Page:The Journal of geology (IA journalofgeology11893univers).pdf/10

the various geological journals. In 1835 Gustav Rose^[1] separated the rocks composed of labradorite and hypersthene, with accessory olivine, mica, apatite and ilmenite, from the gabbros, and included them under the name "Hypersthenfels," at the same time suggesting that the term gabbro be confined to rocks containing labradorite and diallage. Many rocks were described as hypersthenites or hypersthene rocks, because of the supposition that the highly foliated augite in them really belonged to this variety of pyroxene. Delesse^[2] and others showed that the compact feldspar of Haüy, and the jade mentioned by von Buch as an essential constituent of gabbros (afterwards called saussurite by de Saussure Jr., and by Beudant) is in some cases a true plagioclase; and Hunt^[3] showed that in other cases it consists of zoisite, of white garnet mixed with serpentine, or of meionite, and that the rocks containing these substances usually also contain hornblende, with the characteristics of Rose's uralite. Hunt, further, declines to regard the rocks containing a triclinic feldspar and pyroxene (either augite, hypersthene or diallage) as true gabbros. He places them among the dolerites, and declares that the true euphotides described by Haüy and de Saussure are mixtures of smaradite and saussurite; a declaration that Cocchi^[4] made for the Tuscane rocks a few years later. Rocks composed essentially of diallage and saussurite Cocchi called granitones. Whatever may be the virtue of the objections raised to the use of the name gabbro for plagioclase-diallage rocks, it still continued^[5] to be applied to rocks thought to be of this composition, just as hypersthenfels or hypersthenite