Upriver, where the plains end and the canyon lands begin, there is a series of enormous stone totems 4-6 yards in height on both sides of the river. These were erected by the Old Native civilization and include many inland animals which are no longer commonly venerated by the Coastal Tribes. Several kivas are located in the cliff sides and are commonly used by aspiring shamans for vision quests and all tribes for communicating with the totem spirits, though these days members of the Inland Tribes visit more frequently.
If the PCs want to use the kivas and fast and meditate for them, they will work for them and the spirits will contact them - which may lead to initiation as shamans or totem warriors if the spirits find favor in their personality, though for that they must be willing to be true protectors of the land and its people.
It is possible and even likely to find tribals and even a shaman or two here. What's more, the Stone Totem Valley serves as neutral ground to the tribes - no violence may be done here, upon pain of curses by the totems.
Note: A list of all Urbis-related posts can be found here.