Observations of a Naturalist in the Pacific Between 1896 and 1899, Volume 1

Chapter I: Preface

Text size

DURING a sojourn in the Pacific, which covered a period of rather over a year in Hawaii (1896-97), and of two years and three months in Fiji (1897-99), my attention was mainly confined to the study of plant-distribution and to the examination of the geological structure of Vanua Levu.

With Hillebrand’s “Flora of Hawaii” always in my hands I roamed over the large island of Hawaii, ascending the three principal mountains of Mauna Kea, Mauna Loa, and Hualalai, and in the case of my second ascent of Mauna Loa spending twenty-three days alone on its summit. Similarly in Fiji, Seemann’s “Flora Vitiensis” was my counsellor and guide in the matter of plants.

In Hawaii I was in a land of active sub-aerial volcanoes, and I paid my devotions at all the altars of “Pele,” their presiding deity. In Fiji I trod upon the surface of submarine volcanoes that emerged ages since from the ocean and still retain their coverings of sea-deposits. Both in Hawaii and Fiji I lived much among the people; and though my chief interest lay in the comparison of these two types of volcanic islands, I could not but be drawn to the kindly natives whose hospitality I so long enjoyed.

Destiny led me to Vanua Levu in the following fashion. With the relief party to take me down from Mauna Loa there arrived a well-known German naturalist who, like myself, had been interested in coral-reef investigations. We discussed this warm topic at an elevation of nearly 14,000 feet above the sea, with the thermometer at 20° F. As we sipped our hot coffee and listened to the occasional “boom” from the bottom of the great crater, at the edge of which we were camped, I remarked to my friend that I was thinking of spending some months in Samoa. To this he good-humouredly replied that I might leave Samoa to his countrymen and describe one of the large islands of Fiji. International rivalry over that group of islands was then rather keen. However, Dr. K. went to Samoa, and I have now completed this volume on the geology of Vanua Levu, Fiji.

It will not be necessary to lay stress here on the difficulties and hardships connected with the exploration of little known tropical regions. Many will be familiar with all that these imply, where the rainfall ranges from 100 to 250 inches, where the forests are dense, where tracks are few and swollen rivers are numerous, and where the torrent’s bed presents often the only road.

The only extensive geological collections made in Fiji previous to my visit were those of Kleinschmidt in 1876-78, which together with a small collection previously made by Dr. Gräffe were examined by Dr. A. Wichmann. These rocks were obtained from Viti Levu, Kandavu, Ovalau, etc., but not from Vanua Levu. Dr. Wichmann’s paper of 1882, descriptive of these collections, presents us with the results of one of the earliest studies by modern methods of research of the volcanic rocks of the Pacific Islands. It is to this investigator that we are indebted for the establishment of the occurrence of plutonic rocks, such as granites, gabbros, diorites, in Viti Levu.

Although, as far as I can ascertain, few, if any, rocks have been specially described from Vanua Levu, this island was visited by Dana in 1840 when attached to the United States Exploring Expedition under Wilkes. His observations on its geology were published in his volume on the geology of the expedition. Although not extensive they are valuable from their reference to his discovery of trachytic and rhyolitic rocks as well as acid pumice-tuffs in the island. It is singular that his observations have apparently been overlooked by all his successors. Wichmann with this discovery unknown to him remarked on the seeming absence of quartz-bearing recent eruptive rocks from the South Seas.

When the “Challenger” Expedition visited the group in 1875 some geological collections were made which were described by Prof. Renard in the second volume on the “Physics and Chemistry” of the expedition. No collections, however, were made in Vanua Levu. In 1878 Mr. John Horne, Director of the Botanic Gardens at Mauritius, made some important observations on the geological structure of this island and of other parts of the group, which he published in his account of the islands given in “A Year in Fiji.” No collections were obtained by him; but prominence is given to his observations by Dr. Wichmann and others. Like Dana in the case of the acid volcanic rocks, Mr. Horne has forestalled me in his conclusion that Vanua Levu amongst the other larger islands has been formed mainly of the products of submarine eruptions.

The visit of Prof. A. Agassiz to Fiji in 1897-98 gave a fresh impetus to its geological investigation. We are indebted to him not only for his own extensive memoir on the islands and coral reefs of this group, but also for the subsequent important explorations of Mr. E. C. Andrews and Mr. B. Sawyer in Viti Levu and the Lau Islands. These two gentlemen have since published a short paper on the caves of these islands. Mr. Eakle has described the volcanic rocks collected during the visit of Prof. Agassiz. It is, however, noteworthy that, although the collections were made in Viti Levu, Kandavu and in many other of the smaller islands, Vanua Levu is not represented. Mr. Eakle’s conclusion that basic andesites and basalts are the characteristic rocks of the region, the augite-andesites predominating, would apply to Vanua Levu in great part. This island possesses also in fair amount hypersthene-andesites and dacitic or felsitic andesites, which are very scantily represented in the collections examined by Mr. Eakle. In connection with the quartz-porphyries and trachytic rocks which also occur in Vanua Levu, it should be observed that Mr. Andrews describes a rhyolite from Suva in Viti Levu. Unlike Viti Levu, Vanua Levu displays but a small development of plutonic rocks.

