Alaska Gold Rush History and Genealogy

The Yentna district includes the area drained by western tributaries of the Susitna River between Alexander and Sunshine and by its eastern tributaries from Sunshine to and including the Taikeetna River.

Most of the placer mining in the district was in the Cache Creek area on streams draining the Peters and Dutch Hills and near Fairview Mountain (41, 42) about 20 miles to the southwest.

The Peters and Dutch Hills are largely underlain by graywacke and finer clastic rocks, predominantly Mesozoic in age. Tertiary continental rocks, including auriferous conglomerate, occur in the Dutch Hills and are exposed in many creek valleys. Alaskite dikes and small plutons and at least one mafic or ultramafic dike, now altered to silica-carbonate rock, cut the Mesozoic sequence (Clark and Hawley, 1968). Some of the dikes and many quartz veins in the Mesozoic rocks contain a little magnetite, scheelite, various sulfide minerals, and native gold, but none of these occurrences has been developed into a mine. Except in parts of the Dutch and Peters Hills, Quaternary glacial and alluvial deposits blanket bed¬rock in most of the area. Placers include stream and bench deposits of the present streams, glaciofiuvial deposits of Pleistocene age, and Tertiary conglomerates. On the basis of recent work by Clark and Hawley (1968), auriferous quartz-rich conglomerates and breccias on Dollar (3), Thunder (7), and Willow (14) Creeks, once considered to be extensively weathered deposits that were buried on an old erosion surface, are now thought to be the result of erosion of hydrothermally altered zones that follow northeastward-striking steep faults. Most of the gold mined in the Cache Creek area probably came from dredging operations on Cache (2) and Peters (11) Creeks. Streams draining the southeast flank of the Dutch Hills were extensively mined by hand and nonfloat methods. Falls