Cambrian stratigraphy and paleontology near Caborca, northwestern Sonora, Mexico.
1952. Smiths. Misc. Coll. Vol. 119, Nr. 1; 184 pp. 9 fig. 31 plts. with phot. of views (5) and fossils, incl. brachiopods (3) and trilobites (18 plts.) Orig. wrps. with very faint stamp, very good, contents uncut.
1991. Rev. Geol. America Central No. 12; pp. 1-59, 30 fig. 4 fold. & col. geol. maps 1:50.000 in pocket. Comes with 3 related papers (pp. 61-95) on geological structure, petrography and neotectonics of the area. In complete journal issue, orig. wrps. very good.