OF THE HAWAIIAN ISLANDS. 447 



In addition to the severe rains of the tropics, water-spouts have from time to time 

 broken in the mountain valleys, and flooded the plains near the shore. Native traditions 

 are full of such catastrophes, and a number have, within the last half century, visited Maui, 

 Molokai, Oahu, and Kauai. 



Melting snows do not often produce a debacle, owing to the porous nature of the moun- 

 tain summits. Snow is common on Maunas Loa and Kea, not uncommon on Haleakala and 

 Waialeale, but does not extend down the sides below an altitude of eight or nine thousand 

 feet. 



The Place of the Hawaiian Volcanoes in Volcanic Systems. 



In endeavoring to ascertain the connection between the volcanoes of the Hawaiian 

 group and other Pacific ranges, most geologists have noticed the parallel linear arrange- 

 ment of the Pacific insular volcanoes which trend generally north-west and south-east, and 

 have inferred the existence of as many primary fissures in the earth's crust as there are 

 parallel groups of voleanic islands. 



The question arose in my mind whether volcanoes presented in themselves any indication 

 of mutual relation other than mere position on the same line. I did not endeavor to connect 

 the periods of activity or eruption, because I have seen so much independent and appar- 

 ently irregular action in the same vent, as in the lava pools of Kilauea, or in neighboring 

 vents, as Kilauea and Mauna Loa. It was in the shape and position of the craters them- 

 selves that I thought the desired clew might be found. 



Craters of eruption are almost invariably oval or elliptical in outline, and the usual ex- 

 planation of this shape is that the ejections which build up the crater reach the surface 

 through a rent in the earth's crust, and not through a circular aperture, or through one 

 formed by a stellate fissure, as would be the case were the superficial strata of the earth's 

 crust raised around an axis to form the so-called craters of elevation. While the fact of the 

 existence of many elliptical craters has long been known, no importance has been attached 

 to the direction of the major axis. As the elongated form is caused by a rent of greater 

 length than breadth it would perhaps be supposed that the major axis would coincide in 

 direction with the volcanic train, or in other words with the primary fissure in the earth's 

 crust over which the craters occur. 



The trend of the Hawaiian Group is N. 64° W., but there is no crater on the islands whose 

 major axis is parallel to this line. On the contrary a very interesting parallelism is observed 

 among all the craters, and invariably the longest diameter is north and south, or at an angle 

 of twenty-six degrees with the supposed primary fissure. Kilauea, Mauna Loa, Hualalai, 

 Haleakala, Leani, Puawaina, Aliapaakai, the ancient crater of Kauai, all have the same 

 direction, and so with all the craters on the other mountain ridges. Such a deviation from 

 the line on which these craters were supposed to have been formed must have some explana- 

 tion. Are there in any other volcanic regions like examples ? To answer this question we 

 must know the shape and direction of the craters, and this has been almost always neglected 

 in accounts of volcanoes. I give below, however, a list of such as I have been able to 

 determine the position of, from which it will be seen that the major axes are always at right 

 angles to the mountain chains in which they are situated. Another fact will be shown, that 

 the Mexican volcanic train of the nineteenth degree north latitude, commencing with 



54° with no greater daily variation than 19°. At Waime"a, age is 64", the lowest 48°. At Kolda, Kauai, 88" to 50°. At 

 Hawaii, at an elevation of four or five thousand feet, the aver- Waioli, Kauai, 90" to 55°. 



