Download or read book The Bug Creek Problem and the Cretaceous-Tertiary Transition at McGuire Creek, Montana written by Donald L. Lofgren and published by Univ of California Press. This book was released on 1995-08-31 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bug Creek assemblages from Montana, transitional in composition between typical Cretaceous and Paleocene vertebrate faunas, are critical to K-T extinction debates because they have been used to support both gradual and catastrophic K-T extinction scenarios. Geological and palynological data from McGuire Creek indicate that Bug Creek assemblages are Paleocene and restricted to channel fills entrenched into older sediments, suggesting that the Cretaceous component of the assemblage was reworked. Thus, the author concludes, "Paleocene dinosaurs" are an illusion and the K-T survival rate of mammals is low because the presence of Cretaceous mammals in Bug Creek assemblages is also the result of reworking.