The districts between and among the hills are much cut up into lesser hills and ridges, the result of the very extensive denudation to which this region has been subjected. The greater part of this area is drained by the Tambu-lotu tributary of the Wainunu; but in the northern part we cross the watershed between the Wainunu and Ndreketi basins, and to reach Navuningumu we cross the valley of one of the tributaries of the Ndreketi. To the east of the Ndrandramea region extends a broken country, elevated rather more than 1,000 feet above the sea, and from it there rise one or two hills with bare cliff-faces, which are probably composed of similar acid andesites.
Although for the most part composed of these acid andesites, each hill, as far as my observations show, has as a rule its own type of the rock, differing from the others in specific weight, in the texture of the groundmass, and in the relative proportion of the porphyritic constituents. The petrological characters will be found more fully discussed in [Chapter XXI.]; and only some of the more distinctive features will be noticed here in the following description of the district.
The Ngaingai Group of Hills.—Within a space less than a mile square rise Ngaingai, Wawa Levu, and the other three hills above named, so closely clustered together that the collective name of “Hen and Chickens” might be aptly applied to the group.
The peculiar form of Ngaingai is shown in the accompanying profile-sketch. It is the Nangorongoro of the Admiralty chart. The height of the mountain from its base is 1,100 to 1,200 feet. Its ascent, which is not difficult, may be made from the west side. Above its wooded slopes rises its bare rocky peak, from which a magnificent panoramic view of the western half of Vanua Levu can be obtained. Characteristic dacites with porphyritic quartz came under my notice all the way up from the foot to the summit, being occasionally exposed in perpendicular cliff-faces. Specimens taken from the upper and lower portions are uniform in character, and have a specific gravity of 2·57. No other rocks were observed on its slopes. The whole hill-mass is in great part if not entirely formed of these acid andesites.
The contrast between the narrow crested peak of Ngaingai and the dome-shaped summit of Wawa Levu is seen in the sketch; and this is the more remarkable because it is not associated, as far as I could ascertain, with any important difference in geological character. Wawa Levu rises precipitously to a height of 900 or 1,000 feet above its base, and displays often perpendicular cliff-faces on its sides. Its broad level soil-covered summit is mostly covered with young wood, few of the trees having trunks more than 4 inches in diameter, whilst they are usually clothed with damp moss, and are often decayed and rotten.[[49]] True dacites, closely similar to those of the neighbouring Ngaingai and having a specific gravity of 2·61, were displayed often in slab-like blocks from the base to near the top. The rudely columnar structure to be observed in some of the other hills is rarely exhibited. No other rocks came under my notice. The remains of the stone walls of two old “war-towns,” one of them named “Ndaku-i-tonga,” occur on its south and south-east slopes.
Profiles of Ngaingai and Wawa Levu from Nambuna to the south-west. Both are dacitic mountains.
The other three hills of the Ngaingai group were not ascended by me. They show the same bare cliff-faces and have to all appearance the same geological character. Mbona Lailai and Vatu Kerimasi are two blunt-topped conical hills with precipitous slopes that rise respectively about 900 and 700 feet above the country at their base. Vatu Vanaya, about 500 feet in height, has a rounded summit.
The Ndrandramea Group of Hills.—A view of these hills from the westward is given in the accompanying illustration. They have a lower elevation than the hills of the Ngaingai group, none of them rising to over 1,800 feet above the sea, whilst their height from the base is also less, ranging between 400 and 900 feet. They rise, as the illustration shows, in the midst of a densely-wooded broken country.
Ndrandramea, which is 1,800 feet above the sea, has an individual height of about 900 feet. Fijians in distant parts of the island are familiar with the name of this remarkable peak. It has a legendary fame; and like Wawa Levu in the old time it served as a mountain stronghold in times of war. The remains of a stonewall of a “koro-ni-valu” or “town of war,” known as Mata-mei-ndami-ndami, occur on its side, 300 or 350 feet below its summit; whilst among the wild lemon trees that cover the slopes below large ovoid sling-stones 4 or 5 inches in length may still be found. Viewed from the south-east, as shown in the [frontispiece], Ndrandramea has the shape of a woman’s breast; and evidently the origin of its name is connected with this resemblance. But seen from the west and south-west, as in the other general view of the district (page [98]), it has a broadly truncated conical outline, its form being indeed somewhat elongated or elliptical.