The Bureau of Mines evaluated the tin development potential of the uplands between the Kanuti and Hodzana Rivers from 1978 through 1980. Chemical and petrologic data indicate that local granitic intrusions are generally similar to "tin granites" that contain tin deposits elsewhere. The tin mineral cassiterite (sNO2) was identified in chlorite-rich greisen from the sithylemenkat pluton. Greisen zones are located near the intersections of high-angle, linear structural features, and samples contain up to 0.23 pct sn. One bedrock exposure of greisen is 10 to 15 ft wide. Although some lode mineralization is present, the deeply eroded nature of the region suggests larger tin-bearing cupolas may have existed prior to erosion. Extensive stream gravel deposits have not been affected by glaciation, and potential exists for placer tin deposits. Especially favorable is a large semiclosed basin drained by the kanuti kilolitna river. Heavy mineral concentrates collected from surface alluvium in the Kanuti Kilolitna River Valley contained up to 51.2 pct sn (0.02 to 0.4 Lb/yd3sn), up to 5 pct w, up to 0.4 pct cb(nb), and up to 0.1 pct ta. The concentration of heavy minerals is expected to increase with depth. Detailed mapping and extensive surface and subsurface sampling will be needed to quantify the mineral development potential of the lode and placer tin deposits in the uplands.