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A. AGASSIZ.

HARVARD UNIVERSITY.

LIB RAR Y

OF THE

MUSEUM OF OOMPAKATIVE ZOOLOGY.

(Arm

GIFT OF

ALEX. AGASSIZ.

i^jjuu^ol. (3^iJU^ 13. 19 3l

n

OCT 13 1927

MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE,

VOL. XXVIII.

CAMBRIDGE, U.S.A.

PRINTED FOR THE MUSEUM.

1903.

MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE.

VOL. XXVIII.

^CAMBRIDGE, U.S.A.
PRINTED FOR THE MUSEUM.
1903.

University Press :
John Wilson and Son, Cambridge, U. S. A.

CONTENTS.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, in charge of Alexander Agassiz, by tlie U. S. Fish Com-
mission Steamer "Albatross," from August, 1899, to March, 1900, Commander
Jefferson F. Moser, U. S. N., Commanding. IV. The Coral Reefs of the
Tropical Pacific. B3' Alexander Agassiz. pp. xxxiii., 410. 238 Plates. Febru-
ary, 1903.

One Volume Text. Three Volujies Plates.

Itmoirs of tbc Museum of Compratitre ^oologn

AT HARVARD COLLEGE.

Vol. XXVIII.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITIOM ii-Gi THE
TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSt0, BY TIHE
U. S. FISH COMMISSION STEAMER " ALBATROSS," FROM AX^GUST,
1899, TO MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U. S. N.,
COMMANDING.

IV.

THE CORAL REEFS

OF THE

TEOPICAL PACIFIC.

By ALEXANDER AGASSIZ.

WITH TWO HUNDRED AND THIRTY-EIGHT PLATES.

TEXT.

[Published by permission of George M. Bowers, U. S. Commissioner of Fish and Fisheries.]

CAMBRIDGE, U. S. A. :

Prtntcti for tlje fHuseum.
February, 1903.

TABLE OF CONTENTS.

Introduction

Page

33

The Marquesas, Plates 2, 3, 200, and

Fig. 1

The Paumotds, Plates 4-83, 201-207 .
The Paumotu Plateau, Plates 201,

234, and Figs. 1-12

Rangiroa, Plates 4-19, 201, 202; 204,
figs. 3, 4; 205, fig. 3 ; and Figs. 2,

3, 5

Tikahau, Plates 20, figs. 2-4; 201,

202 ; 204, fig. 4 52

Matahiva, Plates 20, fig. 1; 201,

202; 204, fig. 4 54

Makatea, Plates 21-32; 201, 202;

205, fig. 1 ; and Figs. 7, 8 . . .
Niau, Plates 33-36, 201, 202 . . .
Apataki, Plates 37, 39 ; 40, fig. 1 ;

201. 202

Tikei, Plates 40, figs. 2^; 41-44,

201, 203

Kauehi, Plates 45, 201, 203 . .

Fakarava, Plates 46-50; 51, fig. 2;

68, fig. 1 ; 201, 203; 204, figs. 1,7
Anaa, Plates 51, fig. 1 ; 52, 53, 201,

203

Tahanea, Plates 54, 55, 201, 203 .

The Raveskoi Islands

Tepoto 90

Tuanake, Plates 201, 203 .... 90
Takume, Plates 56, 57 ; 58, fig. 2 ;

201, 203, 205 91

Raroia, Plates 201, 203 94

Taenga, Plates 201, 203 .... 98
Makemo, Plates 59-65 ; 75, fig. 4 ;

201, 203, 204 99

Tekokota, Plates 66, 201, 203 ' . . 109
Hikueru, Plates 201, 203 .... 110

56
64

68

71
74

76

84
85
90

Marokau and Ravahere, Plates 70,

figs. 1, 2; 201, 203; 204, fig. 5 .
Hao, Plates 67, 201, 203; 205, fig. 2
Aki-Aki, Plates 68, 69, 201, 203 . .
Nukutavake, Plates 70, figs. 3, 4 ;

71, 201, 203

Pinaki, Plates 72-75, 201, 203 ; 206,

fig- 3

The Duke of Gloucester Islands . .
Nukutipipi, Plates 76, 77, 201, 203 ;

206, fig. 4

Anu-Anuninga, Plates 78, 202, 203 ;

206, fig. 1

Anu-Anuraro, Plates 201, 203; 206,

fig- 2

Hereheretue, Pl.ates 79-83, 201, 203
The Society Islands, Plates 84-105,

201, 202, 208-210

Mehetia, Plates 90, fig. 2 ; 95, fig. 1 ;

202

Tahiti, Plates 84-89. 202, 208-210 .
Murea, Plates 90, fig. 1 ; 91 ; 208,

fig- 6

Huaheine, Plates 92 ; 94, fig. 4 ; 202 ;

210, fig. 1

Raiatea and Tahaa, Plates 93; 94,

figs. 1-3; 96, fig. 2; 210, fig. 2 .
Bora Bora, Plates 96, fig. 3; 97-

103, 202; 210, fig. 3

Maupiti, Plates 104, figs. 3, 4 ; 105,

202; 210, fig. 4

Motu Iti, Plates 104, figs. 1, 2; 202
Tetiaroa, Plates 95, figs. 2, 3; 96,

fig. 1 ; 202

The Cook Islands, Plates 106, fig. 1 ;

211; 212, figs. 2, 5

XI

Page

111
113
116

118

120
125

125

128

130
131

135

140
141

156

157

159

161

164
165

166

1G8

Vlll

CONTENTS.

Page
Aitutaki, Plates 106, fig. 1; 211;

212, fig. 2 1G9

NiuK, Plates 106, figs. 2, 3; 107-110;

211; 212. fig. 1 ; 213 171

The Tonga Archipelago, Plates 111-

125, 213-219 175

Eua Island, Plates 111-114; 122,

fig. 3; 212, fig. 4: 213, 214 . . 180
Tongat ibii, Pl.ati's 115-118; 213-215 188
The Nomiika GroiiiJ, Plates 119, 214,

216 192

The Haapai Group, Plates 217, 218 195

Vavau, Plates 120-125, 219 ... 197

The Fiji Islands, Plates 126-128, 220 204

Kambara, Plates 126, 127, 220 . . 206

The Ellice Islands, Plates 129-137;

212, figs. 6-8; 221, 222; 224,

fig. 1 210

Nurakita, Plates 129, fig. 1 ; 212,

flg. 8; 221 210

Funafuti, Plates 129, fig. 4; 130-

137, 221, 222; 224,' fig. 1 ... 212
Nukufetau, Plates 129, figs. 2, 3;

212, fig. 6; 221 229

The Gilbert Islands, Plates 138-160,

223; 224, figs. 2-6; 226, figs.

1-3 232

Arorai, Plate 223 236

Onoatoa, Plate 223 236

Tapeteuea, Plates 138, figs. 1-3;

223 ; 226, fig. 1 237

Apamama, Plates 138, fig. 4 ; 139,

figs. 1-3; 223; 226, fig. 2 ... 240
Maiana, Plates 139, fig. 4; 140,

flg. 1 ; 223 ; 224, fig. 6 ... . 245
Tarawa, Plates 140, figs. 2-4; 141-

144; 145, fig. 4; 223; 224, fig. 5 . 247
Apaiaug, Plates 145, figs. 1-3; 223;

224, fig. 2 252

Maraki, Plates 146-150, 223; 224,

flg. 3 253

Taritari, Plates 151-160, 223 ; 224,

fig. 4 258

The Marshall Islands, Plates 161-

182, figs. 1, 2; 225; 226, figs.

4-10; 227, 228 . . . . . . . 271

Jaluit, Plates 161-166; 167, fig. 2;

225; 226, figs. 4-10; 227, figs.

