Subdivisions. The Ordovician is the second period of the Paleozoic era. The Ordovician began after the end of a series of extinction events known as the Ordovician-Silurian extinction events which ended around 488 mya.
As a state highpointer, Humphrey's Peak in Arizona was on my bucket list. The trailhead was easy to find. The trail itself was not well maintained and rather rocky, which wasn't too bad going up, but required a lot of caution descending to protect your knees.
The Colorado Plateau, a series of flat lands, gorges, mountains and valleys, extends south into Arizona, and covers most of northern half of the state. The Black Mesa, Painted Desert, and Monument Valley in northeastern Arizona are some of the plateau's most interesting areas. Scattered tree-covered ranges of the Rocky Mountains wind through the Plateau, including the Black, San Francisco and White Mountains. Humphreys Peak is the highest point at 12,633 ft.