714 E. S. MOORE 



by the writer, the orthorhombic pyroxene in all cases being like 

 enstatite. 



From the description given it is evident that these rocks vary 

 from andesite to basalt and that they represent a much more basic 

 phase than any rocks previously erupted in the vicinity of Mount 

 Tarawera. The sequence is very similar to that in all the other 

 volcanoes in this petrographic province. 



GLACIATTON IN THE VOLCANIC ZONE 



There has been much discussion in New Zealand in recent years 

 regarding glaciation in North Island. Outside of the comparatively 

 small glaciers on Ruapehu the writer did not see any evidence of 

 glaciation. Around both Ngauruhoe and Ruapehu there were 

 many bowlders which had grooves very similar to those often made 

 by glaciers. It was surprising to find, however, that in practically 

 all cases these were not due to glaciation, but probably to the 

 action of one mass of rock falling on another when hurled from the 

 craters. This was proved by the fact that the groove would often 

 end abruptly against the wall in a re-entrant angle in such a way 

 that it could not have been produced by glacial action. 



