31 G OKNIXnOLOGY. 



Ilumboklt, of which it Is a reputed tributary. lu the ui>i)er portion of its course of 150 

 miles it is reeuforced to some extent by the drainage of the Shoshone Mountains, a 

 rather high range west of the Toyabes, but as it nears Humboldt Valley it diverges 

 into side-channels and seldom has voluuie sufficient to reach the main river itself. 



The East Uumboldt Mountains are by far the most stern and ali)ine of all these 

 ranges, the main peaks between 11,000 aud 12,000 feet in height, precipitous and 

 ragged, the deeper caiious evidently scooped out by glaciers, gemmed with suowfed 

 lakes beneath the peaks and carrying full sti-eams into the valleys. The southern 

 portion, however, below Fremont's Pass, is less rugged aud of different geological 

 structure, mainly of nearly horizontal strata of limestone. The canons here, often 

 mere gorges, with close precipitous walls, are perfectly dry on the eastern slope, the 

 melting snows sinking almost immediately, but reappearing at the base in bold ice-cold 

 springs. The water from these springs and streams reunites to form lluby aud Frank- 

 lin Lakes, boilies of nearly fresh water, very shallow, and largely occupied by a dense 

 growth of "Tule" {Scirpus validits). As usual in these ranges the western slope is much 

 the more gentle, with a broader line of foot-hills. The streams upon this side form the 

 South Fork of the Humboldt. The 'Clover Mountains' of the Catalogue form the 

 northern extremity of this range, isolated by a depression known as Secret Valley, 

 but of equal height and similar character. 



Such is a general description of the country as far east of the foot of the 

 Wahsatch in Utah. These mountains, ui)ou a broad base of nearly fifty miles in 

 ■width, aud with an irregular crest-line 10-12,000 feet high, have a system of long, 

 deep, well-watered canons, often exceedingly rocky, and sometimes cleft like a gateway 

 to the valley level, with perpendicular mountain-walls on each side, but usually opening 

 out at some part of their course into meadow-like basins or "parks.^ The prevalent 

 western winds deposit their moisture, which they have gathered in the traverse of the 

 Basin, in abundant snows in winter aud at other seasons in frequent and occasionally 

 heavy rains. The upper cailons and mountain sloi>es are to some extent timbered, 

 much more generally so than in any of the ranges westward, and the naked peaks 

 above have a truly alpine vegetation. The Uintahs, which connect immediately with 

 the Wahsatch and extend eastward on the line of the 4:1st parallel for a distance of 

 one hundred and fifty miles to Green River, where they meet the outspurs of the 

 Rocky Mountains of Colorado, have more of the character of those mouutains, with 

 broad open cafions and extended lines of foot-hills, the peaks overtopping those of the 

 Wahsatch, glacier- scored aud polished at the northern base, but the declivity upon 

 the opposite side stretching southward beyond the limits of vision in a high plateau 

 broken only by the deeply-worn channels of numerous rapid streams, tributaries of 

 the Uintah and Green Rivci-s. 



LOCAL AVIFAITN^^C OF TIIK OKEAT BASIN. 



We Iiavo goiio thus uito tletail with reg-ard to tlie more prominent 

 characteristic features of the Great Basin for the reason that the distribu- 

 tion of the birds depends so much upon that of the vegetation; and as we 

 know that the latter is separated into several quite distinct groups, wliose 

 distribution depends upon altitude, humidity, proportionate amount of 