1-3; 228, fig. 2 279

Page

Ailinglap, Plates 168; 171, fig. 1;

225 ; 226, fig. 5 293

Namu, Plates 167, fig. 1 ; 225; 227,

fig. 1 295

Kwajalong, Plates 169, 170, 225;

227, fig. 2 296

Rongelab, Plates 171, figs. 2, 3;

172, 173, 225; 226, fig. 8 ... 303
Likieb, Plates 174-177, 225; 228,

fig. 3 307

Wotje, Plates 178-180, figs. 1, 2;

225; 227, fig. 4; 228, fig. 1 . . 315
Arbno, Plates 180, figs. 3, 4; 181;

182, figs. 1, 2; 225; 228, fig. 4 . 321
Namorik, Plates 225; 226, fig. 10 . 329

The Caroline Islands, Plates 182,
figs. 3, 4; 183-193, 225, 229-
232 ; 233, figs, 1-3 330

Kusaie, Plates 182, fig. 3; 184-187,
225, 229 333

Pingelap, Plates 183, figs. 2-4; 225;
227, fig. 5 340

The Seniavina Islands 342

Ponapi, Plates 188-190, figs. 1-3;

225, 230 342

Andema Islands, Plates 182, fig. 4 ;

183, fig. 1 ; 225, 230 350

Losap, Plates 232 ; 233, fig. 3 . . 351

Nama, Plate 232 351

The Royalist Islands, Plates 190,

fig. 4; 231, 232 352

Truk, Plates 191-193, 231, 232 . . 353
Namonuito, Plates 232 ; 233, fig. 1 363
The Laurones, Plates 194-199; 232;

233, figs. 4, 5 365

Guam, Plates 194-198; 232; 233,

fig. 4 366

Rota, Plates 199, 232; 233, fig. 5 . 376
List of the Stations occupied by the

"Albatross" 379

San Francisco, Cal., to Nukuhiva,

Marquesas Islands 379

Marquesas Islands to Tahiti, Society

Islands, via Northwestern Pau-

moUis 380

Stations in vicinity of the Marquesas

Islands 380

Stations from the Marquesas to Ran-

Siroa 380

CONTENTS.

IX

Page
Rangiroa to Tikahau and to Mata-

hiva 381

Matahiva to Makatea and to Papiete,

Tahiti Island 382

Through the Paumotu Archii^elago . 383

Tahiti to Makatea, via Tetiaroa . . 383

Makatea to Apataki, via Niau . . 383

Apataki to Tikei 383

Ngarue Pass, Fakarava, to Takume,

via Anaa and Talianea .... 383
Takume to Makemo, via Raioia and

Taenga 385

Makemo to Hikueru, via Tekokota . 385
Hikueru to Hao, via Marokau and

Ravahere 385

Hao to Aki-Aki 386

Aki-Aki to Piuaki, via Nukutavake . 386

Pinapi to Nukutipipi 386

Nukutipipi to Ilereheretue, via Anu-

Anuruuga and Auu-Auuraro . . 387

Page

Hereheretue to Tahiti, via Mehetia . 387
Society Islands to Tongatabu, Tonga
Archipelago, via Leeward Society
Islands, the Cook Group, and Nine

Island 388

From Tahiti to the Leeward Society

Islands 388

From Aitutaki to Niue 388

From Niue to Eua (Touga) .... 388

Vavau to Fiji 388

In Fiji Archipelago 389

Fiji through Ellice and Gilbert Islands

to Jaluit, Marshall Archipelago . 389

From Taritari to .Jaluit 390

Through the Marshall Archipelago . 390
Marshall Islands through the Caro-
lines to Guam, Ladroues, and to

Yokohama, Japan 391

Through the Carolines 391

Namouuito to Guam 392

INTHODUCTION.

While in charge of the expedition of the United States Fish Commission
Steamer "Albatross" during the winter of 1899-1900 we visited tlie coral
reef districts of the tropical Pacific, with the exception of the Sandwich, the
Samoan Islands, and the Galapagos. The Hawaiian Islands I had explored
on former occasions, and had also obtained a bird's-eye view of the reefs of
Samoa on my way to examine the Great Barrier Reef of Australia.

It has thus been my good fortune to observe the structure of the great
majority of the coral reefs, atolls, and coral islands of the tropical Pacific,
and to have the benefit of the excellent charts published since the days of
Darwin and Dana. One cannot overestimate the great advantages to be
derived from recent surveys in studying groups of coral islands like the
Fiji or the Society Islands. The charts and " Sailing Directions " contain an
amount of information which no one individual could hope to bring together,
and their publication has made it possible for an observer ' to cover an
immense area and obtain within a reasonable time an insight into the
structure of the coral reefs of an oceanic realm like the Pacific.

In this, as in preceding Reports, I have limited myself to an expo-
sition and explanation of the observations made in each of the coral reef
districts examined, and have only made such comparisons between the
various groups as seemed essential to the proper understanding of the
Report.

These investigations on coral reefs date back to 1877; they have now
covered the principal coral reefs and islands of the Pacific, the West Indies,
and the Indian Ocean. The earlier reports were mainly descriptive, and
limited to statements that the facts observed did not seem to confirm
Darwin's theory of the structure and formation of coral reefs. As the work

xii INTRODUCTION.

was extended the subject proved far more complicated than had been sus-
pected by previous investigators. The explorations were not continued for
the sake of proving Darwin to be wrong, as seems to be the impression of
some of my critics. Year after year the subject of coral reefs became more
engrossing, and it was studied for its own sake. I had no theory of my
own as a guiding star, nor did I attempt to uphold any one of the theories
on coral reefs advanced since the publication of Darwin's " Structure and
Distribution of Coral Reefs."

An immense amount of information regarding the coral reefs and islands
of the Pacific may be found in the journals of missionaries, who have often
spent years at certain localities. Some of the descriptions by Williams,
Whitmee, Gill, and Turner are remarkably accurate, and many of their illus-
trations most interesting ; especially instructive are the reports of the
voyages of English, French, and Russian navigators in the last part of the
eighteenth and beginning of the nineteenth century, containing the first
accurate charts of atolls, barrier and fringing reefs published.

A number of independent travellers have also published sketches of their
journeys. The voyage of the '• Blossom " under Beechey,^ of the '.' Beagle,"
and the United States Exploring Expedition under Wilkes, are memorable
for Darwin's and Dana's reports on coral reefs and the geology of the
islands of the Pacific.

These expeditions have been supplemented by the surveys of the British
Admiralty and the French Hydrographic Bureau, as well as by several
minor expeditions sent out by the United States Government. Their
results include the publication of a series of excellent charts covering nearly
all the oceanic island groups of the tropical Pacific, like those of Fiji, of
Tonga, of the Society Islands, and of many of the Line Islands ; they far
surpass in accuracy the earlier publications and give us a very different
idea of the structure of atolls, of coral reefs, both fringing and barrier,
from that obtained from data available fifty years ago.

Since the " Challenger " expedition, dating with the appearance of Mur-
ray's " Structure and Origin of Coral Reefs " in 1880,'^ Darwin's theory of

■ An excellent analysis of the results of Beechey's voyages by Ainsworth will be found in the
Journal of the Royal Geographical Society of London, Vol. I., 1831, p. 193.
'^ Proceedings of the Royal Society of Edinburgh, X., p. 508.

INTKODUCTIOX. xiii

the formation of barrier reefs and atolls has been subjected to prolonged
criticism. Following Rein and Semper, recent investigators have, w^ith
few exceptions, regarded it as untenable. Semper's investigations in the
Pelew Archipelago have hardl_y received the recognition they deserve. As
far back as 1861 he spent nearly ten months in the Pelews,* and called
attention to the fact that all kinds of reefs (atolls, barrier and fringing
reefs) are found in the Pelews, within a comparatively short distance,
in a region considered by Darwin as one of subsidence, and that at the
southern extremity of the group an elevated coralliferous limestone island
(Ngaur) rose to a height of over 300 feet, containing, according to Wich-
man, fossils of late tertiary age. Semper lays great stress on the effects of
currents between the land rim and the barrier reef in widening barrier reef
lagoons ; reef platform lagoons such as I have described illustrate this well.
He further suggests that marine animals may build up a foundation for the
growth of reef corals, from far greater depths than those at which corals
can thrive.

