Loess (Holocene and Pleistocene) (ORQl;0)

Windblown clayey silt and fine sand. Includes the Pleistocene Palouse Formation and deposits derived mostly from reworking of Palouse Formation. Contains local interbedded layers of soil, caliche, and some water-laid silt and gravel

State	Oregon
Name	Loess (Holocene and Pleistocene)
Geologic age	Pleistocene to Holocene
Original map label	Ql
Primary rock type	silt
Secondary rock type	sand
Other rock types	caliche; gravel
Lithologic constituents	Major Sedimentary > Clastic > Siltstone (Bed)Contains silt, fine sand, soil, caliche, and water-laid silt and gravel Incidental Sedimentary > Clastic > Mixed-clastic > Conglomerate-sandstone (Bed)
Map references	Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.
Unit references	Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000. Walker, G.W., 1973, Reconnaissance geologic map of the Pendleton quadrangle, Oregon and Washington: U.S. Geological Survey Miscellaneus Geologic Investigations Map I-727, scale 1:250,000. [http://pubs.er.usgs.gov/publication/i727] Walker, G.W., 1977, Geologic map of Oregon east of the 121st meridian: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-902, scale 1:500,000. [http://pubs.er.usgs.gov/publication/i902]
Geographic coverage	Umatilla