Boulder’s Rocks Are Telling Secrets 👀🪨

3/23/2026 What's Happenin' Team Boulder
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🪨 Boulder’s Story Is Written in Stone

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Happy Monday, Boulder! 🌞

Think Boulder’s just about the views? Look a little closer. Every trail, ridge, and rock has a story hiding in plain sight—and it goes way deeper than you’d expect. Stick around… once you see it, you won’t hike the same way again.

Want more local recs? Check out our Things to Do in Boulder, Best Restaurants, and Date-Worthy Spots for even more ideas.

Have you ever stopped to actually think about the geology while hiking in Boulder?

Click an option to vote


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🪨 The Story Beneath Your Feet: Boulder’s Geology 101

🪨 The Story Beneath Your Feet: Boulder’s Geology 101

Boulder isn’t just scenic—it’s one of the best outdoor geology museums in the country… and you’re walking through it every time you hit the trails.

🏔️ The Flatirons: Boulder’s Signature Look

Those iconic slabs above Chautauqua? They’re part of the Fountain Formation, laid down about 280 million years ago from sand and gravel eroded off ancient mountains.

Then—plot twist—the Earth pushed them upward like a tilted drawbridge, giving us that dramatic, slanted look we see today.

⛰️ Flagstaff Mountain: The Oldest Rock in Town

Head up Flagstaff and you’re looking at something even crazier—1.7 billion-year-old rock called Boulder Creek granodiorite.

It started as molten material deep underground, cooled into solid rock, and only became visible after millions of years of erosion peeled everything else away.

🏜️ When Boulder Was a Desert

Around 250 million years ago, Boulder looked nothing like it does now. Think sand dunes and dry heat.

That’s when Lyons Sandstone formed—the same salmon-colored rock you’ll see in patios, sidewalks, and even CU Boulder buildings today.

🌊 Yep… Boulder Had a Beach

Fast forward to about 135 million years ago and Boulder was basically coastal.

An inland sea rolled in, leaving behind Dakota Sandstone—you can still spot ripple marks in the rock from ancient waves.

🦕 Ocean Floors & Dinosaurs

That sea stuck around for millions of years, layering the region with sediment.

Much of Boulder today sits on Pierre Shale, formed at the bottom of a shallow ocean while dinosaurs roamed nearby.

❄️ Ice Age Finishing Touches

Then came the Ice Age.

Glaciers didn’t sit directly on Boulder, but meltwater carved out the canyons, shaped the foothills, and helped form the landscape we hike today.

👀 Next Time You’re Out There…

That “just a rock” moment? It’s actually a timeline—deserts, oceans, mountains, and ice all stacked into one place.

Boulder didn’t just get lucky with views… it earned them.


🐐 Rocky Heard You…

He saw what you were excited about this week — and he decided to share a few can’t-miss events over on Instagram. If you like visuals, behind-the-scenes moments, and quick hits of what’s happenin’, this one’s for you.

📸 See what he’s sharing → 📍 Boulder

Give it a tap, a like, or a share — Rocky notices 👀


What's Happenin' Boulder

Monday, March 23

Indigenous Mexican Foodways Cooking Demonstration - Museum of Boulder, Boulder | 5:30 PM to 7:30 PM | Ticketed
Guest Recital: Mantra Percussion, percussion sextet - Chamber Hall (S102), 1020 18th St Boulder, Colorado 80302, boulder | 7:30 PM | Ticketed

Tuesday, March 24

Darcy & Jer - Boulder Theater, Boulder | 8:00 PM to 11:59 PM | Ticketed
eTown Presents The Steel Wheels - eTown Hall, Boulder | 7:00 PM to 9:30 PM | Ticketed

Want more? See the full calendar → Boulder Event Calendar


Real Talk ☕

What’s Happenin’ is 100% free and independently run (yep, it’s just us). If this newsletter helps you discover cool things around town, your support helps keep it going and growing. We truly appreciate any and all love. Thank you for being part of the community.

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💼 Local Jobs Worth Checking Out

You asked for it — we delivered. In our recent poll, a bunch of you said you’d love a tiny job board in the newsletter, so here it is. We believe great communities connect people to great opportunities.

Full-time

Software Engineer at Lockheed Martin | Boulder

🏡 Featured Listing of the Week

🏡 Featured Listing of the Week

Dreaming of a new address? Each week, we’re spotlighting a standout home in town — from charming bungalows to modern builds and everything in between.

💘 Date Spot in Boulder

Boulder dates blend nature and culture effortlessly. Stroll Pearl Street Mall for coffee and people-watching, wander the Boulder Creek Path, or catch golden hour beneath the Flatirons at Chautauqua Park. For something laid-back, North Boulder’s breweries and eateries keep things casual and cozy.

👉 Vote and we’ll share the top picks—chosen by locals—in an upcoming issue. 💌

🍽 Not sure where to eat tonight?

Our Restaurant Finder takes the guesswork out of dining by showing you the best local restaurants based on real reviews and vibes, not just ratings. Whether you’re in the mood for a quick bite or a date-night spot, we’ve got you. No endless scrolling, no decision fatigue...just solid recs.

🧠 Need a brain break?

Play trivia, crosswords, and word searches built just for locals. These games aren’t just fun...they’ll test how well you actually know your city. Great for killing time, learning something new, or proving you’re the true local legend.

🗳 Now Voting: Boulder’s Best Breweries 🍻

Pastries had their moment. Now it’s beer time.

We’re opening voting for Boulder’s best breweries — from iconic names to low-key locals. Post-hike pints, clean lagers, experimental pours.

Got a brewery you never skip?

👉 Vote and help crown Boulder’s best.

Now You Know What You’re Standing On

Next time you’re out at Chautauqua or cruising up Flagstaff, take a second look—you’re literally walking through millions (and billions) of years of history. Pretty wild for a casual Monday hike.

Forward this to a Boulder buddy who loves a good trail 🤝

Got an event or local gem? Submit it here.

Keep the recs coming, keep voting, and if there’s a place you’re convinced belongs on the next list, just hit reply. I really do read every single one.

Forward this to a Boulder buddy who needs a breather.

See you Wednesday, Boulder.

— Ben

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