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PACIFIC SCIENCE, Vol. XX, July 1966 
Fig. 19. Terrain-corrected magnetic profiles (above) HH-HH' and (below) GG-GG' along the island of 
Hawaii (see Fig. 13). 
eroded caldera of this shield. Over this shield 
there is a thin veneer of Honolua soda trachytes 
and mugearites. These were extruded in the 
late Pliocene (?) or early Pleistocene time. 
Generally, the flows on Maui, according to 
Stearns and Macdonald (1942), were fed by 
magma that rose through fairly straight, vertical, 
narrow fractures (Fig. 20). At depth, the dikes 
are massive and cross- jointed ; and, where they 
underlie rift zones, they form dike swarms 1- 
3 miles wide. Bosses and plugs on West Maui 
range from 100 to 3,000 ft in diameter. 
GEOLOGY AND GEOLOGIC STRUCTURE OF 
kahoolawe: Because it appears from the mag- 
