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HARVARD UNIVERSITY

Library of the

Museum of

Comparative Zoology

BULLETIN

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE, IN CAMBRIDGE.

VOL. XXXIII.

CAMBRIDGE, MASS., U. S. A.
1899.

UxivERSiTY Press :
John Wilsox and Son, Cambridge, U.S.A.

\

Bulletin of the Museum of Comparative Zoology
AT HARVARD COLLEGE.

Vol. XXXIII.

THE ISLANDS AND CORAL REEFS OF FIJI.

By Alexasder Agassiz.

With One Hundred and Twenty Plates.

CAMBRIDGE, MASS., U.S.A.:

PRINTED FOR THE MUSEUM.

May, 1899.

TABLE OF CONTENTS.

PAGE

ixtkoduction 3

Some Points in the Liteeatcre on Coral Reefs 5

Track of the "Yaealla." Plate I 13

The Pelagic Fauna of Fiji 14

Classification of the Islands of Fiji 17

Volcanic Islands 18

Koro. Plates 3% 19% Fig. 8 18

Mbatiki. Plate 12 19

Moala. Plates 16, 57 19

Ngau. Plate 11% Fig. 1-3; Plates 12, 13 21

Mambulitlia Keef. Plate 12 21

Nairai. Plate 11% Fig. 4 ; Plates 12, 14, 58, 59 22

Wakaya. Plates 3% 11% Figs. 7, 8; Plates 15, 55, 56 23

Makougai. Plate 11% Fig. 9 ; Plate 15 23

Mbengha. Plates 8, 11% Fig. 5 ; Plates 46-49 24

Kaudavu. Plates 10, 11, 50 28

Great Astrolabe Reef. Plates 11, 11% Figs. 10-13 ; Plates 51, 52 .... 30

North Astrolabe Reef. Plates 11, 11% Fig. 14; Plates 53, 54 31

Budd Reef. Plates 4, 18, 70 33

Komo. Plate 19% Figs. 9-11 ; Plates 22, 6.3-65 35

Olorua. Plate 22 36

Totoya. Plates 16, 19% Figs. 4-7 ; Plates 23, 66-69 37

Taviuni. Plates 4, 18, 60 41

Islands composed of Elevated Coralliferofs Limestone. Plate 2 . 43

Ngele Levu. Plates 17, 17% Figs. 5-12 ; Plates 95-99 43

Nukii Mbasanga. Plates 18, 22% Fig. 18 ; Plate 108 43

Nukusemauu. Plates 18, 103-107 43

AVailangilala. Plates 18, 109, 110 45

Tuvutha. Plates 20, 88, 89 51

Naiau. Plates 20, 22% Fig. 1 52

Vatu Vara. Plate 19 53

Yathata and Kaimbo. Plate 19 54

Aiwa. Plates 21, 22% Figs. 13-15 54

Oneata. Plates 21, 22% Fi^s. 10-12 56

Namuka. Plate 22 57

Yaugasa. Plates 22, 22% Figs. 8, 9 ; Plates 90-93 57

Ongea. Plates 22, 22% Figs. 6, 7 ; Plate 94 ■ 60

Fulanga. Plates 22, 22% Figs. 4, 5 ; Plates 80-84 62

VOL. XXXIII. 1

2 BULLETIN: MUSEUM OF COMPAKATIVE ZOOLOGY.

PAGE

Marambo. Plate 22 65

Wangava. Plate 22 66

Vatu Leile. Plates 9, 17% Figs. 1-4 ; Plates 100-102 66

The Sounds of Fiji 68

The Tertiary Elevated Limestones of Fiji , . . . 71

Islands partly Volcanic, partly composed of Elevated Limestones 88

Kimbombo. Plates 19, 61 88

Exploring Isles : Vanua Mbalavu. Plates 19, 19% Figs. 1-3; Plates 72-77 88

Mango. Plates 19, 22*, Fig. 3 ; Plates 85-87 93

Lakemba. Plate 19 95

Thithia. Plate 20 96

Naitamba. Plate 19 97

Mothe. Plate 22 97

Kambara. Plates 22, 22% Fig. 2 ; I'lates 78, 79 98

Thikombia i ra. Plate 17 99

Sundry Atolls 99

Pitman Reef. Plate 18 99

Motua Levu and Motua lai lai. Plates 18, 112 99

Williamson Reef. Plate 19 100

Bell Reef. Plate 19 100

Adolphus Reef. Plate 18 100

Tova Reef. Plate 23% Fig. 5 101

Thakau Memo. Plates 12, 14, 23% Fig. 6 101

Thakau Lekaleka. Plates 21, 111 , 102

Lagoons of Atolls 103

Extinct Craters and Atolls 109

ViTi Levu Reefs. Plates 1-3, 5-7, 20% Figs. 9-12 ; Plates 24-27, 31-45 . 110

Plateau off Nandi and Yasawa 117

Suva Reef Flats. Plates 5, 28-30, 65, 76 118

Islands and Coral Reefs described from the Charts 121

Viti Levu and Vanua Levu. Plates 3, 3*, 4, 23* 126

Mbukata tauoa, or Argo Reefs. Plates 20, 20% Figs. 5-8 ; Plate 21 ... 124

Thikombia. Plate 17 125

Onoilau. Plate 17«, Figs. 13-16 ; Plate 23% Figs. 1-4 .126

General Sketch of the Fiji Islands and Coral Reefs. Plate 1. . . 131

List of Figures in the Text 153

Explanation of the Plates 135

The Fiji Islands and Coral Beefs. By Alexandek Agassiz.

INTRODUCTION.

On our arrival in Suva tiie first day of November, 1897, we found the
" Yaralla," a twin screw steamer of about five hundred tons, chartered
from the Australasian United Steam Navigation Company, awaiting us.
The boat proved admirably suited for our purpose, the managing agent
of the company at Brisbane, Mr. Elliot Bland, and Captain Downs, of
Sydney, having spai'ed no pains in fitting her out.

Previous to our departure I shipped to Australia our outfit for
dredging, sounding, and deep-sea towing, as well as all the materials
necessary for preserving our collections. This equipment we found
safely stored in the " Yaralla." Dr. W. McM. Woodworth and Dr. A. G.
Mayer accompanied me as assistants. Dr. Woodworth and my son
Maximilian have taken a large number of photographs illustrating the
physiognomy of the islands and reefs. Dr. Woodworth devoted his
time in part to the care of the Worms, and Dr. Mayer to the Acalephs
of Fiji.

I have to thank the State Department at Washington for their kind
offices in obtaining for me letters from the British Foreign Office to
the Government of Fiji. Sir George O'Brien, the High Commissioner
of the Western Pacific, gave us all possible facilities for visiting the
different islands of the group. I am also indebted to the Hon. J.
Stewart, Colonial Secretary, and to the Hon. W. L. Allardyce, Assistant
Native Commissioner, for assistance and advice. To Dr. Corney and
the Hon. John Berry I owe information of value regarding the existence
of elevated reefs at points I have not examined. To Captain Calder, the
agent of the Australasian United Steam Navigation Company at Fiji, I
am greatly indebted for his exertions on our belialf. Finally, Captain
R. Cocks, our pilot, and Captain Thomson, as well as the officers and
crew of the " Yaralla," were indefatigable in promoting our inter-
ests. I have also to thank specially Sir William C. Van Home and
Mr. T. G. Shaughnessy, the President and Vice President of the Cana-
dian Pacific Railway, for placing at our disposal a j^rivate car from

4 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Montreal to Yancoiiver_, and for despatching to Fiji a number of cases
■which could not be shipped via Australia. I am also under great obli-
gations to Admiral Sir W. J. L. "Wharton, R. N., and to Captain W. U.
Moore, R. X., for their unceasing interest and advice while planning my
trip to Fiji.

Thanks to the admirable charts of Fiji, which owe their origin to the
surveys of the United States Exploring Expedition under Wilkes, and
their elaboration in great detail by the subsequent British surveys of
Captain Denham and Lieutenants Moore and Richards, it was possible
to cover a great deal of ground by picking out from the charts the inter-
esting and critical points for examination, and thus to make a very rapid
yet fairly accurate survey of the coral reefs. The accuracy of the Ad-
miralty Charts enabled us to enter safely into the lagoons, and to select
our anchorages with confidence. The reproduction here of the Fiji
charts, together with photographs of the most characteristic views, will
better serve to give a faithful picture of the islands and reefs of Fiji
than lengthy descriptions, and 1 hope in the discussion of the general
questions to be able to illustrate my arguments either by references to
the charts or to the photographs of a group of islands of which Dana
says, " The facts from the Feejee Archipelago illustrate the subject
well."^ The larger scale charts of the Admiralty, such as those of
Kandavu (A. C. 167), of the south and east coasts of Viti Levu (A. C.
167, 845, 905), of Vatu i ra Channel (A. C. 379), of ]\Iakongai and
Wakaya (A. C. 1250), of Suva (A. C. 1757), of Levuka Harbor (A. C.
1244), of Ovalau (A. C. 1249), of such islands as Nairai (A. C. 741), of
Moala (A. C. 1252), of Ngau (A. C. 1251), and of Totoya (A. C. 1248),
contain an inexhaustible fund of information regarding coral reefs, and
would serve as an invaluable basis for a minute zoological and geological
survey of any island group such as I attempted for the Tortugas.^

1 Dana, Corals and Coral Islands, p. 262.

2 Mem. Am. Acad., Vol. XI. p. 107 (1883).

Cambridge, September 1, 1898.

Note. — Owing to my absence from Cambridge and to the delay in
preparing the Plates for this volume its publication has been delayed
( until May, 1899.

AGASSIZ : FIJI ISLANDS AND CORAL REEFS.

SOME POINTS IN" THE LITERATURE ON CORAL REEFS.

It will prevent considerable confusion if, before proceeding with the
account of our expedition to Fiji, I should devote a few pages to the
examination of some of the literature on coral reefs, in the liglit of
the observations we made while at Fiji.

On looking over the literature on coral reefs, one cannot fail to be
struck with the amount of irrelevant matter which has been passed
down from writer to writer. Statements made on hearsay have gradu-
ally become facts. The observations of inexperienced persons receive
general recognition. Special cases are discussed without reference to
their limited or exceptional application. The whole question is often
threshed out de novo, so that it is difficult to separate the new from the
old. And, finally, information gathered from charts is substituted for
observation in dealing with questions which the latter alone can settle.
Every new investigator naturally adds important information from the
field he surveys, and each has in his way described the numerous and
varying conditions affecting the growth and existence of coral reefs in
the tropical waters of the Atlantic and the Pacific. Eecent explorations
Lave only increased the number of questions to be solved regarding
coral reefs ; and until the whole field has been examined in the light of
these questions, it is hopeless to attempt a general revision of the
theories regarding the formation of coral reefs. A revision based upon
a partial examination, though it be more extensive than that of our
predecessors, is usually brushed aside with the statement that even if
the exception described is true, the old theory may yet be true in some
other atoll region. Of course, such criticism can never end, and we may
go on searching forever for this imaginary atoll, or until the last remain-
ing atoll has been hunted down.

In many quarters it has become a question of creed to uphold the
Darwinian theory of subsidence as essential to the formation of atolls
and of barrier reefs. Facts and arguments supporting other explana-
tions ai'B ignored or explained away in the most extraordinary manner.
Regions which are cited by Darwin and Dana as tjrpical become excep-
tions when shown to be no longer characteristic regions of subsidence.
Typical barrier reefs become patch reefs, atolls are dubbed pseudo
atolls ; so that the regions where true barrier reefs or typical atolls,
which owe their origin to subsidence, can be examined, are little by little
becoming very restricted. In fact, if we are to judge of the regions not
yet examined, and which have not been examined by Darwin and Dana,

6 BULL?]TIN: MUSEUM OF COMPARATIVE ZOOLOGY.

there remain as extensive regions of possible subsidence only such isl-
ands as the Marshall and Carolines, some of the atolls of the Gilbert and
Ellice groups, and of the Paumotus. Yet, judging by analogy of the ad-
joining districts of Fiji and Tongn, and of the descriptions given by Dana
of the Paumotus, and by what we may gather from the charts in the
light of our own exploration, it would not be launching a very doubtful
proposition to assert that even in these island groups we shall find that
the explanations we have given of the formation of atolls and of harrier
reefs applies equally well to them. This still leaves the field open for
observations in some of the coral regions of the Indian Ocean, and of
the East Indian Archipelago. But in the districts which have been
described as typical by both Darwin and Dana, recent observations have
shown that other and more natural explanations than the theory of
subsidence are sufficient to account for the formation of atolls and of
barrier reefs.

As is well known, Darwin's experience among coral reefs was limited
to a part of Tahiti, to the west side of Mauritius, and to the Keeling
Atoll. Though he passed through the Paumotus without examining
any of the islands ; ^ according to the narrative of the " Beagle," Darwin
saw in the distance Honden Island, passed by Taiaro along the shore of
Kauehi and sailed between Elizabeth Island and Fakarava (Wittgen-
stein) to Otaheite. Captain Fitzroy also sailed through the Navigator,
Friendly, and Fiji Islands Avithout anchoring anywhere. Dana^ worked
among the reefs at Tahiti, Samoa, aud the Feejees, though he did not
visit the Eastern Archipelago, limiting his observations to the larger
islands, Viti and Vanua Levu and Ovalau. He " twice visited the
Hawaian Islands, landed and gathered facts from fifteen coral islands,
some of them in the Paumotu Archipelago ; ^ one, Tongatabvi, in the

1 Narrative of the Surveying Voyages of his Majesty's Ships Adventure and
Beagle (1826-18.36), Vol. III. p. 539. London, 1839.

- In " Nature" (September 17, 1874, p. 408), Dana reviews a new edition of
Darwin's Coral Reefs suggesting that he had not given sufficient weight to the
effects of temperature in limiting the distribution of coral reefs, and differing widely
from Darwin as to the limits of the area of elevation and of subsidence in the
Pacific. But in spite of minor differences he speaks of the "array of facts of his
own (Darwin's) observations, which illustrate the growth of coral formation " ; and
subsequently, in 1885, when reviewing the whole subject again, Dana says in the
American Journal of Science, Vol. XXX., August-September, 1885. p. 90: "The
evidence which had satisfied him (Darwin) was satisfactory to me when I first
learned of his views in Australia (in 18.39), . . . and more decidedly later when I
had been among the Friendly, Feejee, and other Pacific Islands."

3 Honden, Dean, Aratica, Ahii, Raraka, Manhii, Kawehe, ]\Ietia, Clermont
Tonnerre, and others examined by other members of the Exploring Expedition.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 7

Friendly group ; two, Taputeaua aud Apia, in the Gilbert group, and
five others near the equator, east of the Gilbert group : Swain's, Fakaofii,
Oatafu, Hull and Enderburv Island, as well as the reef region of the
Sooloo Sea and of the Straits of Malacca."

In my account of the coral reefs of the Sandwich Islands,^ I have
given a short resume of the results of the principal investigations on
coral reefs since the days of Darwin and Dana down to 1889. What
has been done since that time will be found referred to in Bonney's
edition of Darwin's Coral Reefs,"-^ in Kent's " Great Barrier lieef," in
Langenbeck's sketches ^ of recent work on the subject, as well as in the
reports of the explorations I have carried on in the Bahamas and Cuba,*
the "West Indies," Florida,® and the Bermudas'' in the Atlantic, and of
the expeditions I have made to the Galapagos,^ the Great Barrier Eeef
of Australia,^ and Fiji.^"

1 Bull. Mus. Comp. Zool., Vol. XVII. p. 121 (1889).

2 Professor Bonney (Coral Reefs, Darwin, 188D, -Sd ed., Appendix II. p. 290),
has evidently confounded the views of Professor L. Agassiz on the extent of
the formation of the southern extremity of Florida by coral reefs, dating back
to 1854, with those which I have published in 1877, in 1880, in 18S8, and again
in 1896. Neither Dall nor Heilprin has examined tlie Florida reefs ; their
studies have been devoted to other parts of the peninsula, and did not extend
south of the northern limit of tlie Everglades. Their criticisms in both cases
apply to the views of Professor L. Agassiz, as my observations were limited
to the reef region, and did not encroach on the area examined by Dall or Heilprin.
But I have plainly shown by the borings at Key West that the recent coral forma-
tion is of moderate thickness, not more than about fifty feet, and that it is underlaid
by a substratum of tertiary limestones, occasionally coralliferous, of a thickness of
nearly two thousand feet. The area probably covered b\' the coral reef of Florida
at the time of its greatest expansion is approximately shown on Plate XVII., Bull.
Mus. Comp. Zool., Vol. XXVIII. No. 2, 1896. I never made the statement quoted
by Bonney that the recent coral reefs extended over any part of Florida north of the
Everglades. On the contrary, I said in the conclusion of my memoir on the
Tortugas and Florida Reefs (Mem. Am. Acad., Vol. XI. p. 116, 1883), "'All this
evidence tends to show that the coral reefs had little, if anything, to do with the
building up of the peninsula of Florida, north of Cape Florida."

3 R. Langenbeck, Die neueren Forschungen iiber die Korallenriffe, Hettner,
Geog. Zeits., Bd. IIL, 1897, pp. 514, -566, 634.

* Bull. Mus. Comp. Zool., Vol. XXVI. No. 1, 1894.

5 Three Cruises of the Blake, 1888, Vol. I. p. 66.

6 Bull..Mus. Comp. Zoul., Vol. XXVIIL No. 2, 1896.
'Ibid., Vol. XXVI. No. 2, 1895.

8 Ibid., Vol. XXIII. No. 1, 1892.

9 Ibid., Vol. XXVIIL No. 4. 1898.

1" Am. Journ. of Science, February, 1898, Vol. V. p. 113.

8 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY.

An excellent account of the Samoan Reefs has been published by Dr.
Kramer/ supplementing the earlier short notice of Dr. Graeff- on the
reefs of the group ; also interesting notes by Admiral Wharton,^ on Sub-
mai-ine Banks of the Pacific. A careful account of the geology of the
Friendly Islands by Lister/ published in 1891, seems to have escaped
the attention of writers on coral reefs. A few notes on the reefs of some
of the islands of the Bismarck Archipelago have been published by Dr.
Dahl/ but the evidence he gives does not seem to me to warrant his
conclusions. The great thickness of elevated reef he found (570 m.)
may (as is the case elsewhere in the Pacific) not belong to the present
epoch, as he takes it for granted, and no one supposes that elevation has
necessarily always taken place uniformly either in time or space over
any great stretch of territory.

The articles by Heilprin ® and by Ortman ' ou what they call " Patch
Eeefs," do not seem to me to have any special bearing on the general
theory of coral reefs. The existence of such " patches " has long been
known and refei'red to by Darwin, and by many writers on coral reefs,
as reef patches. These patches occur in localities where fringing reefs for
local causes would not flourish except at a little distance from shore and
play a very subordinate pai't in the physiognomy of the coast. I am at a
loss to understand the statements of Ortman regarding the reefs of
Kaneohe Bay on the north shore of Oahu. The accurate observations of
Hartt s and of Eathbun on the moderate thickness of coral reefs off the
coast of Brazil seem to have escaped Heilprin and Ortman, as well as other
writers on coral reefs. Rathbun ® has described the reefs along the
Brazilian shore, and finds them all as "having very little height, but
from the surface looking like massive structures." Hartt ■^'* and Eathbun
have described the formation of extensive coral patches and the mode of

1 Ueber den Bau d. Korallenriffe, Kiel, 1897.

2 Samoa, Journal d. Museum Godeffroy, Vol. I.

3 Foundations of Coral Atolls, Nature, Februar\' 25, 1897, p. 390.

* On the Geology of the Tonga Islands, Quart. Jour. Geol. Soc. London, No. 188,
1891, p. 890.

5 Zool. Jalirbiicher, Bd. XI. p. 141.

6 Proc. Acad. N. S. Phila., 1890, p. 313.
^ Zool. Jahrb., Bd. VL p. 632.

8 Hartt, in Chapter IV. p. 174, of the Geo!, and Phys. Geog. of Brazil, 1870,
describes the islands and coral reefs of the Abrolhos and the Recife de Lixo,
where exist the " chapeiroes,'" as rising straight up from the bottom from a depth of
forty to fifty feet.

9 American Naturalist, Vol. XIII., June and September, 1879, Nos. 6 and 9.
1° Geology and Physical Geography of Brazil, Boston, 1870.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 9

building up columnar masses which may eventually reach the surface
forming mushroom- or even bell-shaped structures, of which enlarging
rims may meet, " resulting in the formation of a connected reef surface
supported by many upright pillars underneath from forty to fifty feet
high," the so called " chapeiroes" of the Portuguese. These patches fre-
quently occur near the shore along the margin of a fringing reef, but are
hest developed in the deeper water of the Abrolhos regions and between
these and the city of Bahia, growing upon the submerged rocky ledge.
The number of reef building corals in Brazil is quite small, and Xulli-
pores seem according to Rathbun to play a very important part in the
building up of the limestone reefs.

Professor Bonney ^ summarizes the position of the theory of coral reefs
as now left (1889) in the following terms : " That this theory may have
been expressed in terms a little too comprehensive, that there may be a
larger number of exceptional cases than was at first supposed, is quite
possible. ... It may very possibly be found that, as remarked by
!Mr. Bourne, the history of coral reefs is more varied and complicated
than was at first supposed, but it seems to me that, as the evidence at
present stands, it is insufiicient to justify a decision adverse to Mr. Dar-
win's theory as a general explanation."

Professor Bouney, in spite of his intention to present an absolutely
unbiassed expression, has, in common with most geologists not familiar
with coral reefs, retained the view of the correctness of Darwin's theory.^
It can scarcely be said that the earlier examinations of coral reefs were
made with the detail which has characterized the later explorations.
The original work of Darwin was limited to a narrow field, and sup-
plemented by data derived from charts and descriptions. Its con'ect-
ness depends wholly upon the existence of masses of coral reefs of great
thickness, where coral reefs exist as barrier reefs or atolls, and having
■assumed this the rest naturally followed. For no one will deny that sub-
sidence is one of the possible modes of formation of masses of limestone
of great thickness. But subsequent observers showed most distinctly
that both atolls and barrier reefs occurred in regions of elevation. These
exceptions are not limited to a single area. They occur in regions of
the globe widely separated. "While it undoubtedly is true, as remarked

1 Loc. cit., p. 332.

2 Dana's support of Darwin's theory, based as it was upon very great ex-
perience among coral reefs, has probably been the principal cause of the gen-
eral acceptance of tlie theory in late years, in spite of the attacks of recent

investigators.

10 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

by Professor Bonney,^ that Darwin has noticed most of the causes on
"which stress is laid by his critics, it should also be remembered that
Darwin did not observe the phenomena subsequently examined, but
merely suggested them as possibilities, and his critics may be excused
for giving their observations a relatively greater value than to his
theoretical views.

The whole argument of the great thickness of coral reefs based upon
the analogy of the so called raised reefs of Cuba, described by Prof.
Crosby and myself, or of the fossil reefs, is of little value, as it has been
pretty conclusively shown that these elevated reefs, not only in Cuba
but in the Pacific, are beds of tertiai-y limestone intercalated with beds
of moderate thickness in which corals are found, and the same is true of
older fossil reefs. Furthermore, these huge masses of tertiary limestone
which form the substratum upon which both in Cuba and in the Pacific
recent corals have found a footing, have played no part in the shaping
of the bari'ier or encircling reefs, or atolls, which, as we have attempted
to show, owe their origin in the main to mechanical causes.

Professor Bonney states that " Much stress is laid upon the fact that
many coral islands afford evidences of a certain amount of upheaval ; this
amount, in most cases, is but slight, and its significance appears to me to
have been exaggerated" ; and he considers these indications to prove only
oscillation. As far as the Fijis are concerned, the elevation extended
over the whole group, and has been shown to amount to more than
a thousand feet. In Australia it extended along the whole east coast of
Queensland for more than a thousand miles, and was more than twenty-
five hundred feet in height ! He further says, " If the coral reef be only
a sort of cap concealing a hill of pre-existent rock, we may reasonably
be surprised that the ' ashlar rock ' of coral limestone has in no case
so far yielded to the action of the atmospheric agencies as to lay bare its
inner support." VTe can answer this point most decidedly. In Florida
the substratum underlying the recent coral reefs crops out at many
places, and the highest points of some of the Keys consist of it. So do
some of the hummocks in the southern part of the Everglades near Key
Biscayne. In the Bermudas the greater part of the land of that group
consists of the seolian rocks which underlie the recent coral reef. In
the Bahamas the same is the case, and along the northern coast of Cuba
the tertiary limestone formmg the substratum of the recent reefs crops
out in all directions, while in Australia rocks underlying the Great Barrier

1 Loc. cit., p. 324.

AGASSIZ : FIJI ISLANDS AND COEAL REEFS. 11

Reef can be traced as islands, islets, or negro-heads all along its line
for more than a thousand miles. Finally, in the description of the
islands of Fiji this substratum appears over and over again, either
composed of volcanic rocks, or of great tertiary limestone banks. No
better example can be found of the appearance of the substi-atum of
the recent reefs than in Kaneohe Bay, Oahu, at the Sandwich Islands,
where the reef is studded with islets and negro-heads consisting of
volcanic rocks.

That corals grow in lagoons is well ascertained, and nowhere is it
better seen than in Fiji, where nearly all the islands enclosed by barrier
reefs are edged with fringing coral reefs. But why that should prevent
a lagoon from being formed I cannot see. A lagoon is not bounded
by a reef forming a closed wall rising well above the level of the sea.
The greater part of the i-eef of many a lagoon of an atoll or barrier reef
has from two to three fathoms of water upon it at high tide. The reef is
also riddled on all sides with narrow channels or openings with from one
to two fathoms or more at low tide, in addition to the wider and deeper
passages to leeward, through which access is gained into the lagoon.
But for all this the lagoon exists, while it may not have more than a
few fathoms in maximum depth. This, however, does not prevent the
coral heads on the inner slope of the reef from gradually becoming con-
nected witli the reef, and from encroaching little by little, but very
slowly, upon the outer margin of the lagoon to a depth of seven or eight
fathoms, at which the growth is checked either from the sediment accu-
mulating on the floor, or from the strength of the currents scouring the
bottom of the lagoon. The amount of dead coral which is ground up
upon a reef flat is considerable. Much of it is cemented together and
forms a breccia in the cavities of the coral heads, or in the open spaces
between them. Still more of it is changed into sand and mud, which
cover the floor of the lagoons of barrier reefs and of atolls, and finally
a quantity is carried off in solution after the dead coral has become
thoroughly rotten and crumbling.

Darwin also visited the western side of Mauritius, where, he says : ^ "It
is probable that a reef on a shelving shore, like that of Mauritius, would
at first grow up not attached to the actual beach, but at some little
distance from it; and the corals on the outer margin would be the
most vigorous. A shallow channel would thus be formed within the
reef; and this channel could be filled up only very slowly with sediment,

1 Darwin's Coral Reefs, 3d ed., 1889, p. 72.

12 bulletin: museum of comparative zoology.

for the breakers cannot cut on the shores of the island/ and they do not
often tear up and cast inside fragments from the outer edge of the reef,
while every streamlet carries away its mud through breaches iu the
reef. ... A fringing reef, if elevated in a perfect condition above the
level of the sea, would present the singular appearance of a broad dry
moat bounded by a low wall or mound."

Darwhi, when meeting Semper's objection that the existence of atolls
or barrier reefs in a region of elevation was a fatal argument against
his (Darwin's) views, is obliged to say that therein ''seems to me no
improbability in their having originally subsided, then having been up-
raised . . . and again having subsided." ^ He further says, " The exist-
ence of atolls and of barrier reefs in close proximity is manifestly not
opposed to my views." Certainly not, but their existence in an area of
elevation as claimed by Semper is. Darwin also says that, ""When the
land is prolonged beneath the sea in an extremely steep slope, reefs
formed there during subsidence will remain closely attached to the
shore, and will be undistinguishable from fringing reefs." ^ This seems
to me impossible. The disintegration of the inner edge of the fringing
reef, the action of the sea upon this disintegrated material, the solvent
action of sea water, all will tend to form a channel between the outer
parts of the reef and the shore, as is evidently tlie case in almost all
fringing reefs, which show either an incipient cliannel where boats may
circulate at high water, or a belt of considerable width in which the coi'al
fringing the land has been killed by the silt brought down from the ad-
jacent slopes, and has been decomposed, and, crumbling to sand or mud,
is gradually being carried off at each high tide, forming a channel which
when wide enough and deep enough becomes sufficiently prominent to
change the fringing r^ef into a barrier reef.

The difficulties encountered in attempting to meet the many sugges-
tions made by Darwin regarding reefs which he did not examine are
well exemplified in the account which he gives of Rose Island, one of
the Samoa group.*

1 This would depend upon the widtli and slope of the fringing reef. Many of
the narrow fringing reefs in Fiji have a uniform slope towards the lagoon, and do
not present the structure described by Darwin.

2 Darwin's Coral Reefs, 3d ed., p. 228.

3 Ibid., p. 229.

* Ibid., p. 212 : " The lagoon is very shallow, and is strewn with numerous large
boulders of volcanic rock." (Negro-heads, A. Ag.) He further says : " This island,
therefore, probably consists of a bank of rock, a few feet submerged, with the
outer margin fringed with reefs. Hence it cannot be properly classed with atolls,

AGASSIZ: FIJI ISLANDS AND CORAL REEFS., 13

Bonney ^ similarly takes Dana's account of the easteini half of the
Fiji Archipelago, as if it were based upon actual observations. Dana
did not visit that part of Fiji, but derived his information from the sur-
veys of these islands made by the officers of the United States Exploring
Expedition. Plis statements are derived from the charts.

TRACK OF THE " YARALLA."

The track which we followed (Plate 1) was so arranged as to include
for our first trip one or two of each type of island, and of the different
types of atolls and barrier and fringing reefs in the group. Starting from
Suva the day after our arrival, we visited Mbengha, returned to Suva, and
went in the following order to Ovalau, Wakaya, Makongai, and Koro,
skirted along the western shores of Taviuni, examined the northeastern
coast of the same island, passed out through the Matangi Passage to
Motua Levu and Motua lai lai, and skirted along the western extremity
of the Nanuku reefs. From there we steamed to Wailangilala, where
we landed our boring apparatus and the crew of whites and of natives
needed for working the same. We then turned north, passing close to
Nuku Mbasanga and Adolphus Reef, and entered Ngele Levu Lagoon.
We next examined the Ringgold Islands, paying special attention to
Thombia in Budd Reef. From there we returned to a former anchorage
off Thurston Point on Taviuni, and followed much the same track back
to W^ailangilala, where w-e found our boring party settled and at work.
We then steamed south, examining Williamson Reef, the Kimbombo
islets. Bell Reef, and entered the Vanua Mbalavu Lagoon through the
Ngillangillah Passage. Passing out of the lagoon by the Tonga Pass,
we touched at Mango, Tuvutha, Naiau, and Lakemba. We steamed past
Aiwa, entered the Oneata Lagoon, visited Thakau Lekaleka, touched at
Mothe, entered the Komo Lagoon, the Yangasa Cluster, and the Ongea
Lagoon. We passed by Fulanga close to the entrance, which was too

in which, as we have reason to believe, the foundations always lie at a greater
depth [The Italics are mine. — A. Ag.] than that at which the reef constructing
polyps can live." Yet Dana and Wharton, as weU as Kramer, say that it is an
atoll, and the charts show it to be an atoll fully as much as any similar island
in Fiji. So that if the islands in Fiji which resemble it, and which according to
Dana and my own observations are atolls, yet according to Darwin they would
not be so regarded, we shall have to seek for an atoU answering his requirements
outside of the Fiji group.
1 Loc. cit., p. 310.

14 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY.

shallow to allow our vessel to enter, but near enough to get an excellent
idea of its characteristic structure. We next touched at Kambara, an-
chored in the crater of Totoya, made for Moala, and thence for Solo
Lighthouse, examined the North Astrolabe Eeef, steamed through the
Great Astrolabe Reef, coming out west of Ouo, examined a part of the
northern shore of Kandavu, and then made for Vatu Leile, retumiug to
Suva. On our second trip we visited Xgau, Xairai, the Horseshoe lieef,
Mbatiki, and, entering the Moturiki Channel south of Ovalau, examined
the inner side of the barrier reef as far as Mbau, and explored the bar-
rier reef from Moturiki to Suva.. During our third trip we steamed
along the southei'n coast of Viti Levu, going as far west as Nandronga.
Skirting the reef as closely as was prudent, we were able to follow the
changes of the great barrier reef of Viti Levu west of Suva as it grad-
ually passes into a fringing reef and disappears off the Siugatoka River,
to reappear again, first as a fringing reef, next as a ban-ier reef extending
beyond the Nandi waters to the west of Xaudronga. We then paid
a second visit to Vatu Leile, which we had not been able to examine
properly owing to bad weather, and returned to Suva, having steamed
a little over thirteen hundred miles.^

AVhile we wei'e exploring the reefs in the vicinity of Suva, the
" Yaralla " made tw^o trips in charge of Captain Thomson, one to the
Nandi waters entering through the Xavula Passage, extending as far
north as the Waia Islands to the south of the Yasawa group ; the other
passing close to Vatu Vara, Yathata, and Xaitamba, on the way to Wai-
Sangilala in order to bring back the crew left there to caiTy on the boring.

THE PELAGIC FAUNA OF FIJI.

I brought with me deep-sea tow-nets of the various patterns used by
the Prince of ]\Ionaco, by Dr. Giesbrecht of the Xaples Zoological
Station, and by Hensen on the " National " Expedition, in order to com-
pare their efficiency with the Tanner deep-sea self-closing net in use on
the "Albatross," and which I have adopted on my various expeditions.
Unfortunately, our time in Fiji was so limited and the conditions for
towing at great depths are such, among so many intercepting islands,
that the results likely to be obtained seemed to make it unadvisable to

^ The Islands and Coral Reefs of the Fiji Group, by Alexander Agassiz, Am.
Journ. Sci., Vol. V., February, 1898.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 15

devote the time necessary for such a comparison. So nothino- was done
to test the comparative efficiency of the various deep-sea self-olosin^^
towing nets. When practicable we collected on the reef flats of various
islands and atolls.

A number of hauls were made with the deep-sea Tanner net at
several points in Fiji, such as the Strait of Somo Somo, off the Matangi
Passage, off the west face of iN'ukusemaiiu Eeef, off Blackswan Point, off
the north point of Yatu Leile, across the eastern opening of Mbengha
Passage, and off Suva Harbor. The depth at which we towed varied
between one hundred and seventy-five fathoms and thirty fathoms to
the surface. At the localities where each deep haul was made, a surface
haul was also made. AVe were rather disappointed in the character of
our catch. There were no great novelties; tlie number of Medusse was
usually quite small, but we obtained a large nuuiber of Crustacea.

The contents of the nets varied bxit little at the different localities.
"We obtained young Fishes, Fish eggs and Salpte, Dolioliura, Alcyopidae,
Copepods, Squillte, embi-yos of Macrurans and Brachiuraus, Sapphirina,
Sergestes, Euphausia, several species of pelagic Macrurans, and Ehegma-
todes, Halopsis, Agalma, the bell of a large Siphonophore unknown to
me, Tamoya, many Diphyes, Ectopleura, Oceania, Berenice, Liriope,
Polygordius, Tomopteris, Octopus, Mollusk embryos, Hyalea, x\tlanta,
Styliola, Tiedemannia, and other Pteropods. In fact, the pelagic fauna
seemed singularly like that of the Straits of Florida, but far less
abundant.

Mr. Mayer made also a number of surface hauls, and collected many
species of Acalephs which had escaped the large tow-net, two species
of a Rhizostome, a Eucharis, an Aurelia, and an Idya. The Sagittae
we collected were unusually large ; Collozoon was quite abundant, and
occasionally we collected Globigerinse of a reddish tint, and other
Foraminifera.

During our cruise we constantly passed long windrows of Algae torn
from the reefs, extended patches of a yellow Trichodesmiuni, and masses
of leaves and flowers, and branches of all kinds of trees, floating at the
mercv of the winds and currents.

It is interesting to note that the surface hauls made during our
trip have developed the fact that the majority of the genera of Acalephs
collected in Fiji belong to the same genera as those found on the east
side of the Isthmus of Panama. Tlie great geographical range in the
Pacific of many of the genera of Echinoderms and of Crustacea as well
as of Fishes found in the West Indies has already been noted. The col-

16 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY.

lections of Acalephs made by the "Albatross" in 1891,^ and those we
have made in Fiji, show a remarkable similarity between the West In-
dian Acalephian genera and those of this part of the Pacific. We found
in. Fiji Linerges, Polyclonia, Aurelia, Halopsis, Tiaropsis, Gonioneraus,
Liriope, Bougainvillia, Eutima, Oceania, Aglaura, Eucharis, Idj^a, Agalma,
two genera of Diphyes and Physalia, all genera occurring in the Gulf of
Mexico. This will be brought out in greater detail by Mr. Mayer, who
has in prepai'ation a paper on the Acalephs of our Southern States,
which will appear somewhat later than his report on the Acalephs col-
lected at Fiji. This similarity will undoubtedly be found to extend to
other groups of pelagic animals.

We were fortuuate enough to be at Levuka at the time of the appear-
ance of the " Bololo." On the morning of the 17th of November we
left the ship at three o'clock, bound for a spit named Bololo Point,
about three miles south of Levuka. We had scarcely reached the spot
when our guide put his hand in the water and pulled out one of tlie
worms. In a few minutes the water was full of them, canoes put out from
the shore, men, women, and children were wading on the I'eef exposed
by the tide, with nets, and all kinds of utensils to catch Bololo. As the
light increased, the Bololo increased, and at one time they were so plen-
tiful that the water surrounding our boat must have been filled with them
so thickly as to resemble vermicelli soup. A bucket put overboard
seemed to contain nothing else. We made an excellent collection, and
preserved a large number by different methods. We found, as we had
expected, that their sudden appearance was connected with spawning;
thei'e were males and females swimming about full of eggs and of sperm.
When in captivity they soon discharged these, the water became milky,
and masses of dai'k e2;gs were left on the bottom of the dish. AYith the
escape of the eggs came the collapse of the worm, and nothing was left
but an empty skin scai'cely visible. Thus the Bololo seems suddenly to
disappear. The males are light yellowish brown, the females dark green.
Their activity is something wonderful, and the bursting of the animal
when it discharges its eggs is quite a peculiar phenomenon.

Dr. Woodworth made it an object to collect all the material that
could be got together in regard to the Bololo, and he will prepare a
paper on these interesting Annelids.

^ Reports on the Dredging Operations off the Coast of Central America, Mexico,
off the Galapagos, and in the Gulf of California, in Charge of Alexander Agassiz,
by the U. S. Fish Commission Steamer "Albatross," in 1891, in command of Lieut.
Com. Z. L. Tanner, U. S. N. — XXI. Die Acalephen, von Otto Maas, Mem. Mus.
Comp. Zool., Vol. XXIII. Xo. 1, 1897.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 17

CLASSIFICATION OF THE ISLANDS OF FIJI.

It will greatly facilitate understainling the relations of the islands
and coral reefs of Fiji, if we follow in their description a classification
which will bring together islands and reefs of identical or similar geo-
logical structure.

We may take at first such volcanic islands as Koro, Ngau, and pass
to the larger islands like Taviuni and Kandavu, finishing that class of
islands with descriptions of Mbengha, Komo, and the like. We will
take up next islands and reefs composed wholly of elevated coralliferous
limestones like Marambo, passing to such islands as Xamuka, Ongea,
Falanga, and to such reefs as Wailangilala and Ngele Levu. Next the
island groups in which we find both volcanic and coralliferous limestones,
such as Lakemba, Mothe, Vanua Mbalavu, Kimbombo, and the like,
the two large islands of Viti Levu and Vanua Levu being ti-eated sepa-
rately. This will be followed by an account of the islands and reefs we
did not examine, and finally by a sketch of the atolls, the geological
struct\ire of which could not be determined, and which might owe
their origin to banks of submarine erosion, derived either from volcanic
or fi'om elevated coralliferous limestone islands.

Undoubtedly the islands of Fiji, whether of volcanic origin or of
limestone, would vavy greatly in the height to which they had been
elevated. Naturally, the volcanic islands would be denuded and eroded
to a less extent than the limestone islands, and the comparison of the
islands in Lau might give us some idea of the extent of this erosion
and denudation. The volcanic islands, consisting mainly of breccia,
are of course far more rapiidly eroded than if they consisted of compact
volcanic rocks.

Of course some of the islands which have been named here as vol-
canic or as composed of tertiary limestones may prove on more extended
examination to be composite islands, and in the rapid visit made to some
of the islands we may not always have discerned their most character-
istic features. Yet in a general way steaming between the islands, one
cannot fail to be struck with the totally different aspect of the volcanic
islands and of the islands composed of elevated limestone. A mere
glance is sufficient to distinguish the rounded and gradual volcanic slopes
(Plates 46, 51, 57, 58) from the flat-topped summits and precipitous
cliffs characterizing the limestone islands (Plates 75, 76, 79, 86, 88, 90).

Gardiner has, as we have, classified the islands of Fiji into elevated
limestone islands, into elevated limestone and partly volcanic, and into

VOL XXXIII. 2

18 bulletin: museum of comparative zoology.

volcanic,^ a division which Lister had previously applied to the Tonga
group. Gardiner was, as we were, struck with the difference in the
physiognomy of the islands, the volcanic islands, with their gentle slopes,
rounded summits, or conical peaks, being in striking contrast to the flat-
topped hills with precipitous sides, and the glistening white cliffs of the
islands consisting of elevated coralliferous limestones.

I obtained from various localities in Viti Levu specimens of the
older crystalline rocks belonging to the same series, which, according to
Wichman '^ and Home, have a vei-y considerable extension both in Viti
Levu and in Vauua Levu. The tufas 'and conglomerates are in many
instances fossilliferous, and are considered by Martin as tertiary, not
older than miocene. Wichman concludes that the larger islands must
have existed as a continent during mesozoic and palaeozoic periods, and
that oscillations of level only took place in latest tertiaries. From the
specimens examined by him, Wichman also concludes that Kandavu,
Ovalau, Ono, and some of the Exploring Isles consist principally of
andesites and basalts, and their tufas. According to Home, Taviuni
is the only island of the group which is of purely volcanic origin. This
certainly is not the case. I would mention, among others, Moala,
Thombia, and Totoya.^

VOLCANIC ISLANDS,

Koro.

Plates 3*, 19^^, Fig. 8.

Koro is one of the larger volcanic islands which has not been greatly
affected by submarine erosion. It is about ten miles long with a north-
ern face of five, the east and west sides run to a point. The shores,
with the exception of the southern part of the west coast, which runs
nearly north and south, are bordered by a fringing reef extending about
a mile and a half from shore ; on the east coast the fringing reef is cut
into small incipient lagoons (Nangaidamu Harbor), and has several boat
harbors, generally opposite the mouth of a small river. On the north
coast the reef patches extend nearly four miles from shore, forming an

1 Proc. Camb. Phil. Soc, Vol. IX. Part VIII. p. 457 (1898).

2 Min. u. Petrog. Mittheil. v. Tschermak, Vol. V. Pt. L p. 1 (1882).

3 The specimens of rocks we collected in Fiji at the different islands are now
under examination, and a report on them will follow later.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 19

indistiuct lagoon called Stone Axe Roads. The northeastern extension
of the east coast fringing reef forms an open roadstead. This spur is
covered with magnificient patches of coral in from one to three fathoms.
One can trace from the long line of lava negro-heads — some of these are
quite large — covering the reef jBats, tlie former northern extension of
the island. We could also trace to the south the low bluffs fi'om the
erosion of which have been formed the Hats upon which the fringing reef
has found a footing. A very sti'oug current was flowing over the spur of
Natliomaki Point, driven westward by the easterly trades.

The principal ridge of the island runs transversely across it from the
southern point to its northeastern end. Its highest point is over 1,800
feet. The faces of the island are furrowed by deep valleys.

Mbatiki.

Plate 13.

We did not land on Mbatiki, but steamed close enough to the shores
to obtain some idea of its characteristic features. The highest peak on
the northern side is a little over 600 feet. There are two deep indenta-
tions, one on the west, the other on the south side. It is surrounded by
a shore fringing reef from three points of which spurs extend parallel to
the shore, impounding three narrow shallow lagoons with a depth of
from three to five fathoms. The lagoons are full of coral heads. There
ai'e boat passes into two of the lagoons. The island is of volcanic
origin.

Moala.

Plates 16, 57.

Moala is an island of volcanic origin, triangular in form, the eastern
face indented by a deep bay, fully two miles long, by about three
fourths of a mile in width, with sixteen fathoms in greatest depth. The
highest point of Moala is over fifteen hundred feet. The ridges sur-
rounding the deep bay have the appearance of being the rim of an
extinct crater (Plate 57), broken to the eastward, some points of which
rise from over twelve hundred to over fourteen hundred feet, the bay
formine- the bottom of the extinct crater.

The western part of the north coast is edged by a fringing reef extend-
ing neai-ly a mile off shore ; towards the east the fringing reef proper
becomes quite narrow, while disconnected coral patches of considerable

20 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

width extend towards the northeast extremity of the outer reef. The
outer reef flats are narrow, and run in a southerly direction, forming an
elbow opposite the eastern point of the island at a distance of from one
to two miles, and enclosing the lagoon off the eastern face of tlie island,
the continuation of the deep bay. South of the deep hay the outer reef
nearly connects with the edging reef of the island, leaving a passage

DEEP BAY, EAST FACE OF MOALA.

across the outer reef about a mile in width, the southern horn of which
extends about three miles to the south, then in a westerly direction,
then north until it strikes spurs of the fringing reef on the northwestern
coast of the island, where the outer reef forms in connection with the
fringing reef a series of reef flats full of coral patches and heads. The
lagoon to the southwest of the island is also full of coral patches and
heads, some of them of considerable size, which extend to Herald Road-
stead, the northeastern part of the lagoon, Avhich alone is comparatively
free from obstructions. Owing to the presence of so many patches and
heads the depth in the lagoon is most irregular. In Herald Sound it is
as great as twenty-flve fathoms, and somewhat less off the southwest
and northern coasts. The characteristic heads which crop out from
the shore at so many points are well illustrated by the heads composed
of volcanic rocks which form the spit protecting the anchorage to the
west of Naroi village, on the north shore of the island. Wherever we
dredged we found that the bottom inside the lagoon consisted of fine
volcanic mud mixed with coral ooze and broken shells.

There are two entrances to the lagoon on the east face, one opposite
the deep bay, the other to the soutli, while on the west there is an
entrance to Herald Sound (the lagoon of the southwest side of the
island) near its northern extremity.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 21

Ngau.

