Hot Springs in Fall River County, South Dakota — The American Midwest (Upper Plains)

Mid-Cenozoic Era

~35 million years ago

Photographed by William Fischer, Jr., September 25, 2026

1. Mid-Cenozoic Era Marker

Inscription.

As you arrive in the age of mammals, the world around you undergoes drastic changes. The late Cretaceous sea is gone and the Black Hills have risen, forming the basis for the modern landscape. The land is covered by rainforests, then savannahs, and finally grasslands very similar to today. Early horses and dogs walk alongside relatives of cats and camels. Our best geologic record from this time comes from Badlands National Park.

[Illustration caption reads]
The early horse Mesohippus, and Hoplophoneus, a relative to saber-toothed cats.

Erected by The Mammoth Site of Hot Springs, Inc.

Topics. This historical marker is listed in these topic lists: Animals • Environment • Paleontology.

Location. 43° 25.465′ N, 103° 29.005′ W. Marker is in Hot Springs, South Dakota, in Fall River County. It can be reached from no nearby street. Marker is along the Mammoth Site entrance walkway. Touch for map. Marker is at or near this postal address: 1800 US Highway 18 Bypass, Hot Springs SD 57747, United States of America. Touch for directions.

Regionally, this marker is

Paid Advertisement

Click or scan to see
this page online

in West River.

It is also in the American Black Hills,

in the 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: Pleistocene Epoch (here, next to this marker); Late Mesozoic Era (a few steps from this marker); Paleozoic-Mesozoic Era (a few steps from this marker); Paleozoic Era (a few steps from this marker); Precambrian Era (within shouting distance of this marker); Mammoth Site of Hot Springs, SD (about 600 feet away, measured in a direct line); Woodward Field (approx. 0.4 miles away); Black Hills College (approx. 0.4 miles away). Touch for a list and map of all markers in Hot Springs.

Regarding Mid-Cenozoic Era. Markers and rocks are part of the walk through Black Hills geology leading to the Mammoth Site.

Related markers. Click here for a list of markers that are related to this marker. Follow the markers chronologically

Photographed by William Fischer, Jr., September 25, 2026

2. Mid-Cenozoic Era Marker

through the geologic timeline

Credits. This page was last revised on October 24, 2026. It was originally submitted on October 21, 2026, by William Fischer, Jr. of Reynoldsburg, Ohio. This page has been viewed 12 times since then. Photos: 1, 2. submitted on October 21, 2026, by William Fischer, Jr. of Reynoldsburg, Ohio.