Ran at Topanga Canyon State Park (near Santa Monica, CA) today with Anne. Started off at the State Park parking lot ($6 day use fee with nice bathrooms in the lot) taking Eagle Rock fire road (steep) up 1.5 miles to the point where the fire road junctions with Musch trail. Staying to the left we continued up past Eagle Rock at 2 miles. Passing Eagle Rock, there are many cool volcanic rock formations and possibly marine fossils in the fire road. At mile 3, Eagle Rock fire road junctions with another fire road staying to the right we headed down to Musch trail at 4.4 miles. The remaining 2.2 miles along Musch trail is single track closely following a dry canyon stream bed with a few too many wooden steps for my liking. I'd give this trail a 4 (on 1-10) for running but a 7 for cool geologic features.