Plates 13, 13, 11% Figs. 1-3.

Ngau Island is about eleven miles long, by an average of nearly four
miles in width. It consists of volcanic rocks; a high ridge runs alouo-
the middle with spurs separated by deep valleys extending towards the
east and west coast. One of these spurs forms a deep bay on the north-
western coast. The peaks of the main ridge vary in height from 1,000
to over 2,300 feet. Ngau is pi'otected on the east and north by a
broad fringing reef of a width of over three miles. At the northern
extremity and on the east face there are a few reef boat harbors, cut out
of the fringing reef which also extends along the whole western shore as
a very narrow fringe. As will be seen from the chart (Plate 13), the
small reef harbors are without exception off the mouth of the moun-
tain streams both on the north and east faces of the island ; these in the
rainy season bring down a large amount of mud and prevent the growth
of corals at their mouth: From the southern end of the island extends
in a northwesterly direction an outer barrier reef, varying in width from
a quarter of a mile to three quarters of a mile. This reef is continuous
being only broken in the middle by a narrow ship passage. The general
depth of the lagoon is about twenty fathoms, with a greatest depth of
twenty-nine. The western reef sweeps round the northern face of the
lagoon, its eastern extension becomes broken into disconnected patches,
and the greater part of the northeastern baj^ of the lagoon is tilled with
coral patches which connect it with the fringing reef of the north shore
of the island. There are also numerous patches in the southern bight
of the lagoon, and along the inner edge of the outer reef near the north-
western elbow of the reef. As far as we examined the reef of Xgau the
reef flat was covered with most extensive patches of thriving corals.

There is a small island, Yathiwa, on the very edge of the reef forming
the soutliern horn of Ngau. It holds to Ngau very much the same rela-
tion which Kobu Island does to Nairai, but is nearer the outer edge of
the reef, while Kobu is in the lagoon surrounded by comparatively deep
water.

Mambulitha Reef.

To the south of Ngau we could see the breakers giving the outline of
Mambulitha Reef (Plate 12), separated from Ngau by a channel having
a depth of 750 fathoms. This reef is pentagonal in outline, about one
mile and a quarter long, is awash, has no opening, and encloses a shallow

t

22 bulletin: museum of comparative zoology.

lagoon of pale green water, the sea breaking heavily upon the edges. I
consider this reef as having been denuded and eroded to its present stage,
which precedes that of a more sunken atoll, like Adolphus Reef, with a
deeper lagoon.

Nairai.

Plate 11^, Fig. 4, and Plates 13, 14, 58, 59.

Xairai is a volcanic island, triangular in shape (Plates 12, 14), with
sides of about four miles in length. Its central ridge forms an open arc
to the east, its central peak rising to a height of over eleven hundred feet
The western slope of the island is much less steep than the eastern side.
(Plate 58.) The island is edged b}^ a narrow fringing reef, with the
exception of the most western point, where it expands into a broad
fringing reef, the outer patches of which extend into the outer encircling
reef. The encircling reef surrounding the island is a narrow reef flat,
from a quarter to a mile distant from the eastern side, and from one to
one and a half on the western side. But the prolongations of the horns
of the outer reef to the northeast, south, and west are from four to five
miles distant, forming thus three lagoons separated by long passages.
(Plate 14.) The greatest depth in the lagoons is twenty-six fathoms off
one of the western passages. The general depth is from ten to fifteen
fathoms. The inner edge of the eastern outer reef is fringed with coral
patches. This part of the reef is continuous, having only one boat
entrance nearly opposite the southern extremity of the island. The
western reef has two deep passages, and a boat passage near the south-
em horn of the atoll. This as well as the other points of the outer
reef, both at the northeastern and northwestern horns, are studded with
coral patches. The greater part of the lagoon, extending from the
northern part of the island to the JSI^ayatha Passage, is studded with
rocks and coral patches, undoubtedly the remnants of fragments of the
main island, which crop out in everj' direction within the lagoon, and as
negro-heads upon the reef flats. Jfaikobu (Plate 59), or Magnetic Island,
a small island to the south of Nairai, is one of these outlyers ; it is
ninety feet in height, the base running into ten fathoms, and is covered
with corals. It is further remarkable for the great variation it causes
to the compass. We observed on the top a westerh- deflection of 87°.
The bottom of the lagoon consists of fine coral, coralline sand, and broken
shells, which form large white areas separating the coral patches and
the numerous patches of coralline algae which flourish upon the floor of
this lagoon wherever we examined it. The corals of the fringing reefs
of both Nairai and Ngau were growing specially vigorously.

AGASSIZ: FIJI ISLANDS AND COEAL EEEFS.

23

Makongai and Wakaya.

Plates 3^, 11^, Fig. 9 ; Plates 3^, 11^, Figs. 7, 8, and Plates 15, 55, 56.

Makongai and Wakaja present features nearly identical. Tiiey are
both long lines of narrow reefs, enclosing in the one case an irregularly
triangular lagoon open on its northern face, and in the other an irrcou-
lai'ly shaped parallelogram, with

undulating sides and rounded b -i.

corners. The island of Makongai f-
is somewhat rectangular, with f
many indentations ; it is of vol- | 'i

canic nature, and attains a I M

height of nearly 900 feet. On its | m

eastern face the encircling outer ■* 5

reef becomes its fringing reef at |

several points. It is sepai*ated [ i

by a narrow channel having a ^

depth of twelve fathoms from i \ ,iii&

Makondranga, a small island sim- r
ilar in structure to Makongai. ^.
about half a mile from the outer
reef. The whole eastern encir-
cling barrier reef is broken up
into a number of small patches
with boat passages between them.
With the exception of one boat
passage the western reef forms a
continuous line of breakers, Ijut
on the northern side the reef patches are limited to rocks, grown over

NORTHWEST POINT OF MAKONGAI.

feffiMJ

LEDGE OFF MAKONGAI.

at the base with corals, judging from those we saw while passing into

the lagoon.

24

BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

Makongai is edged with a fringing reef. The islands in the Makongai
lagoon are in the northeast corner close to the eastern face of the outer
reef. The lagoon has a general depth of from thirteen to seventeen
fathoms, with a greatest depth of twenty-one fathoms in the northern
part. The southern part of the lagoon is full of coral patches, remnants
of islands and islets similar to those of the small island of Tambaka, still
connected with Makongai by a neck of boulders, which reaches to the
westward as an extensive flat, and fringed below low water mark with
flourishing patches of corals. Such a patch with a few angular blocks

LEDGE OFF JIAKONDRANGA.

still visible above high water mark, lies off the southwest point of
Makondranga, and many others off the southeastern face of Makongai.
Corals within the lagoon grow in from seven to one or two fathoms.
The rest of the bottom of the lagoon consists of coral and coralline
sand.

Makongai and Wakaya are connected by a narrow reef ridge about a
mile in length. The island of Wakaya is nine miles long, triangular in
shape, tapering to a point, and situated close to the western edge of the
outer reef of the lagoon. A fringing reef edges its eastern face, while
the extension of the outer reef forms the wider fringing reef of the
western shore. Towards the south this part of the fringing reef encloses
two secondary lagoons, one of which has a depth of five fathoms. The
southern part of the outer reef is continuous ; the northeastern face is
broken by several passages, and there are three to the north of Wakaya
on the western face. The highest point of Wakaya is nearly 600 feet,
forming a range of steep bluffs along the northern part of the island,
which slopes very gi-adually to the east. The southern part of the island

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 25

is not more than 300 feet high, and is joined to the rest of the island by
a comparatively low neck. The depth of the Wakaya Lagoon is greater
on the average than that of Makongai ; it reaches a maximum depth of
thirty-six fathoms, with a general avei'age depth of over twenty. There
are comparatively few patches in the lagoon. The bottom consists of
coralline sand and shells. We entered through the northern passage
and crossed the lagoon, and on our way out examined the reef patches
forming the boat passages to the south of it. On the shore of the bay,
near the boat passage, we found a good deal of pumice. We found
traces of elevation on the neck connecting the point on which Lieutenant
Langdale's house is built.

We could not examine the corals on the weather face of the weather
reef, but on the inner side and on the lee reef we found corals flourishing
most luxuriously, mainly Madrepores, Pocillopores, Astreans, Mieandrinas,
Fungise, and a few Gorgonians. They form a belt mainly between two
and seven or eight fathoms, beyond which there seem to be only coral
sand and corallines both on the inner and outer faces of the lee reef.
With the disappearance of Wakaya through denudation and erosion, we
should have an atoll with a substratum of volcanic rocks which very
likely might be covered to a limited depth with islets of coral sand blown
up from the encircling I'eef, — an atoll in no way to be distinguished by
outward appearances from the theoretical atoll built up by corals and
by subsidence.

Mbengha.

Plates 8, 11*, Fig. 6, and Plates 46-49.

Mbengha Island is irregularly shaped, with three deep indentations,
one on the western side, the others on the eastern, nearly cut off the
high point forming the eastern side of Malumu Bay from the main body
of the island. (Plate 48.) The principal ridge, running nearly north
and sontli across the central part of the island, rises abruptly from the
south to a height of over a thousand feet, and has several peaks at-
taining heights varying between 1,200 and over 1,400 feet. The secon-
dary ridge to the east of Malumu Bay is somewhat less than a thousand
feet. On the east face to the south of Solianga are exposed some fine
bluffs consisting of volcanic conglomerate breccia. (Plate 46.) They
are perhaps as good examples as we have seen of the great erosion and
denudation which have taken place in tliis part of the Fiji group.

A moi-e detailed view of the appearance of the volcanic rocks of
Mbengha is given in Plate 47, an eroded shore bluff immediately in

26 BULLETIX: MUSEUM OF COMPAKATIYE ZOOLOGY.

the rear of the beach at Rukua on the west side of ^Ibengha. Similar
volcanic breccia bluffs are characteristic of many points in Fiji.

In aditiou to the main island there are tliree other islands. Moturiki
and Stuart, which are small satellites of Mbengha, and Yanutha, a lai-ger
island near the western edge of the lagoon. Tliese islands have the
same geological structure as that of Mbengha. (Plate 8.)

Mbengha is on the eastern point of the lagoon, separated fi-om the
inner edge of the outer reef by a channel varying in width from a half to
one and a quarter miles, wath a greatest depth of twenty-three fathoms
closer to the island than to the reef. The channel between Yanutha
and the outer reef is about tlu-ee quarters of a mile in Avidth, with a
depth of from eleven to thirteen fathoms. There are in addition a
number of patches of coral rising from a depth of from ten to twelve
fathoms, irregularly scattered over the western part of the lagooa and
along the inner edge of the outer reef.

]Mbengha and Yanutha Islands are enclosed within a long reef over
thirty miles in length, forming an irregularly shaped pentagonal lagoon
with rounded angles. The northern side is open, forming a passage fully
five miles wide, and studded with patches. This part of the lagoon slopes
very gradually from 17 fathoms to 130 or 140 fathoms in the centre
of the Mbengha Passage, separating Mbengha from the island of Viti
Levu.

The northeastern face of the lagoon is flanked by the Pratt Pieefs, those
upon which the low sandy Storm Island is placed, and the Nanuku Eeef.
There are several passages available for vessels on that side of the lagoon.
The iJ^anuku, Sulphur, and Cutter Passages with a depth of from nine
to thirteen fathoms. The southern and southwestern sides of the lagoon
are flanked by a long unbroken coral reef, the Mbengha Barrier Eeef,
varying in width from half a mile to over a mile and a quarter, extending
from Cutter to Frigate Passage. There is a small sand key about the
middle of the Mbengha Reef on its inner edge. To the north of Frigate
Passacre the Yanutha Pieefs form the northwestern side of the Mbengha
Lagoon. They are separated by broad channels ending in the reef of Bird
Island and a long line of patches, the Nisithi Ptocks, which form the western
spit of the wide opening on the northern side of the lagoon. As will be
seen from the cliart, the bottom of the ^Mbengha liagoon is most irregular ;
it is very uneven, varj'ing greatly in depth, and full of heads and patches
overgrown with corals. The rocks and heads and patches are fragments
of volcanic rock, the remnants of the island of ]\Ibengha when it ex-
tended over the gi-eater part of the area now enclosed by the outer reef.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 27

— remnants left from the disintegration and erosion of the former o-reater
Mbengha.

The bottom in the lagoon is a mixture of volcanic mvxd and coral sand
in the vicinity of the islands, but as we pi-oceed towards the reef it car-
ries a greater admixture of coralline aXgse and of coral sand, and in the
belt adjoining the inner edge of the outer reef is made up entii'cly of
fragments of coi-al, of coral sand, and of coralline algte. In the central
parts of the lagoon it is algse and corallines.

The reef rises very gradually from seven fathoms to a depth of from
two to three feet on the reef flat. This is covered w'ith fragments of
dead corals which increase in number towards the sea edge of the reef.
The fragments are covered with algte, corallines, and nullipores, which
cement them together. In depths of seven to eight fathoms heads and
clusters of corals begin to grow. They are separated by wide lanes of
coral sand, and as we rise on the slope of the reef they grow more closely,
forming a wide belt of thriving corals from six to three or two fathoms
in depth, when they grow less profusely, and finally pass into the wide
flat area of the outer reef, made up of broken corals and fragments, and
large masses thrown up on the sea face of the reef, which are gradually
being broken up by the surf beating upon the reef flat.

Storm Islet ^ (Plate 49) is an excellent specimen of a sand key
thrown up by the waves upon the outer reef flats. It is somewhat
less than three hundred yards
long and about eighty yai'ds
wide. The beach is quite steep,
protected by lai'ge patches of
beach I'ock, which surround the
southern extremity of the isl-
and. Tiie crest of the island
is covered with cocoanut trees, screw pines, and casuarinas, as well as
witli an outer fringe of bushes and shrubs.

The greater part of the shores of ]\Ibengha Island are edged with a
fringing reef, and coral patches forming an irregular belt extend into six
or seven fathoms in depth. As the sea breaks but little on the outer

1 Dana has called attention (Coral Islands, p. 241 ) to the advantage which coral
island accumulations have over other shore deposits, "owinpr to the ready aggluti-
nation of calcareous grains," and, as he suggests, with the formation of coral sand
rocks along the beaches and reef rock in the water a rock defence against en-
croachment is produced. So that limestone rocks thus formed will prove a most
effectual barrier to tlie destructive action of the waves.

STORM ISLET.

28 BULLETIN : .MUSEUM OF COMPARATIVE ZOOLOGY.

Mbengha Eeef, I was able to examine the sea face of the reef, and
found that in Frigate Passage both sides of the reef were flanked with
large heads of corals beginning in from five to seven or eight fathoms.
On the outer face, though corals were growing, there were no lar<>e
heads, at about six fathoms w^e found Madrepores, Fungiae, Pocillopores,
small heads of Porites, Astreans, and of IMajandriiias and Gorgonians.
This belt extended to the line of breakers pounding upon the reef flat.
Outside of six to eight fathoms the corals seem to have disappeared, as
the lead brought up nothing but coral and coralline algse sand.

Kandavu.

Plates 10, 11,50.

The extent of the erosion and denudation Avhich has taken place
along the coast of Kandavu is well exemplified by the John Wesley
Bluffs near the village of Taviiki (Plate 10), and similar bluffs rising
to the westward of Tavuki Bay. The John Wesley Bluffs (Plate 50) are
a line of nearly vertical cliff's of volcanic origin cut into wide rounded
lamellar masses, rising to a height of fully 500 feet on the east side of
Tomba ni Tavuki. A part of the hill slopes on the west side of the bay
are covered by the rounded tops of similar rocks cropping out on the
surface, giving the slope the appearance of a graveyard crowded with
dome-shaped monuments.

The heads studding the Bay of Tavuki, and forming the extension of
the oiiter reef patches parallel to the coast, are covered with thriving
corals, growing upon a substructui'e of volcanic rocks, as is clearly seen
from the nature of the negro-heads cropping out in the bay.

.< W^th the exception of the broad fringing reef stretching to the west of
Tavuki, the north shore of Kandavu is edged by a narrow fringing reef
(Plate 10), and from Yale Point to Tomba ni Richmondi an indistinct
barrier reef extends, made up of small distant patches, except where the
Malatta Reefs enclose a wide bay north of John Wesley Bluffs, studded
with coral patches and heads. The south shore of Kandavu is likewise
edged with a narrow fringing reef in Soso and Kandavu Bays inside
of the broad barrier reefs across their entrance. The islands and islets
within the North Astrolabe Reef Lagoon are also edged with narrow
fringing reefs.

Tlie platform of submarine erosion extending north of the eastern
extremity of Kandavu is one of the best examples of its kind we find in
Fiji. The great lagoon, with its islands and islets, represents a stage of

AGASSIZ: FIJI ISLANDS AND COEAL KEEFS. 29

denudation and erosion somewhat more advanced than that existmg on
the eastern half of the south shore of Kandavu.

We cannot fail to notice also the greater width of the shore platform
wherever the coast has a northerly trend, as, for instance, west of Tomba
ni Richmoudi on the north coast, and north of the John Wesley Bluffs,
where the platform is edged by the jNIalatta Reefs and studded with
heads and patches. On the northern coast, however, the frhiging reefs
are narrow, while on the south coast of Kandavu (Plate 10) they take
their greatest development, exposed to the full sway of the southeast
trades. A glance at Plate 11 cannot fail to show the relatively great
width -of the eastern belt of the encircling reef, as compared with that
of the western side of the Great Astrolabe Lagoon.^ In a smaller lagoon
like Nortli Astrolabe Reef, where the breakers pour over the eastern
face, and water flows constantly over the western edge, the difference
in the width of the reef on the two sides is not so marked.

While undoubtedly the widt-li of a reef depends in great measure on
the nature of the platform upon which it grows, yet I do not see the
force of Lendenfeld's statement,^ that while " lateral growth of corals no
doubt takes place, it is not the actual cause of the formation of the
great coral reefs." There certainly is nothing to prevent the swarms of
embryos which float at certain times in the vicinity of a coral reef from
attaching themselves and growing upon any surface witliin reach having
the proper deptli on both sides of any growing reef. Undoubtedly the
extension within the lagoon, both in barrier reefs and atolls, of the coral
heads is due to such a cause, and the wider the reef the closer do the
heads come together as we pass upon the I'eef fiat from the inner edge of
the reef towards the outer marcrin. lu an account of a discussion on
coral reefs ^ by Sollas, Hickson, Rothpletz, and others, Stebbiug stated
that young corals might start on either rising or subsidence, but only
subsidence is favorable. That, it seems to me, depends entirely on the
depth at which they start; they may have 120 feet, and build up a reef
of that thickness, which is fully as thick as most reefs we know anything
about.

1 I cannot agree with Gardiner in his statement that the windward reefs of Fiji
are of about the same breadth. {Loc. cit., p. 4'.i2.) Compare the windward reefs of
Mbengha, of the Great Astrolabe Reefs, and of the east coast of Viti Levuwith the
windward reefs of Wakaya, of Nairai, of Totoya, of the Budd Reef, of Kanathea,
of the Exploring Isles, of the Argo Reefs, of Lakemba, of Aiwa, of Mothe, and of
Ongea ; the latter are certainly as a rule mucli narrower than tlie former.

2 Nature, Vol. XLII. p. 31.

3 Nature, October 12, 1893, p. 575.

30 BULLETIN : MUSEUM OF COMPAEATIVE ZOOLOGY.

Murray,^ who visited Kandavu in the " Challenger," considers the
banks of Fiji surrounding the extremities of volcanic islands as banks
formed from the loose material of the islands spread out laterally by
wave action, the extensive banks extending much fai*ther seaward
there in one direction than in another. Murray has also called attention
to the North Astrolabe Reef, which, if its present condition with Solo
Rock in the centre is due to subsidence, should have a very much deeper
lagoon, instead of the comparatively shallow one characterizing that
reef.

Great Astrolabe Reef.

Plates 11, 11*, Figs. 10-13, and Plates 51, 52.

To the northwai'd of the eastern extremity of Kandavu (Plate 11) ex-
tends the Great Astrolabe Reef. Its eastern face is the extension of
the reef to the eastward of Tomba ni Soso (Plate 10), an irregularly
shaped bay, the mouth of which is protected by a barrier reef. This
barrier reef extends as a fringing reef along the southern coast as far
as Kandavu Bay, where it becomes sepai-ated from the island and forms
stretches of barrier reef patches, with passages leading into the bays
protected by the reef.

West of the entrance to Xgoala Harbor a broad fringing reef extends
along the southern coast nearly to the western spit of Kandavu. Sev-
eral reef harbors are cut out from it, one of which, Tomba Yauravu, is of
considerable size (Plate 10). From Xaingoro Pass the outer reef of the
' Great Astrolabe Reef runs unbroken in a noi'therly direction for a dis-
tance of 2.5 miles round its northern horn, as far as Usborne Pass, which
is an entrance into the lagoon on the western side, aliout a mile from the
apex of the Great Astrolabe Reef. Off Mbulia, the easternmost of the
islands inside the Great Astrolabe Reef, the eastern encircling reef
makes a sharp elbow, and then forms a double curve in a northwesterly
direction to the narrow apex, from which the reef turns sharply south
as far as Alacrity Rocks in a great narrow arc broken in many places.
North of Ono Island there are three well defined passages, but south of
Alacrity Pass the reef becomes much broken up into small patches,
and finally, from Ono Island south the lagoon is open, and has a steep
slope towards the 100 fathom line.

The depth of the lagoon north of Ono is not more than twenty-two
fathoms ; the bottom is most uneven, often passing rapidly from five

1 Nature, July 4, 1889, p. 222.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 31

or eight fathoms to seventeen and eighteen fiitlioms, with a number of
extensive patches, the remnants of former ishxuds now covered with
coral. (PLnte 11.)

Within the Great Astrolabe Reef are included a number of islands
and islets. They are all volcanic in structure, and all Ijear signs of the
gi-eat denudation and erosion to which they have been subjected. Be-
ginning at the north there is Vanua Kula, about 250 feet in height,
covered by scanty vegetation ; next comes Xdravuni, a much larger
island, rising to a height of 350 feet. Yanu Yanu sau and Yanu Yanu
eloma are small islets upon a spit which must have formed a part of

NMARA AXD YAXU TANU ELOMA

iN'mara Island ; to the south of it is Ngasi Mbali. To the eastward
are Yaukuve and Yaukuve lai lai (Plate 52), 400 and 200 feet respect-
ively, connected by a spit, and off the south point of Yaukuve lai lai
extends a long sunken shallow rocky spit. Mbulia and Yambu are to
the north of Ono, the largest of the islands within the Great Asti'o-
labe Lagoon (Plate 51). It has two peaks of over 1,100 feet, and is
indented with deep bays forming finger-like spokes, which further dis-
integration would soon sepai'ate as distinct islands, similar to those of
Vuro and Vuro lai lai off the northeastern point of the island. Between
Ono and the eastern point of Kandavu Island the lagoon is dotted with
numerous rocky and coral patches. Ono, and most of the islands of
the Great Astrolabe Lagoon, are edged with frincring reefs. The eastern
reef fiat is quite broad (Plate 11) ; in some localities it is nearly a mile
wide, besides being fringed along the inner edge by nearly continuous
patches of rocks and corals. On the western face of Ono there are some
fine cliffs, interesting as showing the progress of tlie denudation and
erosion to which the island has been subjected. It seems comparatively
simple to follow with the chart the changes which must have taken place
in separating from Kandavu the islands enclosed within the Great As-
trolabe Lagoon north of that island. They undoubtedly I'epresent the
fragments of the former northern extension of Kandavu itself, which

32 bulletin: museum of comparative zoology.

probably covered the greater part of the area now enclosed bv the Great
Astrolabe Reef.

If we examine Kandavu Island itself (Plate 10), we can easilj- see
how far denudation and erosion, if continued, would cut it up into a
number of larger or smaller islands; as, for instance, an island would be
formed at the neck separating Tomba Kaivala from Koro Levu, a larger
island, by the cutting of the neck separating Tomba ni Xdaku on the
north side from Tomba ni Soso on the south of the island. Finally, the
cutting of the Malatta Isthmus would make two islands of considerable
size of the western half of Kandavu, while the many spits bounding the
deep bays of the island would also become islands similar to Matanuku
on the south side of Kandavu, and connected with it by the broad
fringing reef. These would all be enclosed on the south by the southern
extension of the Great Astrolabe Reef, which is now either a barrier or
a fringing reef along the south coast of Kandavu, while on the north
coast the island would merely be flanked by outlying reef patches sepa-
rated by great stretches bare of reefs, as along the southwestern part of
the Great Astrolabe Lagoon.

Skirting the northern sliore of Kandavu from Tomba Kaivala to
Levuka, we found the physiognomy of the larger island to be identical
with that of the islands of the Astrolabe Lagoon, — high cliffs, formed
by the crumbling of the faces of the shores, sloping to high mountains,
deep bays extending far inland, and a vegetation identical with that of
the adjoining islands. According to the position and proximity of the
islands to the inner edge of the outer reef flat, we found the bottom of
the Great Astrolabe Lagoon to consist of volcanic mud or of coral sand
and coralline algee, or of a mixture of the two.

North Astrolabe Reef.

Plates 11, 11*. Fig. 14, and Plates 53, 54.

Xorth Astrolabe Reef is separated from the northern point of the
Great Astrolabe Reef by the D'Urville Channel, which is about a mile
wide, and with 190 fathoms coralline bottom in the middle (Plate 11).

North Astrolabe Reef encloses an oval egg-shaped lagoon about four
miles in length by three and a half in breadth, with a small rocky islet,
Solo, situated nearly in the centre of the lagoon (Plate 11). The great-
est depth of the lagoon is sixteen fathoms, with very undulating bot-
tom full of rocky and of coral patches along the inner edge of the reef,
and especially over the southern part of the lagoon. Solo is composed

AGASSIZ: FIJI ISLANDS AND COKAL REEFS. 33

of volcanic rocks, and has been very much eroded by the action of the
sea (Phite 54). Corals grow upon its slopes, but they are not very
flourishing, either there or upon the many patches found inside the
lagoon, and which are separated by broad sand lanes, or by dark patches
of nullipores and algse, with a few scattered coral heads.

The reef enclosing the lagoon is continuous except on the north side,
where there are two entraiices into the lagoon, one with thirteen and tiie
other with three fathoms in the channel. The inner side of the weather
reef can be reached quite close to the breakers. There is from one and a
half to two fathoms of water on the reef flat, which is covered by a great
number of flourishing patches of coral, mainly Madrepores, Pociliopores,
heads of Astreans and Mreandrinas, with a few Gorgonians. The patches
are separated by wide areas of coral and coralline sand. Towards the
inner part of the lagoon, as the water deepens, the coral patches are
separated by masses of dead corals and of fragments. Dark patches of
coralline Algse become more abundant, and the coral patches less flour-
ishing and more distant. On the outer edge of the reef, to the south
of Beagle Passage, the reef flat is somewhat narrower than on the east-
ern face, where it varies from 1,000 to 1,800 feet in width ; it is cov-
ered by one to two fathoms of water, and the coral patches appear to
flourish upon its surface fully as luxuriantly as upon the eastern face.
The corals descended in steps to ten or even eighteen fethoms, rising
from the coral and coralline sand separating the heads. They were
most flourishing in the belt of from six to ten fathoms in depth. The
prevailing trades drive a strong current across the lagoon, and the
water of the lagoon rushes out through the northern passages and over
the western reef flats with considerable velocity. The bottom inside
of the lagoon consists mainly of alga, of coralline algte, and of broken
shells and fragments of coral.

It is quite probable that the North Asti'olabe Reef represents an
eroded peak adjacent to the former greater Kandavu, of which Solo
Eock is the only witness left (Plate 53).

Budd Reef.

Plates 4, 18, 70.

Budd Reef (Plate 18) has a narrow outer reef of irregular shape, broken
into many separate patches. These become quite distant on the south-
ern side, leaving the outline of the reef indistinct. The lagoon, as
well as the channels separating the islands enclosed within the outer

VOL. XXXIII. 3

34 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

reef are quite deep, with the exception of that part of the lagoon
which lies south of Yambu and Yanutha and between Thombia and
the northwestern edge of the outer reef. Tlie deepest part of the
lagoon is 47 fathoms and the average depth is between 35 and 40
fathoms.

In addition to Thombia, which is on the northern horn of Budd's Eeef,
there are the islands of Yanutha, Yambu, Mungaiwa, Tai ni Mbeka, and
Kara ni Tinka, which are in the central part of the lagoon. South of the
central islands the lagoon is also studded with rocks, 'as well as in
the southwestern horn of the lagoon. The islands and islets and rocks,
as well as many of the patches, are of volcanic origin. Yanutha, the
largest of the islands, about a mile long and half a mile wnde, rises to a
height of 480 feet. It is connected by a coral reef with Mungaiwa Island
and Mbeka Eock.

The most interesting of the islands is Thombia (Plate 70), the crater
of an extinct volcano, having an exterior cii'cumference of about two

miles. The crater is half a mile in diam-
/>,^^ eter, with a greatest depth of twenty-

four fathoms. The rim of the crater
rises at its highest point in a dome of
nearly 600 feet. On the northeast side
WESTERN END OF THOMBIA. tliB homs of tlic riui arc connected by a

flourishing fringing coral reef about a
fifth of a mile in length, the extension on the ridge connecting the horns
of the fringing reef surrounding the island. Both the inner and outer
slopes of Thombia are steep, and, except on the northwest side, we find
over thirty fathoms within a short distance of the shore.

One cannot fail, on seeing the coral reef growing on the denuded rim
of Thombia with the enclosed deep lagoon having a depth of twenty-four
fathoms, to revert to the old opinion that some of the lagoons of atolls
represented the rim of extinct craters. There is, it seems to me, nothing
unreasonable in the suggestion that many of the small round atolls, or
others perhaps rising from great depths and isolated, represent the de-
nuded rims of such extinct craters as Thombia, or it may be that, if of
greater size, they may represent parts of such larger craters as Totoya, or
of circular islands with interior lagoons resembling extinct craters, like the
Sound of Fulanga. It seems simple to imagine that, when these small
extinct ci'aters have been levelled down, and corals have obtained a
footing, they may have formed such atolls as Pitman's Reef, Motua
Levu, Motua lai lai, Williamson Reef, Horseshoe Reef, and other similar

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 35

atolls in Fiji. We must remember, however, that the formation of such
atolls may also be accounted for as the result of the denudation and sub-
marine erosion of a [)atch of elevated limestone, cut first into a sound, and
then, with the disappearance of the outer rim, into a lagoon surrounded
by a shallow reef flat ; or the same result may be accomplished from the
wearing away of islets of volcanic origin enclosed within the outer reef, as,
for instance, from the disintegration of the islets now left in such atolls as
the Kimbombo Islands, Komo, and others, or of islets consisting of
elevated limestone like the Aiwa Islands, Katavanga, Yekai, and others.
The structure of the negro-heads occurring upon the outer reef flats, or
their position near either a volcanic or an elevated reef region being the
only guide as to the category to which belong such atolls as Thakau
Mata Thuthu, Thakau Vutho Vutho, the Adolphus Eeef, Dibble's, Duff,
and Bell Reefs, Thakau Tambu, Malevuvu, etc.

Such a cluster as Budd Eeef suggests an explanation for the for-
mation of interior atolls, like those described by Darwin as occurring
in the Maldive Islands, very different from the one suggested by him.
Were Thombia cut down by erosion to the water's edge or below, and
changed into a small atoll, we should have a secondary atoll within the
area enclosed by Budd Eeef, and were the other small islands of the
cluster summits of elevated limestone, and should they in their turn be
cut down, they might form in such a large lagoon as that of Budd Eeef
other diminutive atolls, or small atolls enclosed within an atoll. Such
interior atolls, if my view of the formation of atolls is correct, could only
be formed in lagoons of considerable depth and size, so that the seas
formed by the prevailing winds should have a long sweep and rise to a
considerable height, and thus possess great disintegrating power. I shall
refer again, when describing Vanua Mbalavu, to the probable origin of
such great depths as foi'ty-seven fathoms inside of the reef encircling the
islands of Budd Eeef.

Komo.

Plates 19*, Figs. 9-11, and Plates 32, 63-65.

Komo Island is a narrow ridge of volcanic origin, about a mile and a
half in length, rising to over two hundred feet. Its western extremity is
connected by a coral reef full of volcanic negro heads, two of which are
mushi-oom-shaped and of considerable size, with the islet of Komo Ndriti,
itself about seventy feet high. Komo lies in the southeastern horn of the
lagoon (Plate 22) close to the southern face of the outer reef flat, from

36 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

which it is only separated by a narrow boat passage full of negro-heads,
especially numerous off the southeast point of the island. The lagoon
enclosed by the outer reef flat is elliptical. There are two ship passages
through the north face of the outer reef. The northern and eastern reef
flats are naiTow, edged on the outer side by masses of negi'o-heads ; while
the western and southern reef flats are fully half a mile broad, and edged
by an inner belt of heads, the central part of the lagoon is quite clear of
them. The rocks were comjDosed of a volcanic puddingstone (Plate 64),
much like that of Mbengha, Levuka, and elsewhere. This disintegrates
readily, is easily undercut, as we had ample proof in the undermining of
the shore bluffs and the formation of so many negro-heads on the reef
flats and off the spits of the island (Plate 63). The aspect of the islands
of volcanic origin and of elevated limestone is cpiite different as seen
from the sea. The mode of disintegration and erosion of the two kinds
of material can at once be distinguished from the peculiar physiognomy
of the rounded bluffs when composed of rocks of volcanic origin, or of
the vertical shore bluffs deeply grooved and streaked with red earth,
or eroded into domes or conical hills when composed of elevated coral-
liferoiis limestone.

The reefs which encircle Mbengha, Komo, and Budd Eeef, indicate
approximately the land area once probably occupied by those islands.
The islands must have been of considerably greater height ; they have
been reduced by denudation, and their area has been further diminished
by extensive submarine erosion wearing away the ridges and spurs of the
volcanic islands, and leaving submarine platforms of varying width, —
dependent upon the nature of the material to be eroded, and the height
of the land to be cut down, — upon the surface and outer edge of which
corals established themselves. In the case of Kom.o and of Budd Pteef,
the islets which remain show the extent of the denudation and erosion.
In the case of Mbengha the larger islands probably retain more of the
character of the island which once covered Mbengha, representing its
higher peaks, while the islets and rocks are all that remain of its lower
ridges and slopes.

Olorua.

On our way into Komo we saw in the distance Olorua (Plate 22), a
small island with a ridge having three prominent humps, probably of
elevated limestone, rising to a height of 250 feet. The island is sur-
rounded by a fringing reef extending to a point for more than a mile off
the south face. A small lagoon full of heads separates the north shore

AGASSIZ: FIJI ISLANDS AND CORAL REEFS.

37

of the island from the narrow outer reef flat. "We also passed the atoll
of Thakau Vuite (Plate 22), separated from Korao by a channel of
about one and a half miles in width, with a probable depth of about
150 fathoms. The lagoon is about two
miles and three quarters long by two
miles broad, with a greatest depth of six-
teen fathoms ; thei-e is an opening for
boats into the lagoon on the northwest side. The encircling reef flat
narrow, and there is a sand key on the northeast horn of the

OLORUA.

IS

lagoon.

Totoya.

Plates 19% Figs 4-7, and Plates 23, 66-69.

Before entering the western passage through the outer reef surround-
ing Totoya, we steamed round the eastern and northern edges of the
outer reef to obtain a good idea of this interesting islands Totoya
(Plate 23) is triangular in shape, enclosing an inner basin, nearly circu-
lar, of three miles in diameter, and with a greatest depth of 35 fathoms.
The width of the rim varies from two miles to a low narrow isthmus
on the western face (Plate 66), the highest points of the rim being
1,200 feet above sea level. The eastern part of the rim is the broadest
and highest. The basin is open to the south (Plate 67), the horns of
the rim being about two miles distant. Stretching across this opening is
the extension of the outer reef, which connects at the extremities of the

BASIN OF TOTOYA CRATER, FROM THE SU-MMIT OF THE NORTHERN KIM.

rim with the narrow fringing reef bordering the island. Between the edge
of the frins:ins: reef on the western horn and the outer reef there is a nar-
row but deep passage called the " Gullet " (25 fathoms), affording a good
entrance into the basin filling the extinct crater of Totoya, in which we
anchored close to the inner edge of the northern part of the rim. The
outer reef extends unbroken from the entrance on the west side to its

38 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

northeastern exti'emity; it follows irregularly the outline of the shore at
a distance varying from one to over two miles. The outer reef off the
north coast is broken into distant patches, leaving broad passages between
them. North of the western passage the reef is also interrupted, leaving
a boat passage. The outer reef flats are irregularly trapezoidal in out-
line, and quite narrow. The greatest depth in the outer lagoon is 27
fathoms. The eastern arm, and also the northern horn of the lao'oon
and tlie inner edge of the southern face of the outer reef, aj-e studded
with rocks and coral patches. The coi-als on the reef flats are thrivino-,
and those on the patches inside of tlie lagoon are everywhere most flour-
ishing. Many of the patches close to the outer shore line are in the
extension of lateral spurs which have been eroded from the ridge of the
rim. The general depth of the outer lagoon is over 20 fathoms alone
its central channel. Similar spurs run into the inner basin, and have
formed extensive spits on which corals flourish, or islets and islands such
as those figured on Plate 69, near the inner edge of the northern rim of
Totoya. Near the centre of the basin there is an extensive coral patch,
Kini Kini (Plate 23), formed upon the sides of a small islet rising from
the bottom of the crater, as is so often the case in the craters of other
volcanoes (see Plate 71). The volcanic rocks forming its centre are
exposed at low water. The outer rim of the crater of Totoya has a
diameter of six miles; it slopes quite evenly from the crest of the ridge
to the outer and inner shore line ; the slopes are cut by compara-
tively shallow valleys, separated by ridges with rounded crests. (Plates
€7, 69.)

The water which pours into the inner basin over the barrier stretching
across the horns of the crater finds its only outlet through the " Gullet,"
where it rushes thi-ough with considerable velocitv. The scourins' effect
of the waters rushing out of lagoons has been noticed by all who have
navigated among coral reefs, and the strong currents flowing out of the
lagoons through the encircling reefs of openings are constantly referred
to in the sailing directions.

In the extension of the western horn of the crater on the west of the
" Gullet," are two small islets (Plate 68), the remnants of a part of the
southern rim of the crater. Small islets also exist off" the west coast, on
the northern side of the isthmus. They are remnants of one of the
spurs putting out from the west side of the outer rim. From what we
have seen in Totoya, there is little doubt that the fringing reefs, the
shore flats, the coral patches, and in different parts of the lagoon the outer
reef flats are the remants of flats formed by the denudation and subma-

AGASSIZ : FIJI ISLANDS AND CORAL REEFS. 39

rine erosion from the former extension of the slopes of the rim or of its
spurs. These have been more or less connected together by the subse-
quent growth of the corals which have found a footing upon them.
Kini Kini and the other islets about Totoya, as well as the negro-heads
on the reef flats and patches, all show the volcanic substructure upon
which has grown and is thriving now a thin crust of corals.

TOTOYA FROM THE NOKTHEAST, DISTANT FIVE MILES.

It has been difficult to explain the great depth in some of the lagoons
of some atolls (60 fathoms). It seems to me that the conditions occur-
ring in an island like Totoya give us a simple explanation of what such
depths mean in coral districts situated in volcanic regions. Provided
that we assume that these lagoons are in a region of elevation, as are the
Fiji Islands, and that its volcanic peaks or ridges and volcanoes have
been denuded and eroded, and that nothing has been left to indicate
their former existence beyond the reef flats upon which the corals of the
present day are growing. Remembering also that the corals can form
but an insignificant crust upon the slopes and flats which have been pre-
pared for their growth by the processes of elevation and of subsequent
erosion and denudation, and that the features characteristic of the
existing state of things was not brought about by the growth of the
coral reefs of to-day except in a very secondary manner. We are not
discussing the question of the formation of great limestone banks by
subsidence to attain the proper depth at which corals may begin to grow.
We are only trying to give an explanation of the conditions which must
have preceded and have led to the existing state of things.

The deepest water in the crater basin of Totoya is thirty-five fathoms,
and it certainly cannot be held that a lagoon of such a depth has been
formed by subsidence after the coral reefs have begun to grow. Let
us now follow what would have become of Totoya had the denudation
and submarine erosion which have brought it to its present state been
continued during a longer period of time. A very few fathoms more, and
we should have the rim divided into three large islands, — an eastern

40 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

island with a ridge having a height of about 1,100 feet, a western island
with a height of about 800 feet, and a northwestern island with a sum-
mit of the same height. These islands might thus be reduced to three
separate ridges, giving no indication that they had formed part of the
rim of the crater of an extinct volcano.

The denudation and erosion could be carried still farther, leaving only-
islets, the summits of the higher peaks, to indicate the former position
of the rim, the islets being joined by coi'al patches connecting their
extremities, much as the present opening between the horns of the rim
of the crater is closed by the outer reef. AVe may still further imagine
it to be so far cut down as to form reef flats upon which coral would
grow, thus forming a nearly circular atoll with a depth of 35 fathoms,
— an atoll with the formation of which subsidence has had nothiua' to
do. But this is not an imaginary atoll I am reconstructing. A nmnber
of such atolls are found in Fiji, the formation of which can be satisfactorily
explained on the theory that the I'ing of coral patches represents the
rim of an extinct volcano which has been cut away to below low water
mark. Such atolls in the Fijis are probably Thakau Momo, Thakau
Lasemarawa, Thakau Lekaleka, Motaa Levu, Motua lai lai. Pitman
and Williamson Eeefs, and perhaps others.

The example of Thombia, one of the iLinggold Islands, in which there
is only a distant outer reef, would also indicate the possibility of the rim
of the crater of a small volcanic peak cut down to the surface and forming
the circular flats upon which corals might grow. In the case of Thom-
bia such a condition would result in forming a diminutive atoll not more
than a third of a mile in diameter, enclosed within an encircling barrier
reef.

We might also consider the " Boilers," the diminutive " Serpuline
atolls" inside of the lagoon of the outer reef off' the south shore of the
main island of the Bermudas,-^ as a series of such interior atolls, though
the mode of origin is very different from that of subordinate atolls,
formed, as I have suggested, upon the rim of an extinct crater like
Thombia. In either case, the explanation of the formation of such
interior or subordinate atolls is radically different from that given by
Darwin ^ for their growth in the Maldive atolls, an explanation also
accepted by Dana.

It is becoming more and more apparent that each locality must be

1 Bull. Mus. Comp. Zoiil., XXVI. No. 2, 1895, Plates XXII.-XXVI., p. 253.

2 Darwin's Coral Reefs, 3d ed., p. 44.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 41

considered by itself, and that no sweeping generalization can take in
the formation of all coral reefs. Such atolls as those of Alacran on the
Yucatan Bank of the Hogsty Reef in tlie Bahamas owe their origin —
I mean the conditions existing there now — to entirely dilierent causes
from those which have brought about the formation of some of the atolls
of Fiji, and the atolls of Alacran and of Hogsty themselves again owe
their origin to different causes. The barrier reef of Florida does not
owe its origin to the same causes as those which have led to the forma-
tion of the Great Barrier Beef of Australia, or tlie barrier and friniriuff
reef surrounding parts of Viti Levu, or some of the other islands of the
Fiji group.

It is playing wnth words to call such atolls as I have mentioned above
pseudo atolls, as is becoming the fashion, and to speak of the localities
to which Darwin's theory of the formation of barrier reefs and of atolls
does not apply as exceptions to the rule. These exceptions now cover a
good deal of ground. They include nearly all the coral reefs which
have been examined by recent investigators, — from Semper in the
Pelew Islands, Rein in the Bermudas, Murray in Tahiti and elsewhere,
of Forbes, and of Bourne, of Guppy in the Solomon Islands, Kramer in
Samoa, and others, — down to my own in Florida, the Yucatan Bank,
Cuba, Bermuda, the Bahamas, and the West India Islands, as well as in
the Galapagos and Sandwich Islands, besides the exploration of the
Great Barrier Reef of Australia, and of the Fiji Islands. Surely the list
of investigators and of localities is long enough. The negative evidence
is now becoming overwhelming, and the recent borings at Funafuti have
not weakened the position of those who do not recognize the Darwinian
theory as of universal application, and as not having been proved to
exist in a single instance, either by a careful examination of the locality
or by borings.

Taviuni.

Plates 4, 18, 60.

The islands of Taviuni (Plates 4, 18) and of Kandavu (Plates 10, 11)
illustrate admirably the formation of reefs encircling denuded and eroded
extremities of large islands, and readily explain the existence of very
irregularly shaped reefs representing the former outline of the islands
which they replace. Other characteristic points similar in their origin
ai'e the great spits forming the Namena Barrier Reef, which connects
with the extensive reef platforms reaching towards Ovalau from the
southeastern extremity of Vanua Levu (Plates 3, 3*) and the north-

42 bulletin: museum of comparative zoology.

eastern spitof Vanua Levn, which breaks up into Kioaand Rambe Islands
and the reef-bound platform from which they rise (Plate 4).

On the platform of submarine denudation and erosion Xamena and
Vatu i thake Islands, as well as a few isolated rocks on the western edge
of the southeastern horn of the Yanua Levu Barrier Eeef are the only
I'emnants of the former southern extension of Yanua Levu. To the
southeast of this must have existed a dumbbell-shaped island of consid-
erable height, of which only the summits of Makongai and of Wakaya
are left (Plate 3^).

The island of Taviuni is, with the exception of the shore fringing the
northern half of the island and of the point of reefs off Vuna Point,
destitute of reefs. The island is about 23 miles long, from five to eii^'ht
broad, sloping uniformly to the shores from the backbone of the island.
This rises to a height of over 4,000 feet. The main ridge sends off a few
spurs towards the northeastern face of the island. The fringing reef
attains its greatest width to the east of Naiselesele Point. It encloses
a few small volcanic islets, varying in height from GO to 90 feet, and the
somewhat larger island of Mbuimbani (Plate 60), lying to the south, and
which rises to a height of more than 400 feet. To the south the fringing
reef becomes again quite naiTow, and disappears at Laveine Point.

Immediately north of Somo Somo Strait the submarine platform
widens. Koro Levu Islet and Phillips and McPherson Rocks are in-
cluded within shallow soundings covered with reef patches running out
from the west shore of Taviuni. At a somewhat greater distance from
the west shore of Taviuni within the 50 fathom line are Champion,
Breaknot, and Mate Rocks, and to the northeast of Xaiselesele Point the
submarine platform reaches its greatest width, the Gangway Rocks and
the bank connected with them being the most distant of the outliers of

Taviuni.

