12 TOPOGRAPHIC DEVELOPMENT OF KLAMATH MOUNTAINS, [bull. 196. 
sion to advance to the development of a peneplain over wide stretches 
of soft rocks locally along the coast. This peneplain has its greatest 
extent about the South Fork of Eel River and Sherwood, and may be 
called the Sherwood peneplain, to distinguish it from the Bellspring 
peneplain, which lies 500 feet higher. (See PL II, C.) 
Along the Oregon coast, where the more ancient and durable rocks 
of the Klamath Mountains form much of the shore, the development 
of the Sherwood peneplain was not marked, but from the Chetco 
River south, where softer beds of Miocene age form much of the 
land, the Sherwood peneplain attained a wide area. 
Extending inland from the level of the Sherwood peneplain along- 
Rogue River and the Klamath and Eel rivers are broad valleys of 
Sherwood stage high above the present beds of these streams, and 
wherever soft beds occur, as at Round Valley, the valley of Sherwood 
stage widens to a local Sherwood peneplain. 
6. Post-Shemvood uplift. — At the close of the Sherwood stage the 
whole region of the Klamath Mountains and adjacent Coast Range 
experienced a differential uplift. Along the coast the uplift was 
about 500 feet. The amount increased toward the crest of the Kla- 
math Mountains and greatly invigorated the streams, initiating a new 
cycle of erosion. 
7. Garberville stage. — At the close of the uplift just noted began 
the Garberville stage (illustrated, with succeeding stages, in PL II, D). 
The Bellspring peneplain nearest the coast then stood at an elevation 
of 1,000 feet, and the Sherwood peneplain at 500 feet. The Garber- 
ville stage was not so long as the Sherwood, and yet it was long enough 
to permit the rivers where the rocks were relatively soft to carve out 
broad valleys of gentle slope in the yet earlier valleys of the Slier- 
wood stage. The two series of valleys, of the Sherwood and Garber- 
ville stages, are rarely sharply distinguishable. Perhaps the valley 
best illustrating the Garberville stage is that of the South Fork of Eel 
River, where it cuts across the Sherwood peneplain in the vicinity of 
Garberville. 1 The valleys of both stages were broad and often in 
marked contrast with the narrow valleys of later date. 
8. Post- Garberville subsidence. — The Garberville stage was brought 
to a close by a subsidence, the depth of which, although small, 
increased to the eastward, not only ponding the streams but admit- 
ting the tide in the southern branches of the Trinity as far as Hay 
Fork, within a few miles of the present crest of the Klamath Mountains. 
9. Hay Fork stage. — In the water bodies thus formed flu vio-estuarine 
sediments were deposited during the Hay Fork stage, filling the old 
valleys. Among the sediments of this stage shales have been found 
containing sharks' teeth and Miocene leaves. Volcanic dust and 
pumice play an important role in this old valley filling, and traces of 
coal are of common occurrence. 
1 The town of Garberville is on the river in a narrow valley far below the earlier valley of the 
Garberville stage. 
