towards Morass Creek, masses of quartz-porphyry are again 

 seen, tlie argillaceous rocks at contact assuming a jaspery 

 silicified appearance. The gradual passage from the unaltered 

 Silurian sediments into mica schist, gneiss and granite, plainly 

 to be seen on the outer margin of the metamorphic area at 

 Omeo, is in striking contrast to the sharp well-defined line of 

 demarcation between the intrusive porphyries and the argil- 

 laceous sediments they invade. The metamorphic schists 

 occupy the bed of Morass Creek, and are overlain by a con- 

 siderable depth of alluvium, where crossed by the line of 

 section: Ascending the thickly-wooded slopes of Mount 

 Brothers the schists give place to a ternary granite similar in 

 texture to that occupying the valley of the Marengo Creek, 

 but towards the crest of the mountain, the latter is replaced 

 by a distinct porphyritic granite, made up of large prismatic 

 crystals of w^hitish felspar scattered through a base of smaller 

 feispathic crystals, with quartz and black mica. The huge 

 blocks which occupy the crest of the mountain stand out in 

 rounded masses, exfoliating in concentric layers. Descending 

 to the south, towards Omeo Plains, the metamorphic schists, 

 which underlie this lacustrine area, appear to pass downward 

 into a metamorphic granite ; while to the east, at Mount 

 Sisters, about three miles distant, are bluffy outcrops of an 

 intrusive granite, which further to the east passes into a 

 quartz-porphyry. 



The Omeo Plains consist of about 16,000 acres of splendid 

 agricultural land ; fine open plains, with the Omeo Lake in 

 their centre. Some idea of the fertility of these sub-alpine 

 tablelands may be gleaned when it is stated that in 1882 fifty 

 to sixty bushels of wheat to the acre was not an uncommon yield. 

 On the southern margin of these plains, towards Omeo, are 

 open, well-grassed ridges, showing outcrops of mica and argil- 

 laceo-mica schists ; further to the south, at Smoking Grully Hill, 

 are bands of nodular argillaceous schist, intersected by brownish 

 quartz porphyry dykes and seams of igneous, probably dia- 

 basic, rock. At lower levels, these argil laceo-miea schists pass 

 into hard crystalline rocks, gneissose and quartzitic schist very 

 much ramified by numerous igneous and intrusive dykes ; these 

 are well seen in the bed of AYilson's Creek, an afiluent of 

 Livingstone Creek. Ascending the rounded eminence to the 

 south, known as Day's Hill, a mass of intrusive granite is seen 

 to have been lain bare at the crest of the hill. The schistose 

 rpcks at contact are very much altered, assuming the character 

 of hornfels. The rough sketch represented by plate 11. will 

 serve to illustrate the peculiar features of this intrusive mass, 

 and also indicate the position of the alluvial gold workings in 

 the bed of an ancient lake or tarn, which extended, in Tertiary 



