From abstract: The Mount McKinley quadrangle, in south-central Alaska, includes parts of the Alaska Range, the Tanana and Kuskokwim lowlands, and the Kuskokwim Mountains. Schists of Precambrian age crop out in the northern foothills of the Alaska Range. Sedimentary and volcanic rocks of Paleozoic and Mesozoic age are exposed in the Kuskokwim Mountains, where little is known of their distribution and character, and in the Alaska Range, where they occupy the axial part and northern limb of a great synclinorium. Granitic batholiths, largely of Mesozoic age, intrude the Paleozoic and Mesozoic rocks in the Alaska Range.