Applied to the rent at the base of the mountain, it may be said that the early developments of the force were along the edge of the pali. Ages ago the triangular tract of the South Cape witnessed an elevation after the formation of the fissure had given freedom of movement to the land. There was quite an oasis of rich pasture and sugar land raised so much as to lie above the reach of later lava flows. Hence when the blow was struck later in 1868 the rent was developed for three miles up the mountain, and the lava streams flowed about the oasis upon which the buildings were located. To what extent this fault can be traced up the mountain is unknown, though au thors speak assuredly of a rent from the end of the cape to the summit of Mauna Loa. It is interesting, however, to note that the later corresponding eruption of 1887 followed a parallel line of fault several miles farther west.
In the fissure where a little heat was discernible in 1887 there was seen much stalagmitic material containing many crystals of olivine. It must have been a sort of mud, and as elsewhere it and the green mineral came from below in the solid con dition. The basalt at Kahuku is unusually rich in this mineral. With this pasty mass there is much clinker and specimens of these materials were obtained very plentifully from this chasm. This rock assemblage is like that exuded on the border of Kilauea-iki at the same date, as is mentioned later. This may be an important fact in the discussion of the relations of the two great calderas : because this peculiar substance was dis charged in these two localities at the same date. It was not restricted, however, to this particular date.
Mr. Coan visited Kahuku and the country adjacent in Au gust, i868, and has described with great accuracy the features of this cataclysm, as well as the disastrous land slide and sea wave. He climbed to the upper end of the rent, and observed the orifices from whence jets had been thrown hundreds of feet into the air and left behind many ridges and ragged cones of every contour. With partial measurements he estimated the width of the principal flow at one and one-half miles. By unit ing all the branches with the main trunk the area discharged would be one and a half miles wide, ten miles long and fifteen feet deep. The course of the flow was due south, and its con tinuance four days. The amount of matter discharged is small compared with that of 1855.
Mr. Coan adopted the opinion of Judge David Hitchcock that the Kahuku flow came from Kilauea instead of Mauna Loa, at least in part. Coming from an authority second to none among the island observers, many of the residents accepted this deduction; and as the result much discussion ensued. Even upon the map of the islands published by the Government in 1876, under the direction of Professor W. D. Alexander, this
flow is said to be "from Kilauea," with an interrogation point.
Rev. E. P. Baker, the successor of Mr. Coan in pastoral duties at Hilo, has well summed up the main points upon both sides of this controversy in the Hawaiian Gazette for August 29, 1883. For the Kilauea derivation, three reasons may be given: (I) At the time of the i868 eruption the liquid fire all ran out of Kilauea. (2) The earthquakes as reported were more severe at Kahuku, where the lavas finally found vent, than in Kau, (3) The steam vents and fissures below Kilauea, the land slide at Kapapala and the Kahuku rent are on a direct line, supposed to mark the subterranean course of the lava.
Conceding the first two points, the other party explains them by saying that it was probably the terrible shaking of the ground that caused the lava in Kilauea to recede before the time of its normal discharge, and that the efforts of the moun tain to let loose the lava were met by a greater power of re sistance at Kau than at Kahuku. As to the third point, Kilauea and the steam vents, fissures and small discharges of lava at this time, are on a line different from that of the land slide and Kahuku, being more to the south. The land slide was an accident not connected with any flow of lava. Kilauea has its own field of operations entirely distinct from Mauna Loa.
Two other features are brought forward by the advocates of the derivation of the Kahuku discharges from Mauna Loa. (1) The initial point of the Kahuku flow is from two hundred to six hundred feet higher than the level of the lakes in Ki lauea. If hydrostatic pressure is concerned in the dis charges, this stream could not emerge from a point hundreds of feet higher than its sources. (2) There is ample evidence of the locality of the 1868 discharge from Kilauea, given upon the authority of Mr. Richardson of Kapapala. Several acres of lava came to the surface at the time of this discharge, located quite near the ejection of volcanic matter mentioned by Ellis in 1823, and other larger ones have been identified by E. D. Baldwin.
In addition to the data brought forward by Mr. Baker, sub sequent history substantiates his view. There have been two other Kahuku discharges, (in 1887 and 1907), preceded by earthquakes, attended by similar outpours and closely adjacent to the earlier flow, January to, 187o, D. H. Hitchcock, in company with Dr. Hans Beraz and Lord Charles Hervey, ascended to Mokuaweo weo by the way of Kapapala. Steam issued from the banks and floor. There were no indications of recent flows. They rode to the summit; the first time this feat had been accomplished.
June 22, 187o, L. Severance, J. D. Brown and S. L. Aus tin reported similar conditions at the summit.