Semper fii'st called attention to the effect of solution in removing mate-
rial from an atoll, but it is to Sir John Murray - that we owe careful experi-
ments to determine the amount of lime removed by solution and the sugges-
tion of its importance as a factor in the formation of lagoons. Semper
considers the effect of solution in removing lime from the lagoon of an
atoll as balancing the constructive agencies proved by the growth of
corals in it.

To Professor Dana was undoubtedly due the general acceptance of
Darwin's theory of the formation of coral reefs. Dana's views on coral
reefs were based upon the study of the coral reefs of Samoa, the Hawaiian
Islands, Tahiti, the larger Fiji Islands, seven of the islands in the Pau-
motus, of Tongatjibu, of Tapeteuea and Apaiang in the Gilbert Islands,
of Gente Herniosa, Fakaofu, Oatafu, Hull, and Enderbury among the Line
Islands. The publication of his results in 1849^ supporting in the main
Darwin's theory could not fail to supply a mass of evidence wanting in the
Report of Darwin's researches, based as they were upon the survey of the

^ Die Natiirlichen Existenzbedingungen d. Tliiere, Leipzig, II., 1880, p. 39.

2 Proceedings of the Royal Society of Edinburgh, XVII., 1889-90, p. 79.

^ Geology of the United States Exploring Expedition under Commodore Wilkes.

xiv INTRODUCTION.

comparatively limited field of Keeling, Tahiti, and Mauritius. Darwin's
theory was also adopted by Jukes, who had just completed a survey
of the Great Barrier Reef of Australia. The field covered by Dana
and Jukes thus seemed to include all that was essential to satisfy the
demands of Darwin's theory.

Tlie problems which have arisen from a more extended study of the
coral reefs since that time have greatly modified the views so gener-
ally held regarding their origin. A number of explorers in recent years
have attacked limited areas, and their conclusions have in nearly all
instances been opposed to Darwin's theory. It is unfortunate that so much
has been written on the subject of coral reefs by persons who have never
studied them in the field, and who have added to the bibliography of coral
reefs a mass of material which has done little or nothing towards the solu-
tion of the questions at issue.

It may not be out of place to sketch rapidly the characteristics of the
coral reef groups of the Pacific.

The Galapagos ^ and Marquesas are not of special interest as far as coral
reefs are concerned. In both groups corals are limited to restricted shore
areas ; they do not even form fringing reefs ; they are mere patches in the
shallow bays cut into volcanic bluffs.

In the Sandwich and Samoan Islands occur fringing reefs limited to
certain parts of the larger volcanic islands ; on the shores of other islands
they are either absent or reduced to mere patches.

In the Sandwich Islands, Lysan, Lisianski, French Frigate Shoal, Maro,
Hermes, Cure, and Midway Islands are atolls and coral reefs scattered along
the chain of volcanic islets extending to the westward of Kauai. Elevated
coralliferous limestones occur along the southern face of Oahu. On the
northern side ajolian rocks attain a height of twenty to twenty-five feet
and the fringing reefs are underlaid by a base of elevated tertiary limestone
from which a reef flat platform has been eroded.

In Samoa extensive fringing reefs and barrier reefs occur on Upolu. In
Savaii the east face is flanked by barrier reefs. In Tutuila, as in the islands

' At the Galapagos, during a deep sea expedition off the Panamic district, we found nothing of
importance regarding coral reefs. See also Darwin, Coral Reefs, p. 197.

INTRODUCTIOlSr. xv

named above, stretches of disconnected fringing reefs occur along the
southern shores. Rose IsLand is the only atoll of the Samoan Islands ;
it is described as such by Wilkes ; he states that outliers of volcanic
rock are found upon the encircling reef. An excellent sketch of the
atoll is given in Graeffe's Samoa, " Journ. d. Museum Godeffroy," Heft I.,
1873, p. 32, PI. 1.

The Paumotu Archipelago consists of more than seventy atolls, many of
great size and of elevated islands composed of coralliferous limestone. The
low atolls have been cut down from the denudation and submarine erosion
of higher islands, forming sounds or sinks surrounded at first by high rims
subsequently cut into islands or islets with passes leading into the sounds,
until the land rims were reduced to the level they now occupy. The
successive stages of denudation and submarine erosion are represented
by such islands as Makatea, Niau, Rangiroa, Hao, and others. Some of the
easternmost of the Paumotu atolls are diminutive, and such atolls as
Pinaki, Nukutipipi, Anu-Anurunga, Anu-Anuraro are admirable epitomes
of the structure of the larger ones.

Some of the smaller of the Paumotu Islands have a central sink or
apparent depression formed by the closing in of a part of the summit of a
reef flat by beaches thrown up on the sea faces of the islands. If the island
flat is somewhat below low-water mark a shallow lagoon is formed, and
according to the height of the reef flat a dry sink may be enclosed, to
be filled only during the rainy season.

The Paumotus are flanked on the east by Manga Rev^, a cluster of
volcanic islands encircled by a barrier reef, and on the west by the Society
Islands. This group is, with the exception of Tetiaroa, composed of
volcanic islands surrounded by barrier reefs, edging often a very wide
barrier reef flat, enclosing a lagoon of moderate depth. The fringing reefs
of the Society Islands are also noted for their great breadth ; on Tahiti the
reefs of the northwest and western coast show admirably how a wide fring-
ing reef may gradually become gouged out into a barrier reef edging a
shallow lagoon, and ultimately a wide and deep barrier reef lagoon. On
some of the Society Islands the islands on the barrier reef form a nearly
continuous belt, covered with a luxuriant growth of cocoanut trees and

xvi INTKODUCTIOlSr.

of low bushes, separating the barrier reef lagoon from the sea. Erosion
and denudation have been great factors in shaping the volcanic slopes of
the islands of the group, and the wide platform on which the encircling
reefs have obtained a foothold has been cut by submarine erosion.

In the Paumotus there is a great development of buttresses of tertiary
coralliferous limestone ; they run across the beaches of the sea face and of
the reef flat platforms, and are the last remnants of the former elevated
land once covering a large area of the atolls.

In the Ellice and the Marshall Islands, and some of the Gilbert Islands,
we find similar buttresses of modern reef rock and conglomerate indicating
an elevation of a few feet. In the Gilbert Islands we find buttresses of both
modern and tertiary limestone, as we also do in the Paumotus and Fiji.

We should remember the existence of many reefs, elevated to a few feet
only, where the elevated mass consists of recent reef rock material or of
recent conglomerate or breccia. These reefs are not to be confounded with
elevated coralliferous limestones of tertiary age, though they may have
been lifted to a moderate height only and may also constitute the under-
lying base of the elevated modern reef rock.

In the Paumotus, as in other groups like the Marshall, Ellice, and Gil-
bert, the width of the land rim varies greatly. We may state in general
that a part of the land rim is built up on the sea face, a part may simi-
larly be built up from the lagoon side where the atolls are large enough
to be swept by the trades, or the land rim may be increased simultaneously
both on the lagoon side and the sea face. Finally the land rim may be
widened by the material blown or swept over it from the sea face towards
the lagoon side, the latter process rapidly filling small lagoons, or in larger
atolls shoaling the lagoons and restricting their area by the formation of
extensive flats on the lagoon side of the land rim ; or, as in some of the
Marshall Islands, the sand dunes of the lagoon face are blown over the land
rim and encroach upon the outer reef flat platform. Add to this the changes
due to the solvent action of the sea, both on the sea face and lagoon side of
the land rim, and we get an idea of the complicated factors at work in
maintaining an equilibrium between the destructive or constructive agencies
acting on the land rim of an atoll. Any one of these factors may obtain

mTRODUCTION. xvii

the preponderance ; thus in adjoining atolls different results may take place,
according to the conditions which oljtain the mastery. The above factors
are at work in the Paurnotus upon plateaus of elevated coralliferous lime-
stone cut down towards the level of the sea, while in other groups where
the nature of the underlying plateau is not known, they are at work
upon a land rim of modern reef rock, or modern conglomerate or breccia.

