THE ERUPTIVE ROCKS OF NEW ZEALAND. 109 



Crystallitic: a glassy base so crowded with crystallites as to be 



turbid or opaque, surrounding niicrolites or small crystals. 



Teall, pi. xxiii., f. 1 ; pi. xxxvi. and xxxvii. Sub-textures are 



Lonyulitic : the crystallites are colourless, or pale coloured 



rods and irregular particles (Micro-felsitic). 



Glohulitic: the crystallites are opaque granules of iron oxides. 



Vitreous: a clear glass, colourless or brown, through which 



crystallites and microlites are loosely scattered. Teall, pi. 



xxxiv., t. 3 and 4 ; Judd, pi. vi., f. 3 to 8. Subtextures are 



Banded : divided into layers of different colours. Teall, 



pi. xxxiv., f. 1 ; Rutley, f. 7ia. 

 Damascened : contorted layers and threads of different 



colours. Rutley, f. 75. 



Perlitic : with microscopic curved cracks, sometimes 



between straight crack. Teall, pi. xxxiv., f. 5 ; pi. 



xxxviii., f. 1 ; Giekie, f. 22 ; Rutley, f. 76. 



Sphprulitic : containing spherical bodies with a radial 



fiV)rous structure. Teall, pi. xxxix., f. 1 ; Giekie, f. 22. 



Mi'-ritspltiTuHtic : The same but visible with a microscope 



only. Teall, pi. xxxviii., f. 2. 

 A:i-v>]ific : containing elongated bodies, sometimes branched 

 with fibres at right angles to the long axis. Rutley, f. 79. 

 Microvesicular : containing microscopic vesicles, eitfiei 

 rounded f cellular J, Giekie, f. 28, or elongated (pumiceous) 

 pi. viii., f. 2, or hair-like (trichitic) pi. viii., f. 3. 

 Fehitic : an anisotropic aggregate without definite microlites ; 

 either transparent or turbid with crystallites. With or with- 

 out a grey and white mosaic-like pattern visible only between 

 crossed nicols (petrosiliceous). This is a devitrified* glass, 



Amorphous — Non-crystalline, glassy or stony, non-porphyritic. 

 This is the base of the crystallitic, vitreous, and felsitic semi- 

 crystalline rocks and it has the same textures and subtextures. 



These various textures pass into eacli other and occasionally a 

 rock may be partly of one and partly of another texture. This is 

 especially the case with crystallitic and vitreous. 



