Description:
This map has been prepared primarily by photointerpretation, using
mainly 1:120)OOO-scale true-color aerial photographs, supplemented in
places by 1:120,000 and 1:60,OOO-scale color-infrared aerial photographs.
The published Soil Survey Reports on the Tucson and Casa Grande areas
provided useful ground control, but their coverage is limited essentially
to farming areas in the Santa Cruz River valley. Field-check traverses
were made throughout the area, the density of traverses depending upon
the variability and complexity of geomorphic and soil relationships and
upon the available roads; additional field checks will be made before the
final map is prepared.
Soil associations, western half of the Tucson 1o x 20 Quadrangle; (a) northern half, (b) southern half. Scale 1:120,000