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.
Mount Lemmon (O'odham: Babad DoÊ¼ag), with a summit elevation of 9,159 feet (2,792 m), is the highest point in the Santa Catalina Mountains.It is located in the Coronado National Forest north of Tucson, Arizona, United States. dirt access road to the summit on the back side of Mount Lemmon starts in Oracle, which is on state highway 77 northeast of Tucson. It offers a secondary route to the top. This route is popular with off-road 4x4 drivers and with off-road or dual-purpose motorcyclists.