PHYSIOGRAPHY OF THE BEAVERDELL MAP-AREA. 
19 
their dominating ridges: the St. John block lying between Trap- 
per creek and the West Fork river on the west, and Maloney and 
Beaver creeks and Wallace draw on the east and south ; the Lake 
Ridge block which lies east of Cedar, Beaver, and Maloney creeks, 
and west of the Kettle River canyon; the Crystal Mountain 
block, including Crystal mountain and Crystal butte; the Wal- 
lace Mountain block, including Wallace and Curry mountain; 
King Solomon Mountain block; and finally, the Nipple Mountain 
area, which includes Red mountain, Ferroux mountain, Nipple 
mountain and mesa, and Arlington mountain. One or two of 
these blocks are largely covered by Tertiary lavas; the others 
have very little or no lavas on them. The St. John, Lake 
Ridge, Crystal Mountain, and King Solomon Mountain blocks 
are not capped by areas of lava of any size; the Nipple Mountain 
area is largely covered by volcanic rocks, and the Wallace Moun- 
tain block partly so. The two types of interfluve differ somewhat 
in average elevation above sea-level, in the parallelism of their 
component ridges, the degree and character of their slopes, 
and in the relation which exists upon them between topography 
and rock structure. 
Parallel Ridges. 
The St. John block, which is not much incised, may be 
taken as a type of an interfluve with little or no Tertiary lava. 
It is a broad composite ridge consisting of parallel ridges with a 
high ridge line generally near to the middle. 
There is a rough parallelism between major and minor ridges 
with their longer axes trending north-south, north by east, south 
by west, and less often, northeast-southwest. This seems to 
hold in great detail in certain areas where the surface is underlain 
for a distance of several square miles by a batholithic intrusion 
of quartz -monzonite. Such areas are the top of the broad hill 
about one mile west of Clark lake, which is made up of ridges 
and draws with crests 50 feet or more above their troughs, 
lying roughly parallel; the country to the south of Cup lake, 
or the ridges across Maloney creek to the west of it, where in 
travelling across country in an east-west direction, one is con- 
