RT Journal Article SR Electronic T1 Description of a problematic organism from the Devonian at the Falls of the Ohio JF American Journal of Science JO Am J Sci FD American Journal of Science SP 202 OP 209 DO 10.2475/ajs.s3-37.219.202 VO s3-37 IS 219 A1 Frank Hall Knowlton YR 1889 UL http://www.ajsonline.org/content/s3-37/219/202.abstract AB