To the eastward of Taviuni lie the islands of Ngamia, Lauthala, and
Matangi, separated from Taviuni by the Tasman Strait. The plateau
from which these islands rise is really the extension of the shoal lying
to the east of Taviuni and the outer reef which extends from ]\[atangi
east of Lauthala and south of Ngamia, stretching across Tasman Strait
in disconnected patches and joining the fringing reef off Thurston
Point. To the westward of J^Iatangi the outer reef extends only in
broken patches, and is seen also in the many disconnected patches found
in the western part of Tasman Strait. Between Matangi and the
northeastern horn of the outer reef there are two passages across it.
The lao-oon enclosing Ngamia and Lauthala has a greatest depth of forty

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 43

fathoms and an average depth of over twenty, except to the east of
Lauthala, where the outer reef joins the fringing reef which skirts
Lauthala and Ngamia. There are a number of coral patches all through
the lagoon, but they are most abundant along the inner ed<>-e of the
southern line of the outer reef.

Ngamia and Lauthala are both volcanic ; the former rises to a height
of 1,000 feet. Both are indented with deep bays.

Along the shore of Thurston Point we found a conglomerate in course
of formation, composed of rounded pebbles of lava cemented together
with broken fraguients of coral.

ELEVATED ISLANDS COMPOSED OF CORALLIFEROUS

LIMESTONES.

Ngele Levu.

Plates 17, 17*, Figs. 5-18, and Plates 95-99.

Ngele Levu is an elongated pear-shaped atoll, somewhat constricted
at a few points (Plate 17). Its length is fourteen miles and its greatest
breadth seven. The lagoon is enclosed by a continuous outer reef,
varying in widtli from a quarter of a mile to over a mile. The western
face of the outer reef is broken into patches leaving excellent deep
passages for ships. The depth in the lagoon is quite uniform, the bot-
tom being very level, varying in depth from about five to nine fathoms
at the eastern extremity, and sloping very gradually to fifteen or sixteen
at the westei'u entrance. The bottom is composed of coralline algas,
broken shells, and coral sand, as well as masses of dead corals dei'ived
from the disintegration of the former elevated coralliferous limestone
which once covered the whole area of the lagoon. The lagoon is free
from coral patches except at the eastern end, which is studded with
heads of old coral and patches of living coral. These heads also form
a belt of considerable width along the inner side of the outer reef flats.

The reef flats are made up of elevated coralliferous rock which has
been planed oflf to the level of the sea, and scooped out below it to
form the laooon. At the southern of the western entrances there is a
small sand key, and at the northeast end there are three islands, Ngele
Levu, Tai ni Mbeka (Plate 96), and Taulalia (Plate 95). The outer
faces of these islands form the sea face of the outer reef, there being no
outside reef flats. These islands are entirely composed of elevated

44 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

coralliferous limestones, rising on ^ge\e Levu to about sixty feet, on Tai
ni ]\Ibeka to forty feet, and on Taulalia to thirty feet. The process of
disintegration which has taken place can still be seen going on at the
extremities of the island of Xgele Levu. On the reef flat near it, as
well as along the inner beach, crop out many negro-heads of elevated
limestone rock, and between the smaller islands, which are now only
connected by a reef flat, the islands themselves being undercut and their

urn

TAULALIA, NGELE LEVU LAGOON".

surface deeply pitted and honeycombed (Plates 95, 96). On Taulalia
many large domes of harder material, somewhat conical, still exist,
which have not been rounded off to the general level of the island.

We walked a good part of the length of the island of Xgele Levu,
and crossed it at rioht angles. The elevated tertiarv limestome rock
was found cropping out at all points (Plate 97), and towards the north-
eastern shore we came upon a belt of limestone nearly devoid of vege-
tation, which must have risen at points to fully sixty feet above the
shore line. The surface of that part of the island was full of deep
potholes and crevasses of all sizes and shapes, separated by ridges and
columnar or conical masses, some of them fully fifteen feet alove the
general level of the surrounding area (Plate 98). The rock surface in
all directions was pitted and honeycombed, and eroded into thousands
of sharp points and needles, the aspect of this island recalling a similar
structure so common among the Bahamas. At Observatorv Point, the
southern extremity of the island, this very characteristic structure is
quite well marked, and shows admirably the gradual passage of an island
composed of elevated limestone rock into a reef flat identical in all
respects with the reef flats surrounding the lagoon. Plate 99 shows the

AGASSI2: FIJI ISLANDS AND COIIAL KEEFS.

45

characteristic shore vegetation along the narrow cultivated strip of the
island, while Plates 97 and 98 show the inland vegetation.

We found rather distant coral patches growing in the lagoon in from
six to seven fathoms of water, close up to the inner edge of the outer
reef, starting from an underlying base of tertiaiy limestones, fragments
of which we brought up with the dredge. And upon the plane of the
outer rim of the lagoon, composed of the same tertiary limestones, corals
were growing to a depth of from six to ten fathoms, or more perhaps.

"Wailangilala.

Plates 18, 109, 110.

The island of Wailangilala is somewhat triangular, and connected
by a spit of coral beach rock with the small island of Caliaudrovi to

Copied from a Survey

by Cap. B. Cocks

CAKANDROVl

Roek\V.

WAILANGILALA

the northeast. The east side of the larger island is about fifteen feet
above high water mark. Both islands are low, with sandy or beach rock

46

BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

beaches, and covered with cocoanut trees and shrubs (Plate 110). The
islands are in the northeast angle of a nearly elliptical lagoon (Plate 18),
surrounded by a reef flat varying from a quarter of a mile to more than

^ji"

CAKANDROVI

V\'^!1^\NG1LALA

a mile in width. The outer reef is about nine miles in circumference.
There is an entrance for ships into the lagoon in the western reef flats.

The depth of the central part of the lagoon is from 22 to 23 fathoms,
and the bottom is mainly coralline and coral sand, with broken shells.
The inner edge of the reef flat is flanked by a broad belt of coral patches,
which extend upon the fiat itself, with here and there an isolated patch
in six or seven fathoms of water.

Wailangilala was selected, after consultation with inhabitants of the
Fijis well acquainted with the group, as affording an isolated atoll with
a steep submarine slope, and an island on the outer rim on which to

AGASSIZ: FIJI ISLANDS AND COKAL IlEEFS. 47

establish the boring phant. Having a lighthouse on it, with a keeper
and assistants, it afforded unusual facilities for establishing a comfortable
camp for the boring crew, who were at work a couple of days after
landing.

The following is the record of our boring at "VVailangilala.^
From the surface —

To 20 feet, coral and coralline sand with broken shells, like that on
the beach.
20-30 feet, coralline sand.
30-40 " coral and coralline sand, coarse.
40-50 '' fine coralline sand.

49-51 " parts of core of yellow limestone (elev. limestone).
5i_(ji " " " " " " <'

/?-|_'71 il (I I'. It II it (C

71_H0 " " " " " " *'

80-85 " " " " "

It was on the western inner edge of the island (Plate 109) that I
established our boring apparatus, soon after arriving at Suva, and while
under the impression conveyed by the newspapers, and from published
reports, that the second Funafuti boi'iug expedition had demonstrated
that at the Funafuti atoll true coral reefs extended to a depth of 643
feet. This information seemed so positive that had it been received before
the shipping of my outfit to Fiji via Australia, I should have remained
at home, convinced that at any rate, whatever had been my experience in
the West Indies, Australia, and the Sandwich Island reefs, yet that in
a region of typical atolls in the Pacific the conditions of subsidence
suggested by Darwin and Dana might exist, unless the boring at Funa-
futi proved eventually, on closer examination, to have been can-ied on in
the sea face talus of a reef. But my outfit having left, I was not
prepared to accept the preliminary conclusions of Professor David as
recorded by the papers, and I started on my expedition ready to con-
firm by my own borings the truth of the great thickness of modern
coral reefs in atolls of the Pacific, or to give some other explanation
of this apparently overwhelming proof of the correctness of Dar-
win's theory.

From what we saw of the elevated coralliferous limestone at Ngele
Levu, Vanua Mbalavu, Mango, and other points in Lau on our way to
Ongea, it was very evident that these limestones attained a great thick-

1 The bore liole was about five feet above high water mark, and about thirty
feet from the shore line, a few feet nortli of the Landing (figure on page 45).

48 BULLETIX: MUSEUM OF COMPARATIVE ZOOLOGY.

ness, — 800 feet at Tuvutha, 1,000 feet at Vatu Vara. Therefore as
soon as the drill struck the limestones it might correspond to any
height in the beds exposed elsewhere, beds which at Mango, Kambara,
and Vanua Mbalavu we had observed to rest upon a volcanic substratum.
It was natural that immediately on my return to Suva after our first
trip round the Eastern Archipelago I should send to Wailangilala or-
ders to stop further boring, and to bring the crew and machinery back
to Suva. For it seemed a waste of both time and money to bore and
obtain a core from an indefinite datum plane, when the same evidence
could be obtained by the examination of any one of the bluffs of ele-
vated coralliferous limestones with which w^e had become familiar in our
first trip. But, unfortunately, we were not equipped to make a thorough
exploitation of such a section, not being provided with explosives or
drills, and had to content ourselves with somewhat fragmentary collec-
tions at the more accessible points. However, this is a subject which
I hope to attack again under more favorable conditions.

The boring at "Wailangilala shows that the island is the fragment of
an ancient island of larger size, which once covered the whole area of the
lagoon. Being at the northern extremity of the atoll, it was less subject
to the destructive agency of the sea due to the prevailing southeasterly
winds, and thus there was left a wider reef flat, the last to be worn
away by the action of the sea. It also shows that at a depth of forty
feet we meet the underlying elevated limestone forming the substratum
of the northern reef flat of the lagoon. i\s will be noticed from the
Figure on page 46, the western reef flat is much naiTower than the
eastern and less exposed face of the lagoon.

The boring at AVailangilala is from the remains of an upheaved coral
island, as has been suggested by Gardiner ; ^ but it is also the remnant
of an island which once occupied the whole of that part of the atoll.
Aiwa shows a stage antecedent to that of Wailangilala, the island on the
rim of the lagoon being still of considerable heiglit. Many of the reef
rocks (negro-heads), which Gardiner considers as having been thrown up
by hurricanes, are the remnants of the elevated reef rock outliers left
from the denudation of the flats on which they occur, and which once
rose to a greater height but have gradually been eroded and planed down
to their present elevation.

But Gai'diner is wrong in assuming that the islands of the atolls are
converted into land. Such is by no means necessarily the case. The
islands on the rim of an atoll, as Ngele Levu, consist of elevated coral-

1 Loc. cit., p. 445.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 49

liferous limestone rock, and are the remnants of the former land mass
once covering the area of the atoll of Ngele Leva.

Nuku Mbasanga.

Plates 18, 2?^'^, Fig. 18, and Plate 108.

We skirted along a part of the southwestern edge of jSTuku Mbasanga
atoll (Plate 18). The atoll is oblong, a little over two miles long, open
to the northwest, where the reef flats are broken up into numerous
coral heads. "Within the broad reef flats are a small sandy cay, ^""uku
Mbalate on the western face of the atoll, and the islet of Nuku Mbasanga
(Plate 108), the shores of which are covered with coral beacli rock, or
patches of elevated reef rock, judging from the character of the negro-
heads which crop out on the western side. Both the islands are covered
with coacoanuts and shrubs.

There is every reason to believe that the islands of the ISTuku Mba-
sanga group are the remnants of an island composed of elevated lime-
stone, which has been denuded and eroded to its present condition, and
partly covered, as Wailangilala has been, with coral sand.

Nukusemanu and Nanuku Reefs.

Plates 18, 103-107.

To the eastward of Budd Reef, and separated from it by a channel
about nine miles wide, is situated an elongated, angulai", irregularly
shaped atoll, terminating at its southern extremity in a long ridge of
reef flats called the Nanuku Reef. These send out spurs, the extension
of which connects with the Nukusemanu Reef and encloses a lagoon
fully twenty-four miles long and from two to six miles broad. -The
greater part of the eastern face of the reef is not awash, being made up
of a long series of coral reef patches, with from one to six fathoms of
water, with deeper water between it and the extension of the Nanuku
Eeef. A tongue of the ocean runs westward from 118 fathoms in the
gap separating the extremities of the reefs, rising to a ridge with five
to ten fixthoms, separating it from a deep pool with as much as forty-six
fathoms near the eastern face of the central part of the western reef flat
of Nanuku Reef. Only an occasional reef patch rises to the surface on
that face. On the northeast horn is situated Nukusemanu Island, a
small sand key covered with cocoanuts. On the northwest face the
Nukusemanu Reef flats are seen to be well covered with flourishing coral

VOL. XXXIII. 4

50 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

patches, but nearly the whole of the west face until it joins the western
spur of Nanuku Eeef consists, like the east face, of a long but narrow
reef flat, with from two to seven fathoms, and studded with heads. The
greatest depth in the lagoon is 52 fathoms, with an average depth of
from 25 to 40 fathoms. The interior of the lagoon, especially the
northern part, is studded with heads.

We examined the islets on the southern spits of the Xanuku Reef.
The northern islet, Xanuku lai lai, has been nearly washed away during
the hurricane of 1893 (Plate 107). The southern islet is covered with
shrubs and cocoanuts (Plate 104). The eastern face of this islet,
Nanuku Levn, is flanked with beach rock (Plate 106). There were a
large number of negro-heads of beach rock and of elevated coralliferous
rock scattered upon the reef flats adjoining the island (Plate 103), and
both to the north and towards the southern extremity of the reef flat
ridge (Plate 105). Coral heads begin at about seventeen fathoms off" the
lee side of the reef, the patches increase in size and number at twelve
fathoms, and form a very fine flourishing belt between six to one and a
half or two fathoms. "We could trace these coral patches on the nar-
row reef flat ridge extending northward. This ridge is at some points so
narrow that the breakers form a long white mass of rollers as they fall
from the windward to the leeward side of the reef flat. The leeward
pitch is not as steep as the chai'ts seem to indicate. We found a hun-
dred fathoms on that side, hard bottom, at a distance of one and three
quarters miles from the leeward edge of the reef flat, two and a quarter
miles northerly from Nanuku lai lai (Plate 18).

The island which once covered the tract extending from the northern-
most horn of the Nukusemanu Eeefs to the southwestern horn of the
Nanuku Reefs (Plate 18) was probably flanked by outer ridges of hills
running into a long narrow ridge at the southern extremity, of which
Xanuku lai lai and Xanuku Levu islets are the solitary remnants, while
Xukusemanu Island is the only fragment of the northern extremity of
the eastern ridge. There must have been a valley separating the ridges
now indicated by the open lagoon, with a greatest depth of over forty-five
fathoms, extending from Nanuku Eeef to Nukusemanu Reef, which was
cut into at many points all along the outer edges of the ridges, and con-
nected the plateau of submarine erosion with the great sound of the
interior.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS.

Tuvutha.

Plates 30, 88, 89.

Tuvutha Island is triangular iu shape ; its northern face is about one
and three quarters miles long; the island is nearly three and a half
miles long, and trends in a northwesterly direction from the southern
point to the northern face (Plate 20). It is surrounded by a barrier
reef. The greatest width of the enclosed lagoon is about three quarters
of a mile on the eastern side ; it is somewhat naiTower off the western
face of the island. At two points on the northern side of the island the
outer reef becomes a fringing reef for a short distance. There are a
couple of boat passages into the lagoon through the outer reef flats, one
on each side. The lagoon varies in depth from two to nine fathoms.
With the exception of the central part of the eastern lagoon, it is
studded with coral patches and negro-heads. Tiie latter are especially
numerous off the northern flxce of the island between those points
■where the outer reef becomes a fringing reef, and empounds a small
distinct lagoon.

The central ridge, occupying the interior of the northern part of the
island, runs parallel to the west coast, and as far as I could judge con-
sists of coralliferous limestone elevated to a height of eight hundred feet.
The central ridge is surrounded by a more or less continuous ridge, form-
ing an outer rim and surrounding the inner depressed part of the island.
This ridge consists entirely of elevated limestones, forming along the
northern face a collar of steep bluffs (Plate 88). Other parts of the
ridge, especially on the west side of the island, have been greatly
denuded and eroded into rounded peaks and domes, while the southeast
point is marked for its steep bluffs and sharp ridges (Plate 89). Where
the bluffs rise from the shore of the lagoon, they are deeply undercut.
The outer ridge not being low and broken at any point, no interior
lagoon or sound has been formed with the exception of a small bight on
the southern part of the eastern face of the island (Plate 20).

The central volcanic mass which has elevated Tuvutha as well as
Naiau has not broken through the elevated limestones, although it has
assumed the appearance of the wide round rim of an extinct crater.
But, as will be seen in the case of Naiau, the formation of the central
basin is not due to volcanic agencies, but to atmospheric causes.

52

BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Naiau.

Plates 30, 32% Fig. 1.

!N^aiau Island is, like Tuvutha, composed entii'ely of an elevated lime-
stone ridge forming a continuous rim round a central depression stated
to be about 200 feet lower than its highest points, which rise from 530
to 580 feet above the level of the sea. The sea face of the rim rises

NORTH POINT OF NAIAU.

in nearly perpendicular blufis round the island. At their base they are
deeply undercut, and the larger fragments are eroded into dome-like
heads. Off the southeastern point an islet has been isolated from the
island. Naiau is surrounded by a fringing reef broadest on the eastern
face, about half a mile wide, where at half tide boats can pass, between
it and the shore, forming an incipient lagoon, and enter through a
narrow boat harbor passage, out of which, I am informed by our pilot,
runs a strong current. Tliere are numerous negro-heads all along the
outer edge of the fringing reef, especially near the northwestern point of
the island, where the fringing reef is narrowest.

Naiau,^ Tuvutha, Kambara, Wangava, and other elevated islands,
consisting of coralliferous limestone, have been considered to be elevated

Jl-frilj^.llllM'' *l>iC^^-'-

'^UnAiii,>UiimiiLV<hTiiiiiWiaur^iduliia&

^V ' ' I'l'

NAIAU, SEEN FROM THE EAST.

atolls, owing to the existence of a depression in the summit, which is
looked upon as representing the former lagoon. While that may be the

1 Moore, Nature, March 18, 1897, p. 463. Others have looked upon these islands
as extinct craters.

AGASSIZ : FIJI ISLANDS AND COKAL liEEFS. 53

case, I am inclined to consider these central basins as due to the action
of atmospheric agencies, and to look upon them as similar to the gigantic
banana holes, as they are called, occurring in the Bahamas, whicli are
undoubtedly due to the solvent action of tlie rains overcharged with car-
tonic acid, which carry off the limestones, and, percolating through the
mass, leave the saucer-shaped basins characteristic of the so called ele-
vated atolls. In such islands as Xaiau, Vanua Vatu, Tuvutha, Kambara,
and Wangava, the central depression has not extended very far towards
the sea level. But in such islands as Mango the central depression has
formed a small lagoon, in Namuka submarine erosion has carried off one
side of the rim ; in Fulanga (Plate 22) the process has been carried
still farther by the direct action of the sea and of submarine erosion,
forming a large lagoon ; and the conditions existing at Ongea, Yangasa,
Aiwa, and finally at Reid Haven, Wailangilala, iSTgele Levu, etc., illus-
trate the different stages in the transformation by submarine erosion of a
so called elevated atoll of tertiary age into an atoll of the present epoch.
The probable extent to which atmospheric agencies have conti-ibuted
to shape such central basins is also shown fi'om the presence of exten-
sive caves in the elevated limestone islands of Vatu Leile, of Thithia,
and of Ngillangillah, and in the numerous cracks, caverns, and cavities
which characterize the faces of the vertical bluffs of elevated limestone
wherever we have met them in the Fijis (see Plates 74, 77, 92).

^VATU VARA, SEEN FROM THE EAST.

Vatu Vara.

Plate 19.

On the last trip of the " Yaralla " from Suva to Wailangilala, Captain
Thomson examined for me the islands of Vatu Vara, Yathata, Kaimbo,
and Naitamba. The accompanying account is based upon his notes.

54 bulletin: museum of comparative zoology.

Vatu Vara or Hat Island (Plate 19) is one mile and a quarter in
diametei-. Its summit is flat, and falls off on all sides in steep cliffs.
It attains an altitude of 1,030 feet. The cliffs consist of elevated lime-
stone standing out conspicuously through the dark foliage which covers
the island from base to summit. Up to the very summit of the island
the exposed rocks are seen to consist of limestone. The island is
surrounded by a fringing reef nearly a mile in width on the west coast.
On the east and north sides the sea breaks against the neai'ly vertical
limestone cliffs. They are deeply undercut. On the northwest side two
separate masses of limestone stand out midway between the base of the
cliffs and the outer edge of the reef. An incipient lagoon, open to the
north, is forming along a part of the west coast of the island.

Yathata and Kaimbo.

Plate 19.

The islands of Yathata and Kaimbo (Plate 19), which rise respectively
to the height of 840 and 150 feet, are composed of elevated limestone
rock. A fringing reef encloses them both. It attains a width of over
half a mile where it connects the islands, and is nearly a mile wide
off the north of Yathata. Off that shore a number of small islets and
heads stand out between the island and the outer edge of the reef. Else-
where the frincrinK reef is narrow. Between the islands in the middle of
the fringing reef stands out the i.slet of Nuku Levu, *J0 feet in height,
and a few heads. There appears to have been a secondary elevation on
the south side of Kaimbo, where the undercut ledge has been raised about
twenty feet above high water mark.

I am informed by Captain R. Cocks that Katavanga is composed of
elevated limestones.

Aiwa.

Plates 21, 23*, Figs. 13-15.

Aiwa consists of two small elongated islands, the western one of which
is not quite a mile in length (Plate 21). Both are composed of elevated
limestone, pitted and honeycombed, forming low vertical bluffs along
their southern faces. The highest points of the islands are respectively
210 and 200 feet. They are connected by a coral reef awash at low
tide. The islands are in the middle of the southern face of the outer
reef flat, which encloses an elongate narrow triangular lagoon nine miles

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 55

in length. From the extremities of the islands off the south face projects
a horn of the outer reef, forming a small enclosed lagoon separated from
the principal lagoon and with a greatest depth of ten fathoms. The
greatest depth of the principal lagoon is 23 fathoms. The northern face
of the outei' reef is much broken, and flanked by large patches of corals
and heads, with a wide entrance into the northwestern end of the lagoon.
The western face of the lagoon is three miles long. The inner edge of
the western face is flanked by a broad belt of coral patches and heads.
The coral patches are growing upon sunken heads of elevated reef rock,
the remnants of the elevated reef once covering the area now occupied
by the Aiwa lagoon. The reef flats consisted wherever we saw them of
elevated reef rock planed off" to a general level, upon which coral patches
were growing.

This group is hfstorically interesting, as Dana in his Corals and Coral
Islands (p. 2G4) gives a section across the islands and lagoon, which
according to him illustrates very forcibly the effect of subsidence in
the formation of atolls. A more unfortunate selection could not have
been made. But Dana did not visit this group, and took his information
from the charts, or he would not have chosen as an illustration an island
group which consists of elevated limestone rock, — islands which after
their elevation have suffered most extensive denudation and erosion, and
upon the outer edge of the surrounding platform the corals of the present
epoch have found a footing and formed a sheet of very moderate thick-
ness. The lagoon between the encircling reef and the islands has
been hollowed out by mechanical causes similar to those which T have
alluded to elsewhere, and which have in my opinion shaped the lagoons
of all the atolls and barrier reefs of the Fijis.

Dana assumes the lagoon of Aiwa to have been formed during the
slow subsidence of the island enclosed within its reef, while there is every
evidence that the lagoon of Aiwa has been scooped out by submarine
erosion, and the island, consisting of late tertiary limestones, has been
lowered by denudation, and that the limestones after their elevation have
remained at the present level, and that the corals now growing upon the
outer rim and upon the reef flats, as well as the coral heads insid» of the
lagoon, have but little thickness, and that well within the greatest depth
at which reef-building corals can grow.

56

BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Oneata.

Plates 31, 33^, Figs. 10-13.

Oneata Island is a low ridge of elevated limestone, rising to a height
of IGO feet, connected at its eastern extremity by a coral reef with the
islet of Loa, of similar structure to Oneata, and rising to a height of
140 feet. Towards the eastern extremity of Oneata, on the northern
side, the island is indented by deep bays, studded with mushroom-
shaped islets and large heads barely cropping to the surface. The spit

ONEATA.

protecting the bay from the east rises vertically, is deeply pitted, full of
potholes, and honeycombed and perforated by a large opening similar
to the Hole in the Wall at Abaco in the Bahamas. Everywhere on the
surface of the island we found
the elevated limestone cropping
out. The southern face of the
island is also indented with
bays, the beginning of shallow
sounds which are now cutting
Oneata into smaller islands by
undermining the shore line and
forming low vertical cliffs, prob-
ably by the same processes which
disintegrated the area formerly

occupied by the elevated limestones, and of which Oneata and Loa are
the remnants.

Oneata lies about a mile from the inner edge of the outer reef flat,

ISLET OFF ONEATA SHOKE.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 57

enclosing a triangularly shaped lagoon, with a greatest dej^th of 21
fathoms. The length of the southern reef flat is a little over ten miles,
that of the northern face about nine miles, and that of the western and
northwestern faces connecting them is five miles. There are three pas-
sages on the western and northwestern faces, and one through the north-
ern face. The bottom of the lagoon, between the reef patches and heads,
is covered with coralline algee and with coral sand. There ai-e many
large heads scattered along the inner edge of the northern reef flat, and
on the extension of the western extremity of the island.

Namuka.

Plate 23.

We did not visit Namuka, but steamed near enough to the island to
recognize its distinctive features. It is a narrow, undulating ridge, four
miles long, rising to a height of 240 feet ; it is composed of elevated
limestone. On the southern and western faces there are deep bays, or
incipient sounds, which, if extended, would divide the island into a
number of islets. The island is surrounded by a fringing reef off the
southwestern extremity, and off the eastern point of tlie island. Be-
tween these points an outer reef extends off the south coast, forming a
narrow and shallow lagoon full of heads, with five fathoms at its deepest
point. On the northern face the western part of the lagoon is deeper,
having thirteen fathoms. The horns of the outer reef of the northern
and westei-n faces are connected by broken patches and heads which
form tlie harbor of Namuka.

About three and a half miles northeast from the entrance to Namuka
Harbor lies "Wilkes Reef (Plate 22), a flat a little over half a mile iu
length, dry at low water, with outlying rocks and banks within the sur-
rounding 100 fathom line.

*o

Yangasa.

Plates 33, 33^, Figs. 8, 9, and Plates 90-93.

The cluster of Yangasa (Plate 22) consists of four islands and numer-
ous rocks and islets, all of which are composed of elevated limestone.
The largest island of the group, Yangasa Levu, is nearly two miles in
length and about half a mile wide. Its shores are formed of precipitous
cliffs, which surround the whole island ; they are deeply undercut at the
base, perhaps more than any other island we have seen in Fiji. The

58 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

crest of the highest ridge is flat, and runs at a general level of about
300 feet. The highest summit, toward the southern end of the island,
is nearly 400 feet ; off that point there are indications of a terrace at
about one third the height of the island, as if the elevation of this
group had taken place at two successive periods. Yangasa Levu seen
from the west, on the way to Ongea, appears hat-shaped, with a high
terrace forming the rim. The island of Yangasu Levu is from one to
two miles distant from the inner edge of the outer reef flat forming the
eastern horn of the lagoon. Along the western side of the lagoon are

c^^&^^i^^^M^kbikA...^::^.^^

~ii J i^-km

TAXGASA LEVU.

situated Navutuira, in the northwest angle of the lagoon, which rises to
270 feet; this is connected with the islet of Yuvutha (Plate 90) by a
long narrow reef studded with mushroom-shaped rocks rising above
high water mark. The whole of the northwestern part of the lagoon
to the west of the ship passage on the north face of the outer reef flat is
also thickly studded with negro-heads and with mushroom-shaped rocks
of all sizes and shapes, which cover the wide reef flat to the west and
north of Xavutuira. The large mushroom-shaped heads are generally
on the extension of spits or headlands of the two islands named.

The crest of Navutuira is undulating, and from its shores rise low
undercut vertical blufi's. Yuvutha (Plate 90), on the contrary, has a
conical outline, its highest summit rising to 240 feet ; its vertical shore
bluff's are higher than those of Xavutuira, deeply undercut ; they are
nothing but the rim of a sound left from the disintegration, denudation,
and erosion of the adjoining land. Such rims are at a distance readily
mistaken for the rims of extinct craters. We anchored off" the west side
of Xavutuiloma, the most southern of the islands along the west side of
the lagoon. The small bay on the north face of Xavutuiloma resembles
closely a pai*t of the rim of an extinct crater. But that rim and those
forming the eastern and western points are entirely composed of ele-
vated limestone, full of caverns and caves, pits and potholes, many of
them full of red earth, as is the case wherever elevated limestone is
met with; it is deeply honeycombed and cut into ridges (Plate 92),
upon the edges of wliich rise endless sharp pinnacles and needles.
This was also the structure and appearance of the inland slope of
the island where we lauded.

AGASSIZ: FIJI ISLANDS AXD COEAL REEFS. 59

The little bay was studded with mushroom-shaped and conical islets
and rocks, all deeply undercut (Plates 91, 93), and the bottom in from
two to four fathoms was covered with sunken coral patches and heads
rising at all depths.

Some of the islets were covered with bushes and cocoanut trees, like
the main island. The highest point of oS^avutuiloma is 210 feet; it is a
little over one mile in length, and is larger than Navutuira. The shape
of the outer reef flats enclosing the lagoon of Yangasa (Plate 22) is ir-
regularly rectangular, with rounded angles ; the faces are each about
five miles long, the western face being the longer. On the eastern and
northeastern side, the reef flat is quite narrow, but it is studded along
the inner edge with a belt of heads and coral patches and negro-heads.
Ofl" the southeastern horn, the reef flat becomes very wide, projecting in
a point fully two miles beyond its general line. The reef flats of the
southern and western faces are also broad, fully a mile in width in some
places, and at the northwestern horn the reef flat is more than a mile
and a quarter wide.

On the northern face of the lagoon a tongue of deep water (l-to fath-
oms) fully a mile wide runs towards the centre of the lagoon ; this is the
passage used for entering the lagoon. The slope of this part of the lagoon
is very steep, and it is studded with coral patches and heads growing
upon the remnants of the former island of Yangasa. This narrow and
deep tongue of the ocean represents probably an original valley formed
in the uplifting of the island, and has no connection with a subsidence
of the island during the formation of the encircling reef, which has
grown subsequently upon the platform of submarine erosion formed by
the wearing away of the original land mass. The average depth of the
northern part of the lagoon is from 14 to 19 fathoms. The southern
part, between Yangasa Levu and Navutuiloma and the reef flat, is shal-
lower, from six to twelve fathoms, with a still shallower belt along the
inner edge of the southern reef flat.

Off" the southeastern extremity of Xavutuiloraa extend a number of
mushroom-shaped rocks and islets, deeply undercut and eroded into fan-
tastic crests, pinnacles, and summits. The reef flat of the western face
of the Yangasji lagoon is full of thriving coral patches, which extend
along the inner edge, between and upon the negro-heads, down to seven
or eight fathoms. The formation, by erosion and denudation, of diminu-
tive or incipient sounds, as in the bay of Navutuiloma, is interesting as
representing one stage in the action of such processes, of which others
can be followed in the conditions which have been reached by such

60 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

islands as ZS'amuka, Mango, Ngele Levu, Fulanga, Oneata, Ongea, and
others. It is quite probable that the islands and islets of this group
represent the remnants of the submarine erosion and denudation which
have cut the greater island of Yangasa, consisting of elevated limestone,
which once occupied the area of the lagoon, into smaller islands by a
process similar to that now going on to cut up the island of Navutui-
loma, — a process which has left, as indicating its former greater extent,
the islands of the cluster, its rocks and islets, and the numberless heads
cropping out everywhere over the outer reef flats, and in the extension
of the spits and points of its islands.

To the eastward of the Yangasa cluster, and separated from it by a
narrow channel of about half a mile in width and a depth of a little
over 100 fathoms, lies Thakau Levu (Plate 22), an elongated horseshoe-
shaped atoll, nearly four and a half miles in length, with a greatest
breadth of less than two miles. The lagoon enclosed by the outer reef
flat is open on the west face. The greatest depth in the lagoon is 11
fathoms ; it is studded with heads and patches. The reef flat at the
eastern point of the lagoon is fully a mile wide.

South of Thakau Levu (Plate 22) lies the fiat reef of Thakau Thi-
kondua, and the small island Naiabo, of elevated limestone, rising to a
height of forty feet, surrounded by a narrow encircling reef enclosing
a shallow lagoon. Still farther south are the flat reefs of Thakau Reiva-
reiva and Thakau Nasokesoke, both, according to the sailing direc-
tions, dry at low water and steep to all round. AVe did not visit either
Thakau Levu or the last mentioned reefs.

Ongea.

Plates 22, 33*, Figs. 6, 7, and Plate 94.

The Ongea group consists of two large islands, Ongea Levu and
Ongea Xdi-iti, and numberless mushroom-shaped or conical or dome-
shaped islets and rocks, studding both the passage between the two
principal islands or fringing the shoi'es or extending across the openings
of the bays which indent the coast line of Ongea Levu and Ongea JS'driti
(Plate 22). The lai-ger island, Ongea Levu, runs nearly north and
south ; it is four miles long, and varies from one to two miles in width ;
it rises to a height of 270 feet. This island lies in the centre of the north-
ern part of the lagoon, about equidistant from the outer encircling reef
flats, within a channel from three quarters of a mile to a mile in width,
and varying in depth from seven to twelve fathoms. Off the southern

AGASSIZ: FIJI ISLANDS AXD CORAL EEEFS. 61

end of Ongea Levu the lagoon expands, and attains a width of neai-ly
six miles. The onter reef flat is narrow, but expands to a width of
three quarters of a mile off the southern face of Ongea Ndriti, where
it becomes a fringing reef. Ongea Xdriti is nearly two miles long
and one mile broad, and rises to a height of 300 feet. The Barracouta
Passage is the only ship channel leading into the lagoon. It opens
tlu'ough the western reef flat into the widest part of tlie pear-shaped
lagoon, a little south of the extremity of Ongea Levu. The greatest
length of the lagoon is about eig-ht miles.

The Ongea Islands consist of elevated limestone, rising in nearly verti-
cal cliffs along the shore line. This is deeply indented by broad and deep
bays, forming small irregularly shaped sounds, which in the case of Ongea
Levu have nearly cut that island into two (Plate 22). The openings of
the bavs and the shores of the islands themselves on the western and

!»

SOUTinVEST POINT OF ONGEA LEVU.

southei'n faces of Ongea Levu are studded with islets and I'ocks, whicli,
like the ridges of the islands, consist of elevated limestone. They are
most numerous off the wide and deep bay on tlie southern face of the
larger island, and extend across the channel separating Ongea Levu and
Ongea Xdriti (Plate 94). The outliers extending south from the former
island connect with those stretching north from the opposite face of the
smaller island.

The mushroom-shaped rocks and islets also extend along tlie western
face of Ongea Ndriti, but they are not as numerous as on the northern
fixce. On many of the islets are found a few straggling palmettos, iden-
tical with those growing on the principal island. The islets and rocks
as well as the shoi'e cliffs are deeply undercut, and the surface is deeply
pitted, honeycombed, and full of potholes and caverns, and presenting
the appearance so characteristic of the weathered coralliferous limestone
wherever we have found it in Fiji. It seems, however, as if the erosion

62 bulletin: museum of compjleative zoology.

and denudation, and the accompanying weathering, had been more in-
tense as we proceeded southward along the windward islands of Fiji.
The islets and rocks remaining as evidence of the former connection of
tlie islands of this group are perhaps as good illustrations as any we
have seen of the f)rocess which has been going on to reduce to its present
proportions the original reef flat or island, which probably once covered
the whole of the area of the Ongea Lagoon. The bottom of the lasoon
is made np of coral and coralline sand. Half a mile from the north-
eastern horn of the outer reef of Ongea rises a sharp submarine peak, ot
which only the rock rising on the western edge remains, and on which
has been formed the suiall circular reef of Thakau Teteika, about three
quarters of a mile in diameter; while to the southeast, distant about
three miles and a quarter, rises Xuku Songea, a triangularly shaped
atoll enclosing a shallow lagoon with a low sand key at its northern
extremity.

Fulanga.

Plates 22, 22^, Figs. 4, 3, and Plates S0-S4.

Fulanga is an elliptical island deeply indented on its southwestern
face (Plate 22), along which rises a ridge of elevated limestone to the
height of 240 feet. This tertiary limestone rock has been elevated to a
height of 2G0 feet at Quoin Hill, on the northeastern foce of the island.
The " Sailing Directions" (p. 214) represent Fulanga as " of volcanic and

ENTRANCE TO FULANGA.

coral formation, and the circular shape of the island leads to the suppo-
sition that it is the rim of an extinct crater." What I have seen of
Fulanga shows no trace of volcanic rocks, though they may exist on the
southwest shore, which we did not see. ]\Ir. Gardiner,^ who visited
Fulanga, classifies it among the limestone islands. It is quite natural

1 Proc. Cambridge Pliil. Soc, Vol. IX. Part VIIL p. 458 (1898).

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 63

that the honeycombed pitted pinnacles of hard ringing limestone should
be mistaken by inexperienced observers for volcanic clinker-like rocks,
and the locality described as volcanic, especially when taken in connec-
tion with the crater-like aspect of the sounds. The island is surrounded
by a fringing reef nearly a mile in width in some places, and with a pas-
sao-e forming a shallow and very narrow lagoon with a depth of four to
hve fathoms between the outer reef flat and the shore line along parts of
the eastern and of the western face of the island. There is a narrow
passao-e (Plate 82) on the northeastern face into tlie interior basin, but
too shallow to have admitted the " Yaralla." In addition there are also
a number of openings, between the numerous islands and islets into
which the elevated limestone ridge has been cut up (Plate 80). Through
all these the current flows with considerable velocity (three knots). The

EAST SIDE OF FULAXGA.

interior of the basin is full of islets and of rocks, mushroom-shaped or
dome-shaped, all deeply undercut and all consisting of the same elevated
limestone of which the outer ridges ai'e composed (Plate 81). These
islets and rocks are of all sizes and shapes, some of them nearly half a
mile in length ; and they are found in everv part of the basin (Plates
83, 84j. The greatest depth of the interior basin is ten fathoms, with
an average of five to six.

Although the general appearance of Fulanga is much like that of an
extinct crater, yet its formation is due to other than volcanic agencies.
The whole of the area of Fulanfja must formerlv have been covered by
a bed of raised coralliferous limestone. The lower parts of the eastern
face of this elevated flat became cut up into islands and islets, allowing
the passage of the sea, and it has little by little eaten into the body of the
elevated limestone, forming an extensive inner basin four miles in length

64 bulletin: museum of compakative zoology.

by two miles wide, leaving the basin studded with.inuumerable islets
and rocks (Plates 83, 84) such as I have already mentioned. These
islands have usually vertical faces; many of them are conical, dome-
shaped, or mushroom-shaped, like the islands and islets inside of the
interior basin. A similar process has been going on off the northern
point of Fulanga, south of Quoin Hill, where the conical and dome-
shaped and mushroom-shaped islands and islets and rocks are seen to
pass gradually from conical or dome-shaped bluffs along the shoi-e line
into the negro-heads of the outer reef flat off that point. This process
of disintegration must have been similar in every i-espect to that which
has formed the sounds in the Bermudas, eating small bays into the
faces of bluffs inland, these becoming circular with time, vrith only a
narrow opening, and finally leaving merely a narrow ridge or parts of
ridges surrounding a central basin resembling an atoll.

FCLANGA SOUTH OF QCOIX HILL.

If the process which has been shaping Fulanga had been goirg on
longer the result would have been a low ridge on the southwestern face
of an elliptical outer reef flat, with an enclosed lagoon full of islets or
rocks or heads, and here and there perhaps an island or islet indicating
the former existence of the elevated coralliferous limestone ridge ; there
being a passage into the lagoon where it now exists, the lagoon as en-
larged including the true lagoon and the " Sound " basin, — a condition
of things very similar to that found on Oneata, Xgele Levu, Yangasa,
Xanuku, and on Yanua Mbalavu. On the faces of the islands and islets
forming the eastern ridge of the basin of Fulanga rise vertical cliffs
deeply undercut and weathered. The reef flats are full of negro-heads,
some of which are of considerable size. The reef flats are everywhere
covered with extensive stretches of flourishing coi-als.

This atoll-like basin has thus in reality been formed by the wearing
action of the sea, and subsidence has played no part in its formation; on
the contrarv, the coralliferous limestone flat covering the basin has been

AGASSIZ: FIJI ISLANDS AND COEAL EEEFS. 65

elevated to nearly three hundred feet, and it has been subject for a long
period to the action of the atmosphere and of the sea ; the one wearing
down the limestone land into an inner basin or cutting it out into
valleys, and finally into islands and islets ; the other encroaching into it
from the outside, and eventually forming an interior basin studded with
islets, which to all appearance would be a lagoon surrounded by an
encircling reef with its heads and patches and islands and islets. And
yet it would really be a crater-like basin, a " Sound," which by erosion
had become connected with the true bari-ier reef lagoon, and finally even
all trace of the Sound character of the inner basin might vanish with
the disappearance of the old shore line, and the existence of only islets
to indicate tlie former land area.

In the case of Fulanga, Gardiner -^ has well described the action of the
sea both as a solvent and as a disintegrating factor in reducing the rocks
and islets to mushroom-shaped structures, and in the great undercutting
of the cliffs, of which he gives the same illustration as that I give here,
which was kindly furnished me by the Hon. W. L. Allardyce. He says :
"The final result should be a perfect atoll reef just awash, the laud be-
ing dissolved away while the living reef round it continues to grow."
So it does, but the reef has played no part in the shaping of the atoll,
the lagoon of which owes its existence to the formation of the interior
Sound by the decomposition of the elevated tertiary limestone reef mass,
and has no connection with the recent coral reef growing upon the reef
flats or external platforn:t of submarine erosion.

%?;m?aaa^n%'t~— ■-■-g-- -- ■

SOUTHEAST POINT OF MARAMBO.

Marambo.

Plate '-i3.

Marambo is a small circular island about three quarters of a mile in
diameter (Plate 22). It is composed of elevated limestone rising to
160 feet in height. It is surrounded by a fringing reef fully a mile ia

1 Loc. cit., p. 459.

VOL. XXXIII. 5

66 BULLETIN : MUSEUM OF COMPAEATIYE ZOOLOGY.

width off the northern extremity of the island. Off the southwest face
of the ishand there is a shallow incipient lagoon. There is a large crack
running through the peak of the highest point of the island near the
southern point, as if the sea face might scale off at any moment and form
a vertical cliff. There is a fine vertical cliff along the northeast point of
the island over 100 feet in height, deeply undercut. From the lower
edge of this cliff numberless negro-heads extend over the surface of
the fringing reef flat, which is covered by lai'ge patches of.flourishing
corals.

NORTH POINT OF MAEAMBO.

Dana and Darwin both speak of fissures passing through the shore
shelf reef. The fissure we saw at Marambo I attribute to the giving
way of the shore bluffs from the undermining pi'eparatory to its shal-
ing off.

Wangava.

Plate 22.

"Wangava. as seen from the passage between it and the northern ex-
tremity of Kambara, appears to be composed of two parallel ridges of
limestone, elevated to a height of nearly 300 feet. The island is steep to
on all sides, steep cliffs forming its eastern and westei'n faces. It is
suiTounded by a wide fringing i-eef (Plate 22) except off the north face,
where it becomes broken up into coral heads and patches.

Vatu Leile.

Plates 9, 17*, Figs. 1-4, and Plates 100-102.

Yatu Leile, the westernmost island of the group we examined, is tri-
angular in shape, with a small lagoon extending along the eastern and
the northern fixces of the island (Plate 9). The lagoon is comparatively
shallow, not having anywhere a depth greater than five fathoms. Xearly

AGASSIZ: FIJI ISLANDS AND COltAL KEEFS.

67

the whole lagoon is covered with patches of corals and of reef rock, espe-
cially in the southern and western parts. The island of A'atu Leile is
a mass of elevated limestone rock, rising at the southern extremity to
bluffs of about 30 feet on the western side. The series of bluffs forming

WEST SIDE OF VATU LEILE.

the western shore gradually increase in heiofht as we so north, where at
the most westerly point the bluffs are more than 100 feet in height
(Plate 100).

The hlutfs of the western coast are vertical faces witli rounded summits
full of cavities and alternate with short coral sand heaclies. On many
parts of the fringing reef edging the west coast there are still left small
mushroom-shaped rocks, fragments of elevated limestone rock once form-

NORTHWEST POINT OF VATU LEILE.

ing a part of the main island. The northern extremity of the island is
full of caves. Judging from the color of the water, the outer slope of the
reef flat towards deep water appears to be very gradual. The whole island
slopes gently to the eastward, having gradually been denuded and eroded
so as to form a low east shore line, with extensive flats off the north-
eastern point. The west shore is protected by a fringing coast reef

68 BULLETIN: MUSEUM OF COMPAEATIYE ZOOLOGY.

varyiug iu width from a few yards to 300 or 500 yards, or even disap-
pearing entirely along some of the beaches, with many areas of smooth
impounded water within the fringing reef flats. The north side of the
lagoon is protected by an outer reef flat fully half a mile wide in some
places. On it corals are flourishing. There are two passages into the
lagoon, with about ten feet of water in the channel. On the eastern
side the outer reef runs parallel with the coast, gradually becoming "wider
towards the south, where it forms a wide coral flat connecting as a frin-
ging reef the outer reef with the low southern part of the island.

To the west of the lee passage are the small island of Yatu Savu
(Plate 101), consisting of a larger low rock of elevated limestone deeply
undercut and pitted and honeycombed, and of three other mushroom-
shaped rocks of the same structure. Between the lee and the weather
passage are the islands of Yatu Levu and the cluster of rocks Yatu
lai lai (Plate 102), similar in structure and in appearance to Yatu Savu.
These islands and islets are all situated upon the flat of the outer reef.
The whole reef flat is further studded with negro-heads, the remnants of
former islands and islets of elevated limestone.

The presence of these islands, islets, and rocks, as well as the existence
of the extensive flats ofi" the east coast, clearly indicate the manner in
which denudation and erosion have transformed the greater Yatu Leile
which once may have covered the whole- area of the lagoon, leaving only
a part of the main island, with the islands and islets on the outer reef
flats and the innumerable patches of corals flanking the inner edge of the
outer reef. There is a strong current flowing out through the passages
of the northern line of the outer reef.

THE SOUNDS OF FIJI.

