dtlleb.] STAGES OF DEVELOPMENT. 11 
BRIEF SUMMARY OF EVENTS. 
The topographic development of the Klamath Mountains involved 
a long and complicated series of changes, which it is the purpose of 
this paper to set forth. To facilitate the presentation and discussion 
of the facts it seems desirable to give first a brief historical outline, 
enumerating the events in their sequence and designating the more 
important of the special features as they develop. 
Sonic of the general topographic features of the Klamath Moun- 
tains had their beginnings at least as far back as the early Mesozoic, 
but it is not the writer's purpose to go into the past beyond the close 
of the Eocene, from which time to the present the sequence of events 
appears to have been as follows : 
1. Klamath stage. — The Eocene closed in the Klamath Mountain 
region with an uplift initiating a long cycle of erosion, which reduced 
the Miocene land surface to very gentle relief, practically to a pene- 
plain, the Klamath peneplain. (See PL II, A.) 
While the Klamath peneplain was developing, approximately the 
whole of the adjacent northern end of the Coast Range region of Cali- 
fornia southwest of the drainage of Trinity River and its tributaries 
was covered by the sea (see shore line at close of Klamath peneplain 
stage, PI. I) and received a correlative deposit of Miocene sediments. 
2. Post- Klamath faulting. — Toward the close of the Miocene the 
sediments which had been laid down during the Klamath stage were 
displaced and tilted by a series of faults, and raised a little above sea 
level. The adjacent portion of the Klamath Mountain region, embrac- 
ing the Klamath peneplain already developed, was at that time but- 
little disturbed either hy the faulting or by the uplifting, so that the 
Klamath peneplain, although slightly broken, remained evident. 
S. Bellspring stage. — After the close of the disturbance just noted 
the land remained still for a considerable time, allowing the low hills 
of soft Miocene beds along the coast to be reduced nearly to sea level, 
tli us developing by subaerial processes a peneplain over the region of 
the northern end of the Coast Range. This peneplain is practically 
continuous with the peneplain of the adjacent Klamath Mountain 
district. To distinguish it from the Klamath peneplain it may be 
designated the Bellspring peneplain, after a locality where this fea- 
ture is well preserved. (See PI. II, B.) 
Jf. Post- Bellspring uplift. — With the completion of the Bellspring 
peneplain in its extension over the northern portion of the ('oast 
Range, there came an uplift which affected the whole coast of northern 
California and Oregon. The uplift was differential, being about 500 
feet along the coast and an increasingly greater amount toward the 
crest of the Klamath Mountains. 
5. Sherwood stage. — The uplift just noted was succeeded by a long 
halt, during which the land stood still and allowed the cycle of ero- 
