CENTEAL AND EASTEEN NEVADA. 321 



closer examination of its topography discloses a double ridge system, whicli 

 prevails tlirougli the greater part of its extent, giving rise to a series of inte- 

 rior longitudinal basins ; lience the line of the main vv^ater-shed is extremely 

 sinuous, although that of north 23° east would pass through all the principal 

 summits of the range. To the north the range consists of two low and some- 

 what broken diverging ridges, inclosing between them the Park basin, which 

 opens out further north into the large meridional depression called Grass 

 Valley. These ridges rise gradually to the south, preserving a certain paral- 

 lelism, though broken through at various points by the waters of the high, 

 narrow valleys which they inclose, until they reach their culminating points, 

 respectively, in Bunker Hill and Big Creek Peaks. In this extent, although 

 the eastern ridge is generally over a thousand feet higher than the western, the 

 greater part of their surface is drained into Smoky Valley through Park Creek, 

 Birch Creek, and Kingston Creek, which break through the eastern ridge, 

 while only Big Creek flows to the west. For a few miles south of Big Creek 

 Peak, the western ridge forms the main divide of the range, which bends 

 round the head of Kingston Creek, but to the south of it forms a continuation 

 of the main eastern ridge. For a distance of 25 miles south, the range con- 

 sists of a single and, in general direction, straight ridge, with steep, craggy 

 slopes to the east, and long, smooth western spurs. By the bend in this 

 ridge to the westward at Summit Canon, the western summit again becomes 

 the main divide, its continuation to the north being indicated by the widen- 

 ing of the spurs toward the west, which inclose the small basins at the 

 heads of Cross's and Washington Canons, Thi^ ridge grows higher toward 

 the south, till in the sharp peak of Mount Poston it forms the highest crest 

 of the range. The eastern ridge, meanwhile, finds its continuation in the 

 shoulders of the eastern spurs, which, rising into high peaks at the Twin 

 Rivers, inclose the large interior basins of these canons, around whose head 

 the main divide makes another bend to the eastward. These numerous 

 mountain valleys afford most excellent summer grazing ground, their slopes 

 being covered with bunch grass, which remains green and nutritious long 

 after that of the plains is parched and worthless; they form, moreover, nat- 

 ural inclosures, where cattle can be left comparatively unwatched, without 

 danger of their straying. 

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