The Salish are a peaceful race who are protected by a race known as the Spirits. The Salish were once ruled over by the Goa'uld however, the Spirits managed to get rid of them, and allowed the Salish to develop naturally.
The SGC went to the Salish homeworld, and tried to mine their for Naquadah, however, the Salish did not want their planet destroyed, and so they rejected the offer. The SGC were forced to go behind their backs, however the Spirits discovered what they were doing and punished the SGC.
With the help of SG1 the Spirits calmed down, and the Salish buried their gate to stop anyone from entering their planet without their knowledge.