5. Sub-order, Prismatic, of the Augite-Andesites
(Felspar-lathes in flow-arrangement. Aug, matr, flu, prism.)
This sub-order includes dark-brown or blackish semi-vitreous rocks, all but one of which belong to the genus below described. Since the exception (which belongs to genus 17 of the synopsis) differs only in the presence of plagioclase phenocrysts, its separate description is not needed.