The old prospector told them how, in the days of the 49ers, […] the Mexicans had been treated in a way they had practically never forgiven. The land was free. Discovery and appropriation of a mining claim gave title, provided it was staked out and a notice scratched on a tin plate affixed to the claim stake, and likewise provided that the size of the claim accorded with the crude ruling for that region.
Source: wiktionary