186 REV. J. MILNE CURE AN. 



the eye of the observer. Each of us looks at a section with the 

 accumulated experience of his past study. Hence, the veteran 

 cannot make the novice see with his eyes ; so that what carries 

 conviction to one may make no appeal to the other." 



It would be unreasonable to expect that every petrologist will 

 agree with my reading of the facts here recorded, but as a check 

 on error I submit my slices together with the rocks from which 

 they were cut. 



The sketch-map, which I append, will show the principal 

 localities in New South Wales where rocks, referred to in this 

 paper, have been collected. The presence of granite at Buccun- 

 guy, Lower Macquarie, is now recorded for the first time. Here 

 in the heart of the great Tertiary alluvial plains, two small knolls 

 of granite, with a flesh coloured orthoclase, are found. They are 

 evidently the summits of hills, of considerable size, being slowly 

 buried, as the great plains are forming. 



The nature of the rocks selected from Harden, Mt. Harris, Mt. 

 Forster, Mundoran, Rookesy, Mt. Coronga, Mt. Hope, Blayney, 

 Cobar, and at many other places referred to, has not been hitherto 

 studied. The rocks about Cobar are of special interest, as being 

 associated with extensive mineral deposits. The basalts from 

 Orange, Bathurst, Carcoar and Cargo, are notable as the result of 

 the immense lava streams that flowed down from the craters of 

 Mt. Canoblas. The occurrence of leucite rocks at Harden, in 

 addition to the known localities, El. Capitan and Byerock, will 

 prove interesting. 



The diabase of Blayney, and the diabasic porphyrites of Cowra 

 and Wellington, as well as the gabbros of Carcoar, will, I hope, 

 add some new matter to the too scanty literature of Australian 

 Petrography. 



Some More Notable Structures of the Rocks. 



Before describing the rocks in detail, I shall deal in a general 



way, with some features of micro-structure, as exhibited in rocks 



in my collection. Taking the acidic rocks first, I have traced a 



very large development of felsitic rocks over New South Wales. 