Plate 32. ,

Fulanga is also interesting as illustrating the formation of an atoll by
the same causes which have produced the Sounds iu the Bermudas.^
In the case of Fulanga we have a ring of elevated coralliferous lime-
stone raised by volcanic agencies to a height of nearly two hundred feet.
The whole area of Fulanga was probably once covered by coralliferous
limestone, forming an island resembling Kambara or Mango. The island
was, judging from its present condition, highest on the northern side, with

1 Bull. :Mus. Comp. Zool., Vol. XXVI. Xo. 2, 1895, p. 231 ; also Bull. Mus. Comp.
Zool., Vol. XXVIII. Xo. 2, 1896, p. 29.

AGASSIZ: FIJI ISLANDS AND COKAL REEFS. 69

summits nearly as high on the southwest coast, and sloping seaward
towards the east (Plate 80). Atmospheric agencies gradually reduced
its height, cutting out at the same time an interior basin, the eastern
rim of which (Plate 81), being lowest, was soon denuded and eroded in
part. One can readily see (Plate 22) how longer denudation and ero-
sion would reduce the existing Fulauga land to a few large islands left
isolated in the interior of an encircling reef and connected only bv a few
mushroom-shaped or conical islets, the interior of the lagoon bciuo-
dotted with coral heads, the recent corals on the outer edge of the sub-
marine flat forming a reef crust of moderate thickness. This coral rim
has been broken through, and the action of the sea has gradually
hollowed out in the interior a circular sound resembling an extinct crater
(Plate 22), which has arisen solely from the disintegration of the inner
part of the elevated limestone. Many parts of this still exist as small
mushroom-shaped or conical islands (Plate 83).

It is also probable that some of the ancient elevated reef flats may
have been converted into atolls by causes similar to those which have
produced the crater-like Sound of Fulanga. This has perhaps been the
case with such atolls as Xgele Levu, and the Oneata, Ongea, and Yan-
gasa groups. In both Ongea Levu and Ongea Ndriti (Plate 22), incipient
sounds are forming which will cut these islands into two or more com-
ponents, each one of which will in its turn be dissected into smaller
islands or islets, till finally the remaining land may be all reduced to
insignificant islands and islets, as on Ngele Levu (Plate 17), or on "Wai-
langilala (Plate 18), Pteid Haven, A'anua Masi (Plate 20), Motua Levu
and Motua lai lai. Duff" and Adolphus Reefs (Plate 18), or the islets may
have totally disappeared and no vestige of the former land area remain
except the sunken coral heads and rocks of such atolls as Thakau Levu,
Thakau Motu (Plate 22), Thakau Lekaleka (Plate 21), the Ongea
Eeefs (Plates 20, 21), Thakau Tambu (Plate 20), Thakau Mata Thuthu,
and Thakau Vutho Vutho (Plate 17), with the reservation that some of
these atolls may be the result of the denudation and submarine erosion
of volcanic islets or peaks or ridges, and not necessarily of elevated
coralliferous limestones.

Are not islands such as Phoenix, Birnie, Kean, Howland, Baker, and
Enderbury, which have depressions in the centre and no lagoons, islands
which are gradually being denuded to the level of the sea, and the next
stage of which will V)e the formation of a lagoon (sound) by the cutting
in of the sea across the rim at one or more points, forming islands or
islets round the lagoonl We can thus explain the peculiar formation of

70 BULLETIN : MUSEU:M OF COMPAEATIYE. ZOOLOGY.

these islands without having recourse to subsidence. Yet other writers
upon coral reefs would look upon some of these islands as instances of
raised atolls.

The gradual transformation of islands, composed either wliollv or in
part of elevated limestone, into islands with large interior sounds like
Fulanga can be readily followed by examining such islands as Waufava
(Plate 22), Tuvutha, Xaiau (Plate 20), or Vanua Vatu (Plate 21), in
which the interior basin is still surrounded by a high rim. Xext fol-
lowed such islands as Mango (Plate 19), in which the interior basin has
at one extremity been transformed into a diminutive sound ; then follow
such islands as Xamuka (Plate 22), the rim of the basin of which has
been eroded so as to leave only .parts of it, and the outline of which has
been deeply cut into by a large outer sound. We pass next to such a
group as Ongea (Plate 22), and next to such groups as Yangasa (Plate
22), of which the rim of the basin is represented only by four small
islands scattered within the encircling reef; next to Oneata and Aiwa,
where a single island, comparatively small, represents the former extent
of the elevated limestone area of those groups. And a still further stage
of erosion and denudation is represented, as stated above, by Xgele
Levu, Wailangilala, and other atolls in Lau.

Vatu Leile (Plate 9) must have sloped very rapidly eastward to have
attained its present condition, and we can readily follow it to a time
when it will be flanked on the west side by a line of narrow islets very
similar to those now existing on the north side of the lagoon. "WJien
the island and islets in Yatu Leile, !N'gele Levu, Wailangilala, Katavanga,
Eeid Reef, Aiwa, Oneata, Yangasa, and Ongea have disappeared by sub-
sequent erosion, it will be wellnigh impossible to detect the nature of the
substratum upon which the modem reef is growing. At that time the
lagoon will probably have become gouged out much as Xgele Levu has
been. A similar difficulty will naturally be encountered, though at a
later period, in determining the geological composition of the substratum
underlying the modern coral reef in the atolls of Wakaya, Makongai
(Plate 15), Mbengha (Plate 8), North and Great Astrolabe Reefs (Plates
9, 10, 11), Budd Reef (Plate IS), Totoya (Plate 16). Kimbonibo
(Plate 19), Xairai (Plates 12, 14), Komo (Plate 22), and others, when
the islands now existing on the edge or within the encircling reefs have
disappeared from denudation and submarine erosion.

This is another instance of the eri'eat varietv of causes which have been
active in producing the present physiognomy of the reefs of the Fijis,
and shows the impossibility of assigning any one factor, like subsidence.

AGASSIZ: FIJI ISLANDS AXD CORAL EEEFS, 71

for instance, as is done by Dana and Darwin, ns the single cause for
the formation of the many different kinds of atolls and of barrier reef
islands to be found in the Fijis.

THE TERTIARY ELEVATED LIMESTONES OF FIJI.

The existence throughout Fiji of numerous platforms of submarine
erosion at average depths varying within very moderate limits seems to
indicate a condition of approximate equilibrium as far as either elevation
or subsidence is concerned. The elevation of the limestones of late
tertiary age clearly indicates that the origin of the greater number of
the Fiji Islands dates back approximately to that period. This is un-
doubtedly the case with the range of islands known as the Lau or Eastern
Archipelago of Fiji. AVith them we should include the more northerly
islands, the group to the east of Xgamia, and of Budd Reef, including
Thikombia.

It is more difficult to determine the age of the larger islands, Viti Levu
and Yanua Leva, as well as Taviuni, Kandavu, and the volcanic islands
of the Ivoro Sea. "We may assume with a certain degree of probability
that the age of such islands as Nairai and Xgau corresponds with the
age of the volcanic rocks which have lifted the islands of the Lau group
to their present altitude. But in Viti Levu and Yanua Levu the
problem is more complicated. While elevated coralliferous limestones
of late tertiary age occur along the shores of Viti Levu evidently of the
same age as the limestones of Lau.-'^yet there is evidence of the existence
of older rocks as a nucleus of the larger Fiji Islands. So that until the
geology of Viti Levu and of Vanua Levu has been more accurately
studied, we must leave their age undetermined ; but enough is known
of the geology of the shoi-e line to show that the existence of the great
barrier and frino-ing; reefs along the shores of Viti Levu and of Vanua
Levu gives no evidence that the great barrier reefs of these islands owe
their origin to the gradual subsidence, during our epoch, of the islands
themselves.

The existence of the tertiary elevated coralliferous limestone at so
many points in the Fiji Archipelago (Plate 2) seems to indicate a huge
limestone bed of great thickness and extent, formed during tertiary times,
along the flanks of ancient volcanic islands, and elevated by subsequent
intermittent volcanic action during moi'e recent times over ai*eas of

1 Home {A Year in Fiji, London, 1881, p. 165) says that in Viti Levu and Vanua
Levu sedimentary or limestone rocks are found on all mountains.

/ z.

2 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY.

varying dimensions, — areas which might be of considerable extent, like
the Exploring Isles, the Argo Reefs, or smaller areas, like Yangasa,
Oneata, Ongea, Fulanga, and the like, or smaller peaks forming atolls of
very limited circumference, like Wailangilala, Xuku Mbasanga, or iso-
lated limestone rocks of still smaller dimensions, like Yekai, Tavunasithi,
and others.

Of course numerous soundings among the islands of the Eastern Archi-
pelago of Fiji are needed to ascertain the existence of a more or less
continuous plateau of coralliferous tertiary limestone dejDosited either by
accretions upon its surface or formed during subsidence.

I brought to Suva a complete diamond-drill boring apparatus and a
competent man to superintend the work, Mr. William Eyers, recom-
mended to us by the Sullivau Machine Company of Chicago, from whom
the apparatus was obtained. A comparatively small hand machine T>-as
sent, capable of drilling to a depth of from four to five hundred feet ;
an oil motor was also provided to expedite the work with increasing
depth. ^ This machinery had been shipped when information reached
the United States that Professor David of the Univei'sity of Sydney
had left for Funafuti in charge of an expedition to take up the work
Avhere it was left by Professor Sollas, the bead of the expedition, assisted
by the council of the Poyal Society of London.^ The day before leaving
Cambridge for the Pacific, we heard that Professor David's party had
succeeded in reaching a depth of nearly 600 feet, the bottom being still
in coral. This information seemed to settle the coral question, and all
I hoped to accomplish was merely to confirm the work of Professor
David by boring in some other district. Subsequent information re-
ceived from him leads me to think that the matter is not so simple
as represented by the newspapers, and from what I have seen thus far
in the Fiji Island reefs I can only conclude that the boring at Funafuti
has settled nothing, and that we are still as far as ever from, having a
general theory- of the formation of coral reefs. In fact, with the present
information obtained in Fiji, I should never have thought of boring in
the atolls of that group, for reasons which will be given presently.

This evidence shows that any result ootaiued would merely indicate
the thickness of the former elevated limestones at any particular point ;
information wliich could have no bearing ou the main question, if I am

1 I have to thank the Trustees of the Bache Fund of the National Academy of
Science at Washington for an appropriation of SI, 200 towards defraying a part of
the expenses of the boring.

- Proceedings of the Eoyal Society of London, March, 1897, p. 502.

AGASSIZ: FIJI ISLANDS AlsD COEAL EEEFS. 7o

correct in my interpretation of what I have observed ; information, in
fact, wliicli may be obtained as one steams along, without the trouble or
cost of boring. Should I be correct in my inference, I am inclined to
look upon the boring at Funafuti much in the same light, and to assume
that that island is also in an area of elevation, as well as others in tlie
EUice group, and that the great thickness of coral obtained was reached
in the base of an ancient limestone, and that the results obtained by the
boring there do not assist us in any way in coxToborating the theory of
subsidence as essential to the formation of atolls.

The evidence which has been brought forward regarding the great
thickness of modern reefs, as postulated by Darwin, from that of the fos-
sil coral reefs existing during former geologicarperiods, seems to me to
he of little value. Langenbeck -^ and von Lendenfeld -^ have both urged
this point. The former lias given an excellent resume of the subject of
these ancient reefs, although he has no personal knowledge of recent
reefs. All that can be said at present is that these so called fossil
reefs are coralliferous limestones of great thickness, which first occur in
the Devonian ; they are little developed either in the Permian, or Trias,
or Lias. They are again well developed in the Jui-assic period, less so
in the Cretaceous, and increase in Tertiaiy times. That parts of some
of these coralliferous limestone masses represent reefs there can be little
doul;)t, vet the observations we made in Fiji regarding the coralliferous
elevated Tertiarv limestones, which have been considered as elevated
reefs of the present epoch, only show how guai'ded we should be in an
expression of opinion as to what constitutes a fossil reef, — I mean a
fossil fringing or barrier reef, or a fossil atoll, — when we are not able to
decide that point in the reefs of to-day, and when one set of observers
claims that the Tertiary elevated limestones represent elevated atolls,
while tlie other set clearly shows- that these elevated limestones have
played no part in the formation of tlie recent atoll, or barrier reef, but
have merely built up the substratum upon which the moderately thin
crust of recent reefs has established itself.

Granting, even, as is very probable, that when these Tertiary lime-
stones were formed they were formed in great part by subsidence,
and in part by accretion from the carcasses of the invertebrates living
upon their sui'face, this would in no way help us to a satisfactory

1 Langenbeck, R. : Die Theorien iiber die Entstehung der Koralleninsein und
Korallenriffe und ihre Bedeutung fiir Physische Fragen. Leipzig, Abschnitt IV.

2 Nature, May, 1890, p. 29. See also the interesting note by von Fritsch.
quoted by Kramer, he. cit., p. 33.

74 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY.

explanation of the formation of atolls and of barrier reefs by the growth
of the corals of tiie present epoch. Xor would the geological evidence of
the great thickness of similar limestones in past periods be of any
assistance in the solution of the problem if our explanation of the
formation of atolls and of barrier reefs upon platforms of submarine
erosion is correct.

Certainly the analogy of tlie association of volcanic rocks and so
called i-eefs in the Devonian and Trias with similar association in the
Pacific lias no value, as is suggested by Freeh ^ and Langenbeck. The
substratum upon which corals may grow depends upon the geological
structure of the country and its latitude. Such an analogy would
throw out iu great part the reefs of Australia, those of Florida, of the
Bahamas, of Honduras, and of the northern coast of Brazil, which are
not in volcanic regions, and where the substratum is either Cretaceous
or Tertiary.

The only evidence we have of the great thickness of coral reefs, such
as is required l)y the Darwinian theory of tlie formation of atolls and
of barrier reefs, is based upon the great thickness of the so called
elevated reefs observed in the Pacific by Dana, Darwin, and others, and
upon similar observations in Cuba and other parts of tlie "West Indies,
and upon the evidence of the great thickness of the reefs of the Dol-
omite. That the latter are true coral reefs is more than doubtful.
Those rocks are probably great masses of limestone similar to the huge
deposits of so called elevated reefs of the West Indies and of the Pacific.
The evidence obtained by boring, and from recent elevated reefs, shows
that the modem coral reef attains but a moderate thickness well within
tliat of the depth at which reef corals grow. The limestones form
the basis or substratum upon which the recent reefs have obtained
a footinc;. The elevated reefs of Cuba and of the West Indies have
been shown to be Tertiary coralliferous limestones, and the same is the
case with the elevated reefs of the Pacific, if we can judge of their
aae bv that of the elevated coralliferous limestone reefs resembling
them observed by me in Fiji.

The central depression, noted as characteristic of the summit of so
many islands consisting of elevated coralliferous limestones does not show
these islands to be elevated atolls as has been supposed. Tlie summit
basin representing the former lagoon of the island has been formed since
the elevation of the island by atmospheric agencies. This basin is a
gigantic banana-hole, as such depressions ai"e called in the Bahamas,

1 Neues Jalirb. f. Mineral, 1892, Pt. II. p. 173.

AGA.SSIZ : FIJI ISLANDS AND COEAL REEFS. 75

formed by the carrying off the limestone in solution in the pools or ponds
in the summit basins, — basins which with age become deeper and deeper,
forming thus depressions which in some instances have been mistaken,
in the one case for extinct craters, in the other for the la<''oons of
elevated ^tolls.

I would refer to the description of such islands in Fiji as Mango,
Kambara, Tuvutha, Naia\i, Fulanga, and others, as evidence supporting
the explanation here given of the formation of the so called elevated
iitoUs. or course I do not mean to assert tliat an atoll cannot be
elevateil as such, nor tluit such atolls may not exist. I merely wish
to assert that the suuunit basins of islands formed of elevated cor-
alliferous Tertiary limestones in Fiji are islands in the first stage of
disintegration, passing gradually from such types as Naiau ^ and the
like to islands like Mango, then to Fulanga, next to tlie Yaugasa. cluster,
then to Ngele Levu, and finally to Motua lai lai and the like.

The steepness of the slopes of coral reefs has been assumed to be due
to the growtli of corals, and has generally been taken from old and unre-
liable soundings, as has been stated by Admiral Wliarton^ and othei's.
The great depths are generally soundings so far off from the coral islands
as not to give any accurate information.

The actual slopes of coral reefs which have been measured are very
few, and the slopes given are invariably those of tlie underlying sub-
stratum, which may or may not be steep, and tlie inclination of which
has no bearing on the angle of the steep outer slope of recent coral
reefs, which usually reaches only to the very moderate depth of twelve
to fifteen fathoms.

It seems to me that the calculations which have been made by Dar-
win in regard to the thickness of coral reefs, depending as they do upon
the assumption that tlieir great thickness has been formed by sub-
sidence, and that tiiis thick mass rests upon the continuation of the
inner land slope under the coral reef, are assumptions which cannot be
proved, or have not been proved. We should get a totally different
result, that of a comparatively thin crust, if we assume that the land
slope commences at or near the outer edge of the reef wherever the out-
ermost negro- heads have been found. And in a great many cases, the
steepness of the sea face is no greater than the slope of the mountains
of the adjoining land. I have already called attention to the fact that

1 Naiau itself having become depressed in the centre by chemical and atmos-
pheric erosion.

2 Nature, June 19, 1800, p. 172.

76 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

off the south coast of Cuba we have along the sides of Bartlett Deep
fully as steep a pitch as that of any coral reef.

Gardiner ^ has noticed the atoll-shaped shoals inside the great barrier
reef of Fiji (Plate 23^), and compares them to the smaller atolls inside
the large atolls of the Maldive group. See also the Serpuline, atolls of
the Bermudas,- which hold the same relation to the lagoon inside the
outer barrier as the atoll-shaped shoals just mentioned hold in Fiji,
and they certainly are not due to the effects of the debris of the outer
reefs of the present day, as is claimed by Dana.

As long as it was taken for granted that the coral reefs of the present
da}- were of great thickness, it was natural to compare them with the
great beds of coralliferoas limestones occurring iu jjast ages from the
time of the Devonian to the end of the Tertiary period. While there is
abundant proof that some of these limestone beds have been formed
during a period of subsidence, there is also ample proof that they must
have greatly increased in thickness by accretion. But it does not follow
from this that atolls and the lagoons of barrier reefs have been formed
during a period of subsidence, now that we know that a great many of
the coral reefs of the present day attain a comparatively moderate thick-
ness, well within the bath^-metrical limits at which reef building corals
thrive. Xor is there anything to prove that these ancient limestones
represent such modern structures as the atolls, or bordered the lagoons
of barrier reefs, and even if they did it is more natural to suppose that
the lagoons of these ancient atolls, as well as those within the ancient
barrier reefs, must have been formed b}- the same agencies which have
shaped the atolls and the lagoons of barrier reefs iu our days. So that
the analogy between ancient and modern reefs, such as is upheld by Dr.
R. von Lendenfeld,^ while undoubtedly true as far as it applies to the
formation of beds of coralliferous limestones of great thickness, vet has
no application to the actual formation of the lagoon of an atoll or of a
barrier reef.

This still leaves open the question of the mode of formation of such
thick masses of coralline and coralliferous limestone, which, though they
may originally have been formed partly by subsidence, may also have
been formed partly by the gradual pushing out to seaward of the outer
edge of a reef increasing both in height (depth) and in width by the con-
stant pushing out of the mass of debris and of blocks detached from the

1 Loc. at., p. 493.

2 Bull. Mus. Comp. Zoul., Vol. XXVI. No. 2, 1805, p. 253.

3 Nature, No. 1071, May 8, 1890. p. 29.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 77

outer edge upon which corals may flourish and spread seaward, when
the talus has reached the depth at which corals can grow. I am iu-
clined to think that the examination of such a reef will alone give us
an idea of the way in which such thick masses of coralliferous lime-
stones were formed, — most pi-obably by a combination of subsidence,
of accretion, and of lateral expansion.

What the exact age of the elevated limestones is, I am as yd unable
to state. Their aspect and position show them to be of considoi-able
age, and probably antecedent to the present period, and in many ways
they resemble some of the late tertiary elevated limestones I have found
on the north coast of Cuba. The great thickness which the elevated
coralliferous limestones attain in this group, at least 800 feet, also
shows that it may have been deposited" during a period of subsidence,
but not a period of subsidence in our epoch, or which could have had
any effect in shaping the outline of the islands of the Fiji and their
accompanying reefs.

Whether the elevation of the Fiji group corresponds in time with that
of the northern part of Queensland, I am unable to state. I can only
suggest that it is not improbable that the elevation of Queensland and
of the islands to the east of the Solomon, New Hebrides, etc., including
the Fijis and Samoa, may have been synchronous, and that these islands
have, like uoi'thern Queensland, been subject to an immense denudation
and erosion, reducing them to their present proportions. The elevation
having probably, as in northern Australia, been preceded in still earlier
geological times by a great depression, during which the thick beds of
coralliferous limestone may have been formed. Judging from some pho-
tographs I have seen, I should feel inclined to consider the atolls of the
Paumotus to have been formed by causes similar to those which have
shaped those of the Fijis.

The Tonga Islands as described by Lister^ are arranged by him in
three divisions : (a) purely volcanic islands ; (b) islands formed of
volcanic materials laid out beneath the sea and since elevated, with or
without a covering of reef limestones ; and (e) islands formed entirely of
reef limestones.

The islands of tlie Vavau group consist entirely of limestone, the. for-
mation of Avliich must have been at least 300 feet thick. The islands are
flat-topped, and the majority stand at one of three levels of elevation.
Lister 2 figures the terraces of the islands to the south of Vavau. At

1 Notes on the Geology of the Tonga Islands. By J. J. Lister. Q. J. Geol.
Soc. of London, Vol. XLVIL p. 590, 189L

2 Loc cit., p. 608.

78 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Fiji the only signs we saw of terraces were at Yangasa. The terraces
in Fiji are most obscure, and what we find of elevation would seem to
indicate sudden and rapid elevation without periods of rest such as
occur in the Vavau Islands of the Tonga group, or in Cuba/ where the
terraces are so well marked, especially in the vicinity of Cape Maysi.^

Lister speaks of the peculiar shape of the groups, penetrated bv lono-^
narrow, and deep inlets of the sea, a condition of things very similar to
that of Xgillaugillah, and of the north shore of Vanua Mbalavu in
Fiji. Tongatabu is formed of coral limestone tliroughout, and one often
meets with patches of coral, many feet in diameter, on which the lines
of Astrceoids or Madrepores are seen radiating from a common centre.

Lister calls attention to the basis for the growth of coral reefs which
can be foi-med by such islands as Falcon Island.^ He also shows that
in the Tonga Islands, Tongatabu and Xanuku rest on shallow banks,
and where the basis is exposed it is shown at Xanuku and Eua to consist
of layers of volcanic material laid out under water.

Darwin and Dana both suggested that the formation of the Tonga
Atolls was in a period of subsidence, yet it is asserted in the discussion
of the subject* by Mr. J. W. Gregory that his theory (Darwin's) was
not proposed for areas of coral formation in shallow or rising areas.
Why then do Darwin and Dana quote them as examples of their theory?
There is altogether too much of that kind of argument in the discussion
of that theory. Are Darwin's supporters at liberty to carry on the
process of selection till nothing is left of the original statement]

In Samoa and Tonga the volcanoes are still active, and we can, follow-
ing Lister, actually trace the process of elevation and of erosion which
has resulted in Tonga in elevating limestones and volcanic islands similar
in every respect to those we have observed in Fiji. Islands in the last
named group owe their existence to former volcanic action, the evidence
of which is still visible in the existence of the extinct craters of Taviuni,
of Thombia, of Moala, and of Totoya, and this volcanic action is to be
traced throughout the larger islands of the group.

The description of Eua Island in the Tonga group given by Com-
mander Oldham in Nature of May 22, 1890, p. 95, applies admirably to

1 A. Agassiz, A Reconnoissance of the Bahamas anrl the Elevated Reefs of Cuba.
Bull. Mus"conip. Zool., Vol. XXVI. No. 1, p. 110, 1894.

2 R. T. Hill, Notes on the Geology of the Island of Cuba. BuU. Mas. Comp.
Zool,, Vol. XVI. No. 15, 189.5.

3 Falcon Island is stated to have disappeared during an eruption in August.
1898.

* Q. J. Geol. Soc. of London, Vol. XLVII. p. 590, 1891

AGASSIZ : FIJI ISLANDS AND CORAL REEFS. 79

the conditions which I imagine to have existed in the Fijis,^ although the
terraces indicate two periods of elevation, with one of rest, during which
an interior basin similar to the central basin of islands like Kambara,
Wangava, and the like, in Fiji, was formed by atmospheric agencies
probably.

The rocks underlying the coralliferous limestones are stated by Pro-
fessor Judd to be igneous rocks, but not modern volcanic material.
He says, " They are suggestive of ancient volcanic masses that have
been exposed at the surface by denudation, . . . and it is quite incor-
rect to quote examples like this as lending support to the view that all
oceanic islands are of volcanic origin."

Speaking of Eua, which belongs to group (b), Murray according to
Lister is of the opinion that the organic deposits of the island are old,
yet there is no satisfactory evidence to refer them to the Tertiary
period.

Nine or Savage Island is an elevated coralliferous limestone island,
said to be 200 feet high ; - the younger Foster considers that the cen-
tral plain represents an ancient lagoon. It is skirted with enormous
caverns.

The figure and description given by Dana " of Metia or Aurora Island,
one of the ^Yestern Paumotus, recalls many of the raised limestone
islands of Fiji. In the Hervey group at Atiu similar caverns exist, and
they have also been noticed by Captain Beechey at Henderson Island.
Its cliffs worn into caverns rise abruptly to about 230 feet on all sides
except the south, where the island slopes very abruptly, much as Vatu
Leile in Fiji. The surfixce of Metia, as described by Dana, resembles
closely that of Ngele Levu, and he describes the wide shore platform,
"resembling that of the low coral islands" and the modern reef about
its margin.

It will be interesting to see if the great masses of coral blocks, figured
and mentioned by Dana * may not throw some new light on the nature
of the substratum of some of the Paumotus, where he observed them.

The sections of the small island of Masamashu in the Eed Sea^ do
uot seem to me to indicate subsidence, as is stated by Bonney (p. 312).

1 See also the account of Eua, by J. J. Lister, in Q. J. Geol. Soc. of London,
Vol. XLVIL p. 590, 189L

2 Sailing Directions, Pacific Islands, Vol. II. p. 54.

3 Loc. cit., p. 193.

* Loc. cit., pp. 179 and 203.

5 Nature, Vol. XXX VL p. 413.

80 bulletin: museum of compakative zoology.

On the coutraiy, judging from Fiji analogy, the section indicates the
elevation of a submarine bank of coralliferous limestone and its subse-
quent denudation, and the forming of an enveloping reef on its summit
having no relation with the nature of the deeper sea slope.

We collected a number of corals from the elevated limestone rock at
several localities along the south and west coast of Viti Levu, at Suva,
Ngele Levu, Kambara, Ongea, Ngillangillah, and Oneata. I found it
impossible to determine whether the corals were in situ, or had been
rolled or dropped along the sea face to form a talus. The difficulty of
determining this without very considerable blasting at the base, the
face, and along the exposed slopes of the elevated coralliferous lime-
stones, is verv great.

The collecting of corals from the exposed faces of the cliff was almost
hopeless with our appliances. The faces have become extremely hard,
a hammer produces no impression, and the corals are so well embedded
as to make it impossible to cut them out.

It seems impracticable, except where one can actually see the corals
grow along a slope, or on a patch or the sides of a head, to determine in
the elevated reef rock if they are still in their natural attitudes. Madre-
pores and Pocillopores grow in all kinds of 2:)osition ; so do the heads of
Astrseans, Mseandrinas, and other massive corals. Furthermore, the
spaces between coral patches and heads and individual masses of coral
reef are filled either with sand, corallines, or fragments of dead corals.
We can easily see the difficulty of recognizing the former condition of
corals now embedded in a homogeneous mass of hard ringing limestone,
in which the corals often exist as more or less indistinct solidified masses,
barely indicating the genus to which they belong. The coral and coral-
line sand have become solidified into a close limestone ringing to the
hammer. Large spaces have become impregnated with the red earth,
characteristic of coi'al limestone formations, and the masses of coral
fragments form a breccia or puddingstone of corals of the species which
once flourished on the reef. Masses of Nullipores and Orbitolites are
similarly cemented, or form the connection between the individual
masses. The whole again is more or less cavernous, representing either
spaces originally existing on the reef, or cavities which have been formed
by the percolation of water through the mass. As far as I have exam-
ined the corals collected from the elevated limestones, they appear to
belong to the same genera as those now living.

A careful and extended examination of one of the elevated coralliferous
limestone reefs, as at Vanua Mbalavu or Kambara or Mango, for instance,

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 81

where we can begin the study at the very base of the elevated limestoue
reef at its point of contact with tlie underlying volcanic rock, will teach
us a great deal regarding the interior structure of a coral reef. This we
can follow to the surface, or nearly so, by following the faces of exposed
cliffs or the slopes of the ridges. Of course, the uppermost part of the reef
rock, that which formed the original surface of the reef, will have been
denuded and eroded to a considerable depth. Eut it ought to be possible
from the study of an extensive area of an elevated reef, both vertical
and horizontal, to settle the question of the growth of a reef seaward by
its gradual extension upon a talus formed at a comparatively shallow
depth (say twenty fathoms) from the fragments and masses which have
dropped at the foot of the sea slope of the reef, after having been de-
tached by the action of the breakers from the edge of the reef. It is
natural to suppose that there must exist at the base of the reef a num-
ber of coral masses, judging from the multitude which are thrown upon
the sea face of any modern reef when exposed to violent breakers.

Dr. William H. DalP has been kind enough to examine the fossil
mollusks which I collected from the elevated limestone reefs in the
Fijis. He coutirms the impression I had formed of their late tertiary
age. Dr. Dall writes : " The fossils comprise Turbo, Cassis, Lithophaga,
Macha, Teilina, Meretrix, Dosinia, Chama, Pholas, and fragments of
Pecten. None of the genera are extinct. The rock, however, looks
decidedly too old for Pleistocene. I should say the fossils were younger
than Eocene, and might be either Miocene or Pliocene."

The boring which I started at Wailangilala Island in the atoll of the
same name reached at forty feet a limestone similar in all respects to
that composing the elevated reefs we had observed at Ngele Levu,
at Yanua Mbalavu, at Mango, at Yangasa, at Oneata, at Ongea, at
Kambara, at Yatu Leile, and at different points along the eastern,
southei'n, and western shores of Yiti Levu. At some points the elevated
limestones attain a height of over 1,000 feet (Yatu Yara Island 1,030
feet), and the volcanic rocks underlying the elevated limestone reefs
were observed at Yanua Mbalavu, at Mango, at Kambara, and at several
points along the southern and western coast of Yiti Levu. A renewed
examination of tlie elevated reefs of the Paumotus, of the Friendly
Islands, of the Gilbert, Ellice, and other groups of atolls in the Pacific
will be needed to determine their age and correlation to the Fiji ele-
vated limestones. At any rate, it is evident that the tertiary corallif-
erous limestones of Fiji have not played any part in the formation of
1 See Am. Journ. Science, Vol. VI. p. 165, 1898.

VOL. XXXIII. 6

82 bulletin: museum of comparative zoology.

the atolls or islands encircled by recent coral reefs beyond forming the
substratum upon which the recent corals have grown and established
themselves as a comparatively thin crust.

The underlying limestones have performed exactly the same part as
the volcanic substratum in other islands of Fiji, such as Totoya, Kim-
bombo, Wakaya, Makongai, Moala, Nairai, Ngau, and others. In both
cases the platform upon the edge of which the corals grow has been
prepared by extensive submarine erosion, dating from the time when the
limestones were elevated by the volcanic rocks which crop out everywhere
in Fiji, — an elevation which was not necessarily synchronous throughout
Fiji and may have taken place at several distinct periods, so as to make
it often difficult to determine the relative age of the limestones and of
the volcanic masses.

Professor David, of the University of Sydney, has been kind enough to
assist me in obtaining the services of one of his students, Mr. E. C.
Andrews, to collect fossils from the elevated limestones of Fiji. Mr.
Andrews has spent a part of the summer in Fiji, collecting material and
exploring in detail some of the faces and slopes of the elevated reefs of
the Archipelago, and has obtained ample material to determine the age
of these elevated limestones.

In the earlier discussions of the thickness of recent coral reefs by
Darwin and Dana, no attention was paid to the possibility of the sub-
stratum of recent reefs consisting of tertiary limestones. Elevated lime-
stones containing corals of tertiary age were considered as of recent
origin and as pointing to a great thickness of modern reefs. It has
been shown in Florida that the modern reef is not more than about
50 feet thick, and is, according to the borings from the artesian well at
Key West, succeeded by tertiary limestones, in which corals occur at
intervals to a depth of 2,000 feet.

It has been stated by Dana and others that the borings from the
ai'tesiau wells at Honolulu, to the rear of the shore line of the fringing
reef of Oahu, indicate a great thickness of modei'n reef corals. These
statements are based upon the examination of samples of finely ground
particles of limestone accompanied by an occasional fragment of coral,
the age of which has not been determined. The statements are furtlier
supported by the evidence of Mr. J. A. McCandless, the engineer in
charge of the boring, who asserted to both Mr. Dana and myself that in
boring all his wells the tool passed through a great thickness of corals, at
various levels. During my recent visit at Honolulu, I was so fortunate as
to be on the spot where Mr. McCandless was boring a ten-inch well, about

AGASSIZ : FIJI ISLANDS AND CORAL REEFS. 8

o

2,500 feet from the shore line, and perhaps seven feet above hio-h water
mark. Down to a depth of 80 feet nothing but recent reef coral rock
was encountered, but from that point to a depth of over 300 feet the
limestone passed through was of a very different character. It contained
but few corals, being composed almost entirely of the shells of moUusks,
maiuly bivalves. The rock was white, chalky, and resembled in every
way the rocks of the Vicksburg age of Florida and of Yucatan ; but its
age has not yet been accurately determined. Enough, however, is clear
to show that the limestones which form the substratum upon which
rests the recent fringing reef of Honolulu do not belong to the present
period. Mr. ^IcCandless assured me that limestones like those I had
the opportunity of examining while the boring was going on are identi-
cal with those to which he called Mr. Dana's and my attention in 1888,
and that until I pointed out to him that the white limestone was almost
wholly made up of mollusks he had only paid attention to the occurrence
of occasional corals, and supposed that the lower limestone formed the
continuation of the recent modern reef. But, as I have stated, this
lower limestone differs from reef rock both lithologically and in its being
mainly made up of fossil mollusks. ,

It is very clear that when boring in a coral reef district in which it
is difficult or impossible from other data to determine what geological
changes may have taken place, or the probable age of any limestone we
may pass through in boring, it may be very easy to draw wrong conclu-
sions both as to the age of the limestones and regarding the position of
the line of demarcation between the modern coral reef and the under-
lying older limestone substratum.

If my conclusion is correct, that such atolls in the Fiji Islands as Wai-
langilala, Xgele Levu, and many others to which I have referred in this
report, are foi'med upon platforms of submarine erosion of elevated ter-
tiary limestones, and if, further, in similar atolls in the Paumotus, the
Gilbert, Ellice, and other groups, the substratum underlying the mod-
ern coral reef is likewise composed of tertiary limestones, it will become
apparent that such borings as those carried on at Funafuti will not help
us in any way to solve the problem of the formation of atolls by modern
coral reefs. Such a boring, even should it reach the underlying volcanic
substratum, will only give us the thickness of the tertiary coralliferous
limestone beds forming the substratum upon which the modern coral reef
has grown, — a thickness which in the Ellice group can only be ascer-
tained by boring, while in Fiji it can be ascertained approximately from
the height of the islands composed of elevated tertiary limestones.

84 bulletin: museum of compaeative zoology,

I take it that the " cliffs " mentioned by Sollas,^ and that the pinna-
cles described by Gardiner ^ which he calls " the remains of a part of an
old raised reef," found on the inner rough zone of the outer reef, are just
such masses of tertiary limestone as we found throughout the Fijis.

The shoals described by Gardiner ^ seem to me to be remnants of this
elevated reef which have been isolated by submarine erosion, much as
iu Fulanga and Ngele Levu, and other groups of elevated tertiary lime-
stone reefs in Fiji, upon which corals grow with greater or less luxuri-
ance, the bottom of the lagoon between the patches and knolls being
covered with sand.

Gardiner* supposed the atoll of Funafuti to have been formed before
it was elevated. If I am correct in my interpretation of similar reefs
in Fiji, I think, on the contrary, that the low limestone outer platform
which now forms the ring of the atoll was once much higher, covered
a greater area, and has been gradually denuded and eroded to its present
stage, a process which according to Gai-diner and my own observations is
still going on.

Hedley,^ as well as Sollas and Gardiner, assumes an elevation of four
feet from the presence of dead subfossil corals in the position of life
near high water mark. I do not see why the fact that the older lime-
stones of Funafuti form a cone, and have no connection witli the recent
reef formed upon them, should have any bearing either in favor of or
against any theory of coral reefs, even if the formation of the corallif-
erous limestones of Funafuti could only be explained on the subsidence
theory. The lateral growth of the recent reef inwards and outwards is
a feature depending, so far as the outer growth is concerned, wholly
upon the exterior slope of the atoll, and the lateral expansion towards
the interior of the lagoon depends upon a great variety of causes, such
as the depth of the lagoon, the character of the islands on the outer edge
of tlie atoll, the nature and depth of the shallower windward passages
leading into the lagoon, the position of the outer reefs with reference to
the prevailing winds and currents, the geological structure of the sub-
stratum upon which the recent reef is growing, and many other causes.
As far as the filling of the lagoon of Funafuti is concerned, the views of
Gardiner and Hedley are diametrically opposed. The islands may in-

1 Proc. Royal Society of London, March, 1897, p. 502. Nature, September 24,
1896. p. 517. '

•^ Proc. Camb. Phil. Soc, Vol. IX. Pt. VIII., 1898, pp. 430, 431.

3 Lnc. cit., p 434. * Loc. cit., p. 438.

^ Memoir III., Austrahan Museum, Part I. Sydney, 1896.

AGASSIZ: FIJI ISLANDS AND COKAL EEEFS. 85

crease in width, and encroach upon the lagoon, but that is a different
proposition, as shown by Gardiner, from the filling up of the lagoon.

Gardiner ^ assumes that the limestones of the Fijis cannot have had
any different origin from that of many of the atolls and barrier and
fringing reefs of the present day.-^ But it seems to me that, inasmuch
as these elevated limestones are of tertiary age and have been uplifted
to heights varying from a few feet above the level of the sea to nearly a
thousand feet to form subsequently platforms of submarine erosion upon
which the recent reefs have grown, we cannot claim that they have been
deposited, as recent corals have been, within compai-atively narrow bathy-
metrical limits, the dolomitization of the elevated tertiary limestone
having gone on to a considerable extent, while that of the recent reefs
is insio'uificant.

Gardiner ^ looks upon Naiau, Tuvutha, and other islands as perfect
specimens of raised atolls. I have elsewhere given my reasons for not
accepting such a view, and for considering the interior depressions of
such " elevated atolls " as huge sinks similar to those formed in tlie
^olian hills of the Bahamas and Bermudas, and which eventually result
in the formation of sounds or lagoon-like depressions. Gardiner * does
not think it possible that denudation owing to climatic causes could
have been of sufficient importance to have greatly affected the position
of the summits. It seems to me that the gradation we can trace in the
summits and outlines of such old island masses as Naiau, Kambara,
Mango, Fulanga, Ongea, Aiwa, and others indicate, on the contrary,
a most extraordinary denudation and accompanying submarine erosion.
Gardiner* himself has given very much the same examples which I used
in tracing the gradual changes hinted at above, only he attributes them
wholly to the solvent action of tho sea, while I am inclined to call into
action in addition the effect of denudation and erosion, and to attribute
to them a more important share than to the solvent action of the sea
in the successive stages of the changes in the elevated limestone land
masses, from an island with a fringing reef to a true atoll.

Under what conditions these tertiary coralliferous limestones of great
thickness have been deposited is a distinct question from that of the
.formation of atolls through subsidence b}' the upward growth of corals
during the present geological period. Neither the borings .through a
coral reef growing upon a substratum of tertiary limestone, nor the

1 Loc. dt., p. 467. * Loc. at., p. 470.

■■^ Loc. dt., p. 467. ^ Loc. cit., p. 471.

•' Loc. cit., p. 470.

86 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY,

examination of the outer edge of a coral reef formed upon a substratum of
volcanic rocks, has given us in Fiji any evidence of the great thickness
of a modern coral reef. On the contrary, all the evidence I have gath-
ered there tends to prove that a coral reef forms only a comparatively
thin crust upon the platform of submarine erosion, whatever be its geo-
logical structure, upon which it may have fovuid a footing, — a crust of
modern corals of no greater thickness than that within the bathymetrical
range of which reef building corals can flourish.

The examination of the conditions under which beds of coralliferous
limestone of great thickness have been laid down has little in com-
mon with the study of the conditions under which a modern reef is formed.
The stud}' of the conditions under which a modern reef — a reef of the
present period — is formed and increases in thickness has yet to be made,
and such a reef must be carefully selected. Probably a broad fringing
reef resting upon a substratum readily distinguished from the reef rock,
and one on which there existed a sand key close to the outer edge for
boring until the substratum was encountered, would be the most suitable.
But as it would be most difficult to judge from the core obtained at that
or any other point where the growing reef ceased and the talus began to
add to the thickness of the reef, it would be necessary to supplement
this work with soundings taken close together, as well as with an examina-
tion of the bottom by dredging, either with large or small dredges or
with trawls and tangles to obtahi material in as many different ways as
possible. Of course we can hardly expect to bring up in this way many
specimens of reef building corals, but we can surely, by combining the
information obtained from the nature of the soundings, the character
of the bottom as shown in the larger samples seoired by the dredge,
and the occasional fragments of living corals we are sure to bring
up, form some idea of the exact bathymetrical range to which reef
building corals extend, and this is not so difficult a problem as is sup-
posed by Professor Sollas, "We should in determining this remember
that in the interior of large lagoons in which there is an abundant circu-
lation of pure sea water close to the inner edge of the outer reef flats we
have very positive information as to the lower limit to which corals grow
in abundance. AVe know that under these conditions the most flourish-
ing belt of reef builders grows in depths of from three to eight fathoms, and
beyond that the coral patches decrease very rapidly in number and size,
that the patches are with increasing depth separated by wider lanes or
greater areas of coral and coralline sand, or by masses of fragments of
corals and of dead corals. We also know that on the sea face of the outer

AGASSIZ: FIJI ISLANDS AND CORAL REKFS. 87

reef flats wherever they have been examined by means of the sounding
lead, the dredge, the tangles, and the water glass, identical results have
been obtained as regards the bathymetrical range of the reef growing
corals, with the exception that the lower limit of depth seems to be
somewhat greater, and extends in some instances to 17 or perhaps even 20
fathoms. We should also remember that there abound on all coi'al reefs
numberless organisms whose only role seems to be to cement again the
particles and fragments broken by the action of the sea or of boring
animals, and they play a most important part in forming coralline lime-
stone full of reef building corals, which yet have nothing to do with the
increase of thickness of the reef from their own growth. N ullipores,
Algae, Corallines, Foraminifei-a, the minute fragments of corals or small
particles of sand, all continue to act as gi'eat cementers at considerable
depths far beyond that at which reef building corals have ceased to
flourish. They act not only on the surface of the reef in the interior of
the lagoons, but along its sea face and down to a considerable depth,
and all along the outer slope they cement the fragments of corals
which have fallen at the foot of the growing reef, and gradually trans-
form the material of the talus into a hard limestone similar in its
constitution to that of the reef building corals. But iu this lime-
stone formed of talus material, the corals no longer retain their natural
attitude as when growing. It is a breccia of corals or a puddingstone,
consisting sometimes of hufre masses which have fallen from the
growing face of the reef and rolled upon the talus along the sea
slope where such a conglomerate breccia or puddingstone has been
formed, and it reaches the depth of from 15 to 20 fathoms. Corals
can again grow upon this buttress, and thus we may imagine the
reefs of the present day to build outward and increase in thickness.
This was the result which was hinted at from an examination of the
sea face of the reef off Honolulu made in 1888.^ Of course I do not
deny that some reef builders may occasionally live at greater depths than
those I have mentioned, but their casual occurrence at those greater
depths would not materially affect the growth in height and increase in
width of the great majority of coral reefs ; and it is well known that
Oculina, Lophohelia, and other genera, may cover extensive tracts at
depths f;\r beyond those at which so called reef builders flourish."

1 Bull. IMus. Comp. Zool., Vol. XVIL No. S, April, 1889, p. 121.

2 Pourt.iles, Mem. Mus. Comp. ZooL, Vol. XL No. 2, 1871; Wyville Tiiomson,
Depths of the Sea, 1873, p. 432 ; also The Voyage of the Challenger, the Atlantic,
1877, Vol. L pp. 266-273.

88 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

ISLANDS PARTLY VOLCANIC, AND PARTLY COMPOSED OF
ELEVATED LIMESTONES.

Kimbombo.

Plates 19, 61.

The Kimbombo Islets (Plate 61) are a group of three small islands,
one, the highest, of volcanic structure ; the other two, the northern
islets, are composed of elevated limestone, situated in the axis of a tri-
angularly shaped lagoon, with twelve fathoms of water. The reef flat
surrounding the lagoon is continuous, except at the northwestern
point, where thei'e is a passage into the lagoon (Plate 19). In ad-
dition to the islands there are a number of coral patches and iso-
lated rocks along the inner edge of the reef flat and in the west-
ern part of the lagoon. The atoll is nearly five miles in its greatest
length, and the southern face is about three miles long. As we did not
enter this lagoon, I could not satisfy myself regarding the structure of
all the outlying rocks on the outer edge of the submarine platform,
some of which were evidently volcanic, others of elevated limestone.
This is an interesting group, showing how varied the structure of an
atoll may be, and yet the record on the chart be most deceptive, the
substructure of the Kimbombos being volcanic at one extremity, and
consisting of elevated limestone at the other. Half way from Kim-
bombo to Ngillangillah Island rises the small peak of Trigger Rock to
within four fathoms of the surface ; to the east of the group lies Bell
Reef, to the north Williamson and Dibble's Reefs, and Lookout Reef still
farther to the east, all separated by deep channels and rising abruptly
from deep water. The substructure of these reefs is of course unknown,
and may be either volcanic or limestone elevated or eroded to within a few
fathoms of the surface.

Exploring Isles.

Plates 19, 19% Figs. 1-3, and Plates 73-76.

