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. . 12 ~ The remainder (upper 90%) of the Madison Formation consists of dense, mas- .~ ~ sive, recrystallized carbonate rock which contains sparce, poorly preserved, - C: marine invertebrates such as crinoids, corals, brachiopods, bryozoa, and c gastropods. '. The most abundantly fossiliferous of the rock units of the Juniper - Cross Mountain Project area is the Morgan Formation. The fossils, which are all of marine invertebrate organisms, are very well preserved (some by replace- ment by red jasper), and are so abundant in some limestone layers that they are the main constituent of the rock. Collections made below the dam site at the west end of Juniper Canyon and on the western slopes of Cross Moun- tain just south of the canyon there include at least five species of brachi- opods, three species of crinoids (including stem sections and calyx plates), large pelecypods, myriad Fusulinid foraminifera, several species of both fan and branching bryozoa, unusual globular shaped coral colonies, some of which have been replaced by chert, and numerous other types of fossils, all of which clearly indicate the type of life that was prevalent in this area dur- ing the Pennsylvanian Period. The Permian and Triassic strata in the vicinity of the project are generally unfossi1iferous, except for a few amphibian tracks which occur on bedding surfaces of the Weber Sandstone in Dinosaur National Monument. However, this investigator did discover a rather unusual occurrence of large petri- fied wood fragments (probably of the genus Araucarioxylon) within the Chinle Formation where it is upturned against the Cross Mountain Fault about one- fourth mile south of the mouth of Cross Mountain Canyon. Fossil wood is especially useful as a paleoclimatic indicator for the area and time in which the plants grew. ---.,---. ~ '