132 F. W. HUTTON. 



(b) Without quartz. 

 Dunedin — A dark grey I'ock with large crystals of hornblende, 

 up to -80 X -14, and in places speckled with white. S.G. 2-82-1. 

 Section : Ground-mass small, microlitic, including small kaoliniscd 

 felspars, chlorite, numerous small graiiis of magTietite, and a little 

 htvmatite. The porphyritic mineials are felspar, hornblende 

 magnetite and apatite. The felspar is chieHy well t^vinned plagio- 

 clase in crystals up to -15 in length, but there is also a simple 

 felspar which may, perhaps, l)e sanidine. The hornblende is 

 idiomorphic, brown, and usually with a wreath of magnetite 



goes to •12'_in length usually altho. 



igh la, 



•ger c 



rvsbils occur. 



Magnetite is in large gi'ains and ci'j 



»-.tals. 



The 



apatite is the 









imperfect, but 



sometimes shewim' pyramidal termin 



ations 



(Plate 



: viii., fig. ■>), 



sometimes short but usually loTig.th<. h'n 



gtheigl 





'5 the breadth. 



The length is from •02.> to -OG.-) and the 



breadt 



h fron 



, -OOo to -008. 



^H.PV shew distant, but perfect, basal cle 



avage c 



racks, 



andarelongi- 



tudinallv striated by enclosures whic-h 



form b 



ands r 



adiating from 

 lese radiating 



th(> chief axis and unequally developed 



[. Eac 



h of tl 



band, is formed })y small black bacillai 



■ inclus 



ions, J 



>laced parallel 



and with their long axis at right am 



.des to 



the ch 



ipf axis of the 



<i \ -tal. Tlie prisms are colourless exct 



■pt where the 



inclosures are 



N'-i V numerous, here they are dark and 

 \Vt',rn the nicols are parallel and the .-i 



distim 



•tly di, 

 the cr3 



^^l^^M^J^^d 



at an angle of 45' with them the crysta 



'is'beco 





urplish-»n-()Wii 



colour. Apatite in the usual needle-shaped cryst; 



lis is also dis- 



tributed through the rock. There is ab 



,0 a litt 





ite. A white 



.secondary mineral fills cavities. 









Bank', Pfmia.^ula—A brownish-gre 



y roc=k 



with 



large white 



rectangular crystals of decomposing fell 



spar an 



d bUu- 



-;;;;;f;^ 



Section : ground-mass abundant, coar- 





croliti( 



felspar laths and plates from -01 to 



■o/in"l 



engt^h^ 



with a little 



brown glass and grain, of mnun^etite. 







zj::'f 



pliyritic mineral^ an- pla-io<daM.. augi 



t.^Jnu 



1 Imn, 



