Near Mandan in Morton County, North Dakota — The American Midwest (Upper Plains)

Cannonball Concretions

Photographed by McGhiever, June 21, 2023

1. Cannonball Concretions Marker

Inscription. Concretions are spheres of mineral matter once surrounded by rock of a different composition. They occur when a cementing material forms around a center of organic matter such as a leaf, twig, shell or tooth. As the softer surrounding material weathers away, the spheres emerge. Concretions vary in color, shape and size with some as large as 10 feet in diameter.

These spectacular round rocks reminded many early explorers of "cannonballs". This served to name the Cannonball geological formation and the Cannonball River that flows through it.

Erected by North Dakota Parks and Recreation.

Topics. This historical marker is listed in these topic lists: Environment • Exploration • Natural Features.

Location. 46° 45.976′ N, 100° 50.794′ W. Marker is near Mandan, North Dakota, in Morton County. It is on Fort Lincoln Road, on the left when traveling north. The marker is in Fort Abraham Lincoln State Park (fee area), just northeast of the visitor center. Touch for map. Marker is at or near this postal address: 4480 Fort Lincoln Road, Mandan ND 58554, United States of America. Touch for directions.

Regionally, this marker is on the Missouri Plateau

and in Greater Bismarck Area.

It is also in the American Lewis & Clark Corridor,

on the prairies,

and on the Northern Plains.

Globally, it is in North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once Rupert’s Land

and also the Louisiana Purchase.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Fort Abraham Lincoln Military Reservation Boundary Marker (a few steps from this marker); Civilian Conservation Corps

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(a few steps from this marker); Civilian Conservation Corps Project (within shouting distance of this marker); Commanding Officer’s Quarters (within shouting distance of this marker); Slant Indian Village (within shouting distance of this marker); Powder Magazines (approx. 0.3 miles away); Laundress' Quarter: "Suds Row" (approx. 0.3 miles away); Schoolhouse (approx. 0.4 miles away). Touch for a list and map of all markers in Mandan.

Marker and concretions behind the Fort Abraham Lincoln State Park visitor center image. Click for full size.

Photographed by McGhiever, June 21, 2023

2. Marker and concretions behind the Fort Abraham Lincoln State Park visitor center

Credits. This page was last revised on December 25, 2024. It was originally submitted on July 3, 2023, by McGhiever of Minneapolis, Minnesota. This page has been viewed 536 times since then and 85 times this year. Photos: 1, 2. submitted on July 3, 2023, by McGhiever of Minneapolis, Minnesota. • J. Makali Bruton was the editor who published this page.