Read before the Mineralogical and Geological Section of the Academy of Natural Sciences of Philadelphia, December 22d, 1879. " The mineral to which the above title has been applied was found by the writer four years ago, ...". 16 pp. Wraps slightly discolored around edges otherwise the pamphlet is Very Good+ to Near Fine. Laid in a 5" x 2 1/4" paper hand written "With the Compliments of H. Carvill Lewis." ( Have 8 more pamphlets by Lewis, all different titles)