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.
Flagstaff Arizona is at 7,000 feet above sea level, with a population of 66,000 and the home of Northern Arizona University. Looking at cities with a population of 25,000 or more, Flagstaff Arizona is the 2nd highest above sea level in the United States. 6253 feet (1906 m) Stanley.