and on the Age of the Cascade Mountains. 363 
ich. think there are abundant and’ unmistakeable evidences of 
oscillations during the Post-Tertiary period on this coast, some- 
what similar to those characteristic of that period on the eastern 
coast. The subject has been yet, however, but imperfectly 
studied. I shall only speak of what I saw in Oregon and 
Washington, 
forests of firs, 200 feet high, and the absolutely treeless prairies 
there is the sharpest line of definition. _The prairies are slightly 
lower than the wooded rtions, and their relations to the 
r 
Probably indicate a period of subsrdence an Ee eranent re-ele- 
von. Ina word, we have about Puget Sound evidences of a 
