Halfway along the Badlands Loop the colours change. Around the Yellow Mounds Overlook the grey and buff spires give way to low, rounded hills of bright yellow and ochre, some streaked with red and purple, looking more like a painted desert than a prairie. They are a fossil soil, formed when the dark shale of an old sea floor, the oldest rock in the park, lay exposed to the weather after the water retreated, and they glow in the late afternoon sun.
Beyond the mounds the road crosses a wide, grassy basin, the Conata Basin, with buttes and ridges rising on either side. This is mixed-grass prairie, one of the most endangered ecosystems in North America, and it is home to a remarkable variety of wildlife. Prairie dog towns are common, and you will often see these chubby rodents standing upright beside their burrows, barking warnings to each other. The prairie dogs, in turn, support the black-footed ferret, one of the rarest mammals in North America, which was reintroduced here after being thought extinct.
The road through this section is gentle and scenic, with long, straight stretches and wide curves across the basin. The asphalt is good, and traffic is usually light, especially early in the morning. There are frequent pull-outs and viewpoints along the road, and it is easy to stop and take photographs. Watch out for wildlife on the road, especially bighorn sheep, which often graze on the shoulders.
A little further east, the Fossil Exhibit Trail is a short boardwalk with replicas of fossils found in the area and displays explaining the geology and palaeontology of the badlands. It is a good introduction for anyone curious about the strange creatures that once lived here.
There are no services in this part of the park. The nearest fuel and food are at Cedar Pass to the east and in Wall to the north. The weather can be extreme, with very hot summers and sudden thunderstorms. Carry water, wear a hat, and be careful on the trails, which can be slippery and crumbly. Rattlesnakes are present, so watch where you put your feet.