Johnson and Karl (1985) map the rocks in the area of this prospect as Cretaceous graywacke and argillite with sparse, lenticular beds of basalt. The rocks are cut by numerous high-angle, mainly northwest-striking faults. They include the extensions of the faults at the Hirst (SI087) and Chichagof (SI093) mines, which control the mineralization there and straddle this prospect.

Reed and Coats (1941) describe the prospect as auriferous quartz veins up to 3 feet thick in graywacke. The veins are mainly localized along major faults and splits from them that strike northwest and dip steeply southwest, about the same as the bedding in the graywacke. At the time of Reed and Coats' visit, the underground workings included a 45-foot tunnel and a crosscut about 150 feet long with a flooded winze of unknown depth. Surface workings included several pits and trenches. Reed and Coats provide no assay or production figures, but the extent of the workings suggests that some gold may have been produced. Bittenbender and others (1999), citing Still and Weir (1981), report that samples across a 0.2- to 2.8-foot-thick vein contained up to 0.695 ounce of gold per ton.