We entered the^itoll of Vanua Mbalavu, or the Exploring Isles, as it
was called by the United States Exploring Expedition in 18-tO, through
the Is'gillangillah Passage. The reef enclosing the islands is triangular
in shape ; its greatest length is over 22 miles along the southeastern
face ; the breadth from the southeastern to the northwestern horn is 20
miles. The outer reef flats are comparatively narrow, except in a few
places where, near the islands of Munia, Malatta, and Susui, they pass

AGASSIZ: FIJI ISLANDS AND COliAL IlEEFS.

89

into the fringing reef flats. There are two important passes on the
southeastern face,^ the Tongan aud the American Passages. The latter
is a narrow tongue of the ocean cutting into the eastern face of the
slope of the atoll with over 100 fathoms in depth, and opens into a
wide deep submarine valley extending westward into the heart of the
eastern lagoon. The Tongan Pass is a similar, but much shallower and
shorter, tongue of the ocean. On the western side the Andiwathe Pass

NORTHEAST POINT OF VANCA MBALAVU.

leads into a long deep lagoon formed by the outer reef and the west
coast of Vanua Mbalavu. This western lagoon is connected on the
south with the principal lagoon to the east of the island by a narrow
and shallower passage over the fringing reef north of Malatta Island,
and on the north by the passages leading round ]S'"gillangillali Island into
the passage of that name opening through the northwestern horn of the

VANCA MBALAVU, LOOKING WEST.

outer reef, and which extends, gradually widening eastward, along the
northern shore of Vanua Mbalavu until it opens beyond Avea Island
into the large eastern lagoon. Along the northern face of the lagoon
are situated Avea and Sovu Islands. About two miles from the

1 An exception to the usual rule, that entrances to lagoons are on the lee side.

90 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY.

eastern face is the island of Thikombia i lau. On the southern face are
^sgillangilhih, then follows the principal island of the group, Vanua
Mbalavu, the western shore line of which is hollowed out by a deep
indentation forming the western lagoon. Off its southern extremity is
situated Malatta, next Susui, and finally the volcanic island of Mania.
Vanua Mbalavu is fourteen miles long, forming a sharp angle at its
highest and broadest point, where the island is nearly three miles wide
and reaches a height of 930 feet.

The centx'al and highest part of Vantia Mbalavu is volcanic, but
towai'ds the northeast and the south the volcanic rocks have lifted up
an ancient elevated reef which extends from opposite Avea westward.
The volcanic rocks (Plate 72) dip very rapidly to the north, so that
less than half way from Koro Mbasanga to Blackswan Point the bluffs
are elevated limestones. These bluffs are deeply undercut, their surface
pitted and thoroughly honeycombed, and full of potholes. The extent

ISLET OFF NGILLANGILLAII.

of the wearing of this c<3ral rock is well shown by the deep bays and
numberless indentations which characterize the northern coast of Yanua
]\Ibalavu. When we come to the vicinity of Blackswan Point, the
denudation and erosion of the elevated limestone has reached its
maximum. Off the end of the large island lies the little island of
Ngillangillah (Plate 73), which is entirely composed of elevated lime-
stone, which here attains a thickness of 510 feet. Beyond Ngillangillah
there are numerous negro-heads and coral patches, some of them
being of considerable size; they are of ancient coral rock. The coral
heads and negro-heads extend along the whole length of the outer reef

AGASSIZ : FIJI ISLANDS AND COKAL REEFS. 91

flat as far as we followed it to Avea. The blufis forming the steep
sides of the island are undercut and deeply indented, forming gorges
and ravines (Plate 74) which cut into the island or separate dome-like
islets from the adjacent shores. The elevated limestone is full of species
of coral, mainly large heads of species of Astrteaus, of ^I*andrinas, and
Pocillopores, which appear to be closely allied if not identical with those
now living. One of the points of Ngillangillah was mei'ely a thin shell
covering a huge cavern some 50 feet hi diameter and rising to a height
of nearly 100 feet, and full of stalactites. The rock in the pool at its
base was covered with Gorgouiaus and small corals, and abounded in
Comatulse.

The narrow channel lying between the north shore of the large island
and the outer reef is full of flourishing coral patches. The many nar-
row deep canons (Plate 74) cut into the face of the island with the
dome-shaped or mushroom-shaped heads of elevated reef rock projecting
a few feet above the water line give to this shore line a very picturesque
appearance. It is a simple matter to follow the extent of the elevated
reef rock eastward, and to trace the gradual appearance of the central
ridge of volcanic rocks until we come to the headland north of Koro
Mbasauga (Plate 72), where we find only a comparatively small outlier
of the elevated limestone, and a similar one to the south of tlie village.
Northeast of Koro Mbasanga lies the island of Avea (Plate 75), which
rises to a height of 600 feet, and which is wholly composed of elevated
limestone. This island as well as Susui runs at an angle from the
outer reef, and shows the great width of the former elevated reef. From
Koro Mbasanga south and for some distance beyond Lomaloma the vol-
canic rocks occupy the whole width of the island, and the elevated lime-
stone has disappeared to reappear again on the southern spit of the main
island, and to extend eastward in the islands of Malatta and of Susui
and their many outliers, as heads, rocks, and islets, both on the northern
and off the eastern point of the latter island. The island of Munia
consists, like the central part of Vanua Mbalavu, of volcanic rocks. The
island of Thikombia i lau, on the contrary, is composed of elevated lime-
stone rising to a height of 550 feet. Beyond Avea lie the Sovu Eocks,
three small islets about two miles inside the outer reef, also of elevated
limestone, one of which rises to a height of 230 feet. Between Avea
and the Sovu Islets runs southerly for a distance of nearly five miles a
series of narrow coral patches, which, so far as I can judge, are rem-
nants of the ancient elevated limestones, as are probably the heads and
patches of the eastern part of the lagoon beyond the Tongan Pass. Oa

92 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY.

the contrary, many of the heads lying off the central parts of the east
coast of Yanua ]\Ibalavu are undoubtedly of volcanic origin, aud are
merely covered with a thin veneer of growing corals. Some of the small
volcanic rocks and islets oflF the east central part of the east coast of
Vanua Mbalavu are deeply undercut and eroded into mushroom-shape.
By far the finest example of marine erosion of volcanic rocks is seen on
Plate 62, which represents an eroded shore line with mushroom-shaped
rocks oflF the shore, indicating a slight recent elevation. Plate 62 is
taken from a photograph given us by Mr. E. G. Jones, and taken in Lau ;
unfortunately I am unable to state the exact locality. The islets of Yana
Yanu forming the harbor of Lomaloma consist of a yellow volcanic mud
full of rounded pebbles, and some of the spits of the east coast of Vanua
Mbalavu are composed of bedded volcanic mud (soapstone) similar to
that found at Suva and its vicinity. The condition of the islands and
islets and rocks, both of those composed of elevated coral reefs and of
volcanic rock, clearly indicates the great denudation and erosion which

VOLCANIC HILLS BACK OF LOMALOMA.

have taken place, to leave only such fragmentary remains of the land
•which must have once occupied the area of the lagoon. It is possible
that the age of the elevated limestone found at so many points in Fiji
may be comparatively great, and that the ancient limestone forming the
substructure of the reef of the present day may have been deposited in
late tertiary times, immediately before the present epoch. ^

As has been observed, the dip of the lagoon is to the eastward, or
rather, in a general way, towai'd the slopes of the deep tongue of water
forming the American Passage (Plate 19). This would seem to be the
natural result of the elevation of the great flat of tertiary limestones

^ See the report of Dr. Dall, referred to in another part of tliis Bulletin.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 93

occupying the area of Vanua Mbalavu Lagoon, caused by the uplifting
of the ridge forming the crest of Vanua Mbalavu, which has a short
western slope and a long comparatively easy eastern slope, with the
resulting deep valley leading to the American Passage, and perhaps a
secondary elevation caused b}^ the rising of Alunia Island.

The depth of the western lagoon varies between 10 and 20 fathoms,
that of the western part of the eastern lagoon from 6 to 30, while the
eastern part of the lagoon slopes gradually from 20 or 25 fathoms toward
the 100 fathom tongue in the eastern face of the outer reef. On sound-
ing one mile north from the edge of the outer reef, off Blackswan Point,
we found, at 203 fathoms, hard bottom. The character of the bottom
of the lagoon varies greatly according to its proximity to shores or
heads 1:>r patches composed of volcanic rocks or of elevated coralliferous
limestone, or of a combination of both.

ISTowhere in Fiji have we found the fringing corals growing in such
profusion as in the Ngillangillah Channel. AVhile steaming along the
northern face of the reef, close to the outer edge, we had a good oppor-
tunity to note the appearance of the outer reef flat, of a yellowish green
color covered with patches of violet, indicating the areas incrusted by
living corals. Being on the lee side, there was scarcely a ripple along
the outer edge, which was in sharp contrast to the very dark blue of
the water covering the outer slope of the reef, while on the inner side
there was a more or less wide light greenish belt bordering the reef flat
and passing through light blue into the darker blue of the narrow con-
tinuation of the Ngillangillah Passage, itself dotted with greenish or
yellowish patches of coral all along the reef flat, and on many of the
inner patches were scattered negro-heads, consisting of elevated coral-
liferous limestone.

Mango.

Plates 19, 33*, Fig. 3, and Plates 85-87.

Manso is a circular island, the southeastern and southern faces of
which consist of a rim of volcanic rocks, through which rises to a
height of 670 feet the central elevated ridge of the island (Plato 19).
On the northern and northeastern faces an ancient coralliferous lime-
stone has been elevated to a height of from 200 to 300 feet or more.
That part of the elevated limestone which lies across the break of the rim
of the island has been eroded and denuded to form a small lagoon or
diminutive sound (Plate 85). The entrance is flanked by low conical
or dome-shaped mounds and patches deeply undercut, some of which are

94

bulletin: museum of comparative zoology.

mushroom-shaped. A passage has been cut for boats through the shal-
low opening connecting the lagoon with tlie inner sound, which receives
the drainage of the interior of the depressed basin. The elevated lime-
stone bluff's extend from the northern horn of the rim, along the coast
line, towards the landing place on the north face of the island. To the

[

.■^^^^^

3IANGO, SEEN FROM THE NORTHEAST.

east of this, on the north shore, are fine bluff's of elevated limestone,
weathered into dome-like lamellar masses, with rounded masses and
mushroom-shaped heads at the base (Plate 86). A little farther west,
on the beach beyond the bluff's, the underlying volcanic I'ocks crop out
again, and from there south the negro-heads on the western reef flats
are all of volcanic origin.

The island of Mango is almost circular, about three miles in diameter,
surrounded by a barrier reef, which passes into a fringing reef off" the

northern coast near the landing,
and off a part of the southeastern
face of the island. The inner
lacfoon is verv narrow, not more
than a quarter of a mile in width,
and also very shallow. Its great-
est depth is about two fathoms,
and it is further studded with
negro-heads and coral patches,
thus protecting the lagoon to a
certain extent from the invasion
of the sea. The ridge of elevated
coralliferous limestones on the
west side of the island extends

MANGO LANDING, VOLCANIC sciBSTRATUM. '^^ far as the first islct on the

south face of Mango. There the
central volcanic ridge which has raised the reef joins the western edge
of the rim of the island. The ridge runs in a southerlv direction, at a

AGASSIZ: FIJI ISLANDS AXD CORAL REEFS.

95

slight angle with the west coast ridge, and is separated from it by a deep
valley. The three islets off the western part of the southern face of
Mango are all on the outer edge of the reef Hat (Plate 87). They con-
sist of volcanic rocks. The central
islet is the largest, and is com-
posed in part of stratified volcanic
mud miderlaid by harder rocks.
Between the islets, and extending
over the outer reef flats to the
north and to the east, stretch
numerous negro-beads of a vol-

;«'

!M

WEST OF MANGO LANDING, VOLCANIC
SUBSTRATUM.

canic natiTre.

The island of Mango is of the
same type as Fulanga, except that
the erosion and denudation of the
lagoon has not been carried on to
so great an extent, Mango being
composed so largely of harder
volcanic X'ocks. The platform
forming the reef flat is dug out into a very narrow and shallow lagoon,
and both are studded with negro-heads, the remnants of the adjacent
shore slopes. The inner sound, which in the case of Fulanga has been
eroded and denuded to form a large inner basin, consists in Mango only
of a diminutive basin studded with elevated limestone heads and rocks,
and barely connecting with the exterior eastern lagoon ; the sea has not
found its way to any extent through the elevated limestone barrier lying
across the break of the rim of the island.

Lakemba.

Plates 19, 31.

_ The island of Lakemba is elliptical, with a prominent spit extending
off" its southern face. Its greatest diameter is about five miles and a
half. The central mass of the island, which rises to a height of 720
feet, is volcanic ; on the flanks of this, on the northwestern and western
sides, are found nearly vertical steep shore bluffs of coralliferous lime-
stone elevated to a height of from 200 to 250 feet. The ridges extending
along the south shore, separated by a spur from the central mass, also
consist of elevated reef rock. Lakemba is surrounded by a fringing
reef, narrowest off" the northwestern point of the island ; it widens

96 bulletin: museum of comparative zoology.

towards the south off the -nest coast, and on the eastern face of the
island it attains a width of nearly a mile. In continuation of the
fringing reef off the northern face and off the southern spit of Lakemba
extends a naiTow outer reef, enclosing a lagoon, irregularly rectangular
in shape, about five miles in length. The lagoon is thickly studded
with patches and heads; its greatest depth is 14 fathoms; on the east
face of the outer reef there is a passage for steamers. This is another
exception of a lagoon entrance on the windward side. It should, how-
ever, be noted that the east face of the Lakemba atoll is protected to
some extent by Aiwa and Oneata.

The resemblance in shape of Lakemba and Kanathea, the latter of
which we did not visit, is very marked. The encircling reef of the latter
surounds a larger lagoon ; there is also a naiTow extension of the lagoon
on the south side of Kanathea, and a boat passage on the east face.
One mile and a half south of Kanathea, and sepai'ated from it by a
channel with a depth of 131 fathoms, lies the small summit of Morse
Reef ; and off the central part of the northern face of the encircling
reef, Boehm Rock. At Lakemba Gardiner ^ has noticed the flat lime-
stone hills which rise abruptly to a height of 60 to 70 feet on the west
coast, the foundation being volcanic conglomerate, which forms the rest
of the island. Captain Wilson states that on the reefs of the extreme
south some of the islets are limestone, others volcanic, and he considers
the three larger islands in the centre to be the renmants of an old
crater.

Thithia.

Plate 30.

I am informed by Bishop Yidal of Levuka that the island of Thithia,
which we did not visit, is also composed in part of elevated limestone,
in which larfre caverns have been excavated similar to those we saw in
Ngillangillah Island. It is also stated by others to be in part volcanic.
It resembles Mango in outline, appearance, and structure, but is some-
what smaller; the fringing reef surrounding it is narrow. The central
part of the island is probably a volcanic ridge, which has elevated the
ancient limestone surrounding it.

1 Loc. cit., p. 466.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 97

Naitamba.

Plate 19.

The cliffs of the southeast side of Naitamba consist of volcanic con-
glomerates or pudding-stone, which extend along the highest points of
the ridge on that side of the island. But on the northern side of the
island the ridge, rising to a height of over 100 feet, is clearly seen to

NAITAMBA, FROM THE EAST.

be composed of elevated limestone. Xaitamba is surrounded by a
narrow lagoon (Plate 19), which is a little over half a mile wide off
the north side of the island, where its greatest depth is seven fathoms.
On the southwest side the lagoon is very shallow and narrow, the reef
becoming practically a fringing reef. The highest point of Naitamba
is 910 feet.

Mothe.

Plate 23.

The Mothe group is interesting, consisting of a volcanic island, Mothe,
and of Karoni, a low island to the south of it, formed by a short ridge
of elevated limestone rising to a height of 120 feet. An outer reef flat
surrounds both the islands. It runs at a distance of a little over half a
mile from the shoi'e of Mothe itself, which is also surrounded by a very
narrow fringing reef. In that part
of the lagoon there is only from two
to five fathoms of water, and the

KARONI.

channel is studded with heads.

The lagoon enclosed by the Mothe Reef is shaped like a boot, the foot
reaching towards the east and the leg in a northwesterly direction.
Mothe Island is elliptical in outline. Its gi-eatest diameter, running
north and south, is about two and a half miles, and it rises to a height
of 590 feet. There are only boat passages into the lagoon through the
eastern face. Although these passages are on the eastern face, yet they
are practically to the lee, owing to the westerly trend of the lagoon and

VOL. XXXIII. 7

98 bulletin: museum of compaeative zoology.

the projection of Na Potu on the south. The deepest part of the lagoon
is in the eastern point. It is only nine fathoms, and north of Karoni
not more than seven. jSTa Potu, as the eastern point of the lagoon is

NORTHWEST POINT OF MOTHE.

called, is studded with rocks and heads. Off the northwestern point of
Mothe we could distinctly see that the negro-heads rising upon the plat-
form of the outer reef flats were of volcanic origin. Mothe resembles
in shape Lakemba and Kanathea.

Kambara.

Plates 2Z, 22*, Fig. 2, and Plates 77-79.

Kambara Island is elliptical, nearly live miles in length, with a great-
est breadth of three (Plate 22). It is surrounded by a rim of ele-
vated limestone enclosing a depressed basin. The rim has an average
heit^ht of between 300 and 350 feet, with steep cliffs on the sea face
(Plate 77). On the northwest face of the island, near the village of
Tokalau, the elevated limestone ridge is broken through by a conical hill
470 feet high, which is of volcanic origin, and the flanks of which underlie
the elevated limestone ridge resting on its sides (Plate 78). From this
makes out a flat covered with negro-heads, all of volcanic origin, and of
rocks similar to those of the high hill, while on each side the flats are
covered with negro-heads composed of elevated limestone ; on both
grow very flourishing coral patches, and both are steep to, the reef flat,
passing rapidly into deep water, plainly showing that the corals have
had no share in shaping either of these slopes, the one composed of vol-
canic rocks, the other of elevated coralliferous limestone.^ The island is

1 Throughout Fiji we found along the cliffs and sea face of limestone islands
masses of the red eartli so characteristic of the denuded limestones of the Bahamas
and Bermudas, as at Kambara, Ngillangillah, Yangasa, Oneata, Ongea, and other
islands.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 99

surrounded by a fringing reef which ends beyond the northern point of
the island along the base of the vertical cliffs between it and Tolvalau
village (Plate 78), and becomes the merest thread to the soutli of it
for a short distance. Along the rest of the west face there is a narrow
incipient lagoon studded with coral patches, with from one to two
fathoms of depth in places between the outer reef and the shore.

Gardiner ^ describes the interior plateau of Kambara as being about
100 feet above the level of the sea, and that "on the plateau itself are
many small hills, rising nearly to the level of the rim, with very steep
walls, and some springing almost like buttresses from the rim itself,"
and that on this plateau there are a number of deep holes in which salt
water is found and tidal influences are felt. This description corresponds
with what has been observed in the reolian hill basins of the Bahamas
and Bermudas, in which atmospheric agencies ai'e at work to form the
incipient sounds, and finally the gTeat sounds or lagoons of the islands
of these groups.

Gardiner ^ reports that the hills of Thikombia i ra ai'e certainly of
limestone, and at a distance appear distinctly terraced.

SUNDRY ATOLLS.

Pitman Reef.

Plate 18.

Pitman Reef is an oval atoll about a mile in greatest length. We
passed within a cable's length on the west side, and could see the outer
edge of tlie reef flat uncovered at points, and patches of corals growing
upon it. The reef flat seems to be .300 to 3-50 yards in width. It is
widest at the northern extremity. The lagoon is marked on the chart
as being eighteen fathoms deep.

Motua Levu and Motua lai lai.

Plate 18.

Motua Levu and iMotua lai lai are two atolls to the eastward of Lau-
thala reef. The former is somewhat rectangular, about two miles in
length, and encloses a lagoon with a greatest depth of twenty-five
fathoms. On the northwest edge boats can cross into the lagoon. The
latter is nearly circular, a mile in diameter, enclosing a small lagoon.

1 Loc. cit., p. 464. 2 Loc. cit., p. 462.

100 bulletin: museum of comparative zoology.

The 3'ellowish reef flat is widest at its two extremities ; the coral patches
appear to be very flourishing, and a few large negro-heads of coral pro-
truded upon the inner edge of the reef flat. From its diminutive size,
the whole atoll can be taken in at a glance, and it forms an excellent
specimen of its kind (Plate 112), with its broad yellow reef fiat edged
on the outside by the white line of breakers separating it from the
deep blue water, the inner edge passing fi'om yellowish to light green,
then to light blue, and finally to the darker blue of the central part of
the lao'oon.

o^

Williamson Reef.

Plate 19.

We passed close to Williamson Reef, which is a somewhat rectangular
reef flat widest at the eastern face. The greater part is dry at low water,
and encloses a lagoon with thirteen fathoms. The greatest length of the
reef is a mile and a quarter by nearly a mile at its greatest width.

Bell Reef.

Plate 19.

Bell Reef is separated from the Kimbombo cluster by a channel of
nearly three quarters of a mile in width. It is irregularly triangular,
with a reef flat of over half a mile in width. The reef flat of the western
side is open. The sea breaks heavily on the eastern face, but there is
little sea on the western face. The greatest depth in the lagoon is
thirteen fathoms.

Adolphus Reef.

Plates 18, 33^, Figs. 16, 17.

We steamed close to the eastern edge of Adolphus Reef. The outer
rim is somewhat rectangular in outline, -with rounded coi-ners, and
carries from one to four fathoms of water, enclosing a lagoon twenty
fathoms in depth. It can be entered from the southwestern angle.
We could not examine it, as the sea was breaking heavily upon it. We
could, however, clearly distinguish the patches of corals growing inside
of the breakers.

These atolls are excellent examples of the effects of submarine ero-
sion upon areas of different dimensions, ranging in size from Pitman

AGASSIZ : FIJI ISLANDS AND CORAL REEFS. 101

Reef to Motua lai lai, Motua Levii, and to Adolphus Reef. They all
owe their origin to tlie disappearance through atmospheric agencies of
the peaks or ridges of greater or less heights which they represent, and
to the formation of lagoons hj submarine erosion, passing finally into
such sunken banks as the Penguin, Alesa, and other banks discovered
by Captain Field in the " Penguin," and figured in Admiralty Chart
1431 (see Plate 23*). Possibly, as I have suggested in the case of
the smaller atolls, the lagoons may represent the extinct craters of
small volcanoes of which the rim has been planed oiT by the action
of the sea.

We did not visit Duff Reef (Plate 18), which, judging from the chart,
presents no points of special interest or of difference, except iu shape,
from snch atolls as Wailangilala.

Thakau Momo.

Plates 3a, 13, 14, 33a, Fig. 6.

On our way from Nairai to ^loturiki Channel we examined the Horse-
shoe Reef (Thakau Momo) about nine miles northwest of Nairai. Owing
to the high stage of the tide we did not find it awash, and could
only trace the very narrow ring of the yellowish green flat upon which
violet patches of corals could be seen dotted over its surfoce. This flat
being edged on the outside by the narrow wdiite rim of breakers, and
the dark blue water of the deeper soundings on the inner edge being
fringed by a narrow belt of light green passing into light blue and into
the somewhat darker blue water of the central part of the lagoon.

The plan of Thakau Momo (Plate 23*, Fig. 6) shows the narrow rim
forming the outer edge of the lagoon awash, with a depth in the centre
of twelve fathoms. The western edge is worn away, leaving the greater
part of the rim of the lee edge more or less open to the outflow of the
\vater pouring in over the weather edge.

Tova Reef.

Plate 33% Fig. 5.

The plan which is given of Tova Reef is more detailed, and shows a
lagoon with a more complete rim than that of Thakau Momo, with boat
passages on the lee side through the northern and western rim of the
encircling reef. These two atolls are sharp peaks, the one, Thakau Momo,
probably the summit of a volcanic ridge, the other, Tova, perhaps the

102 bulletin: museum of compakative zoologYo

summit of a peak of elevated coralliferous limestone, which have been
denuded to the level of the sea and then subjected to submarine erosion,
forming first a flat, then an incipient atoll of which the lagoon has been
gouged out, in one case to twelve, in the other to sixteen fathoms.
Upon the outer edge of the flats, corals have grown, protecting the rims
to a great extent from further denudation and erosion.

The depth of the plateau from which Tova rises is probably very
considerable. The depth of water at a distance of seven or eight miles
is, judging from soundings to the eastward, perhaps as much as 1,200 or
1,500 fathoms ; while Thakau Momo apparently rises from a shallower
depth of less than 500 fathoms to the north, and about 900 fathoms at
a distance of about five miles.

Such atolls as Thakau Momo, Tova, and a host of others occurring in
Fiji, are identical in tlieir mode of formation with such an atoll as the
Hogsty in the Bahamas,^ the lagoon of which 1 believe to be due to
mechanical causes similar to those which have shaped the above named
lagoons in Fiji. While the former are recognized by writers on coral
reefs as true atolls, the latter are regarded as pseudo atolls. It is juggling
with words to represent structures as diS'erent because the one is in the
Pacific and the other in tlie Atlantic, and because the one is in an area
recognized as stationary or as one of elevation, while the other is in an
area formerly supposed to be one of subsidence and which is now found
to be one of elevation. In both cases the coral rims of the atolls are
shown to be of little thickness. The same authors refuse to recognize
as true barrier reefs, and call them patch reefs, barrier reefs occun-ing
in other districts than those examined by Dana and Darwin, because
they have been shown to be of comparatively moderate thickness. We
can now show, in the very districts which have been selected as typical,
that neither the coral reefs of the atolls nor those of the barrier reefs
have the thickness attributed to them.

Thakau Lekaleka.

Plates 21, 111.

On our way from Oneata to ^Mothe we steamed close to Thakau
Lekaleka (Plate 21), a very narrow reef flat of polygonal outline, some-
what more than a mile in diameter, enclosing a shallow lagoon, judging
from the light blue color of the impounded water. The reef flat rises

1 Bull. Mus. Comp. ZoGL, Vol. XXVI. No. 1, p. 103, 1894.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 103

oil the western edge of a bank sloping to the eastward, the 100 fathom
line being more than half a mile from the eastern edge of the reef flat.

A number of negro-heads, appai'ently coral, could be seen on the
western horn of the reef flat. Plate ill gives a good idea of the
appearance of the curve of the narrow reef flat of one of these smaller
atolls, with the sea breaking over the rim.

LAGOONS OF ATOLLS.

Dana denies that there is any connection between the chnnnels of
lagoons and prevailing currents, and asserts that the channels tend to
be closed by the increase of gi'owing corals. Certainly our experieuce
in Fiji could not indicate such a conclusion, nor are the lagoons in tlie
smaller islands without channels except where a closed ring of coral
sand islets has accumulated on the outer rim, — a rare occurrence,
and one where the lagoon was formed while open to the influx of the
sea. Some of the small islands, with lagoons which are dry, may be
elevated islands reduced to that stage by atmospheric agencies.

While there may be a large amount of coral ooze and nmd deposited
in the lagoon, yet even in the lagoons mentioned by Dana he states
that the sea has access to them, and that they are remarkable for the
salinity of the water and the absence of growing corals within the
lagoon at high water.^

Dana says ^ that nine tenths of the atolls under six miles in length,
half of those between six and twenty miles, and the majority of all
atolls in the Pacific Ocean, have no entrances to the lagoon a fathom
deep, and the larger part of those included in each of these groups have
no open entrances at all. He further says that nine, ranging from
one and a half to three miles in the larger diameter of the reef, have
no lagoon, only a small depression in its place ; two of these take in
water at high tide and the rest are dry (namely, seven), certainly
a very small proportion, and that of diminutive atolls which give us
little information regarding the formation of the larger ones. Surely we
cannot reverse the process and let the formation of the large atolls
precede that of the smaller, as is suggested by Dana,^ for in that case
we should have around the small atolls the platforms or slopes which
have gradually been formed by the filling of the larger lagoon as sup-

1 Dana, Corals and Coral Islands, p. 182.

2 Loc. cit., p. 300. ^ Loc. cit., p. 302.

104 bulletin: museum of comparative zoology.

posed by him, and I know of no small atoll in which any such platform
has been observed.

Neither Dana nor Lendenfeld seem to take into account the mass of
water which is poured into a lagoon, even if it has no boat passage, over
the reef flat at low tide, to say nothing of the period during which the
reef remains covered between low and high water times.

A large atoll, like that of Ngele Levu, if it has been formed by
subsidence, should be of greater depth. This has already been noticed
by Admiral Wharton.^ Ngele Levu is thirty-three miles round, grad-
ually increasing in depth towards the western extremity from four to
sixteen fathoms. It rises gradually from a ridge with a depth of about
145 fathoms, and from a plateau of less than 400 fathoms in depth.
There is no filling up of that lagoon ; it is well scoured, and a strong
current is constantly deepening the entrance and outlets at the western
end, to say nothing of the mass of water which finds its way out over
the reef flat. The lagoon of an atoll is often referred to by writers on
coral reefs as a sort of stagnant pool, which must of necessity be grad-
ually filling. Sixch is certainly not the case in the atolls with which I
am acquainted, and it is the exception. If any one will take the trouble
to examine the hydrographic charts of the coral reef regions, both in the
Pacific and the Atlantic, they will find it to be the exception when the
atoll of a lagoon is really impounded, or that of a barrier reef is shut
out from a most active circulation cai'ried on by the breakers rolling
over the rim of the one and the bai*rier of the other into the enclosed
lagoon. In Fiji, the only atolls which are enclosed and surrounded by
a reef allowing no circulation or access to the sea are small, and play
no part in the physiognomy of the reefs of the group, and I know of
no barrier reef in Fiji the lagoon of which is not well threshed by
the breakers.

An examination of the charts accompanying this report will show on
the rim of the larger atolls, both to windward and leeward, moderate
depths, from one to three fiithoms or less at innumerable places, forming
a regular sieve of passages through wliich the breakers force their way.
An examination of the charts will show the same results as regai'ds the
circulation across the barrier reefs of Fiji. Finally, we should re-
member that at high tide even fringing reefs are washed in every part
and scoured, and that, while at low tide a certain amount of stagnation
in pools may occur, it is only temporarj^, and not tlie natural state of
things.

1 Nature, May 22, 1890, p. 81.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 105

Leudenfeld ^ gives altogether too great prominence to the part played
by dry atolls. They do not occur anywhere except as most diminutive
atolls. The only atoll in Fiji which answers at all to the theoretic
requisitions of Lendenfeld is that of Vuata Vatoa (Plate 23% Fig. 4),
near Turtle Island, in Lau. I have not visited the island, and my
impression is taken from the chart" and the Sailing Directions where
it is described. Yet even that atoll has outfalls on the northwest side,
and the margin is awash at high Avater, evidently allowing large masses
of water to be poured into the lagoon, so that further denudation and
erosion must eventually so modify this atoll that there will be a larger
and more open lagoon than formerly, and it will not fill up as is required
from the other point of view.

EXTINCT CRATERS ANT> ATOLLS.

There is, however, still another phase in the formation of atolls
which has received but little attention, and that is the influence of the
denudation and erosion of volcanic summits or ridges, or of extinct
craters, in the formation of atolls. There are in the Fijis two extinct
craters which are most interesting. One of these is the small extinct
crater of Thombia in the Ringgold Islands (Plates 18, 70). The highest
point of its rim, the extei'ior cii'cumference of which is nearly two miles,
is nearly 600 feet, and it is continuous with the exception of a small
part of its eastern edge, about a fifth of a mile, across which a coral reef
extends, the extension of the fringing reef surrounding the island closing
the entrance to the crater ; the enclosed basin has a depth of 24
fathoms. The other extinct crater is that of the island of Totoya
(Plates 16, 22, 66-69), an isolated peak in the southern part of the
group. It is about six miles in diameter, with an inner basin of three
miles in diameter and a depth of over thirty fathoms. The highest
point of the rim is 1,200 feet, and at two points the rim is low, forming
in one case a narrow isthmus separating the crater basin from the outer
lagoon. The horns of the open rim are connected by a coral reef, over
which thunders the Pacific swell, piling up the water into the great
basin of the crater. This water finds its way out through an opening
called the Gullet, which, though narrow, forms an excellent passage into
the anchorage inside of the crater. This island has not only a fringing

1 Nature, June 12, 1890, p. 148.

2 Admiralty Cliart, Plan 742.

106

BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY.

reef, but also a barrier reef of a triangular shape surrounding it. It is
evident that this barrier has been formed upon the denuded and eroded
spurs of Totoya, which once extended seaward from the outer rim of the
volcano.

Supposing, now, that the erosion of both Thombia and Totoya had
continued for a period of time long enough to have reduced the rims of
these volcanoes to the level of the sea, we should have, as soon as corals
had covered the flats thus formed indicating the former existence of the
rim, atolls of nearly circular form ; the one with a circumference of only
two miles, and a depth of 24 fathoms, without patches in the central
lagoon; the other much larger, more tlian 25 miles in circumference,
having a depth of 34 fathoms inside the lagoon, which would be dotted
with patches, some of them forming part of the rim, others being the
remains of eroded spurs extending towards the centre of the extinct
crater.

Admiral Wharton ^ has given a most interesting sketch of Clipperton
Atoll, in which he confirms the trachytic nature of the " Eock " of Clip-

CLIPPERTON ROCK.
(From a Photograph by J. T. Arundel.)

perton, as determined by Professor Wolff ^ from specimens collected by
Mr. Jensen and kindly sent me by Professor Davidson. The photo-
graphs and specimens collected by Mr. J. T. Arundel, on which Admiral
Wharton's notice is based, have enabled him to give what seems to me
a natural explanation of the character of the atoll. As he says, it is

1 Quart. Journ. Geol. Soc. of London, May, 1898, p. 228.

2 Bull. Mus. Comp. Zool., Vol. XXVL No. 1, p. 174, 1894.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 107

" tlie rare case of coral forming on the lip of a volcanic crater, one part
of whicli alone, perhaps tlie plug, has resisted the action of the sea,
which has worn the rest of it down to the limits of wave action."
The foregoing figure is a view of the rock (trachytic) rising to a height
of sixty-two feet on the rim of the atoll. Admiral Wharton calls atten-
tion to the great depth of this lagoon, perhaps fifty fathoms, as a depth
not improbable if it be the crater of an extinct volcano. It would be
most interesting to have Clipperton carefully examined and mapped.
In the mean time, from its analogy with Totoya and Thombia, it seems
to me that Admiral Wharton's explanation is the only possible one.
We may perhaps add that the old rim may have also been subject to
atmospheric denudation and erosion, in addition to being blown away
in part during some eruption.

There are in the Fijis a number of small atolls from one to three or
more miles in circumfei'ence, the formation of which can also be satisfac-
torily explained on the theory that they have been formed upon the
eroded summits of extinct craters, reducing the rim of the volcano either
to a continuous flat or to flats separated by deeper passages, as in the
case of the low parts of the rim of Totoya, forming entrances into the
enclosed lagoons. Such atolls are Motua Levu, INEotua lai lai, the Adol-
phns Eeef (Plate 18), Bell Reef, Pitman Reef, Williamson Reef (Plate
19), Horseshoe Eeef (Plate 14), and Thakau Lekaleka (Plate 27),
although it is possible that some of these atolls may have been formed
from the submarine erosion and denudation of volcanic peaks or of
elevated limestone masses. It is also possible that some of the larger
groups in which volcanic islands are found, like Yanua Mbalavu (Plate
19), Konio, Mothe (Plate 22),Lakemba (Plate 21), and Mbengha (Plate 8),
may represent parts of the rims of extinct craters, the bulk of the vol-
canic peaks having disappeared from erosion, and left the outer flats
upon which the barrier reefs have grown, while the deeper valleys and
gorges of these volcanic islands represent the undulations of the lagoons,
which vary greatly in depth, reaching in the case of the Yanua Mbalavu
(Plate 19) 72 fathoms in parts of the eastern slope of the lagoon. These
great depths, far beyond any at which corals can grow, represent the
elevated gorges of the slopes of the volcanic peak which probably once
extended over the whole area enclosed by the outer reef, during the
elevation of which the reef which once covered a part of the same area
was lifted to its present or even a greater height.

Such large volcanic centres with extensive craters of considerable
depths are not unknown.. Haleakala (Plate 71) in the Sandwich

108 BULLETIN : MUSEUM OF COMPAEATIVE ZOOLOGY.

Islands has a crater with a depth of nearly 450 fathoms^ ■nhile manv
smaller peaks, some of fully 1,200 feet rise from its bottom, and its
diameter is fully as great as that of many of the larger atolls of the
Fijis. So that, at any rate in a volcanic district, the great depth of
some of the atolls cannot now be considered as a proof of the theory of
subsidence.

A still larger extinct crater than Haleakala is that of Aso San in Japan,
and in Java there are many craters of dimensions fully equal to those
of a number of Fiji atolls.

In addition to ThomV)ia and Totoya, we found at Moala the rim of an
extinct crater forming the deep bay on the east side of the island (Plates
16, 56). The longest diameter of this crater must have been fully
three miles, and had the denudation of the island been carried on some-
wliat further, so as to eat away the low western rim of the crater (Plate
56) and connect the deep ba}' of the east face (the extinct crater} with
the indentation on the west of the island, it would be difficult to detect
the existence of a former extinct crater from the narrow ridge or island
which would rise in the eastern part of the lagoon (Plates 16, 56).

Kramer-' has attempted to account for the elongated outline of so
many of the atolls of the Paumotu, Caroline, Marshall, Gilbert, and
Ellice Islands, upon the theory that they owe their origin to submarine
hot springs and volcanic eruptions, the material of which was distributed
by the trend of the great oceanic currents in the general directions
indicated by these island groups.

While granting that volcanic agencies have raised the coral islands of
the Pacific, we must remember that the shape of the islands and their
extent are due to the size of the plateaus of submarine erosion which form
tlie banks upon which coral reefs have grown. Undoubtedly the sub-
stratum of many of the atolls may have been formed of volcanic ashes by
eruptions similar to that which has thrown up Falcon Island, and which
has been fully described by Lister.^ Yet the great majority of the vol-

1 Bau d. Korallenriffe, p. 88.

- J. J. Lister, A Visit to the newly emerged Falcon Island. Tonga Group, South
Pacific. Proc. Tloy. Geog. Soc, 1800, Vol. XIL p. 157.

The island (Falcon) is composed of fine-grained dark grayish material, arranged
in strata. " A bare brown heap of ashes round wliieh the great rollers break and
sweep the black shore in sheets of foam." The eruption occurred four years ago ;
its present heisht is 153 feet. " Considering how rapidly the island is being covered
by the action of the waves, it is evident that in a few years ... it will have disap-
peared beneath the surface of the ocean. . . . Some distance to the east of it lie two
islands, Namuka iki and Mango, and these islands have been elevated before any

AGASSIZ : FIJI ISLANDS AND CORAL BEEFS. 109

canic islands which abound in the coral reef districts of the Pacific do
not consist of such easily scattered material. In addition, it is well
known that many of the islands are composed of elevated coralliferous
limestones, and that is probably the composition of the substratum of
many of the atolls of the Paumotu, Ellice, Gilbert, Tonga, and Fiji groups.
They indicate the existence of more or less extensive submarine ridges
composed either of limestone or of volcanic rocks, and not necessarily
peaks or summits formed of volcanic ash and spread out by the action
of the currents, as has been mapped out by Kriimer.^ Nor do we know
enough of the configuration of the bottom to justify the statement that
the atolls of a group are not sepai'ated by great depths such as separate
the islands of the Samoan group. The soundings round Funafuti by
the " Penguin," and others near Tonga and in Fiji (Plate l), do not
confirm Ki'amer's views.

The old view entertained by Chamisso regarding the mode of origin of
the substratum iipon which coral reefs are built does not greatly differ
from thfit which we have applied to the formation of coral islands in
Fiji. We have laid greater stress upon denudation and submarine
erosion after elevation by volcanic agencies, while Chamisso ^ accepts
the uplifting of the insular masses to the level at which coral begins
to grow.

considerable thickness of coral grew upon them. They are formed by stratified
volcanic material deposited under water, and are now surrounded bv broad coral
reefs. In them we may read the possible future history of Falcon Island. If no
elevation takes place, the stones and debris will give a resting place to a host
of marine animals and plants, . . . and another fine island will be added to those
summer seas." Recent volcanic action in Tonga and in Samoa does not seem to
have prevented there the formation of extensive coral reefs, as has been suggested
by Dana.

1 Loc. cit., pp. 95-97.

- " Wir denken uns eine Inselgruppe dieser Bildung als eine Felsenmasse, die
sich mit senkrechten Wanden aus der unermesslichen Tiefe des Oceans erhebt und
oben, nahe an dem Wasserspiegel, ein iiberflossenes Plateau bildet. Ein von der
Natur rings um am Rande dieser Ebene aufgefiihrter breiter Damm, wandelt
dieselbe in ein Becken um. . . . Er ist da Stellenweise unterbrochen und seine
Liicken bieten oft selbst grosseren Schiffe Fahrenge dar. . . . Innerhalb dieser
Thore liegen ofters einzelne Felsenbanke. . . . Andere ahnliche Banke liegen hie
und da im Innern des Becken zerstreut." Kotzebue, Reise, Bd. III., Bemerkungen
und Ansichten, 1826, von Adelbert v. Chamisso, p. 106. Chamisso gives an
admirable account of Radack Ralick, and of the fauna, flora, and general aspect of
this low coral island.

110 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY.

VITI LEVU REEFS.
Plates 1, 3, 5, 6, T, 30a, Figs. 9-12, and Plates 24-45.

The great barrier and fringiug reef which follows the southern and
part of the eastern coasts of Viti Levu may be said to begin oli" the north-
eastern extremity of the island of Ovalau (Plates 3, 7). Ofi" that island
a spur of the barrier reef extends in a northerly direction, terminating in
deep water (Plate 3). From that point to otf Tova Peak there is no
barrier reef, tlie bottom being generally muddy, formed from the decom-
position of the islets coniposed of soapstone, which are scattered in great
number between Ovalau Island and the island of Viti Levu. Similar
islands and islets abound along the shore of Viti Levu, and between it
and the outer reef south of Moturiki towards Mbau and the Tomberua
Passage (Plate 7).

The islands of Viwa (Plate 36) and Mbau are both composed of
stratified volcanic mud resting upon harder volcanic rocks, and the whole
shore line of the adjoining part of Viti Levu is made up of the same ma-
terial, judging by what we could see of the shore bluffs as we steamed

FRINGING REEF HARBOR, OFF KORO LEVU.

from the Moturiki Channel to Mbau. The soft rocks of the shores of that
part of Viti Levu are readily disintegrated, and their erosion and denu-
dation have supplied the material for the extensive mud flats (Plate 35)
Ivinu in the area just mentioned (Plate 7), leaving endless patches and
small flats more or less covered with patches of growing corals. These
softer rocks rest upon harder volcanic rocks, the extension of the rocks
which attain a considerable height in Moturiki and a still greater one in
the peaks of Ovalau.^

1 Both Ovalau and Moturiki are surrounded by a fringing reef.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS.

Ill

The formation of the great barrier reef of the southern shores of Viti
Levu is due to causes very similar to those which have given its present
physiognomy to the northern coast of Cuba between Nuevitas and
Matanzas. Along those parts of the island where denudation and
erosion proceed rapidly owing to the soft character of the shore rocks,
very extensive flats have been formed like those south of Ovalau. When
the reef barrier flats have been eroded from a harder base, like volcanic
rocks, the flats are less prominent ; they are somewhat more extensive
where the old elevated coralliferous limestone formed the shore hills ; or
the reef flats may disappear altogether when the harder volcanic rocks
have been only little affected by erosion or denudation. From the na-
ture of the negro-heads scattered upon the reef flats it is generally a
simple matter to ascertain the character of the base of the reef flats of
an atoll or of a barrier reef.

MOTUKIKI CHANNEL.

The islands of Ovalau and of Moturiki (Plate 7), which are enclosed
by the northeastern extremity of the Viti Levu barrier reef, are both of

ENTRANCE TO LEVUKA.

volcanic formation, a kind of conglomerate or breccia similar to that
found at Mbengha, Tavuki in Kandavu, and in many other places in
Fiji. The highest peak of Ovalau rises to a height of nearly 2,100 feet,

112 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

and the shape of its ridges, crests, anti peaks (Plates 33, 34) shows the
effect of extensive denudation and erosion. The island is elliptical, eight
miles long, and about six wide. Moturiki flanks Ovalau on the southwest
side, is low, about five miles long, and connected with the southern face
of Ovalau by an extensive fringing reef flat surrounding its eastern face
and the islands of Yanutha Levu and Yanutha lai lai. The Moturiki
fringing reef is separated from the bai-rier reef by a narrow channel, and
the northern extension, forming the barrier reef off the east coast of Ovalau
(Plate 20*), is broken by a number of deep openings (Plate 7). The
bottom of the lagoon is made up of coral and coralline sand, compara-
tively little mud being washed down from the hill slopes, the water inside
the lagoon being quite clear. From the inner edge of the barrier reef
run out a large number of very flourishing coral patches in from two to
three fathoms, and extending to seven or eight. The j-eef flat is in some
places more than half a mile wide (Plate 20% Figs. 1-5). A good many

NEGRO-HEAD, LEVUKA BARRIER REEF.

negro-heads are scattered upon the reef flats, some of them of consider-
able size. The average depth of the narrow lagoon separating Ovalau
from the barrier reef is from nine to fifteen fathoms, but in some places
there are short stretches with a depth of from sixteen to twenty
fathoms.

Between the Na lulu and the Ngava Passages (Plate 7) an extensive
flat connects the barrier reef with Ovalau, much as the fringing reef of

AGASSIZ: FIJI ISLANDS AND CORAL HEEFS. 113

Moturiki is connected with the bai'rier reef stretch opposite its eastern
face. There is also a simihir connection between the fringing reef off
Bololo Point and the barrier north of Na lulu entrance. The south-
eastern part of the reef off Ovalau and Moturiki being strictly neither a
barrier nor a fringing reef, but a combination of the two, the Xgava and
Na lulu entrances forming reef harbors similar to those characteristic of
frincino- reefs, indicating how the offshore platform of Ovalau has been
eroded and how corals have gradually obtained a footing on the un-
derlying volcanic substructui'e, remnants of which are visible at many
points of the barrier reef flats. One may judge of the extent of the
denudation and erosion which have taken place from the shape of the
peaks and bluffs and ridges which give to Ovalau so characteristic a
profile when seen from the sea (Plates 33, 34). Compare the sharp
peak of Tumuna, the rounded elevations forming the ridge of Xdelai
and of Koro Levu, the sugar loaf of Craig, and the bluffs near Levuka.

LEVUKA.

The spur which has formed the island of Moturiki is covered by low
conical hills, culminating on the eastern summit at Ului Mboa, which is
but little higher than the rest of the island.

