Eel River History and Geology

Serpentinite rock is found all throughout the watershed basin. It is always green and seamed with closely-spaced fractures. Some have a soapy feel and are soft enough to whittle with a knife. This is the kind that is often called " soap stone." Manganese is found in trace amounts around the watershed. Small deposits were mined during the two world wars, but there was never enough to support any large mines. It is easy to overlook because it appears to be a black stain on rocks, or fills in small cracks. Limestone, copper and chromite are other minerals found in minor significance throughout the watershed.

Geologists are not sure from what or how the rock formed. It contains minerals from deep within the earth yet shows no sign of having been molten at any time. It also has a very high melting temperature making it hard to imagine it ever having been magma.

Serpentinite often contains rare beautiful rocks called "bluechist," which are heavy blueish-black rock liberally flecked with intense blue crystals. Jade is another unusual rock found alongside serpentinite and in the watershed of the Eel in minimal proportions. Found in streams and beach gravels, jade is not easy to recognize because it is the same color as the surrounding serpentinite. Jade is noticeably heavier than serpentinite and much harder to break.