In the Rye Patch area in the west-central part of the Humboldt Range, Nevada, Triassic (?) limestones interbedded with silty layers have been intruded by igneous rocks, the principal type being a quartz monzonite. The quartz monzonite is surrounded on the north, east, and south by an aureole of contact metamorphism. On the western side faulting has cut the intrusion so that any metamorphic rocks which may have been formed are not seen at the surface. A long narrow contact zone east of the aureole extends northward a considerable distance.
Metamorphic changes range from recrystallization of limestone to complete replacement by contact silicates. The contact-metamorphic minerals include garnet, diopside, epidote, clinozoisite, idocrase, tremolite, recrystallized calcite, quartz, and minor scheelite.
The sediments are deformed by the intrusion into a small northerly trending arch. Aplite dikes and quartz veins appear related to the arching and also to the formation of scheelite.