The Salish were a group of humans, descended from native Americans from Earth. They were kidnapped by the Goa'uld and deposited on PXY-887 millennia before regaining contact with the Tau'ri. The Salish were aided by Xe'ls, a member of an alien species who fought the Goa'uld until their forces were driven away. These beings chose to remain, co-existing with the Salish in the forms of their "Spirits" to protect them. Like many Native American tribes, the Salish were one with their environment and saw all mechanical disruption in their world (such as mining) to be a malicious act of violence and a rape to the natural environment. Their world was rich in the mineral trinium, the first such planet the S.G.C. discovered.
The Salish had ample supplies of the ore, as they said, by asking the mountain to send the "Ke" down the river, where it was purified by the water over an extended period of time. The Salish possessed the means to develop rudimentary technologies, such as bows and arrows, and commonly used trinium spears and darts. They were effective at tranquilizing intruders for several hours, as well as breaking bullet-proof glass.
Thanks to SG-1, the Salish Spirits, while temporarily on Earth in the S.G.C., were unable to maintain their identity. When the spirits asked the Salish which form they wished the spirits to appear as, the Salish chose their natural, humanoid form. Both the spirits and the Salish returned to PXY-887 to co-exist in a truer partnership. (SG1: "Spirits")