“Hypothetically, a shield might serve, but with sufficient time to experiment and adjust such that today, stone will be required.”

At least, stone seems to be one thing they presently have access to in excess.

“I wish I better knew if the nature of the marks was uniform or specific to the maker, but I suppose that is knowledge we may gain in time. Certainly, if there are more sites such as this we may find ourselves — well, one may hope within more deliberately.”