The bottom deposits on the deep parts of the ocean separating the
atolls or groups of atolls in the Paurnotus are truly oceanic in char-
acter. The many and wide passages dividing the islands are extensions
of the great red clay belt, covering the trough lying to the southeast
of the northern and central Paurnotus between the main belt of the
Paurnotus and the Gloucester Islands line, and a similar trough sepa-
rating the Paurnotus and Marquesas. There is, however, a marked differ-
ence ill the extension of this red clay into the volcanic bottom which
surrounds the Marquesas and its passage into the globigerina-ooze ;
Pteropod and finally coral sand ooze is developed round the Paumotu
Islands in shallower water.

The Cook Archipelago consists of volcanic islands with encircling reefs,
of elevated coralliferous limestone islands and of low atolls, the under-
lying base of which is not known. The elevated islands have narrow reef
flat platforms formed by submarine erosion ; some of the elevated islands
are partly volcanic and partly limestone.

On a small independent plateau between the Cook Islands and Tonga
rises the island of Nine, also composed of elevated coralliferous limestone.

The elevated limestone islands of Tonga and Fiji are flanked by nar-
row reef platforms ; these are not continuous and occur only on parts of
the islands where the sloughing off of the terraces has formed a shore
platform which in its turn has been subject to submarine erosion. On this
platform corals have established themselves, usually as fringing reefs.

The Tonga Archipelago consists of an extensive area of elevated coral-
liferous limestone, greatly denuded and eroded. At the two extremes of the
plateau land masses of considerable extent have been elevated ; the southern
mass, Tongatabu, is greatly indented at its northern face and forms the
southern face of an ill-defined lagoon. The northern land mass, Vavau, is cut

b

xviii INTRODUCTION.

into numerous islands and sounds. Both the northern and southern islands
are terraced. The Haapai group to the north of Tongatabu is flanked with
low islands on the east face, while in the Noinuka group we find elevated
coralliferous limestone islands as well as volcanic or limestone islands where
volcanic outbursts have pushed through the limestone mass.

The bank of which Eua Island is the summit has been elevated to a
height of over 1000 feet and is separated from Tongatabu by a channel
of a greatest depth of not more than 108 fathoms ; a part of the sub-
marine plateau to the south of Tongatttbu extends as far as Pylstaart.
The banks forming the greater Tonga Plateau are sepai'ated by water of
a considerable depth, from 200 to 300 fathoms.

A line of volcanic islands runs parallel with the Tonga Plateau. Two of
its summits, Falcon Island and Metis Shoal, are of great interest, as they
both perhaps indicate the depths to which the action of the sea may extend
in shaping platforms of submarine erosion.' Falcon Island at one time
attained a height of 250 feet ; it now forms a breaking shoal ; Metis Shoal,
with a depth of fifteen fathoms, was once an island, reputed at first, in
1875, to be twenty-nine feet high, subsequently raised to 150 feet.

Admiral Wharton^ has suggested that the depth to which the action of
the waves reaches may be indicated by the change of slope generally taking
place off shore, below a depth of eighty to one hundred fathoms, and further
that the existence of banks in the open sea at a depth of thirty to forty
fathoms may be the limit of depth to which oceanic waves cut down a mass
upon which they act.^ He also suggests that we may have in the future
an opportunity of testing this by sounding the banks now forming on
the former site of Falcon and of Metis Islands in Tonga since their
disappearance.

That such extensive submarine denunation takes place seems to me

1 Wharton, Sir J. W., " Nature," VI., p. 611.

^ Address to the Geographical Section of the British Association, Oxford, 1896 ; " Nature," Feb-
ruary 25, 1897.

3 It is known that the effect of great oceanic currents like the Gulf Stream is felt at consideral)le
depth. At the straits of Bernini in 439 fathoms the bottom is swept clean, as it also is to the north of
Jupiter Inlet along the east coast of the United States as far north as Cape Hatteras, and along this
stretch tlie Gulf Stream carries a certain amount of sill ; this must act like a hydraulic flume and
wear the bottom very perceptibly. This is seen in the sections across the Gulf Stream given in
" Tlirec Cruises of the Blake," Vol. I. p. 258.

INTRODUCTION. xix

abundantly proved from the great variety of submarine platforms formed
at the base of volcanic islands and of elevated limestone masses throughout
the Pacific, the depth of these platforms being fairly indicated by that
of the lagoons enclosed by the encircling reefs or by that of the barrier
reef lagoons.

The formation of huge masses of limestone in which occur at intervals
layers of corals or beds of reef-building corals must have taken place in
areas of subsidence, — the subsidence taking place at a comparatively slow
rate while the coralliferous belts were deposited, and while the non-coral-
liferous limestones were laid down at a more rapid I'ate at a depth greater
than that at which corals could grow. This process has nothing in common
with the formation of atolls. But when these coralliferous masses of lime-
stone of great thickness were elevated either suddenly or intermittently
to heights of more than 1000 feet, the resulting islands in the first case
must have represented either a bed deposited near the surface — if coral-
liferous— enclosing perhaps a lagoon, or a sound, or a basin of solution
and erosion, formed in comparatively modern times, with recent corals
forming a capping of moderate thickness. In the second case, during each
stage of rest the elevated beds were subject to denudation and erosion
by the action of the sea. If each stage was an elevation greater than
the depth at which corals can grow, the denudation and erosion may
have continued long enough to cut the elevated limestone down, or nearly
down to, the terrace which marks the uprising of the mass. Or the
denudation and erosion may merely have gone far enough to open the
circumscribed area to the action of the sea at some points only, and
thus connect what was the lagoon or basin at the first sea-level with the
lagoon or basin or sound of the second stage of rest.

One can readily see how complicated the resultant action may become
when we take into account the varying height of the different stages of
elevation, the condition of the limestone mass and of the coralliferous lime-
stones after the elevation, and the action of denudation and of erosion upon
such an elevated mass, as well as the solvent action taking place on the
summit and sides, and finally the eroding action of the sea upon the interior
basin, should it once break through the outer rim of the elevated basin or

XX INTRODUCTION.

sink, when its lowest point has reached the level of the sea. This break
would thus form an entrance to the lagoon, much as is formed the entrance
to any lagoon or sound. Should this mass be elevated a second, a third,
or a fourth time, we may find one, or two, or more entrances to the old
lagoons and sounds according to the rate of denudation and of erosion of
the elevated mass during the periods of rest.

