Their waters have been highly altered by human activity and most of their native fish are lost, but they have a healthy population of largemouth bass.

[2] Upper Blue Lake is about 1,361 feet (415 m) above sea level, covers about 55 acres (22 ha) and contains about 3,960 acre-feet (4,880,000 m3) of water.

[5] They form a line running in a northeast direction down to Scotts Creek, which drains into Clear Lake.

The land was forced up, and Clear Lake began to drain to the east through Cache Creek.

This is plausible, since there have been tectonic events in the region and Clear Lake is 600 feet (180 m) higher than the Ukiah Valley.

The whole district shows evidences of volcanic action, and has many singular geological features and numerous mineral springs.

"[12] According to Professor Ruliff Stephen Holway (1907) the waters of Blue Lakes and Scotts Creek once drained into Russian River by way of Cold Creek, but in recent prehistorical times a large landslide formed a ridge that diverted these waters to Clear Lake.

The two upper lakes are probably each of them from half to three quarters of a mile in length, and as already stated, are connected so as to form in reality a single sheet of water.

They lie at the bottom of a long, deep valley which rises with almost precipitous sides from the water; intense blue is surrounded by the perpetual green of the dark coniferous forest about them.

Springs in the bottom of the lakes doubtless supply them, and they are heavily stocked with speckled trout, perch, "silver-sides," and other species of fish.

[5] The Blue Lakes Hotel could accommodate 40-50 guests, and had a white sulphur spring on its 320 acres (130 ha) grounds.

The neighboring forests had plentiful game, including deer, rabbits, quail and pigeons.

Fish collected included common carp (Cyprinus carpio), bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), rainbow trout (Oncorhynchus mykiss), green sunfish (Lepomis cyanellus), prickly sculpin (Cottus asper) and brown bullhead (Ameiurus nebulosus).

[1] Of 376 fish caught, 342 were largemouth bass, followed by bluegill (12), common carp (11), green sunfish (9), and one specimen each of brown bullhead, prickly sculpin and rainbow trout.