Grand Canyon Fossils

Remnants Preserved by Time:
Grand Canyon fossils

The Grand Canyon in itself houses thousands of fossils spread in many fossil sites in the rock layers of the canyon. The most prolific site of Grand Canyon fossils is the Kaibab Formation bed located near the starting point of the West Rim. Embedded in the rock layers of the canyon are thousands of fossils that represent geologic eras. The age of rocks in the canyon represent the Paleozoic and Proterozoic eras.

Grand canyon fossils: Paleozoic era
The topmost layer is the Kaibab Limestone that averages around 270 million years old, and sculpts the surfaces of the Kaibab and Coconino Plateaus. It is called the Kaibab "limestone" because of its sandy limestone structure and a sandstone layer at the bottom. Grand canyon fossils found in this layer are corals, brachiopods , sea lilies, sponges, bryozoans, echinoderms (i.e. sea urchins), mollusks (i.e. snails and clams), fish teeth and worms.

The Toroweap Formation is estimated to be about 275 million years old and is mostly composed of similar materials as the Kaibab Limestone and records about the same fossil history. The Coconino Sandstone is about 280 million years old whose rock composition includes pure quartz sand hardened as sand dunes. There are no fossils of vertebrates yet found in this layer but numerous foot tracks of life and fossilized burrows exist here.

The Hermit Shale is a formation estimated to be about 285 years old. The shale rocks that compose this layer are soft and erode easily to form a slope. Found in this layer are plant fossils most abundantly ferns and conifers, tracts and trails of invertebrates, impressions of insects (as from a large dragonfly), and several worm burrows.

Below the Hermit formation is the Supai Group (approximately 300 million years old) composed of four formations: rust red sandstones, shales, siltstones, and jasper (a red chert). The Supai Group records many past environments but recent findings by scientists reveal a coastal desert eolian sands or windblown. Each of the four formations are believed to have been covered at least once by sea but mostly represents a terrestrial environment so that grand canyon fossils found here are those from marine life, reptiles, amphibians, and dry land plants.

The Redwall formation, which is estimated to be about 340 million years old, represents the lowest layer within the Paleozoic era strata. Traces of shallow water life can be found in the entire layer. Grand canyon fossils found in these layers are preserved structures of corals, crinoids, brachiopods, foraminefera, and bryozoans.