Belleview Telescope, March 23, 1900.
(http://i941.photobucket.com/albums/ad256/waldoegray/Oak%20Valley%20fire%20Belleville%20TelescopeMar%2023%201900_zpsrocuaujd.png)
The Elk County history book says that the flour mill in Oak Valley was on the Elk River. It does not mention where the saw mill was located although it must have been on the Elk, at least to begin with, until other sources of power became available.
As late as 1960 the sawmill was still operating on an "as needed" basis.
The flour mill produced Snow Flake brand flour.
The school closed in 1949.
The post office closed in 1954.
The high population was 500 around the beginning of the 20th century.
There was a bank, but no newspaper.
(http://i941.photobucket.com/albums/ad256/waldoegray/oak%20Valley_zpsvjfoxw1m.png)