TOPOGKAPHIC FEATURES OF THE DESERT BASINS. 35 



Goldfield Basin and about 600 feet above that of the Big Smoky. There is another 

 divide at about the same elevation in a gap leading into the Clayton Basin. Both of 

 these divides are believed to be pre-Lahontan and the Basin is thought to have been 

 always inclosed. It has an area of 330 square miles and contains a small playa of 

 usual character. 



THE DIAMOND BASIN. 



The Diamond Valley proper is a narrow north-south trough stretching north from 

 Eureka, Nev., between the Sulphur Springs and Diamond Ranges. In itself it has 

 an area of less than 1,000 square miles, but into its southwest corner discharges the 

 remnant of a former great drainage system which drained the southern portion of the 

 topographically poorly-defined region mentioned on page 16. The area of this 

 drainage system aggi'egated 1,870 square miles and included the present Kobeh, Dry, 

 and Monitor Valleys, the latter extending south to the north end of the Ralston Valley 

 (Armagosa drainage system) near the old town of Belmont. Most of this drainage 

 system is still essentially open, though never fully occupied by water. Storm waters 

 occasionally fill part of it, but seem never to reach the Diamond Valley itself. In 

 many places, especially in the southern end of the Monitor Valley, low and recent 

 alluvial dams have been built and have caused the formation of local playas and 

 marshes. None of these have any present importance. 



The deepest depression of the Diamond Valley contains a very saline marsh or 

 playa carrying a body of common salt of unknown extent and character. The lowest 

 outward pass is Railroad Canyon at the northeast corner and leads into the Hunting- 

 ton River and thence to the Humboldt. This pass is now about 275 feet above the 

 Diamond Valley salt marsh and it is uncertain whether it ever served as a channel 

 of discharge. The writer inclines to the opinion that it did, but that the discharge 

 was by overflow and occurred only during the maximum of the lake expansion. A 

 long subsequent history as an independent valley seems very probable and is directly 

 indicated by traces of old strand lines on the walls of the valley. In this report the 

 valley is classed as landlocked and its area is not included in that of the Humboldt- 

 Carson Basin. 



The present drainage area tributary to the Diamond Valley playa is perhaps 900 

 square miles. The Lahontan period area was 2,800 square miles. 



THE RAILROAD VALLEY. 



The Railroad Valley is the largest of the inclosed troughs of Nevada and lies just 

 southeast of the geographical center of the State, between the White Pine Range to 

 the east and the Pancake Mountains to the west. The former range is one of the best 

 defined of the Great Basin and, being high and continuous, it has formed a permanent 

 divide between the Railroad Valley and the drainage of the Colorado Ptiver. The 

 Pancake Mountains are much lower and less well defined and are crossed by several 

 fairly low passes, through one of which (Twin Springs Pass) the Hot Creek Valley 

 still drains into the Railroad Valley. West of the Hot Creek Valley is the Hot Creek 

 Range, for the most part high and continuous, but cut about its middle by the canyon 

 of the Hot Creek, through which comes the drainage of the southern portion of Fish 

 Spring Valley, lying still farther west. The northern portion of this valley is now 

 cut off by a low alluvial divide, but this is almost certainly very recent. Hot Creek 

 Valley has also two other tributaries — part of the Little Smoky Valley from the north 

 and part of the Reveille Valley from the south. The former is cut by an alluvial 

 divide, north of which the drainage goes to the Gibson Valley, as discussed on page 17. 

 This divide is believed to be pre-Lahontan and to have been a permanent parting 

 between the Lahontan and Railroad Valley drainages. Reveille Valley is cut into 

 three portions by two alluvial divides, the northern portion draining into the Hot 

 Creek Valley, the southern portion into the Kawich (see p. 36), and the middle por- 



