HAWAII.
Hawaii is the most important island of the archipelago, in all re spects, whether physiographic, volcanic or historic. It is the largest, with an area of 4,015 square miles, has its culminating point in Mauna Kea, 13,825 feet, and has been made by the coalescence of the volcanic discharges from five volcanoes, Ko hala, Mauna Kea, Mauna Loa, Hualalai and Kilauea. An in spection of the map, Plate 14, will at once illustrate the special development of these several areas. First is Kohala at the north 'end, with its enormous cliffs and deeply dissected canyons, indi cating a greater antiquity. It stands apart from the other centers with a smaller area, separated from, both Mauna Kea and Huala lai by comparatively low ground. Second, Mauna Kea is covered by cinder cones and is more like the volcanic piles of other coun tries than its typical Hawaiian neighbors. Its seaward border is precipitous but with much less elevation than its neighbor on the north, while on the south Kilauea lacks any considerable cliffs opposite the sea. From Mauna Loa it is separated by a col 6,600 feet high. The former greater extent seaward is obvious. Third, Mauna Loa barely reaches the sea, or not enough for the development of cliffs. The protrusion seaward is clearly ap parent upon inspecting the map. It lies between the two vol canoes Kilauea and Hualalai, both of which come to the sea level without cliffs, because there has not been time enough to develop them.
Hawaii affords the data for observing the differences between subaerial and marine erosion, as well as their combined action. The northeastern shore has felt the influence of the waves of the Pacific, urged along for thousands of miles by the trade wind. Probably the action of these sea-waves is nowhere exceeded in their efficiency, and there is a direct connection between the amount of the erosion or the size of the cliffs and the length of time during which the action of the water has been operative.
In Puna there are no cliffs of enough consequence to be de lineated upon the Government map, and the lava has flowed to the sea within a hundred years. The same is true about the village of Hilo : so that here the erosion has been of the least consequence. The slope seaward is about one hundred and twenty-five feet to the mile. Towards Kohala it is somewhat steeper and has been cut into ravines, nearly seventy in number, for forty miles, while the shores are vertical cliffs. Hence the road must cross all these ravines in zigzag courses, rendering traveling in Hamakua very exhausting. There are many sugar plantations along this coast, often times the streams fall over precipices not far below the road, so that it is dangerous to wade across the water where the cur rent is strong. If one loses his footing he will be carried down
over precipices sixty to seventy feet deep. Captain Dutton esti mates that the sea has encroached upon the east base of Mauna Kea as much as two or three miles. The cliffs and the country behind can be seen very perfectly as one sails along the coast. The gulch named Hakalau, opposite Mauna Kea, is said to be nearly 2,000 feet deep. The road passes along the seashore at the mouth of the valley.
After passing the coast of Hamakua, the cliffs increase in height within the Kohala district. They are 1,500 feet high for a distance of twelve miles, and the land recedes very perceptibly where the erosion has been the greatest. Streams of water can he seen from the passing steamer, pouring down these high cliffs. The canyons are very wide and the plains at their bottoms, a mile wide, are very fertile and constitute the favorite places for residences of the native Hawaiians. Three of these canyons are very well shown upon the map. Waipio is the most celebrated. Communication between these valleys is had only by means of canoes. The people living there are as much isolated as upon Molokai. So immense are these valleys that some have been led to ascribe their origin to volcanic disturbances. It is better to adopt the theory of erosion, and to believe that the land formerly extended some ten or twelve miles out to sea, and con sequently the original Kohala island must have had an antiquity as great as either West Oahu or West Maui. The curvature of the Waipio valley instead of representing a block of lava fallen down from the main mass is an illustration of the tendency to form amphitheaters by erosion. Doubtless there have been ex amples of the falling of segments by faulting, in order to account for the depth of the cliffs under water. This is the style of change common upon Hawaii, as seen in the long cliffs in the Kau desert south of Kilauea.
The greater age of Kohala is also indicated by the vegetation ; the forests there are more diversified than any others upon the whole island.
The earlier authors have usually agreed that the region of Ko hala was the oldest part of Hawaii. It is easy to go further and modify the usual statement of the growth of the archipelago from N.W. to S.E. by saying that in an ancient period Kauai, West Oahu, West Maui and Kohala constituted the group, all of about the same age. It is conceivable that several of the existing islands—like Maui, Molokai and Lanai—may be consolidated in the next geological period, and constitute an area comparable with that of Hawaii.