Named for exposures near Bluff Creek, south-central part of Walnut Wells quad, S1/2 T31S, R17W, Hidalgo Co, NM in Pedregosa basin. Geologic map. Consists of beds of quartz-latitic pyroclastics interbedded with lenticular clastic sedimentary beds; foreign rock fragments are present in the pyroclastic rock. Beds weather differentially and dip toward the west. Reaches a maximum thickness of 1,000 ft 1/2 mi south of Bluff Creek. Individual units lens out toward the north; north of Bluff Creek less than 6 units are present in the formation. Unconformably overlies Timberlake Fanglomerate (new); overlain by Gillespie Tuff (new) with apparent conformity. Partial stratigraphic section measured. Is Tertiary in age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
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