This section focuses on South American fossil vertebrates, excluding marine fish. Extinct families will be emphasized here, as living families were considered in Part 1.

Coconino Sandstone research has demonstrated how catastrophists can use their theory to develop specific hypotheses about a geologic feature (the Coconino Sandstone), and successfully carry out scientific research to test that hypothesis. This is one criteria that science used to determine the scientific value of any theory.

The unnatural mixture and the rapid stratigraphic shifts of fauna seem to require catastrophic water transport into the area. The large geographic extent precludes a local event. Creationists suggest that a world-wide flood could produce results as seen in the Santana Formation and is a better explanatory model.