186 THE GEOLOGY OF THE CANOBOLAS MOUNTAINS, 



They have an extinction-angle of 8°. (2) The felspar of the base 

 is microlitic soda-sanidine. Strands of katapleiite penetrate the 

 phenocrysts and base alike. The pyroxene consists of phenocrysts 

 of yellowish-green, pleochroic eegirine-augite, with extinction- 

 angle=38°, and minute bluish, greenish, to colourless rods of 

 aegirine-augite in the base. Sphene occurs in the base as minute 

 lozenge-shaped prisms surrounded by leucoxene. Grains of 

 magnetite are abundant. A few idiomorphic, corroded, nepheline 

 phenocrysts were observed. Eucryptite(?) occurs in some of the 

 felspar phenocry^sts. A couple of poikilitic aggregates of kata- 

 phorite, with pleoehroism from red to dull brown and bluish- 

 green, occur in parts of the slide. 



Name : Pilotaxitic Trachy-Phonolite. 



Magmatic name : Judithose, near Laurdalose(see Analysis v.). 



No.X636. Trachyte-Porphyry. Loc: Norris's Farm, Spring 

 Creek. 



Handspecimen : compact, bluish-grey rock. 



Texture: holocrystalline, porphyritic, with fine grained trachytic 

 base. 



Composition : the phenocrysts of felspar consist of microcline 

 cryptoperthite; they are allotriomorphic, and have a zone of 

 inclusions just within the border. The inclusions consist of 

 seoririne-augite, mao-netite, zircon, and sao;enitic rutile. A second 

 .growth of clear felspar has been deposited round this zone. The 

 felspar microlites of the base have the properties of sanidine. 

 The pyioxene phenocrysts are yellowish-green, and have an 

 extinction angle of 27-'28*'. They consist of regirine augite. The 

 finer, acicular microlites of the base are grass-green, and have an 

 extinction of 18°, and are therefore more closely allied to true 

 segirine. Strands of katapleiite are developed in the felspar 

 phenocrysts. Some minute yellow rods of laavenite are included 

 in the felspar and occur also in the base. A little felspathoid is 

 probably present in the base. 



Name : Phonolitic Trachyte-Porphyry. 



