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The mica in recent volcanic rocks, gabbros, and diorites is usually Biotite, while that so common in metamorphic limestones is usually, if not always, Phlogopite. Amphibole is a general name for all the different varieties of Hornblende, Actinolite, Tremolite, etc., while Pyroxene includes Augite, Diallage, Malacolite, Sahlite, etc.

Here the difficulty seems to arise from the too intimate and too numerous relations observed in rocks that are thought not to belong to the same family. I found no real basalt or dolerite; but the presence of pyroxene in the amygdaloid of Parapara leaves little doubt of the igneous origin of those spheroidal masses, fissured, and full of cavities.

Plagioclase, microcline and quartz are the predominating minerals, while biotite, titanite, epidote, apatite, zircon and garnet are present in smaller quantities. There is also a small amount of hematite, pyroxene and sericite. The rock, which is of a granitic composition, contains numerous crystallites and has been subjected to considerable strain and crushing, which has resulted in foliation.

There are also numerous included crystals. The rock has been greatly crushed and sheared, and is much finer than No. 4. 6 Cap of Caribou Ridge. A hard compact rock of dark green color, having a mottled appearance, due to the presence of a white mineral. Pyroxene, quartz and augite form the groundmass, as seen in section. There are a few small grains of magnetite,

Their nucleus is almost as hard as basalt, and they are intermingled with little cavities, owing to bubbles of gas, filled with green earth, and crystals of pyroxene and mesotype. Their basis is greyish blue, rather soft, and showing small white spots which, by the regular form they present, I should conceive to be decomposed feldspar.

Now, at Teneriffe, the black rapilli extend from the foot of the Peak to the sea-shore; while the white ashes, which are only pumice ground to powder, and among which I have discovered, with a lens, fragments of vitreous feldspar and pyroxene, exclusively occupy the region next to the Peak.

A dark, compact rock, having a mottled appearance due to grains of plagioclase, and a green color in section. Minerals present are hornblende, biotite, plagioclase, pyroxene, quartz and the alteration products from the feldspar. The rock has been subjected to a strong crushing action, which has been resisted by only small portions of it.

The compact basalt alternates with the strata of porous basalt and marl. M. Hauy considers it a variety of the pyroxene. The porous basalt, which passes into mandelstein, has oblong cavities from two to eight lines in diameter, lined with chalcedony, enclosing fragments of compact basalt.

M. von Buch examined with a powerful lens the species we brought. He discovered that each crystal of pyroxene, enveloped in the earthy mass, is separated from it by fissures parallel to the sides of the crystal. These fissures seem to be the effect of a contraction which the mass or basis of the mandelstein has undergone.

The quartz grains show secondary growth. 13 Altered Gabbro Thirty-two Miles Above Wuchusk Nipi on Nascaupee River. A coarse dark green rock whose principal constituents are pyroxene plagioclase and magnetite. There is a slightly developed diabasic structure and the rock is much altered by weathering; the resultant product being chlorite. 14 Quartizite Bibiquagin Lake.