The GRI Collections
Welcome to the GRI Collections, a representative sample of paleontological and geological specimens housed at the Geoscience Research Institute.
What are fossils?
When the conditions are right, organisms’ remains or impressions can be preserved in rock. Rapid burial is often a factor. Much of what we know about the ecology of the ancient world can be ascertained by the study of fossils.
The Cambrian Explosion
Scientists have long been puzzled by the appearance of diverse phyla in the Cambrian layers. If the geologic column can be read as a timeline, how did most marine phyla appear so abruptly in the same stratigraphic interval?
The Coconino Sandstone
Prior to the 1930s, scientists widely accepted the theory that footprints found in the Coconino Sandstone were made underwater. This theory was abandoned in favor of a dry desert interpretation that fit better with a gradualist paradigm. Learn more about some of the evidence relevant to this controversy.
Radiation of Fish
Several major groups of fishes appear in Devonian and Upper Silurian rocks without a clear lineage of ancestral transitional forms. Significant disparity is observed between these species and those found in lower strata.