RT Journal Article SR Electronic T1 The Cambrian and the Ozark series JF American Journal of Science JO Am J Sci FD American Journal of Science SP 57 OP 60 DO 10.2475/ajs.s3-46.271.57 VO s3-46 IS 271 A1 Broadhead, Garland Carr YR 1893 UL http://www.ajsonline.org/content/s3-46/271/57.abstract AB