BOTANICAL GEOGRAPHY. 463 



readily precipitate the aqueous vapour from the westerly current of air. 

 The same, however, holds good here, from whatever other points of the 

 compass the wind may blow, so that instead of steppes, deserts would be 

 expanded between the Rocky Mountains and the California!! Andes, if this 

 internal country were not also so copiously watered by these mountains, and 

 thereby also subject to local precipitations. The climatal relations of the 

 Oregon-district also perfectly explain the drought of the prairies in the Mis- 

 souri described by the Prince of Wied. 



Prom Columbia, Fremont went to the eastern foot of the Sierra Nevada, 

 as far as the 39th degree of south latitude, following the boundary-line be- 

 tween the steppe- and the forest-regions. Below the 42d degree, at the 

 south water-boundary of the district of the Oregon-river region, the inland 

 country is elevated into a mountain-chain running from east to west, and not 

 void of forests, and this appears to form a connexion between the Californian 

 Andes (S. Nevada) and the Rocky Mountains. 



South of the chain, a desert highland is situated ; it is probably for the 

 most part uninhabitable, and, from the nature of its soil and its declivity, it may 

 be compared with the uninhabitable regions of Persia ; it ought to be called 

 the Californian salt-desert (Fremont's great interior basin). An Indian guide 

 pointed to it, saying at the same time, " There are the great llanos no hay 

 agua, no hay zacata, nada" i. e. Plains without water, without herbage : 

 " Every animal that enters it must die." Entirely surrounded by mountains 

 which form its borders, bounded to the north by the river-limit of the 

 Oregon, to the south by a similar chain, covered with snow, towards the 

 Colorado, and on both sides by the Sierra Nevada and the Rocky Mountains, 

 it only contains internal streams, which lose themselves in the desert or 

 in salt-water lakes, and is perhaps dry and destitute of springs for the space 

 of many days' journey. As the greater part has not hitherto been explored 

 by any traveller, we are confined, with regard to the altitudes, to the follow- 

 ing measurements made by Fremont, which, in fact, only relate to the 

 external margin : on the plateau of the great salt-water lake Utah (41 30' N. 

 lat. and 95 W. long.) = 4200'; Lake Pyramid, at the foot of the Sierra 

 Nevada (39 51') = 4890'; foot of the Sierra Nevada (38 50') = 5020'; 

 on the boundary-mountains, Bear River, on the slope of the Rocky Mountains 

 (42 and 93) = 6400' ; pass from the Bear River to Colorado (41 39') = 

 8230'; pass over the ^Sierra Nevada to the Bay of St. Francisco (38 44') 

 = 9338'. The salt-desert differs from the prairies of Missouri, as from the 

 Artemisia-steppes of Oregon, by its excessive dryness, rocky soil with vol- 

 canic heaps, by the more general presence of salt in the soil, and, as a 

 consequence of these conditions, by the absence of the growth of nutritive 

 grasses ; nevertheless, from the strength and number of the rivers which 

 enter it from the boundary-mountains, we may conclude as to the existence 

 of oases on its streams. The vegetation consists almost exclusively of 



