Alexander's Survey of Moknaweoweo. i6i 



of two other cataracts, which had poured directl)' into the central crater. At the summit I found the 

 deep fissure from which these cataracts had been supplied with lava, and ascertained that it had also 

 poured au immense stream north upon the first plateau and thence into the central crater. Crossing 

 from this place to the north over the first plateau I suddenly came to a circular crater in the bed of 

 the plateau (a), apparently 600 feet deep and a thousand feet wide, with a cone in its centre still 

 smoking. The next daj- we took the transit to the stations in the crater, and the following surveyed 

 along the western brink to the extreme south end where we looked into the south crater (d), which 

 is about 800 feet deep and 2,500 feet wide. The length of the whole chasm I ascertained to be about 

 19,000 feet, the greatest breadth 9,000 feet, and the greatest depth 800 feet, and the area three and 

 six-tenths square miles. 



On the southwest side, near the junction of the central crater with the south plateau (c), 

 I found that there had been another eruption from fissures that were still smoking, and that this 

 eruption had sent an immense stream southward toward Kahuku, and had also poured cataracts into 

 the south crater from all sides. 



I had everywhere observed that there had been great flows from the summit brink down the 

 mountain, and questioned whether the chasm had filled up and overflowed its brim. This, however, 

 turned out to be an incorrect view. The flows have not been from the lowest parts of the brim, 

 but from some of the highest, which could not have been the case in an overflow. The walls of the 

 craters largely consist of loose, old weather-beaten rocks, and large tracts of the plateau are com- 

 posed of old pahoehoe, that has not been overflowed for ages, which would not be the case if the 

 craters had filled and overflowed. 



These outbreaks from fissures around the rim indicate that the lava has rather poured into 

 the crater than out of it : and that it has flowed from such fissures in vast streams down the mountain 

 side. The question arises, how has the lava risen high enough to pour in extensive eruptions through 

 these fissures, almost a thousand feet above the bottom of the crater, without rising in the crater and 

 overflowing it ? The same question has often been asked in respect to the rise of liquid lava to the 

 summit of Mauna Loa without overflowing the open crater of Kilauea, 10,000 feet below. 



While surveying the region, I was extremely interested in the arrangement of the craters; 

 and now, having determined the situation of more than fifty of them on Mauna L,oa, Hualalai and 

 Mauna Kea, I have ascertained that there is a method in their arrangement. They are not arranged 

 relatively tc the mountain on which they are situated, but relatively to the points of the compass. 

 There seems to have been a series of nearly parallel fissures through which these craters have risen 

 in lines running from S. 40° E. to S. 60° E. There are a few arranged in lines running N. 50° E. 



It has been remarked by Mr. W. T. Brigham, in his memoir of 1868 on the volcanoes of the 

 Hawaiian Islands, that while the general trend of the Hawaiian group and of the major axis of 

 each island is N.6o° W., there is no crater on the islands whose major axis is parallel to this line. 

 "On the contrary," he continues, "a very interesting parallelism is observed among all the craters, 

 and invariably the longest diameter is north and south." It would be more correct to say that the 

 major axes of the great craters are usually at right angles to the general axes of the group, i.e., 

 about N. 30° E. Haleakala and the ancient Kipahulu crater appear to take the other direction, but 

 the statement is certainly true of the great craters of Kilauea and Mokuaweoweo, which have other 

 points of resemblance. Thus in both the highest walls are on the western side, and in both the action 

 is working toward the southwest, as is indicated by the fact that the northeast craters are uearly 

 filled up, while the deepest and most active craters are in the southwest end of the depression. 



To retitrn to Kilatiea. There had been little change since 1S82; the islands 

 noticed soon after the formation of the New Lake, in 1S81, proved to be floating 

 islands (see Plate LXII). On the sixth of March both Halemaumau and its overflow, 



Memoirs B. p. B. Museum. V01-. II, No. 4.— II. 1539] 



