The Nawavi Range.
With this remarkable coast range, which fronts the Mathuata sea-border for a distance of 12 or 13 miles between Ravi-ravi Point and Nanduri, I have unfortunately but scant acquaintance. It attains its maximum elevation in Mount Nawavi of 2,238 feet, and is described by Mr. J. P. Thomson,[[60]] who surveyed this coast, as broken in two nearly opposite Niurua, the pyramidal mountain of Koro Navuta rising in the gap. Various other peaks, besides that of Nawavi, are marked in the latest Admiralty chart; they vary in height from 1,000 to 1,700 feet. As this range lies only a mile or less back from the beach, it gives to the sea-border a bold and often precipitous appearance, which is well shown in an illustration in Wilkes’ Narrative of the United States Exploring Expedition (iii. 226).
Basic rocks probably prevail in this range. When I ascended its eastern spurs from Nanduri, and reached a height of 800 feet, only basic tuffs and agglomerates came under my notice. From Dana’s remarks[[61]] it is to be inferred that the “frowning bluffs” opposite Mathuata Island are of similar formation; and it would seem that the rugged black stones, described in the Admiralty Sailing Directions[[62]] as topping the hills behind Ravi-ravi Point, are of the same basic character. From its contour and profile I would gather that, as in the great mountainous ridges that constitute the backbone of the island between Va Lili and Mount Thurston, palagonitic tuffs and clays of submarine origin will, together with volcanic agglomerates, be found far up the slopes of this range, and that the axis will prove to be largely composed of massive basic rocks.
The hot springs referred to by Thomson and others as occurring at the foot of the north and south slopes, namely at Vatuloaloa, Nambuonu, and in another unnamed inland locality, are briefly mentioned on page [31].
The Sealevu Divide.—This broad range which separates the Ndreketi and Lambasa basins is an offshoot from the central mountains at Sealevu and reaches the coast just east of Nanduri. Its highest part according to the elevation given in the Admiralty chart is 1,437 feet. The road from Sealevu to Nanduri, which crosses its broad level summit for a distance of about three miles, does not rise over 1,100 feet. Between 800 and 1,100 feet are exposed calcareous tuffs and clays all largely made up of palagonitic materials. The coarser might be described as sandstones. The clays have 12 per cent. of lime and are foraminiferous and are of the type described on page [321]. The rocks displayed on the lower northern slopes on the way to Nanduri are at first the same submarine deposits, and afterwards decomposing basaltic andesites. It is apparent that in the central elevated part of this range there are hills of volcanic formation more or less completely buried beneath these deposits.