16 GEOLOGICAL MEMOIES. Echinolamjpas hemisjohcericus (Lamk. sp.), vars. Linkii (Goldf.) and rhodensis (Laube), the latter distinguished by its smaller size and less oval form. Vienna basin and Hungary. LauriUardi (Ag.). Yienna basin and Hungary. angustistellatus, sp. n. Nearly circular, slightly produced be- hind ; petaloidia narrow, highly arched. Yienna basin. Conoclypus plagiosomus (Ag.). Yienna basin. Fericosmus affinis, sp. n. Yery like P. latus (Desor), but with a narrower frontal furrow and shorter posterior petaloidia. Yienna basin. Hemiaster rotundus, sp. n. Like H. acwminatus (Miinst.), but of a more rounded form, and with the anterior declivity steeper. Yienna basin. JcalJcburgensis, sp. n. Like H. acumitiatus (Miinst.), but with the petaloidia different and the frontal furrow longer and narrow ; more cordiform than H. rotundus. Yienna basin. Schizaster leithanus, sp. n. Large, cordate, vertex very excentric, frontal furrow long and deep. ParJcinsoni (Defr.). Yienna basin. Karreri, sp. n. Of moderate size, ovate, deeply emarginate in front ; distinguished from >S^. ParJcinsoni by its more excentric vertex and straight petaloidia. Hungary. scillce (Desmoul.). Baden. Desori (Wright). Yienna basin. — — , sp. Upper Austria. Brissomorjjha, g. n. Intermediate between Brissus and Prenaster, differing from the former in the shape of the petaloidia and front, from the latter in size and covering. Fuchsi, sp. n. Yienna basin. Bpatangus euglyphus (Laube). Yienna basin. austriacus, sp. n. Large ; differing from S. regince (Forbes) by its broader petaloidia and several spinose warts placed in zig- zag between the petaloidia ; and from S. pustulosus (Wright) by its deeper frontal furrow and its more rounded form. [Count M.] On the Lavas of Mount Yestjvius. By Herr H. Wolf. [Proc. Imp. Geol. Institute, Vienna, February 16, 1869.] These lavas, according to the author, are all Leucite-porphyries of a homogeneous, slag-hke, porous, and nearly pumicose structure. Their fundamental constituent is a greenish vitreous substance, con- taining microscopic crystals of Plagioclase, Sanidine, and Leucite, — the last predominating both as to size and quantity. Pyroxene and magnetic protoxide of iron have also been observed. Small plates of magnesian mica occur very rarely. [Count M.] ^
