Near Cascade in Cascade County, Montana — The American West (Mountains)

Transition Terrain

Photographed By Barry Swackhamer, August 15, 2022

1. Transition Terrain Marker

Inscription. While walking the trail, look for the angular red, purple, gray, and green colored rocks. You are looking at geologic signs of transition between soft rock of the prairie and erosion-resistant igneous rock that make up the Adel Mountains. Volcanics. These rock fragments blasted skyward from violent volcanic activity some 68 to 75 million years ago. They settled and cemented together with volcanic ash. Over time the less erosion-resistant rock washed away reveling the formation you see today.
This area is a good example of a "habitat edge," where the prairies meet the mountains. Their rich diversity provides important places for wildlife to get water, nest, and seek prey. A botanical study of this area showed over 100 species of prairie and mountain plants found nowhere else but along mountain edges.

Erected by Portage Route Chapter, Lewis & Clark Trail Heritage Foundation (LCTHF).

Topics and series. This historical marker is listed in this topic list: Natural Features. In addition, it is included in the Lewis & Clark Expedition series list.

Location. 47° 11.304′ N, 111° 48.591′ W. Marker is near Cascade, Montana, in Cascade County. Marker is on Old U.S. Highway 91 near Hardy Creek Lane, on the

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left when traveling north. Touch for map. Marker is at or near this postal address: 2325 Old US Highway 91, Cascade MT 59421, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within 6 miles of this marker, measured as the crow flies. Point of Reference (here, next to this marker); Sentinel of the Rockies (here, next to this marker); From Too Much to Note Enough (here, next to this marker); From Indian Trail to Highways (here, next to this marker); July 17, 1805 & July 17, 1806 (approx. 1.4 miles away); The Missouri River Canyon and Old US Highway 91 (approx. 2 miles away); A Volcanic Island in the Rocky Mountains (approx. 2 miles away); Join the Voyage of Discovery (approx. 5.8 miles away). Touch for a list and map of all markers in Cascade.

Photographed By Barry Swackhamer, August 15, 2022

2. Transition Terrain Marker

Credits. This page was last revised on April 29, 2024. It was originally submitted on April 29, 2024, by Barry Swackhamer of Brentwood, California. This page has been viewed 39 times since then. Photos: 1, 2. submitted on April 29, 2024, by Barry Swackhamer of Brentwood, California.