Named for La Garita Mountain (its type area), Saguache Co, CO in the San Luis basin. Formerly included in the Alboroto Rhyolite (Larsen and Cross, 1956). Is well exposed along upper canyon East Willow Creek north of Creede and forms the bulk of La Garita Mountain. Consists largely of densely welded ash-flow tuffs that are equivalent to the Outlet Tunnel and Phoenix Park Quartz Latites of Emmons and Larsen (1923). Divided into the Outlet Tunnel Member (older) and the Phoenix Park Member (younger). Is more than 2,000 ft thick in type, but base not exposed and full thickness not determined. Assigned to the middle and late Tertiary. Formed during subsidence of the La Garita cauldron, and before the Huerto Formation and the Farmers Creek Rhyolite.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Pg. A77-A78. La Garita Member of Fish Canyon Tuff. Reduced in stratigraphic rank and assigned to Fish Canyon Tuff as its middle member. Erupted from the La Garita caldera near the center of the San Juan volcanic field. Consists of the intracaldera rocks previously assigned to the Alboroto Rhyolite† (herein abandoned) by Larsen and Cross (1956, USGS Prof. Paper 258, pl. 1), and named La Garita Quartz Latite by Steven and Ratte (1964, p. D57). Steven and Ratte's (1964) Outlet Tunnel Member† is same as large mass of intracaldera rocks of the La Garita Member and is herein abandoned. Their Phoenix Park Member is retained and assigned to the Fish Canyon as its upper member. La Garita Member is younger than the outflow member of Fish Canyon Tuff, and older than Phoenix Park. Age is late Oligocene.

Source: Publication.