372 



99-54 100-01 



A. Tinguaite. B. Camptonite. C. Microgabbro. 

 All analyses by H. Pisani, Lacroix (loc. cit.). 



99-97 



A. Phonolite. B, C, D, E. Hauynophyre. F, G. Basalt. H. Picrite. 

 I. Limburgite. 



A, B, C, D, F, G, H, analyses, H. Pisani, Lacroix (loc. cit.) ; E, analysis, 

 P. Marshall (Rep. Aust, Ass." Adv. Sci.. vol. 13, 1912, p. 197).; I, analysis, 

 P. Marshall. 



Daly has lately, as is well known, suggested that the alkaline igneous 

 rocks are due to the solution of masses of limestone in a magma of sub- 

 alkaline composition. There appears to be no evidence in support of this 

 theory so far as our knowledge of the alkaline rocks of the South Pacific- 

 islands allows us to form a judgment at the present time. Though volcanic 

 tuffs and breccias are of common occurrence in the Pacific islands, and 

 though they have been examined carefully in several places, no fragments 

 of limestone or sedimentary rock have yet been discovered in them, nor has 

 any material of this kind been found in the lava itself. It is true that Daly, 

 in his summary of the field associations of alkaline rocks in different parts 



