198 REV. J. MILNE CURRAN. 



between two plagioclases. The felspars are well knitted or 

 felted over the field, and show no sign of streaming in any direc- 

 tion. The ends of the laths branch and break off in " match- 

 wood fashion " and are seldom complete. The olivine is largely 

 micro-porphyritic containing much magnetite. With crossed 

 nicols, the composite character of many of the felspars is at once 

 apparent. The structure is intersertal and pilo-taxitic. The 

 order of consolidation appears to have been — 1. magnetite, 2. 

 augite and olivine, 3. felspars. Some of the layers of olivine are of 

 a previous consolidation and some of the magnetite is a secondary 

 product. 



Slice 6. — Basalt, Glen Innes, New England. In hand specimens 

 this basalt is a dark blue-black compact rock of very fine crystalline 

 structure. Cavities, probably caused by steam while the rock 

 was in a pasty condition, are seen in every sample. The rock is 

 sound and shows few signs of decomposition. It forms part of 

 one of the great Tertiary lava flows so well known in the northern 

 districts of this Colony. Under the microscope, the mass of the 

 slice is hypocrystalline-porphyritic, the ingredients being augite, 

 de vitrified glass and olivine. The felspars show signs of corrosion, 

 one very good example of which is seen in this slice. The larger 

 olivines are disposed to form groups with a similar optical orien- 

 tation. Generally the olivines are allotriomorphic and well 

 preserved. The magnetite is not so abundant as in the Tingha 

 basalt. It occurs in grains well distributed throughout the slice 

 and forms neither rods nor wedges. There is no approach to an 

 ophitic structure. 



Slice 7. — Basalt, Glen Innes. In general structure this slice 

 is very similar to the preceding one. There is more clear glassy 

 matter present, and the olivines are all allotriomorphic. A few 

 of the last named minerals are represented by complete pseudo- 

 morphs. 



Slice 8. — Porphyritic Basalt, German's Hill, Mt. Canoblas, New 

 South Wales. This is probably an older basalt than the normal 

 basalt that flowed down the Canoblas towards Orange on one side, 



