Laserfiche WebLink
-9- <br />,~ <br />micro- and mega-invertebrates have been published, among which Ka tech <br />(1959), Cobban (1951), Cobban and Reeside (1952), Jones, et al (1953), <br />Sariento (1957), and Fisher, Erdmann, and Reeside (1960) deserve <br />mention. <br />But while [he invertebrate fauna is well known, very little work <br />has been published on the flora of the Williams Fork and Iles Forma- <br />tions of the Mesaverde Group despite the abundance of well preserved <br />leaves. All [hat has appeared in print are floral lists by Knowlton <br />(1919), and Tidwell (1966), and a short description of a new plant <br />also with a floral list by Cockerell (1910). <br />Totally unstudied is the vertebrate fauna. This is due to the near <br />absence of reported specimens. All that is known is a plesiosaur and an <br />~• _ ~_r , <br />unidentified reptile from *_he Mama"'• ^^ar 'r»d ~r.ion 'Look, 1955), <br />and isolated fish bones and scales. <br />Although the vertebrate remains from the Late Cretaceous are scarce <br />in northwestern Colorado, there is an abundance in the post-Cretaceous <br />deposits. These bones have drawn universities and museums into the area <br />for the past century and they now occupy the laboratories and displays <br />of the museums around the world. The evidence gleaned from the fossils <br />and the fossilbeds have revealed changing environments from warm, wet, <br />tropical conditions to dry, cool semiarid conditions. With each gradual <br />change there was also a change in the animal life forms. Geologically, <br />what had taken place was a continous rise of the Rocky Mountains from <br />the time the Epicontinental Sea had withdrawn until the Cenozoic was <br />well underway. Several additional rises throughout the Cenozoic shed <br />• <br />