What Hance would have found had he dug the canyon, and what we're all able to see now, are the various rock strata (layers) including shale-siltstone, sandstone, conglomerate, limestone, dolomite, and igneous and metamorphic rock.
In that array of rock, several geologic periods can be seen, the oldest dating back to the Precambrian period [source: Scenic.com]. There are 94 types of rock (and minerals, mostly iron, that cause bright colors), as well as caves and steep-walled canyons, and a sizable fossil record (including petrified forests, lungfish, nautiloids and dinosaurs) [source: National Pak Service].
Today, the park holds a diverse set of plant and animal life. There are more than 1,500 plant species (including wildflowers and cactus) plus 355 bird species (including the endangered California condor), 89 mammalian species (including the native Bighorn sheep), 47 reptile species (including the Gila monster), nine amphibian species, and 17 fish species found in the park. More than 35 animal species are endangered or of special concern [source: National Park Service].