diller] THE BELLSPRING PENEPLAIN. 21 
and attains its greatest height about the head of Stony Creek. Where 
crossed by the road from Leesville to Williams the greatest altitude 
observed among the flat- topped hills was 2,110 feet, but on the road 
from Sites northwest to Stony Ford the Grapevine grade reaches a 
height of 2,700 feet and the crest rises to nearly 3,000 feet. A line 
running a little west of north through Bear Valley and the valley of 
Stonj r Creek separates the foothills of Colusa County from the moun- 
tains proper. West of this line are large areas of serpentine, but 
the foothills lying eastward are composed wholly, or almost wholly, 
of Cretaceous strata, usually dipping eastward at a high angle. Con- 
glomerates, sandstones, and shales were cut at equal altitudes by the 
same plain, but now the sandstones and conglomerates appear in 
the even crests of the ridges, while the shales are in the intervening 
valleys, of which Antelope, Bear Creek, and Stony Creek valleys are 
the best examples. The even-crested foothills of Colusa County 
extend through Glenn County to Paskenta, where Paskenta Butte, or 
the lower flat summits near the road at the divide a few miles south 
of Paskenta, afford an excellent and impressive view of the plain 
marked by their summits. The peneplain, so well marked in the foot- 
hills, is greatly deformed along the eastern slope of the mountain 
north of the head of Stony Creek. About the head of Stony Creek 
and Bear Creek, in Colusa County, the peneplain which caps the foot- 
hills is continuous with that of the mountain crest about the head of 
Eel River. The peneplain rises westward to the crest of the range 
with a gradual change of slope from 1° to 12°, and then gradually 
flattens out again near the summit. Along Stony Creek the continu- 
ity has been broken by the broad valley, but from Elk Creek Hill, 
near the town of the same name, to one looking southward the former 
continuity of the plain across the valley is shown by the crests of the 
ridges, and their lower altitude suggests that there is a sag in the 
Bellspring peneplain along Stonj 7 Creek and that Stony Creek is a 
consequent stream. 
In the divide south of Paskenta, as seen from Millsaps, the conti- 
nuity is still nearly preserved. The peneplain of the foothills grad- 
ually increases its inclination from 1° to 3° or more as it approaches 
the mountain, until, without abrupt transition, it attains an inclina- 
tion of 14°, passing into the oldest portion of the mountain slope and 
rising to the crest of the range. On the divide near the road on the 
east side, 2 miles south of Paskenta, the flat-topped hills are covered 
with well-rounded gravel, at an elevation of 1,450 feet, and afford a 
fine general view. The peneplain north of Thomas Creek is less 
broken, and the transition from the gentle slope cut upon the nearly 
vertical Cretaceous shales, sandstones, and conglomerates to the 
mountain slope of 10° and more is gradual and continuous, tending 
to confirm the view that the peneplain of western Tehama County is 
of the same age as that so extensively developed on the western slope 
