You're All Cracked Up: Eleven Hour Gulch

 🚙  US-14A Mileage9.2                                     GPS Coordinates  N 44.26.619   W 103.54.704        4,796 ft.

You're All Cracked Up Update2.pdf

Lesson Guide: PRINT

Both fascinating and unique 

A chasm straight and true

But how it formed and why right here  

This mystery we’ll undo

Field Exploration

Eleven Hour Gulch – the hidden gem of Spearfish Canyon. Because of its slot-like form and steep, vertical walls, sunlight reaches its boulder-strewn depths for only a few moments each day. In this exciting exploration we'll take you into this rocky chasm and delve into the story of its formation as well as the geology behind its dramatic form and appearance. 


This pdf Lesson Guide contains the specific directions for reaching our featured site as well as a detailed explanation of its geologic story. Mileage and coordinates are provided in each document and roadmaps and other learning aids can be found at the Lesson Resources link in the sidebar menu. The document is most useful if taken with you to the lesson site. Exercise extreme caution at the lesson site and along roadways.

Are you ready. . . . Let's Go!                                                S. V.  Fogarty   &   W. R.  Stevens

*Mileage starts at the intersection Colorado Bvd. and US 14A near Spearfish.

Please review the safety advisories in the Lesson Guide and Use great caution should you decide to enter!

Eleven Hour Gulch access point. Parking is located just out of the photo in the lower left corner.  EXERCISE EXTREME CAUTION when crossing roadway!

A chaotic assortment of boulders greet your entry into the gulch. EXERCISE EXTREME CAUTION if you decide to enter! Do not do so if you are not completely comfortable with hands and feet scrambling on slippery, unstable surfaces.




The Narrows

As one proceeds upstream through the gulch its vertical, igneous rock walls begin to narrow until eventually the chasm closes completely.


Continuation beyond this photographic point is not advised. 

Eleven Hour Gulch (Fault?) viewed at 120ft. above road level.  Note the linear trend of the gulch and its relatively smooth walls. Earthquake??

Vertical north wall of Eleven Hour Gulch.

Looking back toward the highway along a smooth, vertical rock face. 

View showing the narrow reaches of Eleven Hour Gulch.

The gulch follows a narrow and linear course throughout in its entire lower reaches.

Gulch Map Annotated.pdf

Topographic map showing Gulch drainage relationships and location.

Gulch Topographic Map. Print out for use at Lesson Site.


Be sure to download our Onsite Geology Lesson PDF posted above for a detailed geologic investigation of this site. 


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