Stop 5: Kaiparowits Fm.
We stop at along side the road between two roadcuts. There is a bluish cast to the light gray rocks in this area. The Kaiparowits formation is mudstones and sandstones. The age is late Cretaceous. These were deposited in sluggish rivers and on flat plains from the mountains to the inland sea. These were heavily forested swampy environs. Palms, cycads, ferns and the earliest flowering plants grew here. This was the age of the hadrosaurs. In 1985 the best known dinosaur, Ornithomimus, was found across the road up a dry creek. The skeleton on this ten foot tall, graceful theropod was fairly complete. It ate small mammals, reptiles and young dinosaurs. A few sacral bones of a Parasaurolophus, a herbivore, were found one mile away. Ceratopsians have been found also, but are rare because it was too early for them. Fossils of large theropods, turtles, "reptilian" birds, diamond-scaled fish, crayfish, clams and snails. This is the latest Mesozoic rocks we'll be in this trip. We take an hour to look for fossils, and find some turtle scrap.
We move on and camp at the developed Escalante Petrified Forest State Park campsite near Escalante.
Stop 6: Petrified Forest
The Morrison Fm is here. Unlike the early Jurassic with its ergs, and the middle Jurassic with its marine and marginal marine units where few dinosaur fossils are found, this is late Jurassic. The Morrison Fm is a result of fresh water deposits as the inland seaway expanded and retreated leaving lowlands. There were active volcanoes in the Great Basin where Nevada is today and hills where Arizona is today. There was drainage from the west with rivers and some lakes. There was abundant vegetation. The dinosaurs died and were buried quickly with flooding. Nearly all the dinosaurs found have been from the Morrison Fm. It ranges from 150 to 800 feet thick and has three subdivisions, with the Brushy Basin member being the most prolific producer of dinosaur bones.
We hike up the camp trail to see some petrified wood. This was the food source for the dinosaurs. The trunks are aligned southwest, possibly indicating their being knocked down by a volcanic blast or mud flow.
We stop for photos above Escalante Canyon which has the smooth cross bedded sandstones of the Navajo Fm. We go over Boulder Mountain at 8000 feet. We turn off Highway 12 left on Highway 24, then north on 24 and then on 72 and onto Interstate 70. A quick left onto Highway 10 to Cleveland and our next stop.