Frommer's National Parks of the American West - Don Laine [27]
The layered look of the Badlands comes from sedimentary rocks composed of fine grains that have been cemented into a solid form. Layers with similar characteristics are grouped into units called formations. The bottom formation is the Pierre Shale, deposited 68 to 77 million years ago during the Cretaceous period, when a shallow, inland sea stretched across the present-day Great Plains. The black mud of the sea floor hardened into shale, leaving fossil clamshells and ammonites that today confirm a sea environment. The sea eventually drained away, and the upper layers of shale were weathered into soil, now seen as Yellow Mounds.
The Chadron Formation, deposited 32 to 37 million years ago during the Eocene epoch, sits above the Pierre Shale. By this time, a flood plain had replaced the sea, and each time the rivers flooded, they deposited a new layer of sediment on the plain. Alligator fossils indicate that a lush, subtropical forest covered the region. However, mammal fossils dominate. The Chadron is best known for large, elephant-sized mammals called titanotheres.
Some of the sediment carried by rivers and wind was volcanic ash, the product of eruptions associated with the creation of the Rocky Mountains. This ash mixed with river and stream sediments to form
clay stone, the main material from which Badlands buttes are constructed. After the Eocene epoch, the climate began to dry and cool, and tropical forests gave way to open savanna. Rivers deposited the Brule and Sharps formations during the Oligocene epoch from 26 to 32 million years ago, and today these formations contain the most rugged peaks and canyons of the Badlands.
Actually, the impressive serrated ridges and deep canyons of the Badlands did not exist until about 500,000 years ago, when water began to cut through the layers of rock, carving fantastic shapes into what had been a flat floodplain. Once again, the ancient fossil soils, buried for millions of years, became exposed. That erosion continues: Every time rain falls, or snow melts in spring, more sediment is washed from the buttes in this ongoing work of sculpting the earth. On average, the buttes erode an inch a year; scientists believe that the buttes will be gone in another 500,000 years.
In addition to its scenic wonders, the Badlands are one of the richest Oligocene fossil beds known to exist. Remains of three-toed horses, dog-sized camels, saber-toothed cats, giant pigs, and other species have been found here; all date from 25 to 35 million years ago.
Flora & Fauna. Largely a mixed-grass prairie, the park contains 56 different types of grasses, most of which are native species, including green needle-grass and buffalo grass. Wildflowers, including curlycup gumweed and pale purple coneflower, add color, with the best wildflower displays in June and July. You won't find many trees here.
Wildlife to watch for includes bison, Rocky Mountain bighorn sheep, pronghorns, and mule deer. Darting in and out of the grass are desert and eastern cottontail rabbits. Prairie dogs thrive here; a prairie dog town is just 5 miles down Sage Creek Rim Road. You might also see a prairie rattlesnake slithering through the grass, plus several nonpoisonous snake species.
Avoiding the Crowds. The vastness of the park means that overcrowding is usually not a problem. Entrance stations, visitor centers, park concessions, and the Loop Road can become busy during the height of the summer season, especially in July and August, but most roads, trails, and services are not overtaxed at any time of the year.
As with most other national parks, those wishing to avoid crowds should visit during the shoulder seasons of April to May and September to October. If you must go in summer, visit early in the day when the numbers of people are lowest and the sun hasn't begun to scorch the earth. Dawn and dusk are ideal times to photograph the unearthly beauty of the park, and are the