The Livingston Formation is a series of pyroclastic rocks several thousand feet thick cropping out on the north side of the Beartooth Mountains. These pyroclastic rocks grade laterally into the Claggett, Judith River, Bearpaw, and Lennep formations of the Montana Group, according to Stone and Calvert [see 1 of references at end of paper], showing that they were being deposited during much of Montana time; they are therefore of Upper Cretaceous age and antedate the Laramide orogeny.
The purpose of this paper is to describe briefly several significant features of the Formation where it is exposed in the Nye No. 2 Quadrangle (Fig. 1) along the southeast edge of its outcrop. It is concluded that much of the Formation was formed by mudflows, and that certain chloritized beds were deposited by hot mudflows.