Quaternary-Tertiary bolson deposits (TXQTb;0)

State	Texas
Name	Quaternary-Tertiary bolson deposits
Geologic age	Phanerozoic \| Cenozoic \| Tertiary Quaternary \| Pliocene Pleistocene
Original map label	QTb
Comments	clay, silt, sandstone, and conglomerate; mostly clay, silt, and gypsiferous fine-grained sandst. in central part of Presidio bolson, coarsens toward margins where lenses of pebble to boulder conglomerate are common, mostly pale red to lt. brown; thickness up to 2,000 ft.
Primary rock type	clay or mud
Secondary rock type	silt
Other rock types	sandstone; conglomerate
Lithologic constituents	Major Unconsolidated > Coarse-detrital > Sand (Bed) Unconsolidated > Fine-detrital (Bed) Incidental Sedimentary > Clastic > Conglomerate (Bed)
Map references	Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000
Unit references	Bureau of Economic Geology, 1979, Emory Peak--Presidio Sheet, Geologic Atlas of Texas, University of Texas at Austin.
Geographic coverage	Brewster - Culberson - El Paso - Hudspeth - Jeff Davis - Presidio - Reeves