Starting from Yavapai Geology Musuem and walking west, once you have walked the short Million Year Trail 150 yards(136 m), you will encounter the second Trail of Time portal, which marks the beginning of the main Trail of Time, that represents the two billion year timeline of Grand Canyon geology.
From here, the walk back through geologic time is scaled so that each meter (1 long step) on the timeline is equal to one million years of Earth's history. The golden "magic meter", on the ground next to the rock column, represents all the things that you saw on the Million Year Trail.
The uppermost layered Paleozoic rocks of Grand Canyon, the Kaibab Formation and Coconino Sandstone, are the theme for the seating rocks and paving stones of this portal. See if you can find the proto-reptile tracks visible in several of the slabs of Coconino Sandstone used for this portal's paving stones. In the seating rocks surrounding the portal, look for gastropod fossils in the pieces of Kaibab limestone or take a closer look at the fine layering of sand grains in the large pieces of Coconino Sandstone.
To the west, look for a wayside exhibit explaining how long it took for the Colorado River to carve Grand Canyon. Touch the river-polished rock!
Trail of Time Overview
The Trail of Time is the world's largest geoscience exhibition at one of the world's grandest geologic landscapes, Grand Canyon National Park. The trail utilizes the unique vistas and rocks of Grand Canyon to help visitors ponder, explore, and understand the magnitude of geologic time and the stories encoded by Grand Canyon rocks and landscapes. Geologic time is immensely long. The 4.56 km (2.8 mi) trail is marked every meter, with 1 meter = 1 million years of our 4,560,000,000 year-long Earth history. Viewing tubes, rocks on plinths, and wayside panels help visitors connect the rocks visible in Grand Canyon to their place along the timeline.
The main Trail of Time can be entered at different points - including the east end near Yavapai Point (young end), west end at Grand Canyon Village (old end), or a middle point where a connecting trail comes from the Park Headquarters parking area (Parking Lot A). Shuttle stops connect each entry point, so you can walk it in several ways and still get back to your car. The entry portals have messages on each side appropriate for those approaching (welcome) or for those completing different segments of the Trail (congratulations).
Located on the South Rim of Grand Canyon National Park, the Trail of Time extends along the paved Rim Trail between the Yavapai Geology Museum on the east and Maricopa Point on the west. The main portion of the Trail between Yavapai Geology Museum and Grand Canyon Village is accessible to wheelchairs and baby strollers, and it is convenient to shuttle bus stops and parking areas in a heavily-visited section of the park.