HISTORICAL. IOI 
Lands, the Staked Plains of Texas, the Chihuahua Desert, the Great 
Basin, and the Colorado Desert were shown approximately within the 
districts which may appropriately be designated as desert at the present 

je Longitude 36? West 30° from 25° Washington 20° 
















Roaning Water 2. 
h 


































































ITNT r 
| t 
| I IHR 













Tr 
| 














A 















| 
Uh 












S 






































CTT 












TTT 















|||! 
Fie 



























° Durango 












TMT 







































AAA 
= LongitudeZaxo West from  402°Greenwich 





SCALE OF MILES 
100 50 O 100 2CO 800 400 500 600 700 
—e——EEE—E—————EEEE EE SS SSS Ss eae | 
Fic. 5.—Western America, showing conceptions of American deserts current in 1835. 
Copied from T. G. Bradford’s Comprehensive Atlas, published at Boston in 
1835. (Reprinted from Publication No. 6.) 
time. This conception of the matter is shown in fig. 6, being a map from 
a text-book on physical geography published in 1859. 
A study of the physiographic, floristic, and meteorological features of 
western North America has resulted in delimiting two great desert areas 
