136 F. W. HUTTON. 



2-7. Section : Ground-mass abundant, microlitic with both felspar 

 and augite ; the felspars -003 in length, and rather in excess of 

 the augite. There is also a considerable amount of chlorite. 

 Scarcely porphyritic, but scattered felspar laths up to -015 in 

 length, and grains of pale greenish augite, -02 in diameter, often 

 glomero-porphyritic. Much of the augite is changed t 

 Magnetite and ilmenite also occur. In dvkes. Hutto 

 N.Z. Inst., Vol. XIX., p. 403. 



In dykes. Hutton, Trans., 



Tekoa, Amuri District. —A 



pale grey compact rock \a 



spots of decomposing augite. S.G. 2-46. Section : Ground-mass 

 very abundant, felsitic, almost colourless, with dark spots of 

 magnetite, and yellow-brown spots of a transparent mineral 

 aggregate ; shews a mosaic with crossed nicols. The porphyritic 

 minerals are plagioclase and augite. The plagioclase crystals are 

 much altered but still shew polysynthetic twinning, they go up to 

 •08 in length. Augite is very rare, it is yellowish-green and goes 

 to -01 only. Associated with slates at the Mandamus River. 

 Hutton, Reports Geol. Explorations, 1873-4, p. 35. 



Mount Egmont, Taranaki.—Yery dark grey rocks with large 

 crystals of green augite and smaller white felspars. S.G. 2-69 to 

 2-86. Section : Ground-mass moderate or small, crystallitic, 

 globulitic, a brown glass opaque with magnetite dust. The por- 

 phyritic minerals are plagioclase, augite and magnetite. The 

 augite is greenish, idiomorphic, in large crystals up to '10 in 

 length. The plagioclase crystals are zoned and up to 08 in length. 



Another specimen is grey, granular in appearance, of small 

 greyish-white felspars and no large crystals. The ground-mass is 

 small, longulitic and contains a little broken brown hornblende 

 with opacite wreaths. From the northern slopes of the mountain. 



Rnapelm. — A black, sub-vitreous rock, indistinctly banded and 

 with scattered small felspars. S.G. 2-614. Section : Ground-mass 

 very abundant, crystallitic, banded with V)lackish and dark grey 

 layers, the dark layers with microlites shewing fluxion. The 

 porphyritic crystals are plagioclase and augite. The plagioclase 

 in crystals up to -035 in length. The augite in small "broken 

 crystals only. From the south slopes of the mountain. 



Mount Pirongia. — A brownish-grey rock speckled with white 



quantity, crystallitic, longulitic, the glass brown, with nuniprous 

 microlites of felspar and augite. The porphyritic minerals are 

 plagioclase, augite, and magnetite. Flugioclase crystals are 

 numerous, up to -03, but a few go to '08, thev shew central decom- 

 position. The augite is greenish, partly iciionioi-phic, partly in 



in diameter or less. There is a little apatite. Hochstetter, New 

 Zealand, p. 314 ; Park, Rep. Geol. Expl., 188.5, p. 140. 



