vol. jo.] lavas at the xorth head, otago haerouii. 395 

 the North Head, Otago Harbour. 



I 



'3 



33 

 | 



1 



1. 





4 4 



X 



D 



■z 



"■ L 



V 



eo 



n 



— iC 



^ 





1—1 — 



•Ti 



N 



01 eo 

 71 -1 



71 





57'22 



59-00 



50-88 



48-60 



43-37 



47-67 48-77 4995 



51-57 



47-37 4767 



5115 



57-60 



1-26 



0-41 



1-68 



223 



1-98 



2-16 1-85 



1-88 



1-49 



2 20 2-08 



042 



055 



15-23 



17-09 



16-75 



1790 



18-73 



17-53 1741 



16-42 18-30 



17-41 17-52 



20-80 2078 



4-32 



5-30 



6-67 



7-12 



6-01 



7-21 5-40 



5-46 



2-10 



324 7 45 



5-95 



4-00 



4-62 



325 



774 



8-00 



6-82 



7-89 7-31 



8-74 



7-04 



11-22 742 



5'5i 



350 



2-20 



021 



1-31 



227 



3-36 



3-45 3-23 



3-19 



2-43 



374 3-38 



1-95 



0-35 



5 '89 



1-46 752 



7-54 



8-48 



8*40 9-42 



7-60 



5-84 



10-80 9-43 



560 



1-98 



3 39 



5-39 2-60 



1-90 



2-50 



1-35 2-55 



2-55 



3-75 



1-26 0-77 



287 



4-67 



5-60 



7-47 



447 



4-14 



338 



3-94 354 



3-83 



7-11 



2-52 3-90 



•V22 



6-05 



0-27 



0-42 



0-35 



0'30 



0-37 



0-37 046 



038 



034 



0-24 038 



0-50 



0-52 



100 



100 



100 



100 



100 



LOO 100 



100 



100 



100 100 



100 



100 



water, as its amount, owing to hydration and serpentinization, was a 

 on ignition of diy powder of each rock is shown below. 



3-78 2-32 3-60 4"21 4*84 3"96 496 \ 4*00 4*40 4*43 620 2'72|2-60 



PI. LIV shows the proportions of the amounts of the various 

 oxides contained in the rocks to that of silica, reduced to per- 

 centages of the amount of silica. This mainly accentuates the 

 curves plotted in the previous diagram (PL L1TI). In both of 

 these the analyses have been recalculated to a total of 100, after 

 the amount of water had been subtracted from the sum. 



All the analyses were calculated according to the chemico- 

 mineralogical scheme of American authors. This classification, 

 however, does not appear to throw any fresh light on the relation- 

 ships of the various rocks. The basalts, in particular, are very near 

 the boundary between Class II and Class III. Nearly all the 

 basalts in the lower part of the series belong to the auvergnose sub- 

 rang, while those in the upper half for the most part belong to the 

 hessose. Xos. 13, 15, and 2-1 are andose, while the phonolites 

 1-1 and 2-5 are essexose. 



