TOPOGRAPHIC FEATURES OF THE DESERT BASIISrS. 27 



The only part of the basin which has suffered severely by stream decay is the long 

 western slope. Here many once vigorous streams have dwindled to little or nothing 

 and have ceased to overflow a few local depressions. In nearly every case, however, 

 a very slight increase of rainfall would be sufficient to clear and restore the drainage, 

 and it can not be believed that the present cut-off condition is of any considerable 

 antiquity. This can not be so surely said of Juniper Lake, east of Adel. The basin 

 of this lake, though small, is relatively deep, and Waring ^ reports two old strands 

 on its walls. It may have been inclosed for a considerable time, but the small size 

 of the basin destroys any present interest which it might have. 



At present the area tributary to the Warner Lakes as a whole is perhaps not over 

 1,500 square miles but during the Lahoutan period the drainage area was probably 

 slightly over 2,000 square miles, there being some uncertainty as to the exact position of 

 the northern boundary. 



THE HARNEY BASIN. 



East of the Christmas Lake Basin is another of very similar character — the Harney 

 Basin. As before, the divides are inconspicuous and run over plains and rolling 

 plateaus of little relief. In the case of the Harney, however, there is no question 

 of the recency of overflow. Russell ^ explored and described the channel through* 

 which the basin discharged into the Malheur River, and which is now stopped by a 

 dam of recent lava. Behind this dam the valley is broad and flat and the impounded 

 waters, instead of overflowing the dam, have spread out to form Malheur and Harney 

 Lakes. 



THE CATLOW VALLEY AND GUANO LAKE. 



It will be recalled that the eastern side of the Warner Valley was mentioned as 

 bordered by the west scarp of an eastward-dipping monocline, the crest of which 

 forms the Warner Moimtains. Still farther east the Steens Mountains form a similar 

 range, but higher and of opposite inclination. In this case the scarp faces eastward, 

 while the gentle slope is toward the west. Essentially the area between these moun- 

 tains is a gentle syncline with its trough running approximately north and south and 

 its flanks cut off by the Warner and Steens Mountain scarps. In detail this shnple 

 structure is far from apparent. The region is one of gently rolling lava plains, much 

 like those already described and with its topography modified by local and irregular 

 folding and faulting and possibly by erosion. It is little known and very inade- 

 quately mapped, and desiccation has destroyed or obscured most of its drainage lines. 

 Its division into specific "basins" is therefore nearly impossible and is not attempted. 

 It is possible to point out only that there are at least two areas of considerable con- 

 centration of drainage, the northern in Catlow Valley and the southern in Guano 

 Lake. The Catlow Valley is of the usual flat-floor type with a shallow intermittent 

 lake. It receives the drainage of Rock Creek from the west and of a part of the 

 Steens Mountains slope from the east. Concerning Guano Lake, scarcely anything is 

 known beyond the fact that it receives the flow of Warner Creek coming from the 

 crest of the Warner Mountaiub to the west. 



At its northeast corner a narrow pass opens from the Catlow Valley into the valley 

 *of the Donner and Blitzen River, one of the tributaries of Malheur Lake. The present 

 divide in this pass is less than 300 feet above the level of the Catlow Valley, and it is 

 natural to assume that this pass was previously a discharge channel, the present 

 divide having been created or raised by subsequent alluvial deposition. However, 

 Waring ^ reports that the Catlow Valley is surrounded by old strand lines and that 

 these are below the divide. It may be, however, that the strands belong to a recent 



1 U. S. Geol. Sur., Water Supply Paper 231, 29 (1909). 



2 U. S. Geol Sur., Bui. 217, 22 (1903). 



3 u. s. Geol. Sur., Water Supply Paper 231, 65 (1909). 