Tlie coralliferous limestone rings would be fairly continuous in case of
a slow rate of denudation and erosion ; if broken through by the action
of the sea and with a rapid rate of denudation, only disconnected patches,
more or less numerous, according to the rate of erosion, would indicate the
former ring ; and finally, with a very rapid denudation and erosion, both of
tlie exterior and interior face of the lagoon, or sound, nothing would be
left of the elevated mass except the submerged reef-ring. This becomes
still more complicated when the limestone mass, while elevated, has been
broken through by the underlying volcanic rocks, and they have displaced
portions of the coralliferous limestone beds and left them more exposed
to the effects of denudation and of erosion, especially when this action has
taken place on the outer face of the elevated mass, and left cuts and
openings connecting the outer sea and the interior basins, which would
thus soon be transformed into great sounds or lagoons. The erosive as
well as the solvent action of the sea would soon level the outer rim to
the plane of the sea, the further disintegration being stopped by the growth
of recent corals or of coralline Alga3 upon the surface of the coralliferous
or massive limestone eroded to the level of the sea or below it.^ With
the more rapid erosion and denudation, both atmospheric and marine, the
limestones would rapidly disappear, and there would be left only the
volcanic mass which had uplifted them, with here and there a remnant of
the limestones to indicate the probable course of events. Of course, when
the volcanic masses come up without elevating any limestone beds the
conditions are much simpler, and it becomes only a question of the

^ According to Dana's views the existence of such foundations " only prove that, in coral seas,
corals will grow over any basis of rock that may offer where the water is right in depth, and do not
nullify any of the evidence of subsidence" (Am. Jour. Scien., XXX., September, 1885, p. 181); yet
these very instances are advanced as supporting the theory of subsidence, and we may justly reply that
they have great interest as they arc opposed to the application of the theory of subsidence as explana-
tory of the formation of coral reefs in the areas where these rock bases occur.

INTRODUCTION. XXI

mode of formation of the recent corals around the base of the elevated
volcanic mass.

The want of continuity of the atolls of the eastern Paumotus, of the
EUice, Gilbert, and Marshall Islands, their separation by considerable dis-
tances and great depths, would seem to preclude the idea of the formation
of tertiary limestones over great areas. The existence of these discon-
nected and isolated limestone islands would suggest their formation upon
mounds or ridges elevated to very different heights below the surface of
the ocean, — the mounds and ridges consisting of volcanic or other rocks
elevated by the volcanic agencies we know to have been active over
very extensive areas of the Pacific from tertiary times to the present
day. In some of the Pacific archipelagoes the areas covered by the ter-
tiary limestones are of considerable extent, as, for instance, the plateau of
the northwestern Paumotus, of the Tonga Islands, and that upon which
the eastern islands of the Fiji Archipelago rise : the so-called Lau or Wind-
ward group of Fiji. Conditions similar to those under which the central
Pacific tertiary limestones were deposited must have been of wide geograph-
ical range ; they appear in the Philippines, the Loyalty, the New Hebrides,
and Solomon Islands, in New Caledonia, in the China Sea, the East Indian
Archipelago, at Christmas Island in the Indian Ocean, the Red Sea, and
the West Indian area.

Dana very justly remarks : " It is important to have in mind that the
coral-reef era probably covered the whole of the Quaternary and perhaps the
Pleiocene Tertiary also, and hence the local elevations that have taken place
in the ocean were not crowded events of a short period." *

The boring at Funafuti will show us the character and age of the rocks
underlying the mass of recent material of which the land rim, not only
of that atoll, but probably also that of the other atolls of the Ellice and
of neighboring groups, is composed ; though of course we can only judge
by analogy the probable character of the underlying base from that of
the nearest islands where it has been ascertained. The bore at Funafuti
reached 1114 feet ; it passed at first through the modern reef rock

^ Dana, J. D., Origin of Coral Reefs and Islands Am/ Jour. Scien., XXX., September, 1885,
p. 173.

XXli INTEODUCTION.

material, and below that must have, judging by analogy, penetrated either
an underlying mass of tertiary limestone similar to that of the raised
tertiary limestones of Tonga, Fiji, Niue, Nauru, and Paanopa, or have
passed through the mass of recent reef rock forming the outer talus of the
atoll of Funafuti. Groups like the Ellice, Gilbert, and Marshall Islands
give us the means of studying the many modes of formation of tlie land
rims in a most satisfactory manner. Nowhere have we been able to follow
as clearly the results of the various agencies at work in shaping the end-
less variations produced in the islands and islets of the land rims of the
different atolls of these groups ; changes due either to slight elevation or
to the incessant handling and rehandling of the older material in place,
or of the fresh material added from the disintegration of the sea or
lagoon faces of the land rim, or of the corals on the outer and inner
slopes. It has been most interesting to trace the ever-changing conditions
which have produced so many variations in the appearance and structure
of the islands, islets, and of the land rims of the different groups.

It is of course most difficult to form an opinion regarding the original
dimensions of an atoll before it spreads laterally after having reached
the surface ; its summit naturally becomes wider as it approaches the sur-
face and its talus may be spread as a thin sheet or disappear entirely in
the deep waters adjoining an atoll.

The Fiji group consists of volcanic islands of elevated coralliferous lime-
stone islands and of islands partly volcanic and partly of limestone. Two
of the volcanic islands are of great size and flanked by wide barrier and
fringing reefs, as well as by belts of older elevated coralliferous limestone
of tertiary age and by stratified beds of the so-called soapstone of Fiji. A
number of the volcanic islands are surrounded by encircling reefs enclos-
ing lagoons of considerable depths.

In the Lau group some of the elevated limestone islands attain a heiglit
of over 1000 feet ; they have a wide reef platform and are more or less hat-
shaped. In others the original limestone mass has disappeared ; nothing
is left, as in Argo for instance, to show its existence except a diminutive
limestone island on the outer belt of the encircling reef.

We find all the intermediate stages between a solid mass of corallifer-

INTRODUCTION. xxiu

ous limestone to one cut into separate columns or wedges surrounding a
central sound or basin, or a basin more or less filled with islands and
islets of limestone to one where the outer limestone masses or the islands
are reduced to a minimum forming either an elevated central area encircled
by a barrier reef or by a belt of low islands.

The volcanic islands surrounded by encircling reefs show a similar
gradation from islands with a flanking belt of fringing or barrier reefs
enclosing a narrow lagoon, to islands with an extensive lagoon enclosed by
a barrier reef belt, or even to an atoll with a volcanic island on the outer
reef flat.

In the Fiji as in the Society Islands, the wider fringing reef flats often
pass gradually into barrier reefs with a narrow lagoon between the outer
edge of the reef platform and the shore line. The rotten condition of
the inner part of a wide fringing reef is most favorable to its removal
by solution or mechanically, and leads to the formation of narrow lagoons,
which may, as is the case in Tahiti, become wide and deep barrier reef
lagoons. The small number of islands and islets of the outer barrier reef
in Fiji atolls contrast strongly with the well-wooded islands and islets on
the encircling belt of the Society Islands.

The disintegration of the masses of corals growing upon a reef is due to
the boring Echini, Mollusks, Annelids, Crustacea, and sponges which infect
the larger masses ; as these become weakened they are torn off by the
waves, and rapidly reduced to shingle. The smaller fragments are then still
further disintegrated by boring sponges and Algoe, and by attrition on the
wide reef platforms both of the sea face and lagoon side reduced first to
coarser, then to fine sand and impalpable silt which may be carried off in
suspension.

In addition to the mechanical destruction constantly going on, chemical
action takes place and sea water carries off in solution large quantities of
lime from the sea face, where we can trace the extent of its action from the
undercut faces of cliffs, of masses of corals, and the rotten condition of
smaller fragments of corals. The same action takes place in the lagoon
even to a greater extent ; in every direction we can trace the effect of solu-
tion on the beach rock beaches, the conglomerate or breccia ledges, the

xxiv INTRODUCTION.

patches of corals, the samples of the bottom, the slopes of the shoals or
ledges within the lagoon, all showing that solution is a prominent factor in
removing carbonate of lime from the interior of a lagoon.

The Ellice, Gilbert, and Marshall Islands represent atolls in which the
movement of the material forming the land rim is the characteristic feature.
With the exception of a few atolls in the Gilberts where the old tertiary
ledge cropped out on the land rim we did not observe the structure of the
foundation upon which the material composing the land rim of the Ellice
or of the Marshall Islands rested. Wliile there is every indication that
the modern reef rock conglomerate or breccia which crops out on the islands
in every direction has been elevated a few feet, yet it has not been suffi-
ciently raised to expose the underlying rocks.

