82 



Prof. Liveing, On the metamorpliism 



[Oct. 29, 



of fine grains of quartz. Tliey have probably been, sandy or loamy 

 beds in the original deposit, and bear a close relation to the thicker 

 quartzite deposit which appears on the other side of the same hill. 

 Seen under a microscope the quartz grains in both deposits shew a 

 similar rather peculiar corroded form. The hornblende syenite and 

 the felsitic beds are both cut through by a large vein of granitic 

 character, nearly vertical, thinning out at top and thickening 

 down to the floor of the quarry, and perhaps further. It is seen 

 on both sides of the quarry, which is a large one. A great deal of it 

 has been removed, but where the quarrymen are now at work it is 

 left standing. It is 5 or 6 feet thick where it is exjjosed and seems 

 thickening as it descends. On the opposite side of the quarry it 

 is much hidden by rubbish, but it rises there to a greater height 

 and seems to divide into more than one vein. Mineralogically it 

 consists of quartz, felspar, and a little hornblende with a few 

 specks of mica. It is separated from the hornblende rock and 

 the felsitic beds by a very thin layer of a sort of soapstone which I 

 have no doubt is decomposed hornblende which has weathered into 

 the crack. Where it crosses the felsitic beds it is not in any way 

 incorporated with them, but for a short distance, a few inches, the 

 felsitic bed has acquired a granitic structure which gradually dies 

 away as the distance increases. The vein must be intrusive, and 







from the closeness with which it fits to the adjacent rock can only 

 have assumed its present position (not its crystalline texture) in a 

 state of fusion. It might be supposed that the granitic character 

 of the felsitic beds near it was due to fusion by the heat of the 



