152 PROCEED] NGS OF THE ROYAL SOCIETY OF QUEENSLxVND. 



The values of the alkalies of these New England rocks 

 have, then, been linked up to form curves independent oJ 

 the main ''Pink Phase" — "Stanthorpe" curve. 



Three analyses are shown in which the K^O and Na^O 

 values do not readily fall on either curve. These are the 

 "'Acid" granites from Tingha, New South "Wales (N.2), 

 the "Sandy'' granite of Stanthorpe (S.l), and the; 

 Enoggera Hybrid. It may be argued that any attempt to 

 lit this "Sandy" granite into the variation diagrams was 

 unwarranted in the first place, as it represents a later phase 

 than the "Acid" granite. However, these two acid phases 

 are very closely associated in the field, and the position of 

 the New England "Euritic" granite (N.4) on the diagram 

 partly justifies the assumption of their close relationship. 

 However, if both the Sandy and Euritic granite be ignored 

 there remains one rock (N.2) in a somewhat anomalous 

 position. 



In Figure 2 the values of CaO and MgO have been 

 plotted in the same manner as the alkalies in Figure 1. 

 In this case the same sets of curves have been drawn, but 

 the natural grouping along three different sets is not nearly 

 so well displayed. Indeed, one might draw one set of 

 generalised curves to which all the values plotted might be 

 referred. 



In both figures it will be noted that the values for the 

 Enoggera (?) Hybrid do not fall on either curve. Any 

 attempt to include them with the Pink Phase or the Grey 

 Phase will serioiislv derange either curve. 



