120 E. 0. Teale: 



show a similar range and variety. One example has very minute* 

 pericline twinning, and may be anorthoclase. 



Iron oxides are a little more plentiful; some occur as very minute 

 grains abundantly scattered through the roek. Corroded xenoliths 

 of both fine grained igneous and altered sedimentary rocks are- 

 moderately numerous. There is an occasional flake of muscovite, 

 and little chlorite but no calcit^ was observed. 



No. 93 may be portion of an agglomerate. It contains numerous- 

 Xenoliths, apparently all of igneous origin. One is an altered ande- 

 site, the others are red, fine grained felsitic rocks, stained witb 

 hematite, and showing small, partly kaolinlsed felspar phenocrysta. 

 The rest of the rock is generally similar to the previous examples. 

 Some of the quarts is rounded, but only slightly embayed. 



No. 91 is a specimen from the Dominioni copper mine, now aban- 

 doned. It is similar in grain, but lighter in colour than the other 

 examples described, but on exposure suffers a superficial red dis- 

 colouration, which appears to be due to the presence of some car- 

 bonate of iron. Otherwise the minerals present are similar. A 

 little copper pyrites is present in the dump, but as the shaft is full 

 of water, nothing could be seen as to the occurrence of the copper. 



Qiiarfz-Ceratophyre . — No. 68. — This rock, is of medium grain, 

 porphyritic, but inclined to be granular in hand specimens, and' 

 has a general grey colour. The analysis show a silica percentage of 

 72.41, very similar to that of the acid rocks generally of this dis- 

 trict, but in the alkalies there is a marked difference in that soda is 

 6.86 and potash only 0.13. 



It is very closely comparable with certain rocks, described from 

 Navigation Creek, Noyang, by Howitt (32), under the names of 

 quartz-mica-porphyrite and quartz-porphyrite. 



Reference to the table with analysis will show the close resem- 

 Iblance. 



Professor Skeats, in reviewing the volcanic rocks of Victoria (28, 

 p. 187),^ quotes Howitt's analyses and gives some additional re- 

 marks on these rocks, describing tliem as quartz-ceratophyres. Re- 

 ferring to one example, lie says, " This rock shows a microcrystal- 

 line granular ground mass of quartz and felspar, with minute 

 microliths of chlorite, replacing probably amphibole. The por- 

 phyritic constituents are as follows : — 



Oligoclasc; of an acid variety, showing both albite and carlsbad" 

 twinning. Quartz in corroded and fractured crystals and chlorite 

 pseudomorphs after magnesia-iron-mica.'' 