To the westward and northward of Ovalau reach the extensive flats
full of patches which connect the west shore of Ovalau with the mainland,
and reach on the northwest to Tova and south towards !\Ibau (Plate 7);
flats which are formed by the disintegration of the low bluffs, consisting
,of bedded volcanic mud (" soapstone "), which must once have extended
eastward close to Ovalau and Moturiki. The patches on the flats are
covered with growing corals.

VOL. XXXIII. 8

114 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

The stretch of strata of volcanic mud constituting the east shore of Viti
Levu north of Mbau undoubtedly once extended farther east, connecting
the main island with the islands of Moturiki and of Ovalau. This readily
explains the changeable character of the barrier reef at different points
along the coast of Viti Levu. Off Ovalau and Moturiki the substructure
of the barrier reef is volcanic, and the negro-heads which crop out upon
its surface at various points plainly indicate this. One of the most
striking of these protrusions being a small mushroom-shaped volcanic
rock on the barrier reef to the south of Moturiki, immediately west of
Thangalai Island (Plate 7). This island and Leluvia, and one or two
keys on the northern part of the great reef south of Moturiki, are small
islets of coral sand thrown up on some of the shallower parts of the reef
flats. The larger islands are thickly covered with cocoanuts and shrubs.
On the southern part of the reef flats immediately north of the Tombe-
rua Passage near the exterior edge is the island of IMumbualau. It is
about thirty feet high, and is composed of elevated corallifei'ous limestone
deeply imdercut, pitted, and honeycombed, while the islands farther
inland off Kamba Point consist of stratified volcanic mud.

Another very striking fragment of elevated coralliferous limestone is
that of Na Vunivatu (Plate 37), on the reef flats to the south of Xasilai
Mouth. The remnants of the elevated reef can be traced south of Tom-
berua Passage on the Nasilai reef flats, and extend on both sides of the
lighthouse. There ai'e numerous heads of elevated limestone, fragments
of former large stretches of the same material. Still farther south the
elevated coralliferous limestone is seen to underlie the island of Nukulau
(Plates 38-41) at the mouth of Lauthala Harbor (Plate 25), as well as
the flats to the eastward and the island of Mokaluva with its flat (Plate
38). The extensive mud flats forming the mouth of the liewa River
have to a gi-eat extent encroached upon the inner edge of the coral
reef flats underlaid by the elevated coralliferous limestone which every-
where crops to the surface to the south of Tomberua Passage. As far
as the Nukulau mouth of the Rewa, the reefs are in reality fringing
reefs growing upon flats of elevated coralliferous limestone, intersected
by deep indentations forming reef harbors. The great extent of the flats
skirtins: the shore of Viti Levu eastward from Suva Point shows the
amount of denudation and erosion to which this part of the island has
been subjected (Plates 24, 25). From off Lauthala Bay (Plate 25) to
Suva, the reefs are extensive barrier reef flats separated by passages
leading into the channel running between the barrier and the shore
(Plate 7). Some parts of the barrier flats are more than a mile wide.

AGASSIZ: FIJI ISLANDS AND COEAL EEEFS. 115

The barrier reef flat north of Tomberua Passage and south of liat Pas-
sage is in many places nearly three miles wide, with an average width of
about two miles. The wide reefs of Serua and of Rovondrau Bays
(Plate 5) are covered with flourishing patches of corals ; what their
substratum is I am luiable to determine from the absence of negro-heads
on the outer reef flats. Judging however from the nature of the head-
lands and of the rocks ci'opping out all along the shore between Serua
and Suvo, it is probably of the " soapstone," — the bedded volcauic mud
so characteristic of the shores of Viti Levu both east and west of Suva,
with the exception of a small key probably of elevated limestone on the
end of Rovondrau Reefs (Plate 5).

To the east of Namuka Harbor, a small reef harbor formed likb the
Navua and the Tongoro pass through the outer reef flats, and the elevated
limestone again forms the substratum of the reef flats. The reef is here
a fringing reef, which can be navigated bv boats near the shore after half
tide, and the outer face is covered with large negro-heads consisting of
elevated coralliferous limestone. "West of the entrance to Suva Harbor
(Plate 5) the reef occurs in successive stretches of fringing or of barrier
reef outside of fringing reefs, forming in some cases small reef harbors,
like Namuka, Nanggara, Vatuloa, Navua, Serua, or, opposite the mouth
of the Navua River, a large open bight, Rovondrau Bay.

The passages through the Yiti Levu barrier reef and its principal
reef harbors, Suva among others, are generally opposite the mouth of
some river or creek, tlirough wliich considerable fresh water carrying
silt flows ; this is especially the case of the Rewa River, whicli brings
through its many mouths an immense amount of silt and detritus, and
has formed a great delta. Both Darwin and Dana have attributed the
formation of reef harbors largely to local currents, to the presence of
fresh water, and to the action of silt. The bringing down of detritus,
especially in the rainy season, and its deposition in channels will keep
the bottom clear of corals, and thus form passages or reef harbors.
The extensive reef which protects the harbor of Rewa has been formed
in part by the erosion of the softer volcanic beds, and in part by the
deposition of the silt brought down by the Rewa and the cutting out
of a barrier channel behind the reef.

To the west of Serua the barrier reef disappears (Plates 5, 6), and the
shore line is now composed of hard volcanic rocks which are not easily
decomposed, or consists of the soft and easily disintegrated volcanic mud
strata extending as a general thing from Mbau to Serua. Although
here and there the harder rocks push out to the shore, where they are

116 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

edged with a fringing reef, or we may find the remnants of the elevated
coralliferous limestone, which is less easily eroded than the volcanic mud
strata, as in the elevated reef in a valley to the north of Suva. This
reef rises to a height of 120 feet above high water mark, and is fully
fifty feet thicli (Plate 31). Its extension can be traced in outliers on
the north shore of Suva Harbor and on islands composed of elevated
limestone at the mouth of the inner harbor of Suva, — islands which
are from sixty to ninety feet in height, and rest directly upon beds of
stratified volcanic mud and capped by similar strata. On the northwest
shore of the inner harbor there is a bluff of the same elevated limestone
rising to about sixty feet. The continuation of the reef can be traced
inland and along the shore for a considerable distance.

The character of the islands within the barrier reef patches of Xamuka
and of Serua indicate that the corals growing upon the flats rest upon
beds of stratified volcanic mud (Plate 5). Here and there we find a
negro-head of the harder volcanic rock upon which the volcanic muds
rest. From Serua westward the fringing reef varies in width from a mile
to a mere narrow fringe of corals close to the shore (Plate 42). Negro-
heads of volcanic rock stud the reef flats, which are here and there
hollowed out into small boat harbors (Plate 6). At the Singatoka
Eiver the fringing reef has disappeared (Plate 6), and the heavy
breakers roll upon a coral sand beach for a distance of about three
miles. Immediately behind the beach rises a line of huge coral sand
dunes, one of which attains a height of 190 feet (Plate 44). At this
point the character of the fringing reef changes again. It is built upon
the remnants of the ancient elevated limestone reef (Plate 43), small
bluffs of which occur all the way between the Singatoka Ptiver and
Xandronga Harbor (Plate 45). Some of the bluffs on the shore
attain a height of more than seventy feet. Negro-heads consisting
of elevated limestone fragments now abound upon the whole line of
the fringing reef, and the two islands which protect the harbor of
Nandronga on the east, and on the west are outliers of the ancient
elevated reef (Plate 45). The height (thickness) of that reef must
have been very considerable, judging from the height of an extensive
bluff, consisting of limestone to the north of the sand dunes at the mouth
of the Singatoka, which must be fully 250 feet. The fringing reef
extends to the west of Nandronga as far as Likuri Harbor, where it
gradually passes again into a barrier reef with a gradually widening
shore passage (Plate 6) as we approach the Nandi waters.

The elevated limestone reef must have extended west as far as Viwa,

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 117

and north again as far as Asawa i lau, both of which islands, as I am
informed by Dr. Corney, consist of elevated limestone (Plate 2). Viwa
is 100 feet in height.^

Plateau off Nandi and Yasawa.

To the westward of Nandi waters (Plate 3), off the northwest coast
of Viti Leva, extends a wide plateau, the result of the denudation and
submarine erosion of that side of the island. The depth of this plateau
is most irregular, varying from ten to forty fathoms. The plateau is
studded with sunken patches, and with rocks and islets and islands. The
southwestern line of islands from the Mololo Islands to Mana is flanked
by an outer line of reef flats, which gradually become smaller and disap-
pear off Tartar Reef (Plate 3). From these the edge of the plateau
crosses toward the north, and the outer reefs reappear again to the
westward of the long chain of the Yasawa group.

The Yiwa Island reef is separated by a narrow, deep channel, with
137 fathoms in mid-channel, from the western edge of the Yasawa
plateau. To the northwai'd of the Malolo Islands are scattered a few
islands, — Kandavu, Lovuka, Tavua, and Yomo. The last is of volcanic

TOMO LAI LAI.

origin, while Kandavu is flanked by beach rock, as is also Tavarua at the
entrance of Xavula Passage. All the islands which Captain Thomson
examined on his way from the Malolo Islands to Waia he found to
be of volcanic origin, — Mana, Tavua, Monu, and others. As I have

1 The elevated limestone'patches vrliich begin at Singatoka extend to the patches
and reef flats north of Xavula Passage (Plates 2, 3). Captain Thomson collected
some pieces of a negro-head on the edge of the reef flat near Tavarua Island
which consisted of elevated limestone.

118 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY.

already stated, Viwa and Asawa i lau are said to consist of elevated
limestone.

The Malolo Islands rise to more than 700 feet. Mana is 240 feet

NORTHERN END OF 3IANA.

high, Mondriki and Monu respectively 590 and 730 feet, and Waia more
than 1,800 feet. The extension northwai'd of the Yasawa group forms
a chain of sixteen high islands for a length of fifty miles, which ter-
minates in the reef of the Ivinsilk Islands on the south of Round
Island Passage, the principal entrance through the Great Sea Reef off
Vanua Levu. The Yasawa Islands, as well as the islands to the westward
of the Xandi Waters, are surrounded by fringing reefs. As will be seen
from the charts, the reefs are on the western face of the plateau (Plate 3) ;
so that the outer reef flats and the chain of inner islands intercept the
full access of the sea, and corals grow hut sparingly inside of that line.

Suva Reef Flats.

Plates 5, 24-30, 65, 76.

Perhaps no reef flats illustrate better the grinding and wearing action
of the sea than those of the barrier reef, both to the east and west of the
entrance to Suva Harbor. All the inequalities of surface seem to have
been levelled off as with a plane, leaving only the shallow pools formed
by the interstices of the large masses of coral (Plates 28-30). The
fauna of the surface of these reef flats is comparatively poor in species,
but abundant in individuals. A large black Ophiothrix, with its disk
hidden in some crack or corner, trails its arms in all directions, and they
literally swarm in all parts of the reef. Towards the outer edge they
are replaced bv Echinometra lucunter, the holes and hollow ways of
which, often over two inches deep, honeycomb the surface, leaving nar-

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 119

row Avails to separate them (Plate 30) ; and finally, near the outermost
edge begins the belt of Madrepores and Pocillopores (Plates 28, 29)
which extends into the line of breakers and beyond. There are few of
the massive type of corals, like Porites, Astraea, and the like, and these
are of diminutive size.

The sui'face of the reef is kept from too rapid wearing by the growth
of marine algee and of corallines which carpet it. The algee are mainly
species of Udotea, of Caulerpa, and of Turbinaria, which in sheltered
pools grow to a considerable size. One finds also ou the surface an occa-
sional large black Holothurian, a blue Linckia, a green Goniaster, a Mu-
reena darting from a pool, a large Cancer trying to hide under a shelving
piece of coral, or a Squilla, or a few specimens of small fish of a brilliant
blue color. There are few Mollusks under the negro-heads and dead
masses of coral scattered upon the reef ; the lower surface of these is
often carpeted with many species of brilliantly colored Sponges, in which
small Mollusks, Crustacea, and Annelids find refuge. The coral masses
themselves are perforated in all directions by boring Mollusks and
Annelids.

The substratum of the eastern and the western reef is made up of
elevated limestone, extending from the shore close to the outer edge of
the reef, independently of the thin crust of corals which grows upon the
outer edge of the reef flat. So it is also with the mushroom-shaped heads
which are found upon the outer edge of the reef flats of Vatu Leile, Mango,
and other islands consisting wholly or in part of older limestones. They
are all composed of the same rock as that of the shores and of the sub-
structure. The outer sea face of the reef flats is steep in all cases, irre-
spective of the increase due to the corals growing upon them, or of the
character of the underlyiug rock, which is only an unimportant factor
in determining the thickness of the sea face edge of the outer reef
flats.

We also examined the outer face of the barrier reef forming the east-
ern edge of the passage leading into Suva Harbor. This reef flat, like
that of the western side of the passage, is entirely made up of ancient
elevated limestone planed down by the sea to a level flat, with small shal-
low pools scattered over the surface. Negro-heads and fragments of the
ancient limestone are scattered over considerable areas on the reef flat ;
many of them have been thi'own up by the sea from the undermining of
the outer edge, others have been torn off from the reef flat itself, and both
are gradually wearing away, leaving fragments of branches of corals and
of coral heads scattered over the reef. The belt of the reef flat close to

120 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

the line of breakers is riddled with holes and channels gouged out by the
Echiuometra common on the reef. These channels look like short wind-
ing drill holes extending in all directions, or merely small potholes in
which the Echinometree live pi'otected from the action of the breakers
(Plate 30). In the same belt corals begin to grow in greater profusion,
mainly Pocillopores, Madrepores, and small heads of Astraeans and of
Goniastrseans or Mseandrinas, a few of these are also found scattered
on the inner pai't of the reef flat. The corals living upon the outer edge
of the reef flat form merely a thin crust, between the patches of which
the substratum of elevated limestone crops out. Similarly, at a great
many other points in Eiji, the outer edge of the reef flat, when exposed
at the very lowest stages of tide, is seen to be edged with a belt of rocks
identical in structure to that which forms the substratum of the reef
flat platform. I may mention Mango, Yatu Leile, and a number of the
islands of Fiji which have been described. The slope of the outer edge
of the reef flat falling off" more or less rapidly has little to do with the
recent reef crust growing upon it ; that only modifies its slope, possibly
to twenty fathoms. The general slope of the sea face of the reef is due
to conditions which antedate the formation of the coral reefs of the
present day.

Dana^ says that beneath the channels (basins) lies in general the
coral rock of the reef region, the inferior part of the great reef forma-
tion, whose upper portions constitute the so called barrier and fringing
reefs. This certainly is not genei'ally the case : see the description of
the flats between Ovalau and Mbau. Dana himself cites a number of
examples which do not accord with his views when describing great
admixtures of coral and of material derived fi-om the mountains adjoin-
ing, and as he well says : " When the materials from both sources, the
shore and the reef, are mingled, the proportion will necessarily depend
on the proximity to the mouths of streams, the bi'eadth of tlie inner
waters or channels, and the direction and force of the cui'rents."

As has already been observed by Dana, *' At low tide the breakers
often cease, or nearly so." ^ It is frequently possible a short time before
the turn of the tide to examine the corals growing on the outer face of
a reef. At Komo we had an opportunity to photograph coral reef flats
where the corals were growing upon a substratum of volcanic rocks
(Plate 65) just as they are growing upon a basement of tertiary lime-
stone at the entrance of Suva Harbor. At Xgillangillah we came upon

1 Corals and Coral Islands, p. 149.

" hoc. cit., p. 131. ,

AGASSIZ : FIJI ISLANDS AND CORAL liEEFS. 121

a fringing reef flat covered with Alcyonariaus (Plato 76), similar to
those figured by Keut.

Gardiner^ has observed the important part which incrusting coralline
algae perform in Fiji in supplying the material for a reef rock of compact
homogeueous structure ; they iindoubtedly assist materially in prevent-
ing the disintegration of dead corals, and their subsequent comminution
by the action of the waves. In an intei'esting article on the calcareous
algse of the Gulf of Naples,^ "Walther has given an excellent account
of the part which coralline algaj like Lithothamnium play in building
up amorphous limestone deposits of considerable tiiickness from the
obliteration of its structure.^ But he has confused the theory of the
formation of reefs with the theory of the formation of limestone deposits
of great thickness, one of which is Ixised on an assumption, the other
which is not in the least open to doubt. It is evident, however, that
those who have examined coral reefs have not attributed to coralline
algae the share which they have in building up recent amorphous lime-
stone deposits of considerable thickness.

The following list of algae collected I owe to the kindness of Professor
Farlow : Amphiroa fragilissima Lam'x ; Galaxaura fragilis Lam'x, var.
fastigiata Decaisne ; Liagora Preissii Louder, var. pacifica Grunow ;
Padina Pavonia (L.) Gaillon ; Dictyata ciliata J. Ag. sterile ; Turbina-
ria conoides Kg. ; Hydroelathrus cancellatus Borg. ; Sphacelaria furci-
gera Kg. 1 sterile ; Caulerpa Freycenetii C. Ag. ; C. clavifera (Turn.)
C. Ag. ; C. complanata J. Ag. ; Halimeda macroloba Decaisne ; H.
Opuntia (L.) Lam'x; H. polydactylis J. Ag. ; Aurainvillea comosa
(Harv.) Murray &, Boodle ; Aur. papuana Murray & Boodle ; Dictyo-
sphseria favulosa Decaisne ; Valouia segagropila (Roth) J. Ag. ; Yalonia
utricularis J. Ag.

ISLANDS AND CORAL REEFS DESCRIBED FROM THE CHARTS.

With the exception of the Argo Reefs (Plates 19, 20), the islands
and reefs we did not visit were insignificant in size, or, judging from
the charts, presented no point of interest not included in those we ex-
amined. I may mention among these Vanua Vatu (Plate 21), a small
circular island with a depressed central summit, about a mile and a half
long. It is- composed of elevated coralliferous limestone rising to 310

1 Loc. cit., p. 477.

2 Zeitsch. d. deutschen geol. Gesell., Heft 2, Bd. XXXVII., 1885, p. .329.
8 See also an article by Fresh, Neues Jahrbuch f. Mineral., 1892, II. 169.

122 bulletin: museum of compaPwATIVE zoology.

feet. It resembles Xaiau on a smaller scale. It is surrounded as is
Tuvutha by a narrow outer reef flat, becoming a fringing reef at several
points of the shore, and enclosing a narrow and shallow lagoon full of
rocks and patches.

There are also a number of atolls presenting no special features. To
the westward of Xgele Levu are two reefs, Thakau Yutho Vutho
and Thakau Mata Thuthu (Plate 17). The former is separated from
Kgele Levu by a channel eight miles wide, with 1-45 fathoms in mid-
channel. The latter is separated fz-om Thakau Yutho Yutho by a
channel 171 fathoms deep and three miles wide. The lagoons have
respectively a greatest depth of 15 and 19 fathoms. They both have
navigable entrances, and the outer reef flats are studded with negro-
heads and coral patches, and there are no islands on the rim. These
atolls resemble Ngele Levu, but are not more than one third of its size.

It is interesting to note that to the westward of Thakau Mata Thuthu
(Plate 17) there is an isolated bank with 74 and 76 fathoms of water,
but separated from it by a narrow channel ; it n^xy be a spur of the
bank upon whicli the atoll of Thakau Mata Thuthu is situated, similar
to Cock's Bank, which is close to the southwestern edge of the 100
fathom line.

Similar atolls and varying gi'eatly in shape are Duff"'s Reef (Plate 18)

to the west of Wailangilala, and to the south Dibble's Poef (Plate 19),

to the east of Yanua Mbalavu, Xuku Thikombia (Plate 19), and Male-

vuvu Reef (Plate 19) ; farther south Thakau Tambu, Yaroua, and the

smaller reefs Thakau Nokeva and Thakau Lasemarawa (Plate 20).

As we steamed from Tuvutha to Xaiau we saw the sandbank in the

centre of Tavanuku i vanua Reef surrounded by a fringing reef somewhat

more than a third of a mile in width (Plate 20). To the southwest of
«

Tuvuthci is also situated a small circular atoll, Tavanuku i wai, with
an outer reef of about half a mile in diameter enclosing a small shallow
lagoon.

To the east of Mothe are Thakau Motu (Plate 22), a large atoll open
to the west, \nth 24 fathoms in the deepest part of the lagoon (Plate
23% Fig. 6), and Thakau Yau (Plate 22), a small circular reef with a
shallow lagoon of impounded water. Xeither of these did we visit. West
of Ivomo, Thakau Yuite (Plate 22), in a line running north and south,
east of the Yangasa cluster, lies Thakau Levu, and southwest of Yanua
Yatu and to the northeast of Totoya the Tova or Xa Yatu Reef (Plate
23% Fig. 5, and Plate 20% Figs. 13, 14). Tova has been well surveyed
(Plate 20% Figs. 13, 14, and Plate 23% Fig. 5) ; unfortunately we were

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 123

not able to visit it, but, as wili be seen, it closely resembles the Horse-
shoe Reef (Thakau Momo, Plate 23% Fig. 6), which we examined. xVU
these islands are atolls with an outer reef flat and a lagoon of moderate
depth, varying from ten to about twenty fathoms as the greatest depth,
with entrances into the lagoon, and with only rocks and patches and no
islands on the outer reef flats.

Thakau Vau, Thakau Laseraarawa (Plate 20), and Thakau Is"awa en-
close impounded water. South of Thakau Levu (Plate 22) are Thakau
Thikondua, Thakau lieivareiva, Thakau Nasokesoke, and Thakau Teteika,
representing probably as well as Wilkes Reef north of Namuka, and the
two reefs Tavanuku i wai and Tavanuku i vanua and Frost Reef, the
summits of small peaks or of crests, now covered only by heads on which
corals have found a footing. In the case of Tavunasithi (Plate 22), Nuku
Songea, Yaroua, Maafu Rock, and the Xukutolu Islets west of Yathata,
the summits are still visible. Xaiabo Islet is the remnant of a small
island now surrounded by a very narrow outer reef flat enclosing a lagoon.

AYe did not visit the Nukutolu Islets (Plate 19), which seem to be the
summits of a former narrow ridge. Frost Reef, to the west of Mango
(Plate 19), is a flat circular reef of about a mile in diameter, with a rock
at its northern edge.

Neither did we examine the following islands and reefs to the south
of the Exploring Isles (Plate 19) : Malevuvu Reef, an atoll nearly three
miles long by half that in width, and a lagoon with thirteen fathoms
gTeatest depth, accessible to boats on the west side ; Katavanga, a small
island, consisting, according to Captain Cocks, of elevated coralliferous
limestone rising to a height of 180 feet, situated in the western part of
the elliptical lagoon encircled by a reef flat widest at the eastern face,
and over three miles in greatest diameter, witli a greatest depth of thir-
teen fathoms, and an opening for small vessels on the northern side of
the lagoon ; and Vekai, an elevated limestone rock nearly thirty feet high
on the inner edge of a cii'cular reef about two miles in diameter, with a
boat passage on the northwest side leading into a lagoon with a greatest
depth of eighteen fathoms. The Malima Reef resembles Kimbombo Reef.
The islets are near the centre of a lagoon about two miles in diameter.

It would not be difficult in most cases to determine how these smaller
reefs have been formed. They are either in part volcanic and in part
elevated coralliferous limestone, or wholly volcanic, or elevated limestone
alone. The result would in either case be the same. The volcanic
islets disintegrating more slowly than the tertiary limestone, it is prob-
able that the reefs, which show no signs of volcanic rocks, have a sub-

124 BULLETIN : MUSEUM OF COMPAEATIYE ZOOLOGY.

stratum of ancient limestone of greater or less thickness, according to
the height to which the particular i-eef has been elevated.

Au atoll formed from the disintegration, erosion, and denudation of an
island of volcanic structure, like Komo, for instance, would not differ in
structure from an atoll like Oneata, formed from the disintegration of an
island composed of elevated coralliferous limestone ; but their origin
would at once be detected, if the islands had disappeared, from the exist-
ence in one case of negro-heads and rocks of volcanic origin, in the other
of coralliferous limestone scattered within the lagoon and on the surface
of the outer reef flats. The steep slopes of these two lagoons, of difi"erent
geological structure, being in no way due to the thin veneer of coral
patches growing upon their respective flats and slopes, but to the fact
that they are a continuation of the slopes of the islands once covering
the ax-eas of Komo and of Oneata Islands, which have been elevated
and since their elevation have disappeared in great part, and have been
denuded and eroded to form the platform surrounding the islands now
remaining to attest their former greater extent. The denudation and
erosion of these islands, being accompanied by the scouring out of the
lagoons from the submarine platform through the action of the sea,
caused by the incessant pouring into the lagoon of a mass of water
which can only find its way out through the entrances into the lagoon
or over the reef flats, where it passes out with considerable velocity,
a velocity obtained in part from the hydraulic head, and in gi'eat part
also from the drift due to the constant driving of the trade winds in a
westerly direction.

North of the Exploring Isles there are some small banks, in from
eight to twelve fathoms least water. They are Alacrity, Jeffreys, and
Lewis Banks. Reid Reef (Plate 20, 20*, Figs. 1-4) is a narrow encir-
cling reef, enclosing a large lagoon with three islets, rising respectively
to a height of sixty, ten, and twenty feet, probably of elevated limestone.
The outer reef flat is narrow on the western side, bordered by a belt of
heads along the inner edge. There are two passages into the lagoon on
the western face. The length of the lagoon is about eight miles, and its
width five. The greatest depth is twenty fathoms.

Mbukata tanoa or Argo Reefs.

Plates 20, 20', Figs. 5-8, and Plate 21.

These reefs are irregularly triangular, about twenty miles in greatest
length. A narrow continuous outer reef flat extends along the eastern

AGASSIZ: FIJI ISLANDS AND COKAL REEFS. 125

and southern faces, but the western and northern faces are bordei'ed by
disconnected reef patches (Plate 21), and towards the northeastern face
from the central part in from twenty fathoms the lagoon slopes gradu-
ally to the 100 fathom line. The western part of the lagoon is full of
separate patches and clusters of rocks and coral patches. Off the west
face lie two small banks, one of which is awash, the other with two
fathoms of least water and covered with heads. Off the east face are
three similar small banks, all of which probably represent the remnants
of isolated peaks or spurs of the former land covering the Argo Lagoon.
The Argo Eeef is separated from the Vanua Masi (Plates 21, 22) atoll
by a narrow channel with a depth of 115 fathoms.

The island of Yanua Masi is not quite half a mile long, eighty feet
high, and is composed of elevated coralliferons limestone. Bacon Islet,
sixty feet in height, is stated to be of volcanic origin ; it lies on the
eastern face of the narrow outer reef flat facing the lagoon. This is
open on the southwest, where the lagoon is studded with heads and coral
patches. The greatest depth of the lagoon of Yanua Masi is twenty
fathoms, the average from twelve to sixteen. The southern part of the
lagoon of Argo Eeef has a depth of thirty-four fathoms, and an average
depth of from twenty to thirty.

We may look upon the Argo Reef (including Vanua ]\Iasi) as vastly
more denuded and eroded than that of Vanua Mbalavu, whicli it re-
sembles in many respects. The islands which probably once covered
the whole area of the Argo Reefs have been disintegrated, and there
remain of them only the islets in Vanua Masi and the innumerable
heads and patches which stud the slope of the Argo Reefs. The slope
of the Argo Reefs corresponds to that of Vanua Mbalavu, and represents
the slope of the volcanic island which thrust up the elevated limestones
now eroded which once covered the great part of the Argo Reef Lagoon
as at Vanua ]Mbalavu. The great open stretch on the northern face of
the Argo Reefs represents a tongue of the ocean which encroached upon
the northern slope of the laiid and has left in the shallower parts only
heads and patches of corals, while in the deeper parts corals have not
obtained a footing.

Thikombia.

Plate 17.

We did not visit Thikombia, the northernmost island of the group,
which I am informed is composed in part of elevated coralliferons lime-
stone rising to a height of four hundred feet. The island is a narrow

126 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

undulating elongated ridge with conspicuous summits (volcanic 1), one of
which is over six hundred feet high ; it is a little over six miles in
length, and situated at the northwestern extremity of an elongated
plateau extending fifteen miles in a southeasterly direction, with an av-
erage depth of thirty to over forty fathoms. The western extremity of
Thikombia, as well as the southern half of the island, is bordered by a
fringing reef, which extends in a long spit made up of patches and
detached rocks for two and a half miles in a southeasterly direction.
Gardiner states that parts of Thikombia are terraced.

Ono i lau.

Plate 17", Figs. 13-16, and Plate 33% Figs. 1-4.

We did not visit the islands to the south of Ongea. Among them
are the Ono i lau Islands (Plate 1), of which some are volcanic and
others composed of elevated coralliferous limestone, the highest island
being 370 feet high. These islands are surrounded by an outer reef
flat, elliptical in outline, about seven miles by four, which is dotted
with islets, rocks, and coral patches. To the south of these islands are
the small islands of Tuvana i tholo and Tuvana i ra (Plate 17% Fig.
13, and Plate 23% Fig. 27), situated on the northern edges of the
circular barrier reef which surrounds them. To the southwest of the
Ono cluster lies Vuata Ono (Plate 17% Fig. U, and Plate 23%Fig. 3),
an oblong reef nearly three miles long and always awash. Turtle
Island to the northeast of Ono is a narrow ridge of elevated limestone,
rising to over two hundred feet, with a barrier reef about four miles
long off the west face, enclosing a narrow lagoon with six fathoms of
water and passing into a barrier reef on the east face. Yuata Yatoa
(Plate 23% Fig. 4) is a detached reef somewhat over two miles in its
greatest length, enclosing a tidal basin into which there is a boat passage
through the reef. This reef lies about two miles to the south of Yatoa,
with two hundred and forty-six fathoms in mid-channel. Yatoa and
Yuata Yatoa are probably the summits of a short ridge. The presence
of elevated coralliferous limestone in this part of Fiji shows that the
area of elevation of the group extended to the southernmost islands.

Viti Levu and Vanua Levu.

Plates 3, 3", 4, 18.

Although there are large stretches of the shores of Viti Levu and of
Vanua Levu (Plates 3, 3% 4) which I have not examined, we may per-

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 127

haps assume from the iuformatiou I have gathered and from an exami-
nation of the charts, that neither they nor the smaller islands and reefs
in the Lau Archipelago, which have been passed by, present any features
which are likely to throw much additional light on the results obtained
from the examination made by the " Yaralla." The ai'ea between the
Yasawa group and the north shore of Viti Levu (Plate 3) has not been
systematically surveyed. All we know is that it is full of coral patches,
undoubtedly the eastern extension of the patches to the northwest of
Nandi waters towards the Yasawa group. How far west of Charybdis
Reef the extension of the deep water bay north of A^atu i ra Channel
reaches is not known. Its northern and eastern limits off Yanua Levu
are well defined on the charts (Plate 3). It is interesting to note that
a very steep slope — fully as steep as any of the sea faces off the reefs or
smaller islands of Fiji, or as steep as the sea faces of the great barrier
reef oflf the south coast of Yiti Levu — runs ofl* the west side of Yanua
Levu from the Makougai Channel beyond Yendua Island (Plate 3), and
off the east side of Yiti Levu from the horn of the reef north of Ovalau
to opposite Charybdis Eeef. Yet on this steep ftice the corals form
only scattered patches over the surface of the flats, extending between
the shore lines towai'd the 100 fathom line, — patches and stretches
which are separated by wide areas in which the bottom is full of heads
of rocks similar to those of the adjoining shores.

Charybdis Reef and the extensive reef on the southwest side of Yatu
i ra Channel (Yatu i ra Reef), represent probably the eroded summits of
a more or less circular island and of an elongated ridge, on the outer
edges of which coral patches have found a footing, and of which Yatu i ra
Islet (one hundred feet high) is the only remnant. The lagoon varies in
depth from twenty-two to twenty-seven fathoms, " with several passages
into it through which the tide runs strongly." Charybdis Lagoon is
full of rocks and patches its average depth is about twenty fathoms ;
its western edge is open, with rocks scattered along its face.

An extensive frino^ins; reef skirts the north shore of Yiti Levu, which
disappears within reach of the influence of Ba River. There is a
wide navigable channel between it and the broad outer barrier reef
patches, which resemble those off the east coast of Yiti Levu, south of
Moturiki Channel.

I have not examined the shores of Yanua Levu, but according to
Horne^ and from some verbal information relating to the barrier

1 John Home, " A Year in Fiji," London, 1881, pp. 167, 168. Home says that
on the southwest side of Rambe a reef has been elevated twenty feet, and that the

128 BULLETIN : MUSEUM OF COMPAEATIVE ZOOLOGY.

reef, its character is similar to that of Viti Levu, the substratum of
the reef flats being either hard volcanic rocks, or stratified Tolcanic
mud, or remnants of elevated limestone. The northern shore of Yanua
Levu from Cape Undu (Plate 4) west is flanked by wide extensive
stretches of barrier reef patches ; between them and the shore exists a
broad navigable channel full of islands and islets, and the whole of the
shore is also indented by deep bays separated by prominent promontories
almost isolated from the larger island ; plainly indicating that the flats
and patches occupy areas formerly covered by large islands or by former
slopes of spurs from Vanua Levu itself, which have been eroded and de-
nuded and separated from the larger island. The outer flats and patches
of the barrier reef, which as it extends westward beyond the Mali Pas-
sage forms the Great Sea Eeef, and is nearh" thirty miles distant off" the
western point of Vanua Levu. The islands and islets off the north coast
of Vanua Levu form a broad belt of islands separated by islets, rocks,
and patches ; on the western extremity of the belt is Yendua Island and
the islets extending westward.

The existence of fringing reefs inside of barrier reefs is a very strik-
ing feature of the Fiji coral islands. Their absence in some localities
has been explained by Dana ^ on the supposition that the conditions
are more favorable to the growth of corals on a barrier than on an
interior fringing reef. Yet in some of the wide lagoons of Fiji the
corals of the fringing reef grow quite as luxuriantly and to the same
depth as those on the outer edge of the barrier reef, and are often
more abundant than those of the lagoon slope of the barrier reef.
Depths of five to six or seven fathoms are those of the most vigorous
growth of corals on the outer face of such barrier reefs or encircling reefs
as I have examined in Fiji, a depth corresponding to that observed in
the Bahamas in similar positions.

Some of the reefs on the northwestern face of Vanua Levu (Plate 4)
apparently illustrate admirably the foi'mation by denudation and erosion
of small reef flats awash, and of reef flats destitute of islands or with
islands encircling a shallow lagoon. It will be noticed that these flats
and pseudo atolls rise from a comparatively shallow platform, — nine to
twenty fathoms, — and evidently represent the different stages of denu-
dation and of erosion of islands which have been left on one side of 'the
reef flat, or have disappeai-ed, leaving an irregular enclosing reef, or have

beach along Savu Savu, as well as Waikava and the adjacent islands, consists of
coral upheaved to a height of thirty feet.
^ Corals and Coral Islands, pp. 138, 278.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 129

merely been denuded so as to be just awash; the scouring of the sea on
the diminutive phUforui of submarine erosion having formed a shallow
lagoon in the first instances mentioned, or a series of disconnected pools.
These flats and atolls are in every way identical with similar reef flats or
atolls formed from peaks or islands rising from great depths : Na Ndongu,
Xnku i ra, Thakau Moi, Laukoto, and Thakau Levu Reefs (Plates 3, 4,
23% Figs. 8-19). See the similar structures of Thakau Nalolo, Thakau
.Utulei, and Xuku i ra, on the eastern part of the north shore of Vanua
Levu (Plate 4, Figs. 8-12).

From the eastern point of Savu Savu Bay and the western point of
Vanua Levu the island is bordered by a fringing reef (P*iates 3% 14),
Savu Savu Bay is protected by an extensive fringing reef off Savu Savu
Point on the east, and by a series of wide barrier reef patches lying off
Knmbalau Point on the west, and stretching in smaller disconnected
patches across the southern face of the opening of the bay. To the west
of Kumbalau Point runs an extensive plateau, the outer edge of which
is from ten to twenty miles off shore, and varying in depth up to about
thirty fathoms. On the outer edge of the plateau are narrow discon-
nected patches of corals and islets and rocks (Plates 3% 4). The plateau
makes out in two prominent points, one, Xamena Reef, elliptical in
shape, about twelve miles long and three miles wide, to the south of
Kumbalau Point. The reef patches enclose an irregular lagoon, in the
southern horn of which lies the island of Namena, about 320 feet in
height (Plate 3*). The other spit of the plateau is triangular in shape,
and extends towards Makongai, from which it is separated by a channel
140 fathoms in depth. The western face of the plateau is bordered
by a line of rocks atod narrow coral patches, often widely separated,
and extending in an undulating line.

The outline of the plateau as it forms the eastern side of Vatu i ra
Channel is rounded, forming a deep bight off Solevu Point, and extending
in a northeasterly direction towards Yendua Island. North of Passage
Island (Plate 3), 104 feet high, the coral patches lose their character of
barrier reef flats; they become small, and are often very widely separated.
The edge of the plateau is bordered with rocks, and the slope as we go
north becomes less steep, passing off Solevu Point gradually into the
deeper waters north of Yatu i ra Channel. But south of Nai Thombo
thombo Point there are extensive reef flats, probably formed upon eroded
flats of such detached spits as Lecupi Point on the south of :\Ibua Bay,
and Lamut Islet north of Solevu Point. The principal one of these reef
flats is Thakau Levu, on which some rocks are still awash at high water.

VOL. XXXIII. 9

130 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY,

It is very probable that this plateau oflF the southwest coast of Vanua
Levu represents the denuded and eroded slope of its western coast when
it once extended near to the 100 fathom line. Tlje only remnants of
this former extension are the islands of Namena, i^assage Island, and
the numberless rocks and coral patches studded over the surface of the
plateau and found along its edge.

The reefs of Makongai and Wakaya represent a stage of denudation
and erosion less advanced than that of the oS^amena Reef, and of the reefs
extending towards Vatu i ra Channel north of Makongai Channel.

From Cape Undu south the shores of Vanua Levu on both sides of
Nateva Bay (Plate 4) are bordered by a fringing reef. From Savu Savu
Bay the south shore is also protected by a fringing reef, which extends
as far as Fawn Harbor ; from there the fringing reef becomes a narrow
barrier reef at a short distance from the shore, passing round Vienna Bay,
and forming the Kioa Reefs, and the Florida and Texas reefs on the outer
edge of the plateau upon which are the islands of Kioa and Eambe (Plates
4, 18). The horn of the Texas reef extends about five miles beyond
liambe, and returns to form a fringing and barrier reef on the north
shore of that island, and connects with the barrier reefs oflf Kumbalau
Point.

The Eambe Plateau (Plates 4, 18), as we may call the eroded eastern
extension of Navukau Promontory, is another admirable example of the
mode of formation by submarine erosion of such plateaus as those off the
southwest coast of Vanua Levu, off the eastern point of Kandavu, and
off the east face of Taviuni. The island of Rambe rises to a height of
over 1,500 feet ; it is nearly nine miles long, and about four and a half
broad (Plate 18). Like Kioa, the other large is^and on the plateau,
which is over 900 feet high, it is of volcanic structure. The plateau
upon which these islands rise, and the accompanying islets, rocks, and
patches, has a greatest depth of thirty-five fathoms, and an average
depth of about twenty.

The Rambe plateau and the one to the east of Taviuni (Plates 4, 18),
from which rise Ngamia and Lauthala, show more plainly than either
Makongai or Wakaya the former connection with the larger islands of
A^anua Levu and Taviuni. The promontory of which Cape Undu is the
termination would, if denuded and eroded, have resulted in the formation
of a plateau spit similar in all respects to that constituting the Namena
barrier reef off the south coast of Vanua Levu. And finally the further
disintegration of such irregularly shaped islands with encircling reefs as
those of Makongai and Wakaya (Plate 15) would give us a ready ex-

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 131

pltuuitiou of the formation of such remarkably sliaped reefs as the Nanuku
and Nukusemanu Eeefs (Plate 18), from the denudation and erosion of
an extended ridge or line of the summits»of independent islands, elevated
at the time wlien the great masses of ancient limestones were raised to
various heights perhaps np to one thousand feet.

The Great Sea Eeef (Plate l) appears on the cliart as the continuation
of the chain of which the Yasawa group of islands are the only rem-
nants, and it may be that it represents its eastern continuation after its
denudation and erosion, and transformation into a submarine platform
for the growth of corals. Similarly the reefs extending to the east of
Vanua Levu towards the Yasawa group may be the western extension of
a range of which Sesaleka Peak and Yendua Islands formed prominent
points.

GENERAL SKETCH OF THE FIJI ISLANDS AND CORAL REEFS.

I went to the Fijis under the impression that I was to visit a charac-
teristic area of subsidence ; for according to Dana and Darwin there is
no coral reef region in which it is a simpler matter to follow the various
steps of the subsidence which has taken place. Dana, in his last dis-
cussion ^ of the coral reef question, states that it is impossible to find a
better sei*ies of islands than the Pijis to illustrate the gradual changes
(brought about by subsidence) which take place in transforming a a'oI-
canic island with a frino'ing: reef to one with a barrier reef, or to one with
an encircling reef ring, and finally to one in which the interior island
has disappeared and has left only a more or less circular reef ring. For
these reasons one of the Fiji atolls promised to be an admirable location
for boring and settling the question of the thickness of the coral reef of
an atoll.

My surprise was great, therefore, to find within a mile from Suva an
elevated reef about 60 feet thick, and 120 feet above the level of the sea,
the base being vinderlaid by what is locally called " soapstone," ^ a kind
of volcanic mud. The western extension of this reef can be traced at

1 Am. Journ. of Science, Vol. XXX., August and September, 1885. Dana says:
" The large Feejee group bears abundant evidence of subsidence in its very broad
reef grounds, barrier islands, and atolls."

" The "soapstone" is largely composed of volcanic deTsris, mixed with tests of
Foraminifera, Pteropods, and Mollusks. Brady (Q. J. Geol. Soc. London, 1888, Vol.
XLIV. p. 1 ) considers the Ehizopod fauna such as one would expect from a depth
of 150 to 200 fathoms.

132 bulletin: museum of compakative zoology.

points along the north side of the harbor of Suva (Plate 7), the islands
of Lambeko, Yuo, and Dra-ui mbotu, which are respectively sixty to
seventy feet in height, being parts uf an elevated reef extending to
low water mark, and now planed off. It was this elevated reef or its
extension westward which we ti-aced from the Singatoka Eiver to the
Xandi Waters (Plate 6). A short distance inland from the mouth
of the Siniratoka there is a blufi" of about 250 feet in height, com-
posed of coralliferous limestone. This blufi is the inner extension of the
elevated patches and limestone bluffs visible on the shore of Viti Levu.
1 am informed by Dr. Corney that the islands of Viwa and Asawa i lau
(Plate 3), to the northward of the Nandi Waters, are also remnants
of this elevated limestone.

But the traces of extensive elevation are not limited to the island
of Yiti Levu. I found that the islands on the rim of the atoll of Xgele
Levu (Plata 17) consisted entirely of coralliferous limestone rock,
elevated to a height of over sixty feet on the larger island. The
northern sides of the smaller islands Taulalia and Tai ui mbeka, as
well as the north shore of Xsele Levu, were on the outer edire of the
rim of the lagoon, deep water running up to the shore line. We next
found that at Vanua Mbalavu (Plate 19) the northern line of islands
were parts of an elevated reef, forming vertical bluffs of coralliferous
limestone rock which had been raised by the central volcanic mass of
the main island to a height of 510 feet at Xgillangillah, at Avea to 600
feet, at the Sovu Islands to 230 feet, and on the main island to a height
of nearly 600 feet, while on the south of the main island the coralliferous
limestone bluffs are very much lower, and those of Malatta and of Susui
reach a height of 420 to 430 feet. Going farther west and south we find
at Mango vertical bluffs of an elevated coralliferous limestone of over GOO
feet underlaid by volcanic rocks at the sea level. At Tuvutha the lime-
stone bluffs are probably nearly 800 feet high. At Xaiau they are more
than 500 feet. At Lakemba (Plate 21) they reach a height of about
250 feet on the southwest side of the island, the greater part of the rest
of the island being of volcanic origin. On the island of Aiwa (Plate 21)
the elevated limestone is fully 200 feet thick. In the Oneata group the
highest point of the elevated bluffs is about 160 feet (Plate 21). South
of the volcanic island of Mothe and enclosed within the same barrier
on the island of Karoni (Plate 22), the reef is about 120 feet thick.

On the three islands of the Yangasa group (Plate 22) the elevated
limestone attains a thickness of 240, 300, and 390 feet, and on On-
gea, the most southeasterly cluster we visited, it attains a thickness

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 13o

of nearly 300 feet. At Fulanga (Plate 22) the elevated limestoxie
attains a thickness of 360 feet, at Kambara (Plate 22) it is about
200 feet thick, and at Wangava (Plate 22) it is perhaps over 300
feet ; these islands may be in part volcanic. Finally, at Vatu Leile, the
most westerly island we examined, the elevated reef forming the island
is fully 110 feet thick.

All this plainl}' shows that the western and soutliei'u part of Yiti Levu,
as far south as Vatu Leile, and the whole length of the windward islands
of the Fiji group, from Xgele Levu on the north to Ongea on the south
(Plate 2), have been subject to an elevation of at least 800 feet ; and there
is abundant proof that the greater part of the thickness of the elevated
coralliferous limestone has been eroded so as to reduce it in certain
localities to the level of the sea, or in others to leave the bluffs and
islands and islets of limestone which we have traced at so many points.

Unfortunately there are as yet but few soundings among the islands
of Fiji (Plate 2). There is a line extending from Xanuku Passage
to the Kandavu Passage, and a number of soundings to the north of
Wailangilala and towards Thikombia, which have developed the ex-
istence of an extensive plateau with a depth of between 300 and -100
fathoms, from which rise all the islands forming the northeastern ex-
tremity of Fiji (Plate 2). The soundings between Xgau and Viti Levu
(Plate 2) also indicate shallower water to the west of that island than
is found either east or south of it. The deep water extends northwesterly
in the passage, parallel with Kandavu. Deep water (1,200-1,700 fathoms)
is found in the triangle formed by ]\toala, Totoya, and Matuku (Plates
2, 16), showing the steep slope of Moala, from 1,200 fathoms at a distance
of six miles, and of Matuku of 1,400 fathoms at a distance of five miles.

