Saturday & Sunday, April 11 & 12, 2026

The Notch: Exploring Ancient Rivers, Beaches, and Dunes

Led by geologists William W. Little and David A. Little

We all enjoy floating on a river or enjoying the crashing of waves on a beach. Such features have existed throughout Earth’s history. How do geologists recognize them in the rock record?

We’ll travel to “the Notch,” a narrow slot canyon located just south of I-70 about 20 miles west of the town of Green River. The Notch opens to reveal the back and forth change between ancient rivers (like the modern South Platte) and sand dunes (similar to the modern Sahara Desert). We will see both from afar and up close the manner in which sediment accumulated and was then preserved such that we can identify these features today.

This is an excellent field trip for folks who want to spend a day among the dramatically tilted rocks of the San Rafael Swell, and also for those eager to see historic geological processes in action. The dirt road to the Notch crosses a wash several times.

See below for important trip information.

  • Participants must drive their own cars.

    Though the Notch is relatively close to Green River, high clearance vehicles with AWD or 4WD are required to navigate sandy wash crossings. 

  • Lunch, water, sturdy shoes, binoculars, camera, and snacks.

  • William W. Little and David A. Little

    William W. Little has a Ph.D. in sedimentology from the University of Colorado and taught as a Professor of Geology for nearly 30 years at various institutions before retiring in 2021 after seventeen years at BYU-Idaho. He also worked as a geologist for the Missouri Geological Survey and now owns and operates W.W. Little Geological Consulting.

    David A. Little has an M.S. degree in geology from BYU. He did a graduate internship with ConocoPhillips, then because of his love for field work decided to become an independent contractor with W.W. Little Geological Consulting. David’s background is primarily with ancient sedimentary systems.

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The Notch cuts into the steeply tilted rocks of the San Rafael “Reef.” Photo by Alison Jean Cole.