he place of an altered 



depoiul on the average composition of a large nuiiiher of specimens 

 and are types only. 



To prevent amlnguity T give definitions of the terminology used 



good figures' of these textures from ^'ew Zealand roeks, I have 

 given references to the plates in Mr. J. H. Teall's " IJritish 

 Petrography"; to those illustrating Professor Judd's paper "On 

 the tertiary Cabbros, Dolerites, 'and Basalts of Scotland and 

 Irolaiid," in tlie Qiiarcerlv Journal of the Geological Societv of 

 London, Vol. xuj., p. -t9 ; and to some of the woodcuts in'.AIr. 

 Rutley's -'Study of Rocks," and Dr. A. (iiekies "Text Book of 



(^'oiKi ro-j)i>r/)/n/riflr — <rranuh\r au^re^ates with independi 



orphou. 

 rystalline, 