The deep channel passing through the centre of the Koro Sea (Plate
2) gradually deepens towards the south until it attains a maximum
depth of over 1,400 fathoms east of Xairai and Xgau, becoming shallower
towards Viti Levu (Plate 12). The water gradually deepens also in
the Kandavu Passage from over LlOO fajhoms north of Xorth Astrolabe
Pieef to over 1,900 fathoms southwest of Kandavu. The soundings to
the north of Xaitamba indicate a i-ido:e with somewhat over 500 fathoms
in depth connecting the plateaus on the two sides of Xanuku Passage
(Plates 2, 18). There are no soundings showing the depths between
the larger clusters composing the Lau or eastern group of Fiji. It
would add greatly to our knowledge of the connection of these groups to
have lines of soundings connecting the diflferent island clusters of Lau.

All the evidence to be gathered in Fiji tends to prove that preceding

134 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

the present epoch there was an extensive elevation, which hfted the
great masses of coralHferous hmestone resting upon the flanks of the
islands to a considerable height, in Some cases as high as 1,000 feet.
The base of the limestone masses rests upon volcanic rocks, as can be
seen at Suva, at Kambara (Plate 78), at !Mango, at Lakeraba, at Xai-
tamba, and at Vanua Mbalavu (Plate 72) it shows the thickness of the
elevated reefs to have been over 800 feet. During this period of uplift
the physiognomy of the islands of the group must have been greatly
changed, and still further modified by the denudation and erosion which
have taken place since the elevation of the ancient limestones. It is to
the changes brought about by the elevation and the subsequent erosion
and denudation that we must look for the causes which have fashioned
the steep slopes of the islands and reefs, and not to the growth of the
thin crust of corals which thrive upon the reef flats forming the sub-
stratum of the modern reef, — a substratum which in Fiji may be of
volcanic origin or composed of elevated limestone, the sea face of which
is the extension of the former land mass and follows its ancient slope,
being only slightly modified by the growth of the crust of recent corals
found upon it.

Similar elevated reefs (probtibly composed of the same tertiary lime-
stone as those of Fiji) have been described by Clark ^ at the Loyalty
Islands, and also by Chambeyron (L.)," and Pelatan (L.).^ Chambey-
ron gives figures of the elevated terraces of Lifou and Ouvea composed
of coralliferous limestone, and there is an excellent photograph taken by
Pelatan of the elevated coral reefs of Lifou, and reproduced in Bernard's*
Nouvelle Caledonie, p. 45. AYhile Mare is said by Pelatan to have five
terraces of elevated coralliferous limestone, and to be riddled with cav-
erns,^ Clark considers the elevated coralliferous limestones of the Loyalty
Islands probably to be Pleistocene.

In the Solomon Islands, Guppy^ has traced extensive elevated reefs,

1 Q. J. Geol. Soc. London. 1847. Vol. III. p. 61.

2 Bull. Soc. Geogr., 1875, p. 566, and Bull. Soc. Geogr., 1876, p. 634.

3 Les T^lines de la Nouvelle Calodonie.

4 L'Archipel de la Xouvelle Caledonie, par Augustin Bernard. Paris, 1895.

5 See also De. Roclias. La Kouvelle Caledonie, p. 90. Grundman, Die Loyalty
Inseln, Peterm. Mittheil., 1870, p. 365.

6 Guppy, The Solomon Islands, 1887, p. 126, and Scott, Geog. :\laj;., 1888,
p. 121, a criticism of the theory of subsidence as affecting coral reefs. Geol. of the
New Hebrides, Friedrick, Q. J. Geol. Soc. London, 1893, XLIX. 227. Campbell, R.,
Geol. Soc. of Australasia, Melbourne, 1889, VI. 19. Strehl, Zeit. f. Wiss. Geog.
Erganz., No. 3, 1890. J. Walther. Bau d. Flexuren, Jena Zeits. f. Nat., 1886, p. 243.
J. Gamier, Ann. d. Mines, 1867, p. 59. Walther, Adamsbriicke, Peterm. Erganz.,
Ko. 102.

AGASSIZ: FIJI ISLANDS AND CORAL IlEEFS. 135

which however he considers as belonging to the present epoch. Elevated
coralliferous limestones also exist in the New Hebrides as well as on the
southei'n shore of New Guinea.

The time of this Fijian elevation we cannot at present ascertain. It is
not unnatural to assume that it was coincident with the elevation of
Northern Queensland, and that the area of elevation included New
Guinea, the islands to the east of it as far south as New Caledonia, and
as far east as the most distant of the Paumotus (Gambler Islands),
and extended northward of that line to include the Gilbert, Ellicc,
Marshall, and Caroline Islands ; and that since this epoch of elevation
the islands within that area have been, like Northern Australia, subject
to an extensive denudation and erosion, many of them being reduced to
mere flats but a few feet above the surface of the sea, others worn away
to represent to-day but a small portion of their former extent. It is
upon the reef flats thus eroded, or around the islands and islets which
are the remnants of a former period, that the corals of to-day have ob-
tained a foothold. And further, by the mechanical action of the sea
combined with that of the trade winds, channels have been excavated out
of the substratum underlying the coral reefs to form the lagoons of the
barrier i-eefs and atolls of Fiji.

So that, as far as we can judge from the case of the Fiji Islands, the
shape of the atolls and of the barrier reefs is due to causes which have
acted during a period preceding our own. The islands of the whole
group have been elevated, and since their elevation have, like the
northern part of Queensland, remained nearly stationary, and exposed
to a great and prolonged process of denudation and of aerial and sub-
marine ei'osion, which has reduced them to their present height. The
submarine platforms upon which the barrier reefs have grown being
merely the flats left by the denudation and erosion of the central island,
while the atolls are similar flats from the surface of which the islands
have at first disappeared and the interior parts of which have next been
removed by the incessant scouring of the action of the sea, the ceaseless
rollers pouring a huge mass of water into the lagoon, which finds its
way out of the passages leading into it or over the low outer edges of
the lagoon. These atolls and islands, suiTounded in part or wholly by
encircling and barrier reefs, have not been built (as is claimed by Dana
and Darwin) by the subsidence of the islands they enclose. They are
not situated in an area of subsidence, but on the contrary in an area of
elevation. The theory of Darwin and Dana is therefore not applicable
to the Fiji Islands.

136 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

The evidence of elevation is not limited to that furnished by the re-
mains of the elevated coralliferous limestone just mentioned, and it is
natural to assume that the elevation we have just traced was but a
part of a more general elevation, which perhaps took place in late tertiary
times, and in which the whole group was involved. It is plain that there
must have been most extensive denudation and submai'ine erosion 0:0 ins on
throughout the group for a very considerable time, geologically speaking.
The outlines of the islands, deeply furrowed by gorges and valleys, the
sharp or serrated ridges separating the valleys, the fantastic outlines of
the peaks and chains of Viti Levu, Vanua Levu, and Ovalau, all attest to
the great work of atmospheric agency which must have been going on
for so long a period.

The extent of the separation of the islands, islets, or isolated rocks
from the points or spurs of the larger islands also bears witness to the
great length of time during which submarine erosion and denudation
have been at work.

The platforms of submarine erosion constitute the characteristic fea-
tures of the islands of Fiji. A glance at the sketch map of Fiji (Plate 1)
and at the detailed charts of diflerent portions of the group cannot fail
to show how extensive this action has been. I need only call special
attention to the northwestern extremity of Viti Levu, the eastern face of
the same island (Plates 3, 7), the southern coast of Viti Levu (Plate 5),
the southwestern and northeastern shores of Vanua Levu (Plates 3, 4,
18), the extensive platform of Kandavu (Plate 11), that of the northern
extremity of Taviuni, Budd Reef (Plates 4, 18), Thikombia (Plate 11),
the platforms of submarine erosion of Mbengha (Plate 8), of Nairai,
Ngau (Plates 12, 13, 14), of Makongai and Wakaya (Plate 15), of
Moala and Totoya (Plates 16, 23), of the Exploring Isles (Plate 19), and
of the smaller islands like Kimbombo and Kanathea (Plate 19), Lakemba
and Oneata (Plate 21), Mothe, Komo, Yangasa, and Ongea (Plate 22),
and a host of other smaller platforms. Finally, platforms of submarine
erosion which have reached the stage of atolls of greater size, like the
Argo Reefs (Plate 21), Reid (Plate 20) and Xanuku Reefs (Plate 18),
Ngele Levu (Plate 17), or those of smaller dimensions, like Adolphus
Reef (Plate 18), Thakau Mata Thuthu, Thakau Vutho Vutho (Plate
17), Duff (Plate 18), Dibble's Reef (Plate 19), Motua Levu, Motua lai
lai (Plate 18), Thakau Tambu (Plate 20), Thakau Lekaleka (Plate 21),
Thakau Motu (Plate 22), Thakau Levu (Plate 22), and others.

Add to this the fact that we are in a region of a former powerful and
extensive volcanic activity, the traces of which can still be seen in all

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 137

directions, and which has undoubtedly played a great part in the lifting
of the island masses and their subsequexat shaping to their present out-
lines. From this evidence I am inclined to think that the corals of to-
day have actually played no part in the shaping of the circular or irregular
atolls scattered among the Fiji Islands, that they have had nothing to do
in our time with the building up of the substructure of the barrier reefs
encircling either wholly or in part some of the islands, that their modi-
fying influence has been entirely limited in the present epoch to the
formation of fringing reefs, and that the recent corals living upon the
outer margin of the reefs, either of the atolls or of the barriers., form only
a crust of very moderate thickness upon the underlying base. This base
may be either the edge of a submarine flat, or of an eroded elevated
limestone, or of a similar substructure composed of volcanic rocks, the
nature of that base depending absolutely upon its character when ele-
vated in a former period to a greater height than it now has ; denudation
and erosion acting of course more rapidl}^ upon the elevated coralliferous
limestones than upon those of a volcanic character. It is therefore natu-
ral to find that the larger islands, like Kandavu, Ovalau, and Taviuni
(Plates 1, 3, 4, 7, 10, 11), are of volcanic origin, while the islands which once
occupied the area of the lagoons of JSTgele Levu, Il^anuku Reefs, Vanua
Mbalavu, the Argo Reefs, the Oneata, Yaugasa, Aiwa, Ongea, and Vatu
Leile clusters, were composed of elevated coralliferous limestones. They
have disappeared almost entirely, leaving only here and there a small
island to attest to the former existence of a more extensive elevated
limestone, once covering the whole area of what is now an atoll (Plates
1, 17, 18, 19-21). Smaller volcanic islands, like Matuku, Moala, Ngau,
Nairai, and Koro (Plates 1, 12, 13, 14, 16), also show the greater or
smaller extent to which each has been eroded after its elevation, being
least in Koro (Plate 3^) and Matuku (Plate 16), and somewhat more in
Moala (Plate 16) and Ngau (Plate 13), and still more in Nairai (Plate
14), while in such volcanic islands with atolls as Mbengha (Plate 8),
Wakaya, and Makongai (Plate 15) the denudation and submarine ero-
sion ^ has been still greater, the islands covering but a comparatively

1 Dana (p. 230) accounts for the formation of the shore platform by the action of
the sea. We go a little further, and assign to the action of the breakers and of the
currents in carrying loose material to sea the formation of channels between the
outer reefs and the shore ; these become lagoons inside of barriers or encircling reefs,
and finally scoop out the lagoons of atolls. Dana (p. 181 ) insists fully as strongly as
Darwin upon the identity of origin of the encircling atoll reef and the outer reefs
enclosing high or low islands : " The lagoons are similar in character and position

138 BULLETIN : MUSEUM OF COMPAKATIYE ZOOLOGY.

small area of that once covered bj the island originally occupying the
area of the lagoon ; this denudation having been carried to a still greater
extent in the Kimbombo cluster (Plate 19), in Komo (Plate 22), and
the islands of Duff Eeef (Plate 18). This process of denudation and
submarine erosion may have gone so far as to leave no trace in an atoll of
its volcanic or of its limestone (elevated) origin, its shape to-day being
entirely due to mechanical action, and having nothing to do with the
growth of the corals which have found a footing upon the flats due to
submarine erosion and to denudation and to the action of the atmosphere
and of the sea.

It seems to me as if the position of an island left on the western or
lee edge of a lagoon depended upon the original position of its highest
point. This appears in the case of Makongai and Wakaya. The ci'est
of the former was probably near the eastern edge, while the highest point
of Wakaya was perhaps nearest the western side of the origi-nal island
(Plate 15). Similarly the highest summit and ridge of Vatu Leile, if our
■views are correct (Plate 9), was on the western face of the original land
mass. The highest ridge of Eambe lies on the northwestern side of the
submarine plateau ; the islands of Budd Reef indicate its highest land to
have been on the northern part of the plateau (Plate 18). In Mbengha
(Plate 8), on the contrary, the highest land mass is found on the east
face of the lagoon. In the Great Astrolabe Lagoon it was in the central
line of the plateau (Plate 10). In Xgau (Plate 13) the highest land lies
to the east, in Nairai (Plate 14) somewhat nearer the centre, in Moala
in the northern part of tlie lagoon. In Totoya (Plate 23) the highest
part of the rim is the eastern edge.

The northeastern part of Ngele Levu must have been the highest ex-
tremity of the Ngele Levu land mass (Plate 17). The islet at the north-
eastern extremity of Wailangilala (Plate 18) indicates the position of
the highest part of that atoll. The highest land of Naitamba, Kanathea,
Vanua Mbalavu, and Katavanga lies on the western part of the plateau
(Plate 19), and also that of Lakemba (Plate 21).

The highest of the land masses of Aiwa, of Oneata (Plate 21), and
of Komo (Plate 22) was on the southern edge of these plateaus. In
Mothe it lay near the northern extremity (Plate 22). In Namuka and
Ongea it ran through the central parts of the group (Plate 22). In
Fulanga the land seems to have been equally high on the northern and

to the inner channels within barrier reefs. . . . The reefs within the lagoons cor-
respond very exactly in mode of growth and other characters to the inner reefs
under the lee of a barrier."

AGASSIZ: FIJI ISLANDS AND COKAL EEEFS. 139

southern edges of the laud mass (Plate 22). In Yangasa the south-
eastern and western faces were probably the highest land of the group
(Plate 22).

Admiral Wharton-^ has suggested "the cutting down of volcanic
islands by the action of the sea, and that this action has a far greater
share in furnishing coral foundations than has been generally admitted."
From our experience in Fiji we may safely modify this to the cutting
down, not only of volcanic islands, but also of other elevated islands,
and their cutting down not only by submarine erosion but also by
denudation and atmospheric agencies, and thus preparing the founda-
tions upon which recent corals have established themselves. Add to
this the elevation of banks composed of volcanic rocks or of sedimentary
rocks up to heights at which corals or corallines can begin to grow,
and we have in addition to their increment in height from the increase
due to pelagic organisms and the decay of other calcareous invertebrates
living upon their surface all the elements needed for the preparation ui
a set of foundations from very ditierent causes.

I have already on other occasions called attention to the powerful
scouring effect produced upon the interior of an atoll or lagoon, or the
channel of a barrier reef, by the mass of water poured into it from all
sides as the huge ocean swells break over the outer rim. This mass of
water can find no outlet against the incessant swell ; it must escape to
leeward through the openings in the outer reef flats, or laterally over the
low pai-ts of their outer edges. It will be noticed that the openings are
usually on the west face of the atoll, the direction in which the prevail-
ino- ti-ades drive the water of the lagoon. The water becomes charjred
with particles of lime or of other material, and we soon have all the
elements of a modified gigantic pothole, from which the churned mate-
rial - is carried out by the currents flowing through the entrances iiito
the lagoon. It has long been known that there is a violent rush of
water out of the lagoons, the velocity attained reaching sometimes four
to five knots. In Fiji I have noticed these powerful currents flowing
out of the passages leading into the lagoons of Fulanga (Plate 22), of
Xgele Levu (Plate 17), of AVailangilala (Plate 18), of Vatu Leile (Plate 9),
uf Totoya (Plate 23j, and racing along the interior channels of the great

1 " The Foundation of Atolls," Nature, February 25, 1897, p. 391.

2 Material derived mainly from the mechanical disintegration of the corals or
substratum forming the surface of the reef, and also in part from the chemical dis-
integration due to the sea water at work to rot and dissolve the limestones of the
reef.

140 BULLETI>' : MUSEUM OF COMPAKATIVE ZOOLOGY,

barrier reef stretching along the south coast of Viti Levu, especially at
Lauthala Bay, Suva (Plate 7), and the reef harbors and passages between
Suva and Serua (Plate 5), and out of the smaller atolls like Motua lai lai,
Thakau Leka leka, Thakau Momo, and others (Plates 12. 18, 21).

The strength of the currents in the channel separating tlie barrier
reef and the shore has been noticed by Semper -^ and by Mobius ^ as
bearing an important part in Mauritius. There is in the Biologisches
Centralblatt, 1889-90, Bd. IX. p. 564, a short review of the third edi-
tion of Darwin's " Coral Pieefs," showing the principal points in the
discussion of the reefs to which Bouney has called attention. But this
discussion is mainly theoretical, and adds no new factors in the problem.
I would refer to what Gardiner ^ says regarding the conditions affecting
the growth of coral reefs in Fiji, where he shows the effect of tidal
currents in the passages of reefs and inside of reefs. Strong currents
prevent the coral larvae from fixing themselves in localities which they
scour, while the corals will thrive off the passages where the currents
have lost their strength. The navigators and naturalists of the U. S.
Exploring Expedition * frequently speak of the rapid outward current
passing through the openings of the reefs, especially during the ebbing
tide. Dana ^ had noticed the great strength of the tidal currents, and
he well explains by their action the great diversity of distribution of
material over the bottom of a lagoon or of a barrier reef channel.

There seems to be no question that the action of the sea can cut out the
lagoons of barrier reefs and of atolls at the depths at which they have been
observed in the Fijis. Although there are individual atolls which show
depths of thirty-five to fifty fathoms and even more, these are excep-
tional depths, which are readily explained as due to other causes than
the scouring action of the sea.

Admiral "Wharton ^ has given an excellent summary of cases showing to
what depths the action of the sea in motion may be felt to a sufficient ex-
tent to move material at depths of fifty to sixty fathoms. As he justly
says, " The effect [of the action of the waves in an otherwise deep sea
over which strong winds are continually blowing] will be to cut down an
island more or less rapidly, according to its constitution, to a very con-
siderable depth below the surface, the final result being a perfectly flat
bank."

1 Natiirl. Existenzbeding. d. Thiere, Bd. II. (1880), chapters 7, 8.

" Beitrage z. Meeres Fauna der Insel Mauritius, Berlin, 1880, p. 29.

3 Loc. cit., p. 484. * Dana, p. 170.

5 Loc. cit., p. 151. 6 Mature, Vol. LV. p. 392.

AGASSIZ: FIJI ISLANDS AND COEAL REEFS. 141

On Plate 22'' I have a series of hypothetical figures to illustrate the
clianges I imagine the islands of Fiji to have undergone from the time
of their elevation to the present day. The only type which is not
repreisented is that of Koro, which is however sufficiently well shown
on Plate 19% Fig. 8. The highest point of Koro occupies a nearly
central position, the eastern platform of suhmarine denudation beinf
only slightly wider than the western. Koro occupies a position inter-
mediate between Makongai and Wakaya (Plate 22^, Figs. 2, 3), where
in the one case the widest platform of submarine erosion is situated on
the west side, and in the other on the eastern face of the island.

The dotted lines surmounting the Figures of Plate 22*" indicate the
hypothetical islands as they may have appeared after their elevation to
the highest point ; the solid lines indicate the heights of the islands as
they are at the present day, and the lower dotted lines in Figures 7 to 12
indicate the position of the imderlying volcanic rocks which have ele-
vated the overlying coralliferous limestones in Figures 7 to 11, while in
Figure 12 the volcanic rocks of Vanua Mbalavu are seen to pass under
the elevated limestones of Thikombia i lau.

In Plate 20% Figures 1 to 5, the dotted lines represent the position of
the volcanic rocks underlying the recent coral reefs forming the barrier of
the hai'bor of Levuka, upon the platform of submarine erosion consisting
of volcanic rocks, as reiDresented by the dotted lines in those Figures.

Figures 1 to 5 represent the hypothetical outlines of volcanic islands.

Figure 1, that of Xairai, with a narrow barrier reef off the east coast
and a wide platform of submarine erosion on the western face, with
heads and patches which probably represent higher points of the
original Naii-ai as indicated by the dotted lines. Figures 2 and 3
represent modifications of a volcanic island having probably in one case
its highest point nearest the eastern edge of the lagoon, and in the
other nearest the western side of the lagoon (Alakongai and Wakaya).

Figure 4 represents ^Ibengha, in which there must have been a
western ridge, and perhaps also a central ridge, more or less parallel
with the two main ridges of Mbengha near the eastern edge of the
lagoon.

Figure 5 represents the continuation of a former great ridge northward
from Kandavu towards the Xorth Astrolabe Reef, which has been
denuded and eroded into a series of islands now existing in the Great
Astrolabe Lagoon.

Figures 6 to 11 represent the former outlines of islands composed of
elevated coralliferous limestone. In the case of Figure G, Tuvana i ra,

142 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

the central limestone hill is flanked by two nearly equal platforms of
submarine erosion which are scarcely more than i-eef flats. In Figures
8 and 10 are represented conditions in which, as in Vatu Leile, we have
a very shallow lagoon with reef flats both on the east and west, and the
remnant of the original island rising to a hundred feet at the western
face. In Figure 10 we have the eastern end of the Ngele Levu Lagoon,
with the islet of Taulalia on the north side of a shallow lagoon. Imme-
diately beyond Taulalia all trace of the former elevated island composed
of limestone disappears ; the lagoon becomes deeper as we pass to the
western entrances, and the only traces left of the original Xgele Levu
Island are the extensive reef flats on the north and south side of the
deeper lagoon.

Figures 9 and 1 1, Ongea and Oneata, indicate the amount of erosion
and denudation which probably has taken place to reduce the islands as
originally elevated to their present condition.

Figure 7 represents the manner in which the great central Sound of
Fulanga, with its narrow outer lagoons, has probably been formed by
the denudation and erosion of the central part of the limestones com-
jwsiug the island, aided by the solvent action both of the fresh water
finding its way through the central limestone mass, and that of the salt
sea after it had once gained access to the inner Sound of Fulanga.

Figure 12 gives a hypothetical section across Vanua Mbalavu, show-
ing: the extension westward of the volcanic rocks which have raised the
island of Thikombia i lau, near the central part of the lagoon, composed
of elevated limestone. The elevated limestone to the westward of
Thikombia either having all been denuded and eroded or bi'oken up
into masses readily decomposed, the fragments of which still exist to the
northeast towards Ngillangillah and south towards Malatta Island.

The sections which I have given (Plates 11% 17% 19% 20% 22% 22^)
plainly indicate the general flatness of the lagoons, with a slight
inclination in the direction of the flow of the water in the lagoon
toward the ship passages leading into the lagoon, and the outline of
the islands which have first been cut down by atmospheric agencies
show irregularities which disappear finally when they have come
within the scope of submarine erosion, resulting in such " sunken "
banks as the Penguin Bank (Plate 23% Figs. 7, 13). By "sunken"
we do not mean in any way to refer to subsidence as a factor in
producing such a bank. The mass of water which is poured into a
lagoon on the windward face of a reef, and transforms it into a gigantic
pothole, is something enormous. The breakers follow one another in-

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 143

cessantly, and the hydraulic head obtained is timply sufficient to account
for the scouring of the lagoons after the I'eef has once established it-
self as a bank, and amply sufficient to wear away from the slope of
the islands the platform upon which the coral reef is built. The to-
pography of this platform is naturally much varied, depending upon the
character of the shore line, the direction of the valleys of the shore
hills, and their composition. A glance at the charts accompanying this
Bulletin will show all possible conditions of submarine erosion in the
cutting down of the submarine platforms of the islands of Fiji, and
in the manner in which islands, islets, and rocks have been left, attesting
their former greater extension in the various clusters of the Archipelago.

When the principal openings are not on the lee side of the lagoons, as
is the case with Vanvia Mbalavu (Plate 19), and the Argo Reef or Totoya
(Plate 23), Fulauga (Plate 22), and a few others, there is usually a sim-
ple reason, such as the lower elevation of the island once covering the
area of the lagoon at some point not on the lee side, or the fact that the
lagoon has been formed on a steep volcanic slope looking eastward or
northward, so that deep ravines or tongues of deep water cut into tlie
lagoons, and intercept the coral patches forming its rim on the weather
side, and thus leave a windward passage. It is by some such orogenic
condition that we must explain the existence of deep soundings within
atolls, — soundings which in no way indicate a subsidence, as has been
assumed by Darwin, and which according to him were not to be ex-
plained by any other hypothesis. Such deep ravines are of coui'se also
to be traced on the slopes of the larger islands where we find, crossing the
shallow plateaus on which coral patches grow, valleys of considerable
depth, which appear as deep soundings within the area of an outer reef
flat such as in the great plateau off Viti Levu and Yanua Levu (Plates
3% 4), or of Kandavu (Plates 10, 11) and Taviuni (Plate 4), which
according to Darwin would indicate a subsidence, while, on the con-
trary, they are a part of the results of the elevation and lifting up of
that region of Fiji.

Xor are the great depths found close to narrow lines of corals an
indication that the corals have grown up as a nearly vertical wall from a
depth of two to three hundred fathoms or more. It merely indicates
tliat the corals foi'm a thin crust, at most 120 feet in thickness, over a
sharp volcanic ridge, the summits or crest of which have either reached
by elevation the depths at which corals can grow, or have been denuded
by submarine erosion to form a platform below the level of the sea,
where corals have found a footing upon them.

144 BULLETIN : MUSEUM OF COMPA.RATIVE ZOOLOGY.

My observations iu Fiji only emphasize what has been said so often,
that there is no general theory of the formation of coral reefs, either of
barrier reefs or atolls, applicable to all districts, and that each district
must be examined by itself. At least such has been my experience in the
Bermudas, the Bahamas, Cuba, Florida, the West Indies, the Sandwich
Islands, and Australia. The results of this trip show plainly that Dar-
win's theory is not applicable to the Fiji Islands, notwithstanding the
borings at Funafuti, and that, in all the cases I have examined, the reefs
form but a thin crust upon the underlying base, the shape and composi-
tion of which is not in any way due to the growth of corals of the
existing period.

Cambridge, Massachusetts,
October Ist, 1898.

AGASSIZ: FIJI ISLANDS AND COKAL EEEFS.

145

INDEX.

Abrolhos Islands, p. 9.

Adolplius Reef, pp. 13, 22, 35, 66, 100, 101,

107,136. Pis. 1, 18, 22a.
Ahii Island, p. 6.
Aiwa Islands, pp. 13, 29, 3.5, 48, 53, 54, 55,

85, 96, 132, 137, 139. Pis. 1, 21, 22a.
Alacran, p. 41.

Alacrity Bank, p. 124. PI. IS.
Alacrity Bay, PI. 3.
Alacrity Pass, p. 30. PI. 11.
Alacrity Pvocks, p. 30. PI. 10.
Alexa Bank, p. 101.
Alg;B, List of, p. 121.
Allardyce, W. L., pp. 3, 65.
American Passage, pp. 89, 92, 93. PI. 19.
Andiwathe Inland, PI. 19.
Andiwathe Passage, p. 89. PI. 19.
Andrews, E. C, p. 82.
Aratica Island, p. 6.
Argo Reefs, pp. 29, 72, 121, 124, 125, 136,

137, li3. Pis. 1, 20, 20a 21, 22b.
Asawa i lau, pp. 117, 132. PL 1.
Aso San, p. 108.
Atiu, p. 79.

Atolls, Sundrv, pp. 99-103.
Avea Island, pp. 89. 90, 91, 132. PI. 19.

Ba River, p. 127. PI. 3.

Bache J'und, p. 72.

Bacon Island, p. 125. PI. 20.

Bahamas, pp. 10, 41, 44, 128.

Bahia, p. 9.

Baker Island, p. 69.

Barracoiita Passage, p. 61. PI. 22.

Bartlett Deep, p. 76.

Beagle Passage, p. 33. PI. 11.

Beecliey, Capt., p. 79.

Bell Reef, pp. 13, 35, 88, 100, 107. Pis. 1,

19.
Bermudas, pp. 10, 40, 41, 65.
Bernard, A., p. 134.
Bird Island, p. 26. PI. 8.
Birnie Island, p. 69.

VOL. XXXIII. 10

Biscayne, Key, p. 10.
Bismarck Archipelago, p. 8.
Blaekswan Point, pp. 15, 90, 93. PI. 19.
Boehm Rock, p. 96. PI. 19.
Bololo, pp. 16, 113.

Bonney, Prof., pp. 7, 9, 10, 13, 79, 140.
Booby" Rock, PI. 20.
Bourne, pp. 9, 41.

Breaknot Rocks, p. 42. Pis. 4, 18. ,
Brown Passage, PL 17.
Budd Beefs, pp. 29, 33, 34, 35, 36, 49, 71,
136, 138. Pis. 1, 4, 18, 70.

C^SAR Rocks, PL S.

Caroline Islands, pp. 6, 108, 135.

Challenger Monnt, PL 10.

Chambeyron, p. 134.

Chaniisso, p. 109.

Champion Rocks, p. 42. PL 4.

Chapeirccs, pp. 4, 9.

Charybdis Reef, p. 127. Pis. -1, 3.

Clermont Tonnerre, p. 0.

Clipperton Atoll, pp. 106, 107,

Cock's Bank, p. 122. PL 4.

Cocks, Capt. R., pp. 54, 123.

Combe Bank, PL 21.

Corney, Dr., pp. 117, 132.

Craig, p. 113.

Crosby, 0. W., p. 10.

Cuba,''p. 10.

Cutter Passage, p. 26. PL 8.

Dahl, Dr., p. 8.

Dall, W. H., pp. 81, 92.

Dana, .J. D., pp. 5, 6, 13, 27, 40, 47, 55, 67,

74, 70, 78, 79, 82, 8-3, 102,103, 104,115,

120, 128, 131, 135, 138, 140.
Darwin, C, pp. 5, 6, 8, 9, 10, 11, 12, 13, 35,

40, 41, 47, 67, 71, 73, 74, 75, 78, 82, 102,

103, 115, 131, 135, 138, 140, 143, 144,
David, pp. 47, 72, 82.
Davidson, Prof., p. 106.
Davura, PL 23a.

146

BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Dean Island, p. 6.

Deep Bay, p. 20.

Deep Passage, PL 17.

Dibble's Reef, pp. 35, 88, 122, 136, 138. Pis.

1,19.
Dra ni mbotu. p. 132.

Duff Reef, pp. 35, 101, 122, 136. Pis. 1, 18.
DTrville Channel, p. 32. Pi. 10.

Elevated Ldhestoxe Islaxds. p. 43.

Elizabeth Island, p. 6.

Ellice Islands, pp. 6. 73, 83, 109, 135.

Euderburv Island, p. 7.

Ethel Reefs, PI. 3.

Eua Island, pp. 78, 79.

Everglades, p. 10.

Exploring Isles, pp. 18. 29. 72. 88, 123, 124,

136. Pis. 1, 19, 19a, 72-76,
Extinct Craters, p. 105.

Fakaofu Islaxd, p. 7.

Fakarava, p. 6.

Falcon Island, pp. 78, 108.

Farlow. p. 121.

Fawn Harbor, p. 130.

Field, Captain, p. 10] .

Fiji Islands, Classification of, p. 17.

Fitzrov, Capt., p. 6.

Florida Reefs, p. 130. Pis. 4, 18.

Forbes, p. 41.

Foster, p. 79.

Freeh, pp. 74, 121.

Friendly Islands, pp. 6, 7, 8.

Frigate" Passage, pp. 26, 28. PI. 8.

Fritsch, p. 73.

Frost Reef, p.. 123. PI. 19.

Fulanga Island, pp. 13, 17, 34. 53. 60, 62, 63,

64, 65, 69, 72, 84, 85, 95, 132, 139, 142. 143.

Pis. 1, 22, 22a, 80-84.
Fulanga Passage, pp. 75, 84. Pis. 1, 22,

22b.
Fulanga Sound, p. 69.
Funafuti, pp. 41, 47, 72, 73, 83, 84.

GaMBIER ISLAXDS, p. 135.

Gangway Rocks, p. 42. Pis. 4, 18.
Gardiner, pp. 17, 18, 29, 48, 62, 65, 76, 84,

85, 96, 99, 121. 126, 140.
General Sketch of Fiji. p. 131.
Georgia Channel, PI. 18.
Gilbert Islands, pp. 6, 7, 83, 109, 135.
Graeff, Dr., p. 8.
Great Astrolabe Lagoon, 32.
Great Astrolabe Reef. pt). 14. 29, 30, 31, 32,

138. Pis. 1, 11, lla 51. 52,
Great Barrier Reef, pp. 10. 41, 128. 130.
Great Sea Reef. pp. 115, 13L Pis. 1, 4.
Gregory, T. W., p. 78.

Gullet Passage, pp. 37, 38, 105. PL 23.
Guppy, pp. 41, 134.

Haleakala, p. 107. PI. 71.

Hartt, C. F,, p. 8.

Hawaiian Islands, p. 6.

Hedle.v, p. 84.

Heilprin, p. 8.

Henderson Island, p. 79.

Herald Pass, PI, 11.

Herald Roadstead, p. 20, PI, 13.

Herald Sound, p. 20. PL 23.

Hervey Group, p. 79.

Hickson, p, 29.

Hill, R. T., p. 78.

Hogsty, pp. 41, 102.

Honden Island, p. 6.

Honolulu, Borings at, pp. 82, 83, 87.

Home, pp. 18, 71, 127.

Horseshoe Reef, pp. 14, 34, 101, 107, 123.

Pis. 1, 3a 14, 23a.
Howland Island, p. 66.
Hull Island, p. 7.

lAMBt; Island, PL 4.
Islands from Charts, p. 121.
Islands partly Volcanic and partly Lime-
stone, p, 88.

.Jeffrey' s Bank, p. 124. PI. 18.
John Wesley Bluffs, pp. 28, 29. PI. 10.
Jones, E. G., p. 92.
Judd, ProL, p. 79.

Kaimbo Island, pp. 53, 54. PL 19.
Kambara Island, pp. 14, 48, 52, 53, 68, 75,

79. 80, 81, 85, 98, 99, 133. Pis. 1, 22,

22a, 77-79.
Kanathea Island, pp. 29, 96, 98, 136, 138.

Pis. 1, 19.
Kandavu Island, pp. 14, 17, 18. 28, 29, 30,

31, 32, 33, 41, 71, 117, 130, 133, 134, 136,

137, 142. 144. Pis. 1. 10, 11. 22b, 50.
Kandavu Passage, p. 133,. PL 1.
Kandavu Town, PL 10,
Kaneohe Bay, pp, 8, 11.
Karoni Islet^ pp. 97, 98, 132. PL 22.
Katavanga Island, pp. 35, 54, 70, 123, 138.

Pis. 1, 19.
Kawehe Island, p. 6.
Kean Island, p. 69.
Keelinsr Atoll, p. 6.
Kent. W. Saville. pp. 7, 121.
Kia Island, PL 4.
Kimbombo Islets, pp. 13, 17, 35, 70, 82, 88,

100, 123, 136, 137. Pis. 1. 19, 61.
Kini Kini. pp. .38, 39. PI. 22.
Kiusilk Islands, p. 118.

AGASSIZ: FIJI ISLANDS AND COEAL IlEEFS.

147

Kioa Island, pp. 42, 130. Pis. 4. 18.
Kioa Reefs, p. 130. PI. 4.
Kobu Island, pp. 2L 122. Pis. 12, 14, 59.
Komo Island, pp. 13, 17. 3.5. 3G, 37, 70. 107,

120. 124, 1-30,' 137, 139. Pis. 1, 19* 22,

63-65.
Komo Lagoon, p. 13.
Komo Xdriti Islet, p. 35. PL 22.
Konaoe Island, PI. 23^.
Koro Island, pp. 1-3, 17, 18. 137, 141. Pis.

1, 3a, 19a
Koro Levu Islet, pp. 32, 42. PI. 4.
Koro Levu Tomi, pp. 32, 110. PI. 6.
Koro Mbasauga. pp. 90. 91. PL 19.
Koro Sea. pp. 71, 133. PI. 1.
Kramer. Dr., np. 8, 13. 41, 73, 108, 109.
Kumbalau Point, pp. 129, 1-30. PL 4.

Lagooxs, p. 103.

Lakemba Island, pp. 13, 17. 29, 95. 96, 98,
107, 1.32. 1.34, 1-36, 138. Pis. 1, 19, 20, 21.

Lambeko, p. 132.

Lamut Island, p. 129.

Langenbeck, R. v.. pp. 7, 73, 74.

Late i Tonga Islet, PL 20.

Late i Viti Islet, PI. 20.

Lau Group, PL 1.

Laukoto Reef, p. 129. Pis. 3, 23a.

Lauthala Harbor, pp. 114, 140. PL 5.

Lauthala Island, pp. 42. 43, 130. Pis. 4, 5,
18.

Lauthala Reef, p. 99.

Laveine Point, p. 42. Pis. 4. IS.

Lecupi Point, p. 129. PI. 4.

Leluvia Island, p. 114. PL 7.

Lendenfeld. R. v., pp. 29, 73, 76, 104, 105.

Levuka Harbor, pp. 30, 111, 112, 113, 117,
141. Pis. 7, 20a, 22a.

Lewis Bank, p. 124.

Lifu. p. 134.

Likuri Harbor, p. 116. PI. 6.

Likuri Island. PL 6.

Lister, J. J„ pp. 8, 18, 77, 78, 79. 108.

Loa Islet, p. 56. PL 2.

Lomaloma, pp. 91, 92. PL 19.

Lookout Reef, p. 88. PL 19.

Maafu Rock, p. 123. PL 20.

Makondranga Island, d. 24. PI. 15.
Makongai Island. pp.'l3. 23, 24, 25, 42, 82,

129, 130. 1.36, 1.37, 1-38, 141. Pis. 1. 3a,

lla, 15.
Makongai Passage, p. 127. PI. 3a.
JIalacca Straits, p. 7.
Malan Bank, PI. 20.
Malatta Island, pp. 88, 89, 91, 132, 142.

PL 19.

Malatta Reefs, pp. 28, 29. PL 10.

Maldives, pp. 35, 76.

Malevuvu Reef, pp. 35, 122, 123. Pis. 1, 19.

Mali Passage, p. 128. PL 4.

Malima Islets, p. 123. Pis. 1. 19.

Malolo Barrier Reefs, Pis. 3, 6.

Malolo Islands, pp. 117, 118. Pis. 3. 6.

Malolo Passages, Pis. 3, 6.

Malolo lai lai Island, PI. 3.

Mamanutha Islands, Pis. 1, 3.

Mambulitha Reef, p. 21. PL 12.

Mana, pp. 117, 118. Pis. 3, 23a.

Mango Island, pp. 13, 47, 48, 53. 60, 75, 80,

81, 85, 93, 9L 9-5, 96, 119, 120, 123, 132,

134. Pis. 1, 19, 22a, 85-87.
Manhii Island, p. 6.

Marambo Island, pp. 17, 68. Pis. 1, 22.
Mare, p. 134.

Marshall Islands, pp. 6, 135.
Martin, p. IS.
Masamashu Island, p. 79.
Matangi Island, 42.
Mataugi Passage, pp. 13, 15, 42. Pis. 4,

18.
Matanuku Island, p. 32. PI. 10.
Mate Rock, p. 42, Pis. 4. 18.
Matuku Island, pp. 133, 1-37. Pis. 1, 16.
Mauritius, pp. 6, 11.
Mayer, A. G.. p. 15.
Mavsi, Cape, p. 78.
Mbatiki. pp. 14, 19. PL 1, 12.
Mbau Island, pp. 14, 110, 113, 115, 120. PI. 7.
Mbengha Island, pp. 13, 17, 25, 26, 27, 29,

36. 70. 107, 111, 136, 1-37, 138, 141. Pis.

1, 8, lla, 22b, 46-49.
Mbengha Lagoon, pp. 26, 27. PI. 8.
Jlbengha Passage, pp. 15, 26. Pis. 5, 8.
Mbengha Reef, p. 28.
Mbua Bay. p. 129. Pis. 3, 4.
Mbuimbani, p. 42. PI. 4.
Mbukata tanoa Reefs, p. 124. PL 21.
Mbulia Island, pp. 30, 31. PL 11.
McCandless, J. A., pp. 82, 83.
McPherson Rocks, p. 42. PI. 18.
Metia Island, pp. 6, 79.
Miller Reef. PL 18.
Moala Island, pp. 14, 18, 19. 20, 78, 82, 108,

1.3_3. 136. 137. Pis. 1, 16, 57.
Mobius, p. 140.
Mokaluva, p. 114. PL 5.
Monu Island, p. 118. PL 3.
Moore, p. 52.

Morse Reef. p. 96. PL 19.
Mothe Island, pp. 13, 17. 29. 97. 98, 102, 107,

122. 132, 136, 1-39. Pis. 1. 22.
Moturiki Channel, pp. 14. 101, 127. Pis. 3, 7.
Moturiki Island, pp. 26, 110, 111, 112, 113,

114. Pis. 3, 7.

148

BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Motua Lpvu Eeef, pp. 13, 34, 40, 69, 99, 101,

107, 136. Pis. 1, 4, 18.
Motua lai lai Eeef, pp. 13, 34, 40, 69, 75, 99,

101, 107, 136, 140. Pis. 1, 18. 112.
Mumbualau Island, p. 314. PL 7.
Mungaiwa Island, p. 34. PI. 18.
Munia Island, pp. 88, 90, 91, 93. PI. 19.
Murray, Sir John, pp. 30, 41, 79.

Na lulu, pp. 112, 113.

Na Ndongu, p. 129. Pis. 4, 23a.

Xa Potu, Mothe Island, p. 98. PI. 22.

Xa Tandola Harbor, PI. 6.

Na Yatu Eeef, p. 122.

Na Yunivatu, p. 114. PI. 37.

Naiabo Islet, pp. 60, 123. PI. 22.

Naiau Island, pp. 13. 51, 52, 53, 67, 75, 85,

122. 132. Pis. 1, 20, 22a.
Nai Ngalo Ngalo Harbor, PI. 10.
Naingani, PI. 7.
Naingoro Pass, PI. 11.
Nairai Island, pp. 14, 21, 22, 29, 70, 71, 82,

101,'133, 136, 137, 141. Pis. 11a, 12, 14,

22b 58. 59.
Naiselesele Point, p. 42. PI. 18.
Naitamba Island, pp. 14, 53, 97, 133, 134.

138. PI. 19;
Nai Thombo thonibo Point, p. 129.
Naniena Island Eeef, pp. 41, 42. 129. Pis.

1, 3a.
Namuka Harbor, p. 115. PI. 5.
Namuka Island, pp. 17, 53, 116. PL 1.
Namuka i lau, pp. 57, 60, 123, 139. PL 22.
Nandi Bay Waters, pp. 14, 116, 118, 127,

132. pi. 3.
Nandi Plateau, p. 117.
Nandronga Harbor, pp. 14, 116. PL 6.
Nangaidamu Harbor, p. 18. PL 3a.
Nanggara, p. 115.
Nanuka Island, pp. 64, 78. PL 5.
Nanuku Islets, p. 49. Pis. 18, 103-107.
Nanuku lai lai, p. 50. PL 107.
Nanuku Levu, p. 50. Pis. 103-106.
Nanuku Passage, pp. 26, 133. Pis. 1, 18.
Nanuku Eeefs, pp. 13, 26, 49, 50, 131, 136,

137. Pis. 1, 18.
Nasilai, Pis. 5, 7.
Nasilai Light, p. 114. PL 5.
Nasilai Reef, PL 5.
Nateva Bay. p. 1.30. Pis. 1, 4.
Nathomaki Point, p. 19. PL 3*.
Navigator Islands, p. 6.
Naviti Island, Pis. 1, 3.
Navua Eiver, p. 115. PL 5.
Navuka. p. 1-30. PL 4.
Navula Passage, pp. 14. 117. Pis. 3, 6.
Navula Eeef, Pis. 3, 6.
Navutuiloma IslanS, pp. 58, 59, 60. PL 22.

Navutuira, pp. 58. 59. PL 22.

Ndaku Isthmus, PL 10.

Ndehai, p. 113.

Ndravuni I>Iand, p. 31. PL 11.

New Caledonia, pp. 134, 135.

New Hebrides, p. 77.

Ngamia Island, pp. 42, 43, 71, 130. Pis. 1, 4.

Ngasi Mbali Island, p. 31. PL 11.

Ngau Island, pp. 14, 17, 21, 22. 71, 82, 133,

136, 137, 138. Pis. 11a 12, 13.
Ngava Passage, p. 112. PL 7.
Ngele Levu, pp. 13, 17, 43, 44, 47, 48, 49, 53,

60, 64, G9, 70, 75, 79, 80, 81, 83, 84, 104,

122, 132, 133, 130, 137, 138, 139, 142.

Pis. 1, 17, 17a, 22b, 95-99.
Ngillangillah Island, pp. 78, 80, 88, 89, 90,

93, 96, 120, 132, 142. Pis. 19, 22b.
Ngillangillah Passage, pp. 13, 88, 93. PL

19.
Ngoala Harbor, p. 30. PL 10,
Nisithi Reefs, PL 8.
Nisithi Rocks, p. 20. PI. 8.
Niue Island, p. 79.
Nmara Island, p. 31. PL 11.
North Astrolabe Reef, pp. 14, 28. 29. 30, 32,

33, 70, 133, 141. Pis. 1. 11, 11a, 22b,

53, 54.
Nuku i ra Island, p. 129. Pis. 4, 23a.
Nuku Levu, p. 54. PL 19.
Nukulau Island, p. 114. Pis. 5, 38-41.
Nuku Mbalate, p. 49. PL 18.
Nuku Mbasanga Island, pp. 1.3, 49. Pis.

18, 22a, 108.
Nuku Mbasanga Reef, pp. 49. 72. PL 18.
Nuku Songea, pp. 62, 123. PL 22.
Nuku Thikombia Reef, p. 122. PL 19.
Nukusemanu Island, pp. 49, 50. PL 18.
Nukusemanu Reef, jip. 15. .50, 131. PL 18.
Nukatolu Islets, p. 123. PI. 19.

0.\HU. pp. 8, 11.

Oatafu Island, i). 7.

Observatory Point, p. 44. PL 17.

Oldham, Commander, p. 78.

Olorua Island, pp. 36, 37. Pis. 1, 22.

Oneata Island, pp. 56, 60, 64, 69, 70. 72, 80,

81, 06,102. 132, 136, 137, 139, 142. Pis.

