The mines around Scott Valley attracted many immigrants from many parts of the United States and the world, attracted to the area by news of the California Gold Rush of the 1850s. Irish and Portuguese immigrants remained as ranchers in the area after making enough on the gold fields to purchase property tracts in the valley. In the early years of the Twentieth Century, the northern Scott River tributaries of Moffitt and McAddams creeks were extensively settled by the Portuguese. The Irish surname Marlahan lives on after that family received a shipment of British hay seed infected with the seed of a plant known as Dyers Woad. Those seeds spread their spawn throughout Scott Valley, culturing a plant known in the area as "Marlahan Mustard". The plant has a beautiful, canary plume in the spring which matures to small, black, hard seeds. Unfortunately, the herbivore beasts of burden will not eat hay in which this plant exists, and ever since it has been a scourge on the ranchers of Scott Valley.