What was the purpose of the deep mortar holes found in almost all shelters? Is there a significance of the various sizes?
Deep mortar holes, shallow mortar holes, natural concavities, and cupules have elicited a lot of interest over the years but much remains unresolved. There are round mortars and boat-shaped mortars, and mortars so deep they have broken through the rock, and mortars with little channels, mortars with lids, upside-down mortars, and sideways mortars, mortars on creek beds, in rock shelters, on uplands, in bedrock, in boulders, and so on. Such diversity in form and location probably reflects diversity in function as well. The use of natural concavities that strongly resemble mortar holes and some mortar holes as well is clearly related to storage or retention of water. This is particularly evident on the Eldorado Divide where petroglyphs are often found surrounding natural potholes and concavities on waterless uplands (including one at Lewis Canyon where water is easily available). In some of the more isolated spots, limestone lids were still lying next to the holes and a scouting report f
