rUYSlCAL FEATURES OF THE GREAT I3AS1N. 313 



Cailon, Utah Lake, and Salt Lake City. Work was coiitiiuic-d at main 

 camp until August 1 Gtli, when collections and notes were packed and our 

 field-work ended. 



PHYSICAL FEATURES OF TIIK GREAT BASIN. 



While the region traversed by the survey after its equipment embraces 

 the entire distance from Sacramento City, California, to points in Utah 

 eastward of the Salt Lake Valley, the actual field-work began only at the 

 eastern base of the Sien-a Nevada, and was thus entirely confined to the 

 interior area of continental drainage known to geographers as the Great 

 Basin, and which we shall frequently refer to in the following pages by this 

 name, as well as by that of the "Litenor," a convenient synonymous term. 

 This vast area coiTesponds almost strictly in its geographical boundaries 

 with the " Middle Province" of zoologists. The route of the expedition 

 was mainly across the middle portion of tlie Great Basin proper, so that 

 the fiiuna encoimtered was that typical of the Middle Province. 



In few regions is the influence directed on the distribution of birds by 

 that of the plants so manifest to the observer as in the one vuider consid- 

 eration; and as vegetation is influenced so materially by configuration of 

 the surface, conditions of the soil, elevation, etc., a brief description of the 

 physical features of the country embraced within the limits of our trip is 

 necessary to the intelligent understanding of the nature of the ^liddle 

 Province avifauna, and the manner in which it is divided into bands of 

 restricted range, according to conditions of environment. Such an excellent 

 description of the field of our investigations has been given by Mr. Watson, 

 the botanist of the expedition, that we cannot do the subject greater justice 

 than to quote the following from "Geograjjhical Notes," on 2)ages xiii-xvii 

 of the Botanical Report:^ — 



' Profi'ssioiiiil Papers of tlio Eii{,niieer DeitartiutMit, U. S. Army, No. 18. Eoport 

 of tlie Geological E.xploratioii of the Fortieth Parallel, made by order of the Secretary 

 of War accordiug to acts of Congress of March 2, 18G7, aud March 3, 1801), under the 

 direction of Brig, and B'vt Major General A. A. IIuuii»hrey.s, Chief of Engineers, by 

 Clarence King, U. S. Geologi.st. Volume V, Botany. By Sereno Watson, aided by 

 Prof. Daniel C. Eaton and others. Submitted to the Chief of Engineers, and published 

 by order of tlie Secretary of War under authority of Congress. Illustrated by a Map 

 and Forty Plates. Washington: Goverunieut Printing Otlice, 1871. 

 10 



