J2§ ON THE TRANSITION GREENSTONE 



Still lower down the brook, to the north-east, I 

 niet with three stratified beds of a singular variety 

 of Greenstone, alternating with strata of grey- 

 wacke, and in all respects conformable. These 

 beds are from six or eight, to ten or twelve feet in 

 thickness, and are almost entirely composed of 

 compact felspar, with very little hornblende, 

 which is generally of a light greenish- grey colour, 

 and of a slender acicular form ; but sometimes the 

 colour is red ; and in this case it is very decom- 

 posable, and by falling out, leaves the stone vesi- 

 cular. One of these beds has been worked for 

 millstones ; but I should suppose it must be an 

 indifferent material for that purpose. It contains 

 iron-pyrites, — one of the characters which enables 

 us to discriminate between Sienite and Sienitic 

 Greenstone. 



Proceeding still down the water to the north- 

 east, and leaving behind us the usual Transition 

 rocks, we come to a thin bed of Sienitic Green- 

 stone, resting immediately upon the grey- wacke, 

 and covered by a bed of great thickness, of a dis- 

 tinct granular aggregate rock, composed of red- 

 dish-white or flesh- red felspar, greenish-black 

 hornblende, and brownish-black mica. This 

 bed is made up of strata from one to three feet in 

 thickness, corresponding in direction, dip, and in- 

 clination, with those of the grey-wacke, above 

 and below it. It alternates occasionally with the 

 &bove Sienitic Greenstone, and with thick beds of 



