DETAILED DESCRIPTIONS OF ROCKS. 65 



large crystals of pink felspar, crosses it, apparently interbedded with 

 the less porphyritic rock ; and still further in the same direction a 

 band of diabase, vesicular in places, is badly exposed above the por- 

 phyritic rhyolite and is also apparently interbedded. A small patch 

 of granite is exposed at the base of the ridge close to this end on the 

 north side. The veins running into the rhyolites from this are very 

 coarse in texture, with crystals of hornblende up to three inches in 

 length. 



Along the northern side of the main range the patches of rhyolite 

 exposed on the spurs apparently form the remains of a dome arching 

 over the granite, the relics of what were once continuous sheets, rising 

 into jagged peaks easily distinguishable at a distance from the more 

 rounded contours of the granite. Occasionally, however, the rhyolites 

 are seen to strike directly towards the granite, and it appears as 

 though the latter had partly invaded and remelted the rhyolites, alsorb- 

 ing and replacing them, and had partly forced up the sheets of rhyolite 

 from beneath. Large masses of the rhyolite have been broken off and 

 included in the granite, and sometimes the edges of these masses have 

 been altered, the porphyritic crystals visible in the interior of the mass 

 haying disappeared. Veins of granite, sometimes fine and at other 

 times coarse grained, are nearly always to be found intrusive in the 

 rhyolites near the boundary (PL IV, fig. 4). 



In a ravine about half a mile to the south of Golia a band of brec- 

 cias and tuffs occurs in the rhyolites close to the granite boundary 

 and strikes directly towards it. Here the band is not altered where it 

 is in contact with the granite, but further to the east, at the head of a 

 broad valley due east of Golia, where a similar band of breccias and 

 tuffs, probably the same, is again exposed, the tuffs on approaching the 

 granite are altered into a porcellanous rock with a conchoidal fracture. 

 Some of the fragments in the breccia beds are water worn pebbles. 



Less than two miles to the south of the Saora range another large 

 mass of hills runs parallel to it, extending for about 14 n iles from east 

 to west and about 5 miles from north to south, and risigg to an altitude 



( 65 ) 



