NEOCENE, DE ROSITSVOR THE KLEAMATEL REGION: 
CALIFORNIA. 
Description.— In the Klamath region west of the Sacramento 
River, chiefly in Trinity county, there are several deposits of 
alluvial gravel and sand which seem to correspond to the aurif- 
erous gravels or ‘high-level channels” of the Sierra Nevada 
region. They were first mapped in 1892 by Diller’ as Neocene 
deposits, and correlated with the Ione formation. Four sepa- 
rate areas are known within Trinity county, one in the old valley 
Om Urininy River between Trinity Center and junction) City, 
another in Hay Fork valley, the third in Indian Creek valley, 
and the remaining one in Hyampour valley. Doubtful remnants 
may occur near Lowden’s ranch and Big Bar on Trinity River. 
These deposits occur in valleys of erosion, trenched deeply 
into the hard metamorphic rocks. The distinguishing charac- 
teristics of the old or Neocene valleys are (1) their great 
width compared with the Pleistocene valleys; (2) their flat bot- 
toms ; (3) their abrupt termination at both ends; and (4) their 
usually containing remnants of Neocene channel deposits. The 
writer is familiar with three of these valleys and will describe 
them in some detail. 
Scott valley, in Siskiyou county, has a length of about twenty 
miles and an average width between three and four miles. Its 
direction is north-south and it lies between parallel ranges of 
mountains of which that on the west consists of very resistant 
formations, including micaceous quartz, schist, serpentine, and 
granodiorite, and attains a general elevation above the valley of 
four thousand feet. The range on the east is not nearly so high, 
owing to the formations composing it being the rather soft slates 
of the Devonian and perhaps Carboniferous. The valley itself 
is trenched largely into these slates, but reaches serpentine and 
the older schists beneath them. Undoubtedly the unusually great 
* Fourteenth Annual Report of the U.S. Geol. Surv., Pl. XLV. 
377 