The formation of the extensive Millepore and Porites flats described from
Taritari represents a stage of land growth somewhat more advanced than
we find it on some of the faros of the Maldives where the faces of the
slopes and surface of the flats are covered with thriving corals (generally
Pocillipores and Madrepores). The formation of the flats at the Maldives
I shall shortly have occasion to describe. I need here only call attention
to the existence at the Maldives of an earlier stage in the formation of
such flats as the Millepore and Porites flats of the Gilbert and Marshall
Islands.

The atolls of the Ellice, Gilbert, and Marshall Islands are noted for their
extensive lagoon flats, for the formation of gaps, of bays, and of secondary
lagoons, where they take a greater development than in any other group of
coral reefs in the Pacific. There are only a few small coral islands among
these groups which have no lagoons ; they are more numerous among the
Marshall Islands. The shape of the atolls varies greatly in the Ellice,
Gilbert, and Marshall Islands, and in no groups is the outline less like the
mythical typical circular atoll ; this is especially marked in the Gilbert and
Marshall atolls.

The land rims of these groups are narrow, but nowhere is the land rim
reduced to such an insignificant width as in the Marshall Islands. There are
no important islands in any of the lagoons ; they contain shoals, ledges, and
sand keys, but no well-wooded islands, as in the Paumotus and Fiji, except

mTRODUCTION. xxv

close to the lagoon edge of the land rim where they form secondary lagoons.
Nauru and Paanopa to the west of. the Gilbert Islands are elevated corallif-
erous limestone islands, rising to over 250 feet, similar to the elevated islands
of the Paumotus and Fiji.

We noted in the Marshall Islands the large amount of sand blown into
the lagoons from , the sea face through gaps. Much of this sand is held
in suspension and carried out through the passes on the lee side, while a
part of it forms spits and flats near the gaps and passes of the weather side.
A part of the sand goes to fill the lagoon ; a part is carried off and reduces
the width of the land rim on the sea face.

The Carolines are divided into high volcanic islands surrounded by fring-
ing, barrier, and encircling reefs, low atolls with groups of islands reduced to
narrow encircling reef flats on which a few islands have been thrown up
on the weather face, the underlying foundation of which is not exposed and
atolls where the islands and islets of the surrounding reef flat platform
consist of elevated coralliferous limestone. In Ponapi the barrier reef fiats
are wider than round any other volcanic island in the Pacific.

The southern islands of the Ladrones, the last group of islands we exam-
ined, are partly volcanic and partly composed of elevated coralliferous
limestone, while the northern islands are volcanic and have no coral reefs.
Coral reefs take but a slight development either in Guam or Rota; the reef
flat platforms are narrow, irregularly scattered ; at Guam they take their
greatest development at San Luis d'Apra and along parts of the western
coast. At San Luis d'Apra a deep reef harbor has been eroded from the
elevated coralliferous limestone flat which once jutted out to the north
of Orote Point to Cabras Island. Guam is one of the largest of the
islands composed in part of coralliferous limestone and in part of volcanic
material.

We may approximately classify the atolls, elevated islands, and volcanic
islands where reefs are found into the following; categories:

Large volcanic islands with barrier and fringing reefs, like Tahiti, Viti,
and Vanua Levu, the larger Samoan Islands, New Caledonia, the Solomon,
New Hebrides, and Sandwich Islands ; in these the land mass occupies a
large area as compared with that of the reefs. Viti Levu and Vanua Levu,

xxvi INTRODUCTION.

as well as the Solomon,' New Hebrides, and Oahu in the Sandwich Islands,
are partly flanked by elevated coralliferous limestone.

Next may come smaller volcanic islands with barrier and fringing reefs,
like the Pelew Islands, Yap, Truk, Ponapi, Kusaie ; the smaller New
Hebrides and Fiji Islands, like Nairai, Makongai, Mbengha ; the volcanic
islands of the Cook group, as Aitutaki, Rarotonga ; the Home Islands,
Rotumah, the Marquesas, and such islands as Maupiti, Bora Bora, Raiatea,
Huaheine, Eimeo, in which the area of encircling reefs is as large, if not
larger, than the enclosed volcanic mass.

Volcanoes like Totoya and Thombia in Fiji show the possibility of the
formation of an atoll-like island by the growth of corals on the submerged
or denuded rim of an extinct volcano, enclosing a central basin: the old
crater of the volcano. In Totoya the extension of the volcanic reef rim
forms a barrier reef surrounding the island and enclosing a barrier reef
lagoon, with ship passes leading into it.

Niuafou and Tofua in Tonga are both islands with extinct craters filled
with brackish water. Were the rim cut down to below the level of the sea,
they would become reef flats enclosing a deep lagoon, as is the case with a
part of the rim of Thombia and Totoya.

Elevated coralliferous limestone islands, probably of tertiary age, with lim-
ited areas of narrow reef flat platforms, like Makatea, Nine, Nauru, Paanopa,
Naiau, Wangava, with ill-defined sinks or basins occupying part of the summit.

Elevated coralliferous limestone islands, like Mango, Kambara, Tuvutha,
in which the sink is better defined and where a volcanic outburst has
broken through the rim or central part of the sink or both.

Elevated islands of coralliferous limestone, like Fulanga, Yangasa, Ongea,
where the sea has eaten through the limestone rim towards the inner sink
cutting the rim into islands, and has formed a sound or lagoon dotted
over with limestone outliers forming undercut and weathered islands and
islets. The encircling land rim may disappear or be reduced to a few
heads, as in Argo, Ongea, or Yangasa.

' Dr. Guppy has given an excuUent account of the gcoloi^y of the Solomon Islands. He was the
first to ('all attention to the great importance of the comparatively thin elevated coral reefs of those
islands and to the existence in the Pacific of underlying calcareous rocks probably of tertiary age.
"The Solomon Islands: their Geology . . . by II. B. (lUppy. London, 1887."

INTRODUCTION. xxvii

Elevated coralliferous limestone islands, cut down nearly to the level of
the sea by atmospheric agencies, like Niau in the Paumotus, with a shallow
sink (lagoon) connecting with the sea only through the porous mass of the
land rim, or Rangiroa, and the majority of the islands in the Paumotus
and some of the Gilbert Islands (Apamama, Tapeteuea), with a lagoon
enclosed by a land rim composed of disconnected islands and islets form-
ing passes and gaps communicating with the sea ; islands all noted for the
great development of buttresses of modern reef rock and of tertiary age
on the reef platforms, the remnants of a higher land mass now denuded
to the level of the sea. Similar outliers in the lagoon form shoals, islands,
and islets.

Extensive elevated limestone masses, like those of the Tonga Archi-
pelago with volcanic outbursts of limited e.xtent that have pushed through
the limestone masses.

Atolls with disconnected limestone and volcanic islands, the remnants of
islands partly volcanic and partly limestone, like Guam and Eua, only on
a smaller scale. In these the volcanic outbursts as well as the lime-
stone masses have been denuded and eroded, and formed the groups of
Vanua Mbalavu, Lakemba, Naitamba, Mothe, and the like.

Low atolls, like those of the Ellice, Marshall, and the Gilbert Islands
in part, where the land rim is reduced to a minimum and best developed
on the weather side, and where the material composing it is subject to
constant transport, the material being derived from the corals growing on
the sea slope of the reef flat platforms and from the disintegration of the
slightly elevated modern reef rock conglomerate or breccia. Atolls all
characterized by the great changes taking place in the extent of the
islands of the land rim, owing to the formation of sand bars, shoals, flats,
bays, the closing of gaps, the filling of lagoons by sand blown in from
the sea face, the throwing up of extensive dams on the lagoon flats to form
secondary lagoons, the existence of reef platform lagoons; the islands on the
land rims of these atolls being flanked with coral sand, shingle or boulder
beaches on the sea face, with sand beaches or beach rock flats on the lagoon
faces. The islets, shoals, and islands in the lagoons are either patches of
elevated modern reef rock or knolls of growing corals, many of them with

xxviii INTRODUCTION.

deep passes, usually most numerous on the lee side. The corals growing
on the sea slope of the reef platforms are often overwhelmed by sand dunes
blown over the land rim from the lagoon flats.

