Fassett (2009) claimed that dinosaur fossils are present in strata of Paleocene age in the San Juan Basin of New Mexico-Colorado. As the late astronomer Carl Sagan frequently said, "extraordinary claims require extraordinary evidence," and we believe that Fassett has failed to provide the extraordinary evidence needed to conclude that dinosaurs lived during the Paleocene.
Fassett (2009) based his claim primarily on palynologic and magnetostratigraphic data, but also used geochemical analyses to support his conclusions. Here, we address these arguments to demonstrate that based on the data analyzed by Fassett there is no robust scientific basis for assigning a Paleocene age to any dinosaur fossil in the San Juan Basin. Place names referred to here are located in
Fassett (2009, figure 1).