232 



REV. J. MILNE CURRAN. 



Fig. 4. — Cross-twinning in Orthoclase as seen in Granite from the Bur- 

 dekin River, Queensland, with a magnifying power of 30 diameters. The 

 crystal is represented as it appears in polarised light, with the nicols crossed. 



Fig. 5. — Basalt, from Vegetable Creek, Emmaville, as seen magnified 45 

 diameters. The figure shows a characteristic section of olivine decomposing 

 along the cracks into serpentinous matter. The other minerals present are 

 lath-shaped felspars, granules of augite and olivine, magnetite in black 

 opaque grains, and some glassy matter. 



Fig. 6. — Basalt, Mount Pleasant, Bathurst, as seen with a magnifying 

 power of 45 diameters. The figure shows a characteristic section of augite. 

 This crystal exhibits an hour-glass structure in polarised light with crossed 

 nicols. 



Fig. 7.— Coarse grained Basalt, from Beni, Dubbo, New South Wales, as 

 seen magnified 25 diameters with the nicols inclined. Large crystals of 

 augite are seen penetrated by plagioclase laths giving rise to an ophitic 

 structure. 



Fig. 8.— Diabase porphyrite, Blayney, New South Wales, under a mag- 

 nifying power of 30 diameters. Microporphyritic crystals of a monoclinic 

 pyroxene are seen, set in a granular base, made up of plagioclase, grains of 

 augite and magnetite. 



Note. — The figures of the plates have been all drawn from micro-photo- 

 graphs taken by the Author. It was not considered necessary to reproduce 

 the map handed in with this paper, and referred to on page 186. 



Index. 



PAGE. 



Absorption spaces in Tachylite 212 



Acidic rocks 220,230 



Acid, treatment of slices in 181, 208 



Armidale... 

 Augite rocks 



porphyrite... 



Basalt 



■ American ... 



Armidale . . . 



Bathurst ... 



Byerock 



Canoblas ... 



Carcoar 



Cargo 



Dubbo 



Emmaville... 



El Capitan 



Forest Reefs 



flow, structure in 



German's Hill 



Glen Innes 



204 



230 



221 



... 195-211 



230 



204 



,.. 186,207 

 .. 186,210 



198 



186, 190, 207 

 ... 186, 190 

 ... 205, 206 



205 



... 186, 210 

 ,.. 203,204 



190 



198 



198 



Basalt, Gulgong- 



Harden 



Invtrell 



Kiama 



Lucknow . . . 



Mundoran . . . 



Nerriga 



ophitic 



Orange 



porphyritic 



leucite 



Tingha 



Vegetable Creel: 



Basalt Glass 



Carcoar 



Hill End ... 



Lachlan 



Vegetable Creek 



Bald Hills 

 Basic Rocks 

 Bathurst 186, 188, 



PAGE. 



196 



.. 186, 210 



205 



209 



... 203, 104 



186 



221 



190 



.. 190, 203 



190,198 



... 210 



197 



204 



182, 192, 211 



212 



213 



213 



213 



208 



230 



190, 207, 214 