Atolls like Tarawa, Tapeteuea, and Nonuti in the Gilbert group, and
Makemo, Fakarava, and others in the Paumotus, with a well-developed
land rim on the weather face flanked on the lee by submerged reef flats.

Finally, such islands and islets as Tikei, Nukutavake, and a number of
small islands with central sinks or depressions formed by the beaches
thrown up on the outer edge of the flat or summit of the island, leaving an
open central space enclosed by the beach dams. Similar islands occur in
the Gilbert group, as Arorai and Tamana ; Mejit, Lib, and Jemo in the
Marshall, and Nurakita and Nanomana in the Ellice groups.

The soundings taken by the "Albatross" in the Marquesas show that
two of those volcanic islands are connected by a plateau with a depth of
800 fathoms (PI. 200, Stations 24-28, p. 380). The soundings in the Pau-
motus (PI. 201, Stations 34-60, 70-120, p. 380) developed the plateau from
which the northwestern islands of the group rise,' a plateau with a depth
of about 800 fathoms. The soundings among the central and eastern
Paumotus developed smaller plateaus or spurs uniting adjoining atolls, and
also showed that the eastern atolls and islands are separated by channels
of great depths (PI. 201, Stations 122-172, p. 385).

The Society Islands are also separated by deep cliannels (PI. 202, Sta-
tions 65-75, p. 382), and deep soundings separate the Cook Archipelago
from Nine and Tonga (PI. 211, Stations 181-187, p. 388).

In Tonga the general depth of the three component plateaus is about
fifty fathoms ; the plateaus themselves are separated by channels with not
more than 250 fathoms (Pis. 213, 214) ; the land masses of Tongatabu,
Haapai, and Vavau slope gradually into the general level of their respec-
tive plateaus, and the scattered islands of Nomuka rise very gradually from
the main plateau at a depth of twenty-five to thirty fathoms.

Somewhat shallower water exists between Tonga and Fiji (PI. 213,
Station 188, p. 388) than between Niue and Tonga. The soundings in the
channel between Yangas^, Mothe, and beyond indicate the shallower

1 See p. 25, Figs. 1-12.

INTRODUCTION. xxix

depths (324 fathoms) of the southern extension of the eastern plateau of
Fiji, upon which are situated the Lau group of atolls and islands (PI. 220,
Stations 189-193, p. 389).

The Admiralty Charts of Fiji and north of that group contain numerous
soundings (PI. 221). As far as practicable we intercalated our soundings
with those already published ; we sounded usually within a half or a third
of a mile off the different islands and atolls, as well as in the centre of the
channels separating them. We showed that in the Ellice group, as had
already been indicated by the " Penguin," the atolls are separated by deep
channels (PI. 221, Stations 194, 195, p. 389). We found the same to be the
case in the Gilbert Islands (PI. 223, Stations 196-207, p. 389), though some
of the atolls (Apaiang, Tarawa, and Maiana) are, as in the Paumotus, united
by a comparatively shallow plateau. Over 2500 fathoms separates the
Gilbert from the Marshall Island.s (Stations 208-212, p. 390) ; the atolls of
the Marshall Islands are, like those of the Ellice and Gilbert groups, sepa-
rated by deep channels, a few of the atolls (Namu and Odia) being united
by shallower plateaus (PI. 225, Stations 213-238, p. 390).

The islands and atolls of the Carolines are separated by deep water
(PI. 232, Stations 239-244, p. 391), and between the Carolines and Guam
the United States Steamer " Nero " obtained, about one hundred miles
southeast of Guam, the greatest oceanic depth as yet recorded (5269
fathoms). Nothing is known of the submarine slope of the Carolines with
the exception of the soundings taken by the " Albatross " a short distance
off Port Lottin and Nama (Stations 239, 242) ; the depths correspond to
those off similar islands in the Society and Gilbert Islands. The sound-
ings of the " Challenger" and of the "Nero" indicate great depths between
the volcanic islands of the line extending from Guam to Japan (Pis. 1, 234).

We took a number of soundings off the atolls of the Paumotus, Gilbert,
and Marshall Islands at a distance varying from one mile to a quarter of a
mile. These soundings, like those off the Paumotus, varied from 225 to
over 400 fathoms, and only showed that at those distances from the shore
we had already reached the oceanic slopes of the atolls. They all indicate,
within those limits, steep slopes in the upper part of the reefs (see the List
of Soundings for these groups, p. 379).

XXX INTRODUCTION.

There are as yet comparatively few soundings off the sea faces of atolls
and reefs to give lis more than very general ideas regarding the slope of
the upper parts of a coral reef. A number of soundings are known taken
a distance of half a mile or a mile from the edge of the reef, but within
that distance comparatively few data exist. We must except the soundings
of the " Challenger " on the outer slope of the barrier reef off Papiete
and the soundings off Funafuti by the " Penguin;" they are more numer-
ous than those taken off any other atoll and show great diversity in the
slope on the different faces of the atoll.

All the soundings known indicate that coral reefs rise independently
upon sunnnits formed by tertiary limestones or volcanic rocks, summits
which have been formed either by elevation or submarine denudation
or upon summits of accretion forming submarine banks.

The nature of the underlying base is naturally an important factor in'
determining the pitch of the sea slope ; we may assume that the steep
slopes of the upper part of reefs is due to the sloughing off of the lime-
stone cliffs down to thirty or forty fathoms, much as they are sloughed oft'
from the faces of elevated islands above higli-water mark. If composed
of volcanic ash or harder volcanic material the slope in one case will be
very slight, spreading rapidly laterally under the influence of the waves ;
in the other the slope of volcanic material will not differ materially
under water from that above high-water mark. When the slope is a talus
of reef material it may lie at a steep angle or may follow closely the
slope of the underlying base below the depth at which corals or Nulli-
pores grow.

In the Atlantic the slopes off the Florida barrier reef have been carefully
sounded ; they are not steep, but pass very gradually into deep water. The
same is true of the slopes off the Bahamas sounded bj' the " Albatross "
under Captain Tanner, and of those off the Bermudas as determined by the
"Challenger." These all are in marked contrast to the steep sea faces off
the Great Barrier Reef of Australia, off Tahiti, and Fiji. The slope of
Masamarhu Island^ in the Red Sea has been carefully surveyed; it is quite
abrupt to a depth of about eighty fathoms. Two excellent sections have

' "Nature," 18S7, p. 413.

INTRODUCTrOJ^". xxxi

been published of Macclesfield Bank,' the one showing a steep fall to a
depth of about 100 fatlioms, preceded by a very gradual slope to the fifty
fathom line and a more gradual slope from the 100 to the 700 fathom line.
The other, nearly at right angles, shows a longer upper slope to the fifty
fathom line and a less steep slope to 400 fathoms than the corresponding
depths of the first section.

The legend of the chart (PI. 234) which has been prepared to illustrate
the distribution of the coral reefs in the Pacific requii'es some additional
explanation.

Many of the volcanic islands represented as without belts of elevated
limestones have unimportant patches of fringing reefs ; these have not
been noted, having no important bearing on the question of the theory
of the coral reefs. They are such islands as the Bonin Islands and other
volcanic islands north of the Ladrones extending toward Japan, and some of
the Sandwich and Marquesas Islands.

