BY H. I. JENSEN. 595 



4. The normal order of consolidation for these rocks was followed. 



5. Name : Trachytic Soda-Trachyte. Magmatic name, Phle- 

 grose {cp. Tables i. and ii.), 



W.17. Loc: Timor Rock near base. (Plate xxx., figs. 1 and 2). 



1. Handspecimen a bluish-grey even-grained rock like the 

 preceding. 



2. Texture hypocrystalline and even-grained, with trachytic 

 fabric. 



3. Composition : felspar forms about 90% of the rock; it occurs 

 in laths, most of which exhibit Carlsbad twinning, crosscracks, 

 and other common characteristics of sanidine; but the refractive 

 index is almost identical with that of canada balsam, so that the 

 mineral is probably anorthoclase. There is also present a little 

 oligoclase in laths showing albite twinning and straight extinc- 

 tion. Albite also occurs. The blue-green soda-amphibole is next 

 in importance. It occurs scattered throughout the rock in 

 minute stunted rods and elongated grains. The pleochroism 

 colours are deep blue, greenish-blue, and greenish-yellow. 

 Abundant inclusions of varying shapes and sizes occur. They 

 appear to be chert fragments brought up from a depth by the 

 lava. The soda-amphibole has aggregated round these fragments. 

 A little interstitial quartz occurs. It was the last mineral to 

 crystallise out. A little yellow interstitial glass is also present. 



4. Order of consolidation normal. 



5. Name : Trachytic Soda-Trachyte. Magmatic name, Phle- 

 grose (see Analysis W.16). 



W.114. Loc: Paddy's Rock, Naman Range. 



1. Handspecimen greenish-grey, mottled; like some of the 

 Glass House Mountain comendites in appearance. 



2. Texture : holocrystalline, even-grained, with trachytic fabric. 



3. Constituents : lath-shaped anorthoclase felspars, moss-like 

 .aggregates of minute prismatic crystals of soda hornblende, inter- 

 stitial segirine, and a little interstitial isotropic material, probably 

 a felspathoid. 



4. Name : Trach3^tic Soda-Trachyte. 



