494 C. H. HITCHCOCK MOHOKEA CALDERA 



chief discharge of lava was on the flank of Mauna Loa several miles 

 west of Mohokea, and there was another from Kilauea in the opposite 

 direction. 



Eruptions of Lava from the lower Levels 



The Mauna Loa flows may be classified by the altitudes at which the 

 discharges take place. First, those from the upper part of the dome, as 

 those of 1843, 1852, 1855, 1859, 1880, 1889, and 1899, starting from 

 9,000 to 11,000 feet above the sea. They are strongly characterized by 

 a hydrostatic connection with the central pit at Mokuaweoweo. The lava 

 comes from the extreme depth under the ocean to the caldera, and after 

 two or three days' stay at the summit it breaks out quietly on the side of 

 the mountain, and may flow to the sealevel in the course of several 

 months. The other class, as represented by the flows of 1868 and 1887, 

 shows first the same supply of lava at the summit, but breaks out low 

 down, 3,000 or 6,000 feet above the sea, with violent earthquakes, those 

 lowest down being the most frightful, and the lava issues tumultuously 

 through long fissures. I can now add quite a number to the list of those 

 that have issued from the lower level. They were prehistoric, so that it is 

 impossible to connect them with manifestations in Mokuaweoweo. 



In this class I will include several undefined aa eruptions east of Pa- 

 hala. The first poses on the government map as having been erupted in 

 1823, and is quite near Kilauea. As there represented, I think it is made 

 up of three eruptions. The first, prehistoric, 9,300 feet above the sea, 

 near Puu ula ula, well* shown on E. D. Baldwin's unpublished survey. 

 This probably was of the first class, originating high up. The second 

 part must have been of the kind originating low down, starting near the 

 line between the Mauna Loa and Kilauea areas, at an elevation of more 

 than 3,000 feet. A macadamized road now crosses it diagonally for as 

 much as 6 miles, and it is certainly of prehistoric age. It has moved 

 southwest with very little fall. The third part originated from Kilauea 

 in 1823, and is probably the only area that came to the surface at that 

 time. It was visited by Eeverend Mr Ellis in 1823 and is described in 

 his journal.* 



The second mention is that of one or more ancient flows between the 

 Halfway House and Pahala. Some of them cover the yellow ash beds, 

 others are much older, or at least they had their day before the deposit 



* I have been unable to discover from whence the compilers of the map could have 

 derived the theory of the connection between the upper eruption of Mauna Loa and 

 that from Kilauea in 1823. None of the Survey officers, past or present, can state 

 whence the information was obtained. 