1, 21, 22, 22a, 22b.
Oneata Lagoon, p. 13. PL 22.
Oneata Passage, Pis. 1, 21.
Onirea Islands, pp. 13, 17, 29, 47, 53, 58, 60,

62. 69. 70. 72. 80, 81. 8-5, 124. 126. 132, 133,

136, 137, 139, 142. Pis. 22, 22a, 22b, 94.
Ongea Lagoon, p. 13.
Ongea Levu, pp. 60. 61, 69. Pis. 1, 22.
Ongea Ndriti, pp. 60, 61. 69. PL 22.
Ono Island, pp. 14. 18. 30, 31. PL 11.
Ono i lau Islands, p. 126. Pis. 1, 17a, 23a.

AGASSIZ: FIJI ISLANDS AND COKAL REEFS.

149

Ortmann, p. 8.
Ouvea, p. 134.
Ovalau Island, pp. 6, 13, 18. 41, 110, 111, 112,

113, 120, 127, 13G, 137. Pis. 1, 3, 3a, 7.
Ov;itoa, PI. 23*.

Passage Island, pp. 129, 130.

Paumotus, pp. G, 79, 81, 83, 108, 135.

Pelagic Fauna, p. 14.

Pelatan, p. 134.

Pelew Islands, p. 41.

Penguin Bank, pp. 101. 143. Pis. 22b, 23a.

Phillips Rock, p. 42. PI. 18.

Phoenix, p. G9.

Pitman Reef, pp. 34, 40, 99, 100, 107. PI. 18.

Pourtales, L. P.. p. 87.

Pratt Reefs, p. 26. PI. 8.

Quoin Hill, pp. 62, 04. PI. 22.

Rambe Islasd. pp. 42, 127, 130, 138. Pis.

1, 4, 18.
Rara ni Tinka Island, p. 34. Pis. 4, 18.
Raraka Island, p. 6.
Rat Passage, p. 115.
Rath bun, R., p. 8.
Red Earth, p. 98.
Reid Haven, pp. 53. 69. PI. 20.
Reid Reef, pp. 70, 124, 136. Pis. 1, 20,
Rein, p. 41.

Renard Passage. PI. 11.
Rendell Passage, PI. 17.
Rewa River, pp. 114, 115. PI. 5.
Rewa Roads, PI. 5.

Ringgold Isles, pp. 13, 40, 105. Pis. 1, 4, 18.
Rose Island, p. 12.
Rothpletz, p. 29.
Round Island, Pis. 1, 3.
Rovondrau Bay, p. 115. PI. 5.
Riikua, p. 26. " PI. 8.

Samoa, pp. 6, 8, 12, 77, 78.

Savu Savu, pp. 128, 129, 130. PI, 4.

Scatterbreak Channel, PI. 17.

Semper, pp. 12, 41, 140.

Serpiiline Atolls, pp, 40, 76.

Serua Harbor, pp. 116, 140. PI. 6,

Serua Reef, p. 115. Pis. 5, 8.

Sesalcka Peak, p. 131.

Shark Reef, PI. 5.

Simonoff, PI. 1.

Singatoka River, pp. 14, 116, 117, 132, Pi. 6.

Solevu Point, p. 129. PI. 4.

Solianga, p. 25. PI. 8.

Sollas, pp. 29, 72. 84, 86.

Solo Ruck Light, pp. 14, .30, -32, 33. Pis. 11,

53.
Solomon Islands, pp. 41, 77, 134.

Somo Somo Strait, pp. 15, 42. Pis. 1, 4, 18.

Sooloo Sea, p, 7.

Soso Bay, p. 28.

Sounds of Fiji, p. 68. PI. 22.

Sovi Harbor, PI. 6.

Sovu Islets, pp. 89, 91, 132. PI. 19.

Sovu Passage, PI. 19.

Stebbing, p. 29.

Stone Axe Roads, p. 19. PI. 3a.

Storm Islet, pp. 26, 27. PI. 8.

Stuart Islet, p. 26. PI. 8.

Sulphur Passage, p. 26. PI. 8.

Susui Island, pp. 88, 90, 91, 120. P>. 19.

Suva, pp. 13, 14. 47, 48, 72, 80, 92, 114, 115,

116, 140. PI. 5.
Suva Harbor, pp. 1.3, 15, 116, 117, 118, 119,

120, 132. Pis. 5, 24-30.
Suva Reef. p. 118. Pis. 5. 24-31, 65. 76.
Swain's Island, p. 7.

Tahiti, pp. G. 41.

Tai ni Mbeka Islet, pp. 43, 44, 132. PI. 17.

Taiaro, p. 6.

Tambaka Island, p. 24. PI. 15.

Taputeuea, p. 7.

Tasman Strait, p. 42. Pis. 4, 18.

Taulalia Islet, pp. 44, 1-32, 142. Pis. 17, 22b.

Tavanuku i vanua Reef, pp. 122, 123. PI. 20

Tavanuku i wai Reef, pp. 122, 123. PI. 20.

Taviuni Island, pp. 13, 17, 18, 41. 42, 71,78,

1.30, 136, 137. 144. Pis. 1, 4, 18, 60.
Tavuki Bay, p. 28.
Tavuki Viflage, pp. 28, 111. PI. 10.
Tavukie Isthmus, PL 10.
Tavunasithi Island, pp. 72, 123. Pis. 1, 22,
Texas Cape Keef, p. 130. P)s. 4, 18.
Thakau Lasemarawa, pp. 40, 122, 123. Pis.

1, 20.
Thakaii Lekaleka. Lan, pp. 13. 40, 69, 102,

107, 136, 140. Pis. 1, 21, 111.
Thakau Levu, Lau, pp. 60, 69, 122, 123, 136.

Pis. 1, 22.
Thakau Levu, Yanua Levu, p. 129. Pis. 3,

4, 23a.
Thakau Mata Thuthu, pp. 35, 69, 122, 136,

Pis. 1,4, 17.
Thakau Moi, p. 129. Pis. 3. 23a.
Thakau Homo, pp. 40, 101. 102, 123, 140.

Pis. 3a, 12, 14, 23a.
Thakau Motu, pp. 66, 122. 136. Pis. 1, 22.
Thakau Nalolo. p. 129. Pi. 4.
Thakau Nasokesoke, pp. 60, 123. PL 22.
Thakau Nawa, p. 123. PL 20.
Thakau Ndavui. PL 7.
Thakau Nokeva. p. 122. PL 20.
Thakau Reivareiva, pp. 60. PL 22.
Thakau Tambu, pp. 35, 69, 122, 136. Pis. 1,

20.

150

BULLETIN: MUSEUM OF COMPAEATIYE ZOOLOGY.

Thakau Teteika, pp. 62, 120. PL 22.
Thakau Thikondua, pp. 60, 123. PL 22.
Thakau Utulei. p. 129. PL 4.
Thakau Yau, pp. 122, 123. PI. 22.
Thakau Yuite, pp. 37, 122. PL 22.
Thakau Yuthp Vutho, pp. 35, 69, 122, 136.

Pis. 1, 17.
Thangalai Island, p. 114. PI. 7.
Thikombia i lau Island, pp. 00, 91, 141, 142.

PI. 19.
Thikombia i ra Island, pp. 99, 125, 126, 133,

r.ir>. PI. 17.

Thithia Island, pp. 53, 96. Pis. 1, 20.
Thombia Isle, pp. 13, 18, 34, 35, 40, 78, 105,

106, 107, 108. Pis. 4, 18.
Thomson, Sir AYyville, p. 87.
Thomson, W., pp. 3, 14, 53, 117.
Thurston Point, pp. 13, 42, 43. Pis. 4.

18.
Thuvu, PI. 6.

Tokalau, pp. 98, 99. PI. 20.
Toniba Kaivala, p. 32. PI. 10.
Tomba Koro Levu, PI. 10.
Tomba Ndavingeile, PL 10.
Tomba ni Kaseleka. PL 10.
Tomba ni Ndaku, p. 32. PL 10.
Tomba ni Richmondi. pp. 28, 29. PI. 10.
Tomba ni Soso, pp. .30. 32. PL 10.
Tomba ni Tavuki, p. 28. PI. 10.
Tomba ya uravu, p. 30. PL 10.
Tomberua Islet, PI. 7.
Tomberua Passage, pp. 110, 114, 115.

PL 7.
Tonga Islands, pp. 77, 78, 109.
Tongatabu, pp. 6, 78.
Tongan Passage, pp. 13, 89, 91. PI. 19.
Tongoro Anchorage, PL 5.
Tongoro Pass, p. 115. PI. 5.
Totova Island, pp. 14, 18, 29, 34, 37, 38. 39.

67. 78. 82. 105. 106, 107. 108, 123, 133,

136, 138, 140, 143. Pis. 1, 16, 19a, 22i>,

23, 66-69.
TovaPeak, pp. 110. 113.
Tova Pteef, pp. 101, 102, 122. 123. Pis. 1.

23a.

Trigger Rock, p. 83. PI. 19.
Turtle Island, pp. 105. 126. PL 1.
Tuvana i ra, pp. 126. 142. PI. 23a.
Tuvana i tholo, p. 126.

Tuvutha Island, pp. 13, 48. 51. 52, 53. 70,
75, 85, 122, 1.32. Pis. 1, 20. 88, 89.

Undu Cape. pp. 128, 130. Pis. 1, 4. 17.

Undui, Pi. 23a.

United States Exploring Expedition, pp. 13,

88. 140.
Usborne Pass, p. 30. PI. 11.

Vaxua Kula, p. 31. PL 11.

Vanua Levu, pp. 6, 17, 18, 41, 42, 71, 118,
126, 127, 128, 129, 130, 131, 132, 144.
Pis. 1. 3, 3a, 4.

Yanua Masi Islet, pp. 09, 125. PL 20.

Vanua Mbalavu Channel, p. 13.

Yanua Mbalavu Island, pp. 17, 35, 47, 48,
64, 78, 80, 81, 88, 89, 90, 91, 92, 93, 107,
122, 125, 132. 134. 136, 137, 138, 141, 142,

143. Pis. 1, 19, 22b.

Yanua Vatu Island, pp. 53, 70, 121, 122.

PI. 1, 21.
Yatauua Channel. Pis. 1, 17.
Yatoa Island, p. 126. PI. 23a.
Vatu i ra Channel, pp. 127, 129. 130. Pis.

3, 3a.
Vatu i ra Islet. PL 3a,
Vatu i thake. p. 42.
Vatu lai lai Islet, PL 9.
Vatu Leile Island, pp. 14. 15, 53, 66, 67, 70,

81, 119, 120, 133, 137, 138, 139, 142. Pis.

1, 9, 17a, 221), 100-102.
Vatu Levu Islet, PL 9.
Vatuloa, p. 115. PL 5.
Vatu Savu, p. 68. PI. 9.
Yatu Vara Island, pp. 48, 53, 54, 81. PL 19.
Vavau Group, pp. 77, 78.
Vekai Rock, pp. 35, 72, 123. Pis. 1, 19.
Yidal. Bishop, p. 96.
Vienne Bay, p. 130.
Viti Levu,'pp. 6, 14, 17, 18, 26. 41, 71, 80, 81,

110, 111, 115, 126, 127, 128. 133. 1.36, 140,

144. Pis. 1, 3, 5-7, 20a 24-45.
Viwa Island, Mbau, pp. 110. 132. PI. 7.
Viwa Island Reefs, pp. 116, 117. Pis. 1, 3.
Volcanic Islands, p. 18.

Vomo Island, p. 117. Pl. 3.

Vomo lai lai. p. 117.

Yuata Ono Reef, p. 126. PI. 23a.

Yuata Yatoa, pp. 105, 126. PI. 23*.

Vuna Point, p. 42. PI. 4.

Vuo, p. 1.32.

Vuro, p. 31. PI. 11.

Vuro lai lai Island, p. 31. PI. 11.

Waia Islands, pp. 14, 117. PL 3.

Waikava, p. 128.

^YaiIangilala Island, pp. 13, 14, 17, 45, 46,

47, 48, 49, 53, 69, 70, 72, 81, 83, 101, 122,

133, 138, 139. Pis. 1, 18. 109, 110.
Wakava Island, pp. 13. 23. 25, 29. 42, 82,

1.30. 136. 137. 138, 141. Pis. 1, 3a, 11a,

12, 15. 55, 56.
Walther, J., pp. 121, 134.
Wangava Island, pp. 52, 53, 70, 133. Pis.

1. 22.
Washington Cape, PL 10.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS.

151

Washington Mount, PI. 10. ]

Wharton, Admiral, pp. 8, 13, 75, 104, 106,

107, 139. 140.
Wichmann. p. 18.
Wilkes Reef. pp. 57, 123. PI. 22.
Williamson Reef, pp. 13, 3-1, -10, 88, 100, 107.

PI. 19.
Wilson, Capt., p. 96.
Wittgenstein, p. 6.
Wolff, Prof., p. 106.
Woodworth, W. McM., p. 16.

Yale Mount. PI. 10.

Yambu Island, pp. 31, 34. PL 11.

Yangasa Cluster, pp. 13, 53, 57, 59, 60, 64,

69. 70, 72, 75, 78. 81, 122. 132, 136, 137,

139. Pis. 1, 22, 22a., 90-93.

Yangasa Levu, pp. 57. 58, 59. PI. 22.
Yanu Yanu eloma Islet, p. 31. PI. 11.
Yanu Yanu Island, p. 92. PL 19.
Yanu Yanu san Islet, p. 31. PI. 11.
Yanutha Island, p. 34. Pis. 4, 8, 18, 23.
Yanutha Reefs, Mbeugha, p. 26. PL 8.
Yanuya, PI. 23a..
"Yaralla," Track of, p. 13.
Yaroua Islet, pp. 122, 123. PL 20.
Yasawa Islands, pp. 117. 118, 127, 131. Pis.

1,3.
Yathata Island, pp. 14, 53, 54, 123. Pis. 1,

19.
Yathiwa Island, p. 21. PL 12, 13.
Yaukuve Island, p. 31. PL 11.
Yaukuve lai lai Island, p. 31. PL 11.
Yendua, pp. 127, 128, 129, 131. Pis. 3, 4.
Yuvutba Island, p. 58. PL 22.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 153

LIST OF FIGURES IN THE TEXT.

PAGE

Deep Bay, East Face of Moala 20

Northwest Point of Makongai 23

Ledge off Makongai 23

Ledge off Makondranga . 24

Storm Islet 27

Nmara and Yanu Yanu Eloma . 31

Western End of Thombia 34

Olorua 37

Basin of Totoj^a Crater, from the Summit of the Northern Rim 37

Totoya from the Northeast, distant five Miles 39

Taulalia, Ngele Levu Lagoon 44

AVailangilala and Cakandrovi. . , 45,46

North Point of Naiau 52

Naiau, seen from the East 52

Vatu Vara, seen from the East 53

Oneata 56

Islet off Oneata Shore 56

Yangasa Levu • 58

Southwest Point of Ongea Levu 61

Entrance to Fulanga 62

East Side of Fulanga 63

Fulanga South of Quoin Hill 64

Southeast Point of Marambo 65

North Point of Marambo 66

West Side of Vatu Leile 67

Northwest Point of Vatu Leile 67

Northeast Point of Vanua Mbalavu 89

Vanua Mbalavu, looking West 89

Islet off Ngillangillah 90

Volcanic Hills back of Lomaloma 92

Mango, seen from the Northeast 94

Mango Landing, Volcanic Substratum 94

West of Mango Landing, Volcanic Substratum 95

Naitamba from the East 97

Karoni 97

Northwest Point of Mothe 98

Clipperton Rock 106

Fringing Reef Harbor, off Koro Levu HO

Moturiki Channel m

Entrance to Levuka HI

Negro-head, Levuka Barrier Reef 112

Levuka H'^

Vomo lai lai . . , H'

Northern End of Mana 118

AGASSIZ: FIJI ISLANDS AND COKAL REEFS. 155

EXPLANATION OF THE PLATES.

PLATE 1.

Sketch Chart of the Fiji Islands with the Track of the " Yaralla," reduced from
Admiralty Chart No. 2691.

PLATE 2.

The same, indicating the position of areas of elevated coralliferous limestones.

PLATE 3.

Northern and Northwestern Part of Viti Levu and Southeastern Point of Vanua
Levu. From Admiralty Chart No. 2691.

PLATE 3«.

Namena Barrier Reef, Koro, Makongai, and Wakaya Islands. From Admiralty
Chart No. 4-10.

PLATE 4.

Vanua Levu and Taviuni. From Admiralty Chart No. 2691.

PLATE 5.

Southern Coast of Viti Levu from Nasilai to Serua. From Admiralty Chart
No. 845.

PLATE 6.

Southwestern Coast of Viti Levu from Serua to Malolo Passage. From Admiralty

Chart No. 845.
I

PLATE 7.

Eastern Coast of Viti Levu from Suva to Ovalau. From Admiralty Chart
No. 905.

PLATE 8.
Mbengha. F>om Admiralty Chart No. 167.

156 bulletin: museum of comparative zoology.

PLATE 9.
Vatu Leile. From Admiralty Chart No. 846.

PLATE 10.
Western Part of the Island of Kandavu. From Admiralty Chart No. 167.

PLATE 11.

Eastern Part of Kandavu, Great Astrolabe and North Astrolabe Keefs. From
Admiralty Chart No. 167.

PLATE lla

Sections across.
Ngau Lagoon from north to south (Plate 13).
Ngau from northwest to southeast (Plate 13).
Ngau from west to east (Plate 13).
Nairai from west to east (Plate 14).
Mbengha from west to east (Plate 8).
Viti Levu (Shark's Peak) across ^Mbengha Passage, and Mbengha

(Plate 8) from northwest to southeast (Plate 8).
Wakaya from west to east (Plate 15).
Wakaya across southern part of Lagoon (Plate 15).
Makongai from west to east (Plate 15).
Ono, Great Astrolabe Reef from west to east (Plate 11).
Mbulia, from west to east Great Astrolabe Reef (Plate 11).
Vanua Kula, from west to east Great Astrolabe Reef (Plate 11).
Great Astrolabe Reef from south to north, from Nai Salimu, Kandavu,
to D'Urville Channel (Plate 11).
Fig. 14. Solo Rock, North Astrolabe Reef (Plate 11).

PLATE 12.
Ngau, Nairai, and Mbatiki Islands. From Admiralty Chart No. 441.

PLATE 13.
The Island of Ngav. From Admiralty Chart No. 905.

PLATE 14.
The Island of Nairai. From Admiralty Chart No. 905.

PLATE 15.
The Atolls of Wakaya and Makongai. From Admiralty Chart No. 905.

Fig.

1

Fig.

2.

Fig.

Fig.

4.

Fig.

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Fig.

10.

Fig.

11.

Fig.

12.

Fig.

13.

AGASSIZ : FIJI ISLANDS AND CORAL KEEFS. 157

PLATE 16.
The Islands of Moala, Totoya, aud Matuku. From Admiralty Chart Xo. 4-41.

PLATE 17.

Eastern Point of Vanua Levu, Thikombia to Ngele Levu. From Admiralty Chart
Xo. UO.

PLATE 17".

Sections across.
Vatu Leile, northern end, from west to east (Plate 9).
Vatu Leile, centre of island, from west to east (Plate 9).
Vatu Leile, southern part, from west to east (Plate 9).
Vatu Leile, from south to north to Vatu lai lai (Plate 9).
Xgele Levu, from north to southeastern extremity of Lagoon (Plate 17).
Xgele Levu, from north to south through Taulalia Island (Plate 17).
Xgele Levu, from north to south, east of centre of Lagoon (Plate 17).
Ngele Levu, from north to south, west of centre of Lagoon (Plate 17).
Xgele Levu, from north to south, near western part of Lagoon (Plate 17).
Xgele Levu, from western entrance of Lagoon to eastern extremity

(Plate 17).
Xgele Levu, west to east, south face of Lagoon (Plate 17).
Ngele Levu, west to east, north face of Lagoon (Plate 17).
Tuvana i ra, from south to north (Plate 23'').
Vuata Ono, from south to north (Plate 23").
Ono i laii, from southwest to northeast (Plate 23").
Vuata Vatoa, from south to north (Plate 23").

PLATE 18.

Rambe, northern point of Taviuni, Ringgold Islands, Xanuku Reefs, Wailangilala,
to Alacrity Bank. From Admiralty Chart Xo. 440.

PLATE 19.

Yathata to Xaitamba, Kimbombo Islets, to Lookout Reef, Exploring Isles, Mango
to Katavanga. From Admiralty Chart Xo. 441.

PLATE 19".

Sections across.
Fig. 1. Vanua Mbalavu (Exploring Isles), from west to east to the American

Passage (Plate 19).
Fig. 2. Vanua Mbalavu, from west of Lomaloma to Thikombia to encircling

reef (Plate 19).
Fig. 3. Vanua ^Mbalavu. from southeast to northwest across Sovu Islands

(Plate 19).
Fig. 4. Totoya, from west to east through Kini Kini (Plate 23).

Fig.

1.

Pig.

2.

Fig.

3.

Fig.

4.

Fig-

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Fig.

10.

Fig.

11.

Fig.

12.

Fig.

13.

Fig.

14.

Fig.

15.

Fig.

16.

158 bulletin: museum of comparative zoology.

Fig
Fig,
Fig
Fig
Fig
Fig
Fig

5. Totoya, from north to south through Kini Kini (Plate 23).

6. From western rim of Totoya to deep water (Plate 23).

7. From northern rim of Totoya to deep water (Plate 23).

8. Koro Island, from west to east (Plate o'^).

9. Komo, from south to north (Plate 22).

10. Komo, from west to east (Plate 22).

11. Komo, from southeast to northwest Passage (Plate 22).

PLATE 20.

Fig.

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Thithia, Tuvutha, Thakau Tambu, Naiau, Reid Reef, and Northern Part of Argo
Reef. From Admiralty Chart No. 441.

PLATE 20^
Sections across the Barrier Reef of Levuka Harbor. From Admiralty

Chart No. 1244.

Fig. 1. From the shore of Ovalau through north entrance (Plate 7).

Fig. 2. From the shore of Ovalau across Lekaleka Reef, about half a mile south

of north entrance (Plate 7).
Fig. 3. From the shore of Ovalau across Lekaleka Reef, about three quarters of

a mile north of south entrance (Plate 7).
Fig. 4. From the shore of Ovalau to the Beacon, Levuka, through the south
entrance (Plate 7).

From Naquima Point across Mbalavu Reef (Plate 7).

Reid Reef, from south to north across the islets (Plate 20).

Reid Reef, from south to north (Plate 20).

Reid Reef, from soutli to north (Plate 20).

Reid Reef, from west to east (Plate 20).
Fig. 10. Argo Reef, from south to north to outlying reefs (Plates 20, 21).
Fig. 11. Argo Reef, from south to north (Plates 20, 21).
Fig. 12. Argo Reef, from south to ncu-tli to passage (Plates 20, 21).
Fig. 13. Argo Reef, from west to east (Plates 20, 21).
Fig. 14. Ovalau, from flat to westward to Barrier Reef (Plate 7).
Fig. 15. Longitudinal section across Nandronga Harbor (Plate 6).
Fig. 16. Fringing Reef, north of Tandola (Plate C).
Fig. 17. Incipient Barrier Reef north of Likiiri (Plate 6).
Fig. 18. Tova, from south to north (Plate 23").
Fig. 19. Tova, from west to east (Plate 23").

PLATE 21.

A^anua Yatu, Lakemba, Argo Reefs, Aiwa, Oneata, Thakau Lekaleka. From
Admiralty Chart No. 441.

PLATE 22.

Olorua, Thakau Vnite, Komo, IMothe, Thakau Motu, Thakau Vau, Wilkes Reef,
■\Yangava, Kambara, Namuka, Yangasa, Thakau Levu to Thakau Naso-
kesoke, Fulanga, Nuku Songa, Ongea, Marambo. From Admiralty Chart
No. 441.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 159

PLATE 22a.

Sections across.

Fig. 1. Naiau, from west to east (Plate 20).

Fig. 2. Kambara, from west to east (Plate 22).

Fig. 3. Mango, from west to east (Plate 19).

Fig. 4. Fulanga, from southwest to northeast (Plate 22).

Fig. 5. Fulanga, from west to east (Plate 22).

I'ig. 6. Ongea, from west to east (Plate 22).

Fig. 7. Ongea, from south to nortii (Plate 22).

Fig. 8. Yangasa, from northwest to southeast (Plate 22).

Fig. 9. Yangasa, from south to nortli to passage into Lagoon (Plate 22).

Fig. 10. Oneata, from south to north (Plate 21).

Fig. 11. Oneata, from west to east (Plate 21).

Fig. 12. Oneata, from south to north to passage into Lagoon (Plate 21).

Fig. 13. Aiwa, from southwest to northeast (Plate 21).

Fig. 14. Aiwa, from south to north to passage into Lagoon (Plate 21).

Fig. 15. Aiwa, from west to east (Plate 21).

Fig. 16. Adolphus Reef, from west to east to passage into Lagoon (Plate 18).

Fig. 17. Adolphus Reef, from southeast to n-orthwest (Plate 18).

Fig. 18. Nuku Mbasanga and Nuku Mbalate, from west to east (Plate 18).

PLATE 22".

Diagrammatic sections showing liypothetical changes due to erosion and sub-
marine denudation of some typical islands of Fiji. The dotted lines indicate
the assumed outlines of the ancient islands.

Nairai.

Makongai.

Wakaya.

Mbengha.

Great Astrolabe Reef.

Tuvana i ra.

Fulanga may have been elevated either at the rim or have been a
dome-shaped mass.

Ngele Levu.

Ongea.

Vatu Leile.

Oneata.

Vanua Mbalavu.

PLATE 23.
The e.xtinct Crater Totoya. From Admiralty Chart No. 1248.

PLATE 23«.

Fig. 1. Ono i lau. From Admiralty Chart No. 742.
Fig. 2. Tuvana i ra. From Admiralty Chart No. 742.
Fig. .3. Vuata Ono. From Admimlty Chart No. 742.

Fig.

1.

Fig.

2.

Fig.

3.

Fig.

4.

Fig.

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Fig.

10.

Fig.

IL

Fig.

12.

160 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY.

Fig. 4. Vuata Vatoa. From Admiralty Chart No. 742.
Fig. 5. Tova Eeef. From Admiralty Chart No. 742.

Fig. 6. Thakau Momo or Horseshoe Reef. From Admiralty Chart No. 741.
^Fig. 7. Penguin Bank. From Admiralty Chart No. 1431.
Fig. 8. Na Ndongu Reef, nortli shore of Vaiiua Levu. From Admiralty Chart

No. 440.
Fig. 9. Nuku i ra Reef, northwest coast of Vanua Levu. From Admiralty Chart

No. 379.
Fig. 10. Thakau Moi, north coast of Viti Levu. From Admiralty Chart No. 379.
Fig. 11. Laukoto Reef, northwest coast of Vanua Levu. From Admiralty Cliart

No. 379.
Pig. 12. Thakau Levu, northwest coast of Vanua Levu. From Admiralty Chart

No. 379.
Fig. 18. Section across Penguin Bank. From Admiralty Chart No. 1431

PLATE 24.

Barrier Reefs forming entrance to Suva Harbor. Namuka Island and Moivuso
Point on the right. Mountains from Serua to Nimosi District in distance.

PLATE 25.
Barrier Reef .across Lauthala Bay. Nukulau and filokaluva Islands in distance.

PLATE 26.

Barrier Reef Flat, west side of entrance to Suva. Mountains of Nimosi District
in background.

PLATE 27.

The same Reef Flat as Plate 26, extension to line of breakers.

PLATE 28.
Pocillopora Flat Barrier Reef, east side of entrance to Suva.

PLATE 29.
The same as Plate 28, extension of Barrier Reef, Pocillopora Flat, to the South.

PLATE 30.

Channels dug by Echinometra lucunter. Barrier Reef Flat on eastern side of
entrance to Suva.

PLATE 31.

Elevated Limestone Bluff northeast of Suva, distant seven eighths of a mile from
Government Wliarf.

PLATE 32.

Elevated Limestone Islet. Inner Harbor of Suva.

AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 161

PLATE 33.
Tlie Island of Ovalau seen from the east.

PLATE 34.
Levuka (Ovalau) seen from outside the Barrier Reef.

PLATE 35.

Flats of Volcanic Mud to north of channel of Barrier Reef, looking southwest from
Mbau.

PLATE 36.

Viwa Island, Mbau Waters, composed of stratified volcanic mud. North of channel
of Barrier Reef.

PLATE 37.

Nasilai Barrier Reef seen from the east. Negro-heads of elevated limestone.
Nasilai Light in distance.

PLATE 38.
Nukulau and Mokaluva Islands seen from the southwest.

PLATE 39.

On north shore of Nukulau Island, elevated limestone beach.

PLATE 40.

Nukulau Island Barrier Reef Flat from the southeast. Negro-heads, elevated /
limestone.

PLATE 41

Nukulau Island Barrier Reef Flat, extension to line of Breakers.

PLATE 42.

Fringing Reef Flat off Koro Levu, east coast of Viti Levu. Negro-heads, volcanic
rocks.

PLATE 43.

Fringinji; Reef Flat south of Singatoka River. Elevated limestone outliers along
the shore.

PLATE 44.
Sand Dunes north of Singatoka River. Fringing reef has disappeared.

PLATE 45.
South Point of Thuvu Harbor. Elevated limestone and fringing reef.

VOL,. XXXIII. 11

162 bulletin: museum of compaeative zoology.

PLATE 46.

Volcanic Cliffs, East Shore of Mbengha, near Solianga Village.

PLATE 47.
Shore Bluff, Volcanic Breccia. Rukua, west shore of Mbengha.

PLATE 48.
Highest Ridge of Mbengha, volcanic, seen from Moturiki Bay.

PLATE 49.

Western Point of Storm Island, eastern edge of Mbengha Lagoon.

PLATE 50.

John Wesley Bluffs, Kandavu Island, volcanic.

PLATE 51.

Northwest Side of Ono Island, volcanic, inside of Great Astrolabe Reef Lagoon.

PLATE 52.

Yaukuve lai lai Island, volcanic, seen from the west, inside of Great Astrolabe
Reef Lagoon. Ono in the distance.

PLATE 53.

Solo Rock Lighthouse, North Astrolabe Reef Lagoon.

PLATE 54.
Solo Rock, volcanic. North Astrolabe Reef Lagoon.

PLATE 55.
West Face of Wakaya Island, volcanic. Surf on Fringing Reef.

PLATE 56.

North Shore of Wakaya Island, volcanic, forming south side of Boat Passage lead-
ing into Wakaya Lagoon.

PLATE 57.

Looking into deep Bay on east side of Moala, volcanic, from outside of Barrier
Reef.

AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 163

PLATE 58.
Southwestern side of Nairai, volcanic, seen from Anchorage inside the Lagoon.

PLATE 59.

Kobu Island, volcanic (Magnetic Island), inside of Nairai Lagoon, seen from the
north.

PLATE 60.
Islets (Mbuimbani to left) off north point of Taviuni Island, volcanic.

PLATE 61.

Kimbombo Islands seen from the east, distant two and a quarter miles ; to the left,
Volcanic Island, and Elevated Limestone to the right.

PLATE 62.

Eroded Shore Line, Volcanic Rocks, Islands of Lau. From a Photograph by E. G.
Jones, Esq. (Thithia teste Andrews.)

PLATE 63.

Northeast Point of Komo, Volcanic Rock Outlier.

PLATE 64.
Beach on the North Shore of Komo, Volcanic Rocks, Komo Ndriti in the distance.

PLATE 65.
Pocillopora Fringing Reef Flat, Komo Island.

PLATE 66.

East Rim of Totoya, seen across the Isthmus, inside the Lagoon of the Western
Coast of the Island of Totoya.

PLATE 67.

Opening into tlie Totoya Crater Basin, seen from the West approaching the
" Gullet," inside the Lagoon.

PLATE 68.

Islets to the West of the " Gullet," looking into the Totoya Crater Basin from the
Entrance into the "Gullet."

PLATE 69.

Islet off the Inner Edge of Northern Rim of Totoya, seen facing the Eastern Inner
Rim of the Crater.

164 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

PLATE 70.
Eroded Kim of Crater Basin of Thombia, Budd Reef Lagoon, Ringgold Isles.

PLATE 71.

Crater of Haleakala, Hawaian Islands, from a height of about 2,000 feet on the
edge of the rim.

PLATE 72.

Northeast side of Vanua Mbalavu Island, seen from inside of the Lagoon. The lo\y
ridge along the shore consists of elevated limestone, also the conical hill to
the left ; the rounded hills in the background are part of the volcanic nucleus
of the island.

PLATE 73.

Northeast Point of Ngillangillah Island, inside Vanua Mbalavu Lagoon, seen from
the East. Elevated limestone.

PLATE 74.

Canon, east shore of Ngillangillah Island, Vanua Mbalavu Lagoon. Elevated
limestone.

PLATE 75.
Avea Island (600 feet). Vanua Mbalavu Lagoon. Elevated limestone.

PLATE 76.
Alcyonarian Flat, Ngillangillah Island.

PLATE 77.

Limestone Bluff north of Tokolau Beach, Kambara, Wangava in the distance.

PLATE 78.

Volcanic Hill south of Tokolau, Kambara. The elevated limestone extends to the
valley on left of hill. The negro-heads and shore platform underlying the
limestone are volcanic.

PLATE 79.

Elevated Limestone Cliffs, Northwest Shore of Kambara. Neither fringing nor
barrier reefs along this part of the coast.

PLATE 80.

Southeast Side of Fulanga. High hills in the southeast corner; shore line of low
limestone hills in the foreground, seen from outside of barrier reef.

AGASSIZ: FIJI ISLANDS AND COKAL EEEFS. 165

PLATE 81.

Looking into Fulanga Lagoon and Sound. Limestone islets across the rim of the
Sound. Limestone islets and hills in the distance.

PLATE 82.

Entrance into Fulanga Lagoon and Sound, seen from the east.

PLATE 83.

Limestone Islets in Fulanga Sound, and Islets across eastern Margin of Sound.
From a Photograph by Mr. Hathaway. Limestone Bluffs of Inner Rim of
Sound looking east.

PLATE 84.

Undercut Limestone Islets in Fulanga Sound. From a Photograph by the Hon.
W. L. Allardyce.

PLATE 85.

Low Gap, looking across Barrier Reef, into closed Sound of Northeast Coast, Mango.

PLATE 86.

Elevated Limestone Bluffs, East Coast of Mango. To the right along the beach
the volcanic rocks underlying the limestone crop out.

PLATE 87.
Volcanic Islets on the southwest side of Mango, on the edge of the Barrier Reef.

PLATE 88.
Northwest Point of Tuvutha. Elevated limestone (800 ft.).

PLATE 89.

Southeast Point of Tuvutha. Elevated limestone.

PLATE 90.

Yavutha Island (240 ft.). Elevated limestone, distant IJ miles from the southeast
inside of Yangasa Lagoon.

PLATE 91.

Looking into Bay on north side of Navutuiloma Island, Yangasa Lagoon. Ele-
vated limestone.

PLATE 92.

Point (elevated limestone) on North Shore of Navutuiloma, Yangasa Lagoon.
Yavutha Island in the distance.

166 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY.

PLATE 93.
Islets (elevated limestone) in Bay of Navutuiloma, Yangasa Lagoon.

PLATE 94.

North Shore of Ongea Ndriti (elevated limestone).

PLATE 95.

Taulaha Islet, distant two miles, northern edge of Ngele Levu Lagoon. Seen from
Anchorage inside of Lagoon. The cones are composed of elevated limestone.

PLATE 96.

Northern Point of Tai ni Mbeka Island, elevated limestone, northern edge of Ngele
Levu Lagoon.

PLATE 97.

Pitted and Honeycombed Surface of central part of Ngele Levu Island, with typical
inland vegetation.

PLATE 98.

Pitted and Honeycombed and Denuded Surface of Ngele Levu Island near eastern
shore, with conical mounds and deep crevasses.

PLATE 99.

Vegetation, West Shore of Ngele Levu Island.

PLATE 100.

Elevated Limestone Bluffs, Northwest Shore of Vatu Leile, seen across barrier reef
line.

PLATE 101.

Vatu Savu Islets (elevated limestone) on northern edge of Vatu Leile Lagoon.
The low eastern shore of the islanc^ of Vatu Leile (elevated limestone) in the
background.

PLATE 102.

Vatu lai lai Islets (elevated limestone) northern rim of the Vatu Leile Lagoon.

PLATE 103.

Southern Horn of Nanuku Levu, seen from the south. NanukuLevu Island in the
distance.

PLATE 104.

Nanuku Levu Island, seen from tlie west across the Western Reef.

AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 167

PLATE 105.

Southern Reef Flat of Nanuku Levu Island.

PLATE 106.
Beach Rock on East Shore of Nanuku Levu Island.

PLATE 107.

Negro-Heads (elevated limestone) occupying Position of Nanuka lai lai Island.

PLATE 108.

The Islands of Nuku Mbalate and Nuku Mbasanga, seen from the west across the
encircling reef.

PLATE 109.

Western Point of Wailangilala Island, distant one third of a mile from anchorage
inside tlie Lagoon.

PLATE 110.

Northeast Point of Wailangilala Island, seen from Lighthouse Tower.

PLATE 111.
Southeast Horn of Thakau Lekaleka, Oneata Passage.

PLATE 112.
Northeast Horn of Motua lai lai, seen from the east.

Rll iSIAKDSAND CORAL ReEFS.

Plate 1.

Valoa or Turtlr I j^

Fbl lSLAIvu.>ASU jORAL RliEFS

Pl.ATK Z.

I

FIJI ISLANDS AND CORAL REEFS

I>l. .1.

Soundings in fath.

,„?'

-_-"»\^ .- - .-V.

■^^i5^ a»

•»• /|>i#» y <. V" .■"•.L V"

1 S LAN 1) 8 ^ w> r "'''"^^"J; "S. ■aI'" »> " »'

Rxporad. 18B0

FIJI ISLANDS AND CORAL REEFS

Pi,. S."

■» , ■"

DM1* I ' ; U " fc. • " •- ' ,

.T lit" *» "w ••*.!»». ' *»!*

.|»o " „ »• faV'

Sw «l a* jj ""jo ■»!> '"»,.-,

!&■»*: J» " '^ *

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'•*-",

AUlon^ *•<>».* -^i. -■ '■*«< 3 "^

^•Ki'fe

*«A*-e. Aufii' 5rtS»''

KORO

P'-WJin^J:^^"^

Soundings in fathoms.

THE HELIOTTPE PRINlmO CO., 009TON

Fill ISl.ANOS AND fORAL KEKKS

rrs'

PL. 4.

THE MELIOTTPE PRInTlHi! CO., SOSTOM

fljl ISLANDS AND CORAL REEFS.

Pi.. 5.

NASILAI TO SERUA

flUBVETSD BY LlSirfT W. U. MOORK . BJI| lST«-7.

Dtmfly mtmtti Kiili. ^an tOO tB lOOO ft*l hlgi

Soundings in fathome.

5 Ml LES

V

MBCNGHA PASSAGE

ai-^ ■

iHi/r/re"

r.1.1 oouod

!E HIUOTTVE PRIHTINO CO..

I FIJI ISLANDS AM) CORAL REEFS

^? -K ^<f ■01' yj

^ J I

SERUA TO MALOLO.

■•'#'=

SoliiidlllKs In falhomt.

■I^'

:'&^

,^'

=-#

#^^'.S.Mi

f

FIJI ISLANDS AND CORAL REEFS.

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-^1 .»^_J*-- -■-,•.•.'••••.■ .-■^•■■■■i-

■Art

Wm^'--''^^^^'-f^'

-'^':^m:^^':^mm■

' 3 v'ST'?'- •■■•.- Vat

Soundlngi In /alhomt.

FIJI ISLANDS AND CORAL REEFS.

PL. 8.

Soundings in fathoms.

THE HELIOTYPE PRINTINO CO., 0O8TON

FIJI

ISLANDS AND CORAL REEFS.

Pl,.9.

117 40

>fo

VATU LEILE

Soundings in fathoms.

5 Ml LES

THE HELIOTYPE PHINTINQ CO., BOSTON

FIJI ISLANDS AND CORAL REEFS.

PI..10.

M.mylf-^)'^" "^-^J

5*"

^-"r- If**?^.--'. .... „«■■ ^y A-

"'- V>^X...»^*r,. ..;.i5^^^_ .-VV'

Soundings in fathoms.

THE HELIOTYPE FfilNTINQ CO., BOSTON

JI ISLANDS AND CORAL REEFS.

PL. 11.

"•*-.,

\ '^''.C.T.„„,

THt HEiioTvPE PBiNTiHo CO., eoeroN

Fbi Islands AND Coral Reefs

Plate, ll?

SomidifK/s in fatha/ns
Heufhts in f'l-et

FIJI ISLANDS AND CORAL REEFS
Wakaya 5d\

1 <!.. ..1™— •^9i:rti I

PL. 12.

I .V»* xiJarviTSO )

„.. *'*; »40

' M lSeerlm,741 >

*^'

c^

jicUnS-"-

Mbatiki °,:-V^;i?^d'^«°'»»i*m.^

,.>e plan, r*!.

<»>>

^,-'" NAIRAI s^ph^74i>

M 5-«« ♦•?,\*6 i(»i-,«>j« yiviso

ao

i^^e "as

753

NGAU I.

Soundings in fathoms.

MaJTibuli-,-

arc **' «6 li «o "^^aip

360 340

7fl3

zSo aTo ^-f^^
■.i_ DaaT 1W« ;''awaa7i,^aZway«hreaJevuf

L*Mi. or CbooanLtt I.

JOSS

120** . 20«

. HELIOTVPE PRINTINO CO.. BOSTON

FIJI ISLANDS AND CORAL REEFS.

PL. 13.

179 20'

\

119 20

Soundings in fathoms.

5 Ml LES

1__., L_

THE HELIOTYPE PRINTING CO., BOSTON

FIJI ISLi\.NDS AND CORAL REEFS-

Pl.14-.

179 20

1740

iMTxetr'nv atrf .h

i^r-ajK^atfebb

Soundings in fathoms.

THE HELIOTVPE PRINTIMO CO., SOiTOM

FIJI ISLANDS AND CORAL REEFS.

Pl.15.

773°

-Si^*

Jl»tii«^rar'>£g<i

if . »«? IT - - »>. . "

-«*?,

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1740

M M "^ 16 ®
■ " « - '

27 40

179

THE HELIOTVPE PRINTmS CO., BOSTON

FIJI ISLANDS AND CORAL REEFS.

sSo

WIS

5 MILES

•to

^^ aio ISO

«f6 ISO "ISC': so

PL. 16.

MOAJ..A IS,t,T>ianlBBZ}
V^W* Sprue i^^

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179&

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di^o

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HW F 4 C"^a7^ 5prMe flif*

■»iYj «

"°„!|cg^'

Soundings in fathoms.

•'"•^

THE HELtOTYPE PRINTING CO., BOSTON

Fill ISLANDS AND CORAL REEFS.

Pi.. 17.

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^■-J* .-^NgelgLcvru Lagoon;- ^ j --ff •A.i5fOS''>^»3!

2^0

THE HELIOTfPE PRINTING CO-, BOSTON

5 MILES

Ji

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Soundings in fathoms.

Fui Islands AND Coral Rbefs

Plate. 17?

1 4-.

\'\i a t a O 11 o

Vii I (1 J, I- 1 I p
Soul hern pari I

Se a I. e V e- i

Va t u L t- 1

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(South lace) N^ele I, e V u

Sea Leuri

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.y c t\. l.evHt

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Svu Level.

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3 naif

FUffi. 1/1

Fi^s- 13-16.

Sea Level

( N o r I h s 1 d p ) N ^" e 1 e J^ e v u

N ^' e > e 1. f

Sounrhri^s in fathoms.
Ik'iyhis in /'/•/' I .

B Mti^iel liMoiiDK

\D CORAL REEFS,

<s^mL^ -A^f'-'-l

PL. 18.

s

^

Soundin^H In fathom h.

FIJI ISLANDS ANO CORAL RKEFS.

P,.. 19.

Ji -'as

w^^ ■ Lookout IT.

as

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■ ..^arT .*" at ™

ofKi-'NuliuThihombia. ff

EXPLO RI N G
ISLES

■HE MELIOTYPE PRINTIMO CO,, BOSTON

Soundings in fathoms.

Rii IsLuiDS/iKD Coral Reefs

Plate, I9«

4

in ISLANDS AND CORAL REEFS.

PL. 20.

•^Sr*^'°Mg"^'°^ ""'■™*'

is THITHIA

./£n

/ QuBii^R^ofTraiBrt ^^^ J

M«AflOofeS

SoundlngB in fathoms.

-^J^-.

( '•.• B***V^ Thaka4j Tambu

«»'■ iff io

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'?'

g--..3'

^

' .s -f^^^Reid Reef

^

130

Northern Part of Argo Reefs.

THE HELIOTVPE PRiNTrNG CO.. BOrrSh

Mil IsLAKDSAm Coral Reets

Plate. 20*

l.ovuko Harbor StMlMret

Fi^a. 14-17

Fill ISLANDS ANH CORAL REEFS.

Pl..:il.

^^/0-i:T^y.y^ '

jflo jw-.ji'a-wia*^, ' V ' lee aoo

MBUKATATANOA or
I,, AHGO REEFS

^■<»'

LAKEMBA if

4

Soundings in fatiioms.

OJSTfJATA PylSSAGE

PfllNTtNO CO.,

FIJI ISLANDS AMI CORAL REEFS.

PL. 22.

KAMBARA

(2^? Wilk..Rf

4^ NAMUKA (BBOi

&^;

ThaJ<au N^sokeaoke

^f-^--^

Soundings in fathoms,

FULANGA

rut HEUOTVPi pnmTiNe oo., boston

Fill iSIANDSAND CORAL RbEFS

Plate 22"

Soufte/inys irt /at/ioms
Heights in ffct

FUl Islands AND Gorai. Reefs.

Plate 22b

SonndinifH in fafhoms.
Heitfhts ut /'fit.

Fiji Islands and Coral Reefs

Plate 23.

• fa. =i - ^~'t"" "

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H ?: R A L D ^^

2j M* s o u X D y

'1- - -11/

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ff®!^®-^^

SOUNDINGS IN FATHOMS
H EIGHTS IN FEET

; Islands AKD Coral Reefs

Plate. 23»

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"Fiji Islands and Coral Reefs."

Plate 31.

M. A., PHOTO.

ARl07iP£. £. B.EKS'AOT, h-Y.

ele'n/ated limestone bluff, north of savA.

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Plate 46.

MAX AGASSIZ, PHOTO

THE HELIOTVPE PRINTING CO- BOSTON

CLIFFS, EAST SIDE OF MBENGHA.

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Harvard MCZ Library

3 2044 066 302 yoy

BOOKBtN .: :

MAR 8 - 1984
100 CAM*;Ri:)rL stp'

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