through the regions in question and by con- 
ference with official and private surveyors, railway engineers, pros- 
pectors, and others familiar with the country. It is impossible to 
acknowledge all these sources in detail, but the writer wishes to make 
special acknowledgment of the kindness of Prof. G. E. Bailey, of_ 
Los Angeles, in tendering the use of his collection of personal maps 
and notes of the desert basins of California, as well as in communi-— 
cating the various conclusions Hesiialig from his extensive travel in 
these regions. 
The topographic data from all the sources mentioned have been — 
collected, carefully compared, and the final conclusions used in plat- 
ting on base maps the boundaries of the various basins. From these 
maps have been calculated the areas given in the following pages. 
Every possible care has been used in the platting of the lines and in 
the computation of the areas, and it is believed that accidental errors 
have been almost if not quite eliminated. In nearly all cases the 
areas as given may be considered accurate within 10 per cent and in 
most the accuracy is far greater. In a few places, mainly in country 
of slight relief and where divides are inconspicuous, the position of 
present and past water partings remains uncertain, and the areas are 
correspondingly open to doubt. All such cases are noted in detail 
- 
in the text and, in general, a perusal of the text will indicate the 
probable accuracy and assurance of the various conclusions better 
than could be done by any general statement. 
THE GREAT BASIN AND ITS DEVELOPMENT. 
The most important areas of internal drainage in the United States 
lie within the so-called ‘‘Great Basin’’ of Utah, Nevada, and Califor- 
nia. This is by no means a unit, but an area of somewhat complex | 
topography divided. into a number of basins of various ages and 
_characters.. In order that this topography may be the better under- 
_ stood it is necessarv ‘9 discuss briefly the history of its development, 
and this is perhaps ‘ \e more useful since its development has been. 
in Many ways pai2i-l to that of other undrained areas which le 
beyond its borders. here is scarcely a phase of basin topography 
- elsewhere that has no. its counterpart in the Great Basin. 
