Photo1Toadstool Geologic Park gets its name from the bulky sandstone blocks balanced on seemingly impossibly narrow pedestals of sediment seen throughout the area. The sandstone blocks, many of which still bear tracks of extinct animals, are remnants from a river that flowed through the area over 30 million years ago, and subsequent weathering has broken the sandstone down into blocks. The rocks giving Toadstool its moonscape appearance were deposited by wind and streams between 45-26 million years ago. Volcanic ash from the west coast being driven by the prevailing winds also came to rest in northwest Nebraska. The alternating reddish and greenish bands of color apparent in the area are due to soil development during the wet or dry seasons when the ash was deposited. Red-tinged layers formed during wet seasons when iron in the ash oxidized or “rusted,” while the greenish layers indicate soil formation during dry seasons.

This volcanic ash accumulating also explains why the flora and fauna are so precisely fossilized. Silica minerals dissolved from the ash filled the pore spaces in the skeletons to strengthen the bone, allowing it withstand weathering.

Extinct animals preserved at Toadstool Geologic Park include: tortoises, rhinos, birds (ducks, shorebirds, herons) , saber toothed cats, early dogs,  large pig-like animals, oreodonts (sheep like), small tusked deer, early 3 toed horses, early camels, brontotheres (8 ft tall rhino-like),  bats, snakes, rodents, and lizards–just to name a few.  During this time, grasses were not much established in the area, so the herbivores were browsers. The climate nearly 45 million years ago appears to have been humid subtropical, but by 26 million years ago the climate was very dry. 

If you enjoy natural wonders and have a taste for living history preserved in rock, hike Toadstool Geologic Park.  The site includes a camping and picnic area.

USDA Forest Service
Nebraska National Forest
125 North Main Street
Chadron, NE 69337
(308) 432-0300