This reminds me of the brontotherium (thunder beast), a giant prehistoric mammal similar to a rhinoceros, but much larger. The Sioux sometimes found fossilized

This reminds me of the brontotherium (thunder beast), a giant prehistoric mammal similar to a rhinoceros, but much larger. The Sioux sometimes found fossilized brontotherium bones after heavy rainstorms. They believed them to be the bones of creatures that ran over the clouds and caused thunder. One of my children's books about prehistoric creatures said the brontotherium was named by a paleontologist who was familiar with the Sioux myth.