RT Journal Article SR Electronic T1 On some phonolitic rocks from Montana JF American Journal of Science JO Am J Sci FD American Journal of Science SP 394 OP 399 DO 10.2475/ajs.s3-50.299.394 VO s3-50 IS 299 A1 Pirsson, Louis Valentine YR 1895 UL http://www.ajsonline.org/content/s3-50/299/394.abstract AB