Humbug Spires and that Interesting Brass Cap

General Land Office survey cap
A General Land Office survey
cap on the trail to the Wedge,
located in Humbug Spires
Wilderness Study Area. 

Story by Cyndi Eide, Realty Specialist, Montana/Dakotas State Office; and Lisa Scheirer, Realty Specialist, North Dakota Field Office 

Drivers traveling south on Interstate 15 between Butte and Dillon who glance out their side window will see a series of impressive granite outcroppings. The jagged teeth of the rocks are worth slowing down for. 

This is the Humbug Spires Wilderness Study Area, known for its outstanding rock-climbing and hiking opportunities. 

At the beginning of the three-mile trail to a spire known as the Wedge, sits an interesting brass cap sticking 18 inches out of the ground. You could trip over it if you weren’t paying attention. 

The Wedge
The “Wedge,” located in the
Humbug Spires Wilderness
Study Area in western Montana.

In looking closer at the round brass cap, you’ll see the letters, and numbers T1S, R9W and s13, s14, s23 and s34. These notations correspond to the rectangular system of public land surveys which extend over the public domain. This brass cap leads to records maintained at the Montana/Dakotas State Office. The historic survey notes and plats are also available at www.glorecords.blm.gov. The plat and notes depict the unique topography of this special place and serve a critical role in all the work that led to the Wilderness Study Area’s designation with the passage of the Federal Land Policy and Management Act of 1976.  

In Montana during the late 1800s and early 1900s, the General Land Office surveyors began their work, marking section corners on the ground using whatever materials they had on hand—like rocks, wood posts, and trees. They documented their work with notes and plats. Around 1908, they began setting iron posts with brass caps. 

This cap along the Humbug Spires trail was originally set in 1915 by the surveyors Royston C. Durnford and P. J. Sweeney. 

So, the next time you’re out hiking in your favorite public place, remember to look down every now and then. You just might find one of these special brass caps. 

The Humbug Spires Wilderness Study Area is an amazing place to visit. For more information on Humbug Spires, contact the Butte Field Office, or visit the BLM Library at https://archive.org/details/suitabilityrepor00bolm