Precambrian crystalline rocks in the central Wind River Range consist of intermediate granitic rocks, felsic to intermediate gneisses, agmatites, and diabases. The agmatites are thought to be reconstituted sedimentary rocks with a complex history of recrystallization, shattering and partial fusion. Chemical equilibrium appears to have been obtained at the close of each of several episodes of agmatization. The cause of the shattering is not known. Much of the agmatite host rock appears to represent a retrogressive product from higher grade granulite or high amphibolite facies rocks.