We measured rock strength and amount of fracturing in the two different rock types, sandstones and carbonates, in Last Chance Canyon, New Mexico, USA. Where there is more carbonate bedrock, hills and channels steepen in Last Chance Canyon. This is because the carbonate-type bedrock tends to be more thickly bedded, is less fractured, and is stronger. The carbonate bedrock produces larger boulders than the sandstone bedrock, which can protect the more fractured sandstone bedrock from erosion.