Marin County authorities are investigating a death in the Mount Tamalpais watershed.

The investigation began Wednesday afternoon when a hiker spotted someone lying motionless in a ravine off Hidden Meadow Trail, which is in a remote area west of Ross and south of Fairfax. The hiker called down to the person and received no response.

The hiker called authorities, and the Marin County Sheriff’s Office responded with a Marin Municipal Water District ranger, said sheriff’s Lt. Keith Boyd. Rescuers climbed down and found the body.

Boyd said there was no immediate sign the death was suspicious and the victim could be a hiker who fell. A county coroner’s investigator was called out to begin the identification process.

Rescuers arranged to remove the body by helicopter line and take it to the Deer Park School site for the coroner’s investigator.