204 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.W., 



planes of the laniinse are found to arrange themselves in rudely- 

 parallel planes perpendicular to the lines of pressure. Whatever 

 may be the explanation, we have here at Bathurst a foliated or 

 schistose structure developed in sedimentary rocks when in contact 

 with an intrusive granite. When a fragment of these ancient 

 sediments is found above, and resting on, the granite, the foliated 

 structure lies horizontally, and when found adjoining the granite 

 mass, the folia stand vertically. A diagram showing the intrusive 

 veins at Locksley will be found on PI. xv. fig. 1. The sketches 

 were made some eight years ago, when the face of the cutting was 

 fresh. I examined the same section a few months ago, and 

 although the rocks have disintegrated a little and vegetation is 

 beginning to take hold there, the intrusive veins can be easily 

 studied. 



With the evidence of these sections before us, we are now in a 

 position to enquire into the origin of the granite. Everything 

 that we know points to the one conclusion, that the Bathurst 

 granite is intrusive. The granite alters rocks with which it comes 

 in contact. It sends tongues, veins and dykes into the adjoining 

 rocks. Nowhere can we trace a gradual change from a sediment 

 to a rock granitic in structure. The proximity of granite has 

 converted phyllites into hornfels. It has caused a rearrangement 

 of old minerals in the sedimentary strata, and caused the 

 development of one new mineral in abundance, namely, mica. 

 But this is all. Nothing approaching a granite can be found 

 resulting from any metamorphic process, and in no one section 

 have I ever discovered anything like a change from a clastic to a 

 holo-crystalline rock, granitic in composition. 



When I first examined the rocks around Bathurst the prevailing 

 impression left on my mind was that the granite melted away by 

 insensible gradations into the surrounding rocks. A more minute 

 examination rendered this position untenable; but it will be 

 interesting if we can yet discover a granite truly metamorphic in 

 origin. There can be no difficulty, as far as chemical composition 

 of some slates goes, in believing that the constituents of a slate 



