What we’re about
This group's goal is to get exercise while exploring and learning about the geology and natural science of the San Francisco Bay Area. The aim is the mid-point between the hiking groups that don't stop long enough to explore and learn about what they're passing and the nature groups that see lots of great stuff, but don't get that much exercise.
Hikes will be lead by members with knowledge of unique, exotic, or otherwise fascinating features of our area. If you have a favorite hike that you'd like to lead, drop a suggestion and I'll make you a leader (you just have to commit to coming on the hike and sharing your knowledge).
Everyone with interest is invited, and presentations should be aimed at people with interest but not necessarily a strong academic background in the subject (although some conversations occasionally get pretty deep).
Our primary focus will be on geology, but we won't pass up a good tidbit of information about the flora and fauna as we hike.
I've finally started putting together a website with more details on the geology of our hikes. You can find them at https://geology.trampleasure.net/ A few direct links to pages on my site include:
Upcoming events (4)
See all- Sibley Volcanic Regional Preserve: 5 miles, 800 feet elevation gainRobert Sibley Volcanic, Old Tunnel Road Staging Area , Orinda , CA
Join us for a Mothers' Day hike at Sibley Volcanic Regional Preserve, a unique gem nestled in the Oakland Hills, offering panoramic views, fascinating geological formations, and a peaceful escape from the bustle of the Bay Area. This 928-acre preserve is centered around Round Top, an extinct volcano that last erupted over 10 million years ago. Over millennia, tectonic activity and erosion have exposed the volcano's interior, creating an open-air classroom of lava flows, volcanic breccia, and ash deposits that tell the story of California’s dynamic geological history.
Our journey will take us along well-marked trails like the Round Top Loop and the Volcanic Trail, where we’ll pass through oak woodlands, grassy hillsides, and rocky outcrops. We'll make time to stop at interpretive signs, admire striking views of Mount Diablo and the San Francisco Bay, and explore features like the Mazzariello Labyrinth—a hand-built spiral path that invites quiet contemplation amid nature.
This hike is perfect for curious minds, nature lovers, and anyone looking to stretch their legs in a beautiful and educational setting. The pace will be moderate and suitable for most fitness levels, with plenty of breaks to soak in the surroundings. We're starting at the base of the park, near the Caldecott Tunnel, so it's uphill for the first half, then 'all downhill.' We'll take a short lunch break somewhere near the top.
Kids are welcome, dogs are not.
A donation of $2 is requested at the start of the hike, and I'll 'pass the hat' at the start of the hike. You are welcome to contribute any amount. This helps to cover Meetup fees and buy me a cup of coffee.
If you need a ride from Orinda BART, I can pick up people. You'll need to arrive at the BART station on the 9:44 train (if coming from the west) or the 9:52 (if coming from the east). Leave a comment if you'd like a ride.
On Saturday evening before the hike, I'll send my cell number to everyone who has RSVP'd, in case you run late and need to find us.
More details about the hike and the geology, including a map and videos, can be found at geology.trampleasure.net.
- Mammoth area, hot creek camping/hikingObsidian Flat Group Campground, June Lake, CA
Registration is now open on my geology.trampleasure.net website.
- You need to register on that site to be officially included.
- When you register, you will not pay online, but I'll send you information about how to pay (PayPay, Venmo, CashApp, Zelle, or good old check in the mail).
- If you can't make all five days, you can still register if you can make at least three days of hiking.
- The road to Devil's Postpile is closed for construction until July, so we won't he able to visit this this year.
Just a placeholder to let folks know this is happening. You can RSVP to this event if you think you will come, but we'll create another event in late April for confirmation of your attendance.
We have Obsidian Flat Group Campground reserved for June 15-21. This is a 'primitive' campground that only has vault toilets (no running water), but is located right below an obsidian dome, and not near any other campsites, so we'll be on our own.
If anyone wishes to stay in a hotel, there are options in the Mammoth area, or elsewhere along highway 395. I recommend getting a reservation early, as they may book up (especially the more budget-friendly ones). The campground is closest to Crestview, but is also close to Mammoth. Folks who stay in the hotel are welcome to join us at the campground for socializing, campfire, etc.
More details about the trip, including maps, photos, and geology information, can be found here.Update on getting there through Tioga pass (Highway 120).
This is considered the best and fastest way to get to our destination from the SF Bay Area, but Peak Hour Ticketed Entry tickets are required (even if you have a Senior or other National Parks pass).
I just bought one last night (5/6) and as of that time there are still 231 left. The only timeframe that was available was 6:00 AM to 2:00 PM, which should work well for getting through. This means you can enter during those times. The pass is good for three days, so you'll need to buy one for the drive out and one for the drive back. They are only $2; I think it's just about limiting the number of people going into the park. I'd buy one now if you think there's a chance you are going to need it.
Here's the address for the tickets:
https://www.recreation.gov/timed-entry/10086745/ticket/10086746
If that doesn't take you directly to the page, try this one and click on Book Now:
https://www.recreation.gov/timed-entry/10086745
