264 Geology of 



Age axd Thickness. 

 This combination of strata, which is of great thickness, resembles in 

 many respects the rocks found in the kelson ProYince, which form 

 amongst other ranges, the Mount Arthur range. The latter has yielded 

 fossils of old palaeozoic, probably silurian, age. In some of the slates 

 from the "Waihao, traces of fossils are observable, but too faint for 

 recognition. In some sections where the strike and dip are constant, I 

 have travelled nearly ten miles without finding any change, from 

 which we might assume that this formation is at least 40,000 feet in 

 thickness. However, it is very possible that a reduplication of the 

 strata has taken place here and there, which has become effaced, or 

 was not observed by me, in which case the thickness of the formation 

 would be much less. 



Igxeoes Rocks. 

 In the longitudinal zone running parallel to the main axis of the 

 Southern Alps, first alluded to, I found no traces of igneous rocks, 

 but, in the southern portion of the province, in the ranges forming 

 the western banks of the Makaroa river, numerous dykes of igneous 

 rocks, generally of small dimensions only, have been injected into the 

 phyllites. Some of them are melaphyres, often amygdaloidal, which, 

 on the banks of the River Young, near its junction with the Makaroa, 

 can be observed in situ. On the eastern declivities of Castle Hill,, 

 near the head of the Makaroa, large blocks of phyllite crossed by 

 d\ kes of diorite and dioritic porphyry, were lying on the mountain side, 

 having doubtless been brought down from near the summit. In these 

 dykes, angular pieces of phyllite are enclosed. Similar rocks were 

 met with in the upper course of the Haast river, in nearly every 

 affluent coming from the west, so that there is no doubt that the 

 strata belonging to the formation under review have, in the eastern 

 portion of the folds, been broken through by igneous rocks for a long 

 distance. 



Mixeeal Teen's. 

 The interlaminarions of quartz forming regular layers in the- 

 micaceous schists and phyllites, as well as the smaller aggregations,, 

 or strings of quartz, occurring in great variety and under different 

 conditions, are to a certain degree auriferous, but they appear to be 

 so very poor that only under a combination of most favourable circum- 



