The next chapter in Earth's history corresponds to the Mesozoic Era, or "middle life" -- 285 to 70 million years ago. Read "pages" 956-987 and discover that dinosaurs lived and died, birds evolved from reptiles, and the first primitive mammals appeared. The mesas on the North Rim of Black Canyon along Highway 92 in Curecanti reveal exposures of rocks deposited during the Mesozoic. But the best place to find thse layers is along the shore of Blue Mesa Reservoir.
At the downstream end of the Black Canyon you might see a thin strip of pink or yellow rock at the very lip of the north side of the canyon. This is the Entrada Sandstone formed when a massive stack of sand dunes covered much of this region. Hike the North Vista Trail to come in close contact with these rocks. The mesas on the north rim of the canyon and along Highway 92 in Curecanti reveal exposures of additional rocks deposited during this time period. The best place to find the Morrison Formation is along the shore of Blue Mesa Reservoir in Curecanti.
The Morrison is one of the most widespread and easily recognized rock formations in the Southern Rocky Mountain and Colorado Plateau regions. Its strata (beds or layers) contain iron oxide and other minerals responsible for the red and green colors that make the Morrison Formation so easy to identify. It is also renowned for its dinosaur fossils!