S. Poivers — Notes on Hawaiian Petrology. 273 



onlv four islands of the group, Kauai, Oahu, Molokai, and 

 Maui, but their presence is suspected on and near Niihau 

 and on Molokini, a small cone between East Maui and 

 Kahoolawe. With very few known exceptions they are 

 confined to local centers of eruption and all but six of 

 the local centers are tuff cones. In each instance of & 

 local center the eruption has been long after the main 

 volcano became quiescent. There is also a striking con- 

 nection between the tuff cones and the shore lines at the 

 time of eruption. All the cones were erupted near or 

 through shallow water. More striking yet is the fact 

 that nephelite has been found in rocks from all but two 

 of the tuff cones at sea level in the Hawaiian Islands 

 which have been examined petrographically. The two 

 exceptions are Koko Head and Koko Crater, but addi- 

 tional collections may show nephelite-bearing. basalt in 

 these cones. 



A list of occurrences of nephelite-bearing rocks in 

 local centers of eruption is given below. Most of the tuff 

 cones of which specimens were not available to Doctor 

 Cross are difficult of access and therefore few additions 

 to his identifications are possible. 



Kauai: Crater Hill (Kilauea Crater), tuff cone, melilite- 

 nephelite basalt. (Cross, Powers) 

 "West Oahu: Laeloa Craters (named by C. H. Hitchcock. 1900) 

 Puu Palailai, lava cone, nephelite basalt? (Powers) 

 Puu o Kopolei, lava cone, nephelite basanite. (Cross) 

 Puu Kapuai, scoria and lava cone, nephelite basalt. 



(Cross) 

 Puu Makakilo, scoria and lava cone, nephelite basalt. 



(Powers) 

 East Oahu: 



Diamond Head, tuff cone, nephelite basanite. (Cross) 



Punchbowl, tuff cone, nephelie basalt. (Cross) 



Salt Lake Craters (2) tuff cones, nephelite basalt. 



(Cross, Powers) 

 Mauumae Cone, tuff and scoria (northwest side), melilite- 



nephelite basalt. (Powers) 

 Rocky Hill, lava cone (Moilili Quarry and Honolulu black 



ash ) , melilite-nephelite basalt. ( Cross ) 

 Ulupau Crater, tuff cone, melilite-nephelite basalt. 



(Powers) 

 Puu Hawaii Loa, tuff cone, melilite-nephelite basalr. 



(Powers) 

 Koko Head, tuff cone, olivine basalt. (Powers) 

 Koko Crater, tuff cone, olivine basalt. (Powers) 



