Not just paths, either. Some places had entire swathes of ground covered in what appeared - to my eye - to be shredded rubber (perhaps recycled tires?) fixed into place in a slightly mounded path. The overall effect was to mimic mulch.
|Here's an example from Fredericksburg.|
|Here's the edge of a patch of rubber that was placed around an exhibit panel near the Burnside Bridge at Manassas.|
|Here's the alternative - the badly eroded path up Big Round Top at Gettysburg|
Does anyone know what the technical term for this material is? Has anyone seen it anywhere but National Parks?