Eocene Canyon
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| | Difficulty:3B III (v3a2 III) Raps:4, max ↨150ft
Red Tape:No permit required Shuttle:None Vehicle:Passenger | ||||||||||||||||||||||||||||||
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| Condition Reports: | 21 Feb 2026
"The main wall is a cool feature covered in clam fossils, which continue down the watercourse for quite a while as you descend.. Our group did this |
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| Best season: | Oct-Apr
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34.3172, -118.6599
34.2971, -118.6801
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Introduction
An intriguingly unique drainage that cuts through the sedimentary fossiliferous marine layer from the Eocene Epoch (56 million to 38 million years ago) revealing a myriad of ancient marine fossils, the primary draw of this canyoneering route.
Approach
Park at the Las Llajas trailhead and proceed along the gated road. Keep right at the fork in the road and onto the dirt road. After about .4 miles from the start, take the trail off of the main dirt road in Las Llajas Canyon at 34.30186, -118.67891. There is a trail on the right side of the road climbing steeply up the ridge to the NE. Follow this trail for about 1.6 miles. A beautiful trail affording ever grander views of Simi Valley and the surrounding mountains. You'll reach a summit with a cairn around 34.31498, -118.65859. Leave the trail around here wherever looks best and descend North into the drainage. Once in the drainage follow the least brushy path until you reach the start of the techincal section around 34.31752, -118.65991
Descent
The canyon drops precipitously starting with a 10' downclimb into a hanging pothole/ledge big enough for 4-5 people
Rappel 1: 150' off of a manzanita tree DCR. This is the main rappel of the route with fossils all over the wall.
Make your way down the canyon and don't forget to check out all of the marine fossils strewn about everywhere.
Further down the canyon there are 3 more short 15-20' rappels which had water flowing during the first descent (Dec 2025 after heavy rains). The lower you get into the canyon the brushier it becomes (all that water). You could try and ascend the ridge DCR once the canyon starts getting brushy to avoid this section, or make your way through and go up the ridge DCR shortly after the 4th and final rappel.
Either way you go, you'll eventually end up back at the road on the other side of the creek, further up Las Llajas canyon from where you left to climb the ridge.
Exit
Follow the dirt road in Las Llajas canyon back to your car.
Red tape
Beta sites
Trip reports and media
Background
First known descent by Alden Anderson, Andrew Irwin, Angela Kennedy, Ceth Parker, Eileen Beall, Jesse Johnson, Jessica Leila & Mike Tran on December 26th 2025. A beautiful sunny day after 8 inches of rain in the previous days. Green mountains, blue skies and a whole lotta fossils.