North Park in Billings in Yellowstone County, Montana — The American West (Mountains)

Montana's 70 Million Year Old Beach

The Rimrocks

Photographed By Barry Swackhamer, September 15, 2020

1. Montana's 70 Million Year Old Beach Marker

Captions: (upper left) A couple enjoying the Rimrocks in 1925. They are on the southern side of the Yellowstone River at what is now known as the Four Dances Recreational Area. Fred Inabnit, a local mountaineer, is seen on the left.; (lower left) Depiction of Western Interior Seaway.; (lower middle, L and R) A late 1930s view of North 27th street going up to Billings airport. Road widening efforts took out the sandstone on the right side of the photo., Montana Senators Lee Metcalf and Mike Mansfield introduced a bill to create Rimrocks National Monument near Billings in 1970. In 1971, the idea was rejected due to existing commercial development and the airport.; (lower right) Poem about the rimrocks, 1930, from Billings Polytechnic Institute, now Rocky Mountain College.

Inscription. According to geologists, during much of the Cretaceous Period (144 to 65 million years ago), a large portion of Montana was covered by a shallow inland sea called the Western Interior Seaway. The rims towering above Billings are composed of a cemented layer of fine-grained sand and silty mud, known as Upper Cretaceous Eagle Sandstone. It was deposited 70 to 80 million years ago as shoreline and offshore bars of the great sea.
A number of local buildings and homes use the sandstone for foundations or exterior walls. The Parmly Billings Library, now the Western Heritage Center, and several buildings at Rock Mountain College were constructed using local sandstone. A returning visitor to Billings in 1926, amazed by the growth of the city commented, "the Rimrocks haven't changed much."

Topics. This historical marker is listed in this topic list: Natural Features.

Location. 45° 47.074′ N, 108° 29.846′ W. Marker is in Billings, Montana, in Yellowstone County. It is in North Park. Marker is on Montana Avenue (Business Interstate 90) near North 22nd Street, on the right when traveling east. Touch for map. Marker is at or near this postal address: 2200 Montana Avenue, Billings MT 59101, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Billings' Humble Beginnings (here, next to this marker); How the Railroad Shaped Our Town

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(here, next to this marker); Explorer, Guide, and Hunter (a few steps from this marker); Children of the Large-Beaked Bird (within shouting distance of this marker); The Fight or Flight of the Nez Perce (within shouting distance of this marker); Battle of the Little Bighorn (within shouting distance of this marker); Billings' Chinatown (within shouting distance of this marker); The Purity Bread Company (within shouting distance of this marker). Touch for a list and map of all markers in Billings.

Photographed By Barry Swackhamer, September 15, 2020

2. Montana's 70 Million Year Old Beach Marker

Credits. This page was last revised on February 16, 2023. It was originally submitted on March 5, 2021, by Barry Swackhamer of Brentwood, California. This page has been viewed 209 times since then and 29 times this year. Photos: 1, 2. submitted on March 5, 2021, by Barry Swackhamer of Brentwood, California.