RT Journal Article SR Electronic T1 Permian geology of northern Brazil JF American Journal of Science JO Am J Sci FD American Journal of Science SP 425 OP 443 DO 10.2475/ajs.s4-37.221.425 VO s4-37 IS 221 A1 Lisboa, M. A. R. YR 1914 UL http://www.ajsonline.org/content/s4-37/221/425.abstract AB