Description: Kaibab chert forms as nodules within the Kaibab Formation limestones of the Colorado Plateau. The brown mottling in the material consists primarily of the silica skeletons of ancient sponges of the genus Actinocoelia.
Description: Kaibab chert forms as nodules within the Kaibab Formation limestones of the Colorado Plateau. The brown mottling in the material consists primarily of the silica skeletons of ancient sponges of the genus Actinocoelia.