Nielson, J.E., Howard, K.A., and Glazner, A.F., 1993, Introduction to the area south of I-40 and north of I-10, Calif. and Ariz., in Sherrod, D.R., and Nielson, J.E., eds., Tertiary stratigraphy of highly extended terranes, California, Arizona, and Nevada: U.S. Geological Survey Bulletin 2053, p. 87-93.