During the Late and early Historic periods, the northern Channel Islanders made extensive use of 2 imported materials: redwood from coastal northern California and high grade asphaltum from mainland coastal seeps. These materials were essential to many tasks, but were perhaps most important for plank canoe construction and caulking, water-proofing of vessels, and repair of many kinds of objects. Recent discoveries on Santa Cruz Island provide new information on an expanded range of uses of these materials, including residential construction and possibly ceremonial activities. A partially-excavated redwood-pole structure and a large asphaltum basin are highlighted for discussion.