In conclusion it should be pointed out that much remains to be done in the geological exploration of this island, and that I would have spent a third year in this task much to my profit. Still I hope that a period of two years devoted to its investigation will be regarded as some excuse for a certain over-confidence in the expression of my opinions.

To enumerate all those from whom I received much kindness in these islands would be a lengthy task. My indebtedness is very great to Bishop Vidal, Father Rougier, and to various other members of the Roman Catholic Mission, and I experienced similar favours at the hands of Mr. Williams and other Wesleyan Missionaries in Vanua Levu. Mr. F. Spence and Mrs. Spence showed me great kindness, and from Dr. Corney I received valuable assistance on my arrival in the group. To the planters my debt is equally great, more especially to Mr. Barratt, Mr. Dods, and Mr. Mills.

In conclusion I would suggest the foundation of a “Fijian Society” for the investigation of the islands, for the gathering together of all that has been written about the group and its people, and for the advancement of science.

HENRY BROUGHAM GUPPY.

_June, 1903._

_Note._—A type set of my geological collections representing the
massive rocks from this island has been kindly accepted by the
Curator of the Geological Museum, Jermyn Street.

LIST OF SOME OF THE PRINCIPAL AUTHORITIES QUOTED IN THIS BOOK

DANA, J. D., on the Geology of Fiji in vol. x, Geology, United States
Exploring Expedition Reports, Philadelphia, 1849.

KLEINSCHMIDT, T., “Reisen auf den Viti-Inseln,” Journal des Museum
Godeffroy, heft 14, Hamburg, 1879.

HORNE, J., “A Year in Fiji,” London, 1881.

WICHMANN, A., “Ein Beitrag zur Petrographie des Viti-Archipels,
Mineralogische und Petrographische, Mittheilungen,” band v, heft 1,
Wien, 1882.

RENARD, A., on andesites from Kandavu, “Report on the Petrology of
Oceanic Islands,” vol. ii of “Physics and Chemistry,” Challenger
Expedition, 1889.

AGASSIZ, A., “The Islands and Coral Reefs of Fiji,” Bulletin, Museum of
Comparative Zoology, Harvard College, vol. xxxiii, 1899, Cambridge,
Mass.

EAKLE, A. S., “Petrographical Notes on some rocks from the Fiji
Islands,” Proceedings, American Academy of Arts and Sciences, vol.
xxxiv, no. 21, May, 1899.

ANDREWS, E. C., Notes on the limestones and general geology of the Fiji
Islands, with special reference to the Lau Group. Based upon surveys
made for Alexander Agassiz. With a Preface by T. W. Edgeworth David.
Bulletin, Museum of Comparative Zoology, Harvard College; vol.
xxxviii, Cambridge, Mass. 1900.

CONTENTS

CHAPTER I

GENERAL INTRODUCTORY REMARKS ON SOME OF THE LEADING PHYSICAL
FEATURES OF THE ISLAND

Its remarkable shape, 1.—Its building up, 2.—Study of its profile,
3.—Mount Seatura.—Regions of acid andesites.—Basaltic
tablelands.—Great ridge-mountains, 5.—Boundary of the regions of basic
and acid rocks, 6.—Its primary features, the dacitic peak, the
basaltic plateau, and the ridge-mountain

_Pages_ 1-6

CHAPTER II

ON THE EVIDENCE OF EMERGENCE OR OF UPHEAVAL AT THE SEA-BORDERS

Elevated coral reefs scantily represented, 7.—Apparent absence of coral
reefs in the early stages of the emergence, 8.—Elevated reefs confined
to the coast and its vicinity.—Detailed examination of the
sea-borders, 9.—Silicified corals and siliceous concretions the only
evidence in many localities of the upraised reefs, 13.—The relations
of the mangrove-belt to the reef-flat, 14.—Indications of a very
gradual movement of emergence in our own time, 15.—The rate of advance
of the mangroves, 16.—Conclusions, 19

_Pages_ 7-20

CHAPTER III

THE HOT SPRINGS OF VANUA LEVU

The thermal springs of other parts of the group, 21.—The hot springs of
the Wainunu valley, 22.—The boiling springs of Savu-savu, 25.—Analyses
of the water, 28.—The hot springs of other localities,
31.—Distribution of the springs, 35.—The algæ and siliceous deposits,
37.—The cold and thermal springs of Hawaii and Etna, 38.—Infiltration,
the source of the springs, 39.—A view negatived by Prof. Suess.—List
of the hot springs of Vanua Levu, 40.—Summary of the chapter, 42

_Pages_ 21-42

CHAPTER IV

DESCRIPTION OF THE GEOLOGICAL AND GENERAL PHYSICAL FEATURES OF
VANUA LEVU

Naivaka, 43.—Korolevu Hill, 45.—Bomb formation of Navingiri,
46.—Remarkable section near Korolevu, 48.—Wailea Bay to Lekutu,
50.—Mount Koroma, 51.—Mount Sesaleka, 53.—The Mbua-Lekutu Divide,
55.—The Mbua and Ndama plains, 55.—The shell-bed of the Mbua river,
58.—Lekumbi Point, 60

_Pages_ 43-60

CHAPTER V