There are many fossil sites in the Grand Canyon, but none is more prolific than the 270 million year old Kaibab Formation beds near the start of the West Rim Trail. To find the site, park near Bright Angel Lodge and walk west along the Rim. You will pass the bus stop at bottom of the hill. Walk up the trail about 200 yards (300 steps) to the first really spectacular open views on huge semi-flat rocks jutting out over the Canyon to your right.
The fossils are even better on the other side of the trail from here—the left side as you ascend. Look in all the ledges and outcrops. You will surely find dozens of fossils of many types. With a little care you can find all the species on these pages--and more/! All photos were taken here.
Remember: there is no collecting allowed at Grand Canyon. But for a fabulous family activity, see how many fossils you can find and check off. Take a magnifier!