Volcanic islands, like those of the Society, Cook, Fiji, or Caroline Islands,
which are colored blue with a yellow ring, indicate the presence of barrier
and of fringing reefs. Islands partly volcanic and partly elevated limestone,
as in the Lau group of Fiji, or in Tonga, are also surrounded by fringing
and barrier reefs, or reef flat platforms. Elevated coralliferous limestone
islands are similarly surrounded in part by fringing reefs or by reef flat
platforms and barrier reefs. This is the case in elevated islands with sinks,
or in elevated islands which have been eroded to the level of the sea, the
land rim of which surrounds a sound; the underlying base of barrier. and
fringing reefs of the elevated islands being tertiary limestones.

Islands and groups colored yellow indicate low atolls elevated perhaps
a few feet, but of which the land rim consists of modern reef rock or con-
glomerate or breccia, the underlying base of which is not known.

The Great Barrier Reef of Australia and its extension along the coast
of New Guinea' to the Louisiade Archipelago, as well as the barrier reef of
New Caledonia, is colored to indicate that these barrier reefs are probably
underlaid by the submarine extension of the rocks of the adjacent shores.

1 Cliina Sea. Report on the Results of Uredgings obtained on the Macclesfield Bank; Admiralty,
1894, 3 Charts.

xxxii INTRODUCTION.

The track of the "Albatross" on PI. 234 will indicate those islands which
are colored from our observations, or from other reliable information, as
well as those which have been colored by analogy.

A very convenient " Index to the Islands of the Pacific Ocean " with
tlieir synonymy has been published by Dr. William T. Brigham in No. 2,
Vol. I., of the Memoirs of the B. P. Bishop Museum (1900). It will be
noticed that the spelling of many of the atolls and islands often differs
in the text, in the charts, and in the "Sailing Directions." This has been
unavoidable, as the English, American, French, and German charts have
not adopted the same nomenclature as that of the English " Sailing Direc-
tions." This I have generally followed. Even the nomenclature of succes-
sive editions of the same charts often varies.

An exploration like that made by the "Albatross" through the tropical
Pacific suggests a number of interesting problems, such as the comparative
study of the fauna and flora of oceanic islands, the geological examination of
the volcanic, continental, or oceanic islands scattered throughout the Pacific ;
to say nothing of the study of the human races inhabiting them. Such
studies become each year more difficult from the inroads of civilization,
which affect the inhabitants as well as the fauna and flora.

It was our intention to investigate the marine fauna of each of the
great oceanic groups of islands and trace the passage of the littoral into the
abyssal fauna, and to obtain the material needed for a comparison of iso-
lated oceanic faunae to one another. Unfortunately we were not able to
carry out this part of our programme.

After the publication of the results of my expedition to the Maldives
during the winter of 1901 to 1902, I hope to present in a connected form
a resume of the observations recorded during the fifteen seasons I have
devoted to the study of coral reefs.

In spite of all that has been accomplished during the last twenty-five
years towards settling the debatable points of the theory of coral reefs,
much remains to be done. Most important is an extensive system of boring
at well-selected points, to include barrier and fringing reefs and atolls in
volcanic or other districts, as well as elevated coralliferous limestone islands
or islands partly limestone and partly volcanic. Tiie boring should be sup-

INTEODUCTION. xxxiii

plemented by lines of soundings and dredgings taken from low-water mark
to the depths at which oceanic slopes are met.

The data thus obtained would give us the pitch of the slope of the strata
underlying a barrier and a fringing reef, and of its continuation beyond
the outer edge of the barrier reef. For an atoll tlie bore would indicate
the width of the talus, the original dimensions of the summits upon which
the recent reef rock material was deposited, and the extent of lateral
growth, both seaward and lagoonward. This would give a degree of pre-
cision now wanting in the observations I have recorded.

ALEXANDER AGASSIZ.
Newport, Rhode Island, October 20, 1902.

THE MARQUESAS.

Plates 2, 3, 200, and Fig. 1.

On the 14th of September we obtained our first view of the Mar-
quesas Islands, Hatutu, distant about ten miles. This island is quite
barren, and seen from the north presents no such strilving shores as
those of Nukuhiva.

The appearance of the coast line of Nukuhiva and of its slopes clearly
indicates the immense amount of erosion to which the Marquesas Islands
have been subjected. Steaming along the southern coast from oflf Chicka-
koff Point past Tai oa Bay to Tai o-hae, one follows a huge, lofty, nearly
vertical wall (PI. 2, fig. 1), broken into by the deep valleys facing
the bays and harbors of that part of the island.' To the rear of these
rises, to a height of over 3000 feet, the ridge which forms the backbone
of Nukuhiva and separates the valleys fronting on the north from those
facing the south and east.

On the northeast shore a number of needle-like peaks have been
left at Adam and Eve Point, and peculiarly shaped rocks stand out
prominently at the enti'ance of Comptroller Bay and to the north of
Cape Martin. The southwest point is also marked by a prominent
line of cliffs projecting beyond the general outline of the promontory.
The western outline of Nukuhiva is quite unbroken, its face formed
by a rather gentle uniform barren slope, stretching from the highest
central suunuit to the shore. On the southwest point of Ua ])u occur
sharp pinnacles and cones of disintegration similar to those of the
north shore of Nukuhiva.

' The finest examples of erosion in Nukuhiva are found on the face of the cliffs forming the
ridge on the west side of Tai oa Bay (PI. i. fig. 1).

1

2 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Looking into the narrow entrance of the deep Tai oa Bay, we can
trace the bedded hnes of hiva. following the general slope of the island,
and running across the numerous ridges, spurs, and diminutive peaks
which cover the steep slopes of the western side of the bay (PI. 2,
fig. 1).^ The volcanic strata, as cut by the valley, are seen to dip at
an angle of about 20"^ towards the sea, and the steep western .slope is
gouged by deep channels forming .secondary ridges or rather lamellae,
regular knife edges, along the whole western face of the valley. The
crests of the ridges and their faces are cut into endless peaks and
cones extending far up the continuation of the valley of Tai oa Bay.

The high wall of stratified volcanic ash which extends between
Tai oa Bay and Tai-o-hae Bay is full of deep holes and caverns and pits
(PI. 2, fig. 2), and through it is cut Tai-o-hae Bay, where we anchored
during our stay at the Marquesas. The harbor is surronn<led by the
sharp ridge running in a southerly direction from a peak rising to over
2100 feet to the north of the valley, forming a huge amphitheatre at
the back of the bay. The slopes of the ridge are bare, but the valleys
leading to the peaks are more or less well wooded. The entrance of
Tai-o-ha^ Bay is flanked on each side by two rocks called the Sentinels ;
they are remnants of the points which once extended farther out to sea
on both sides of the entrance to that harbor.

The general account of Nukuhiva may serve for the other islands of
the group. They show the .same prominent features, — a central ridge with
spurs extending towards the coast separating deep valleys ; their shores
either cut into deep bays or amphitheatres, or edged by high, steep vol-
canic cliffs formed by the disintegration of points once extending into
the sea, or by uniform lava slopes reaching from the central backbone.
The islands have their steepest faces on the eastern exposures attacked
by the southeast trades and the prevailing easterly winds which blow
from October to April.

The Marquesas Archipelago^ consists of three fairly well defined
clusters, trendino- in a y-eneral direction from southeast to northwest

1 A similar difT is fi<;iire(l on A Chart 1640 to the rear of Resolution Bay on Tauata Island, one
of the southern cluster of the group. ^ A. Chart 1640.

THE MARQUESAS. 3

(PI. 200). The northern ckister consists of tliree small islands, two of
which are volcanic, and the others (Coral Inlands') are reported to be
two small coral islands on a shoal. According to the statement of the
natives, this is the only point in the Marquesas where corals grow in
abundance, as elsewhere in the Marquesas corals are limited to a narrow
fringe or patches of fringing reefs on the shores of tlie bays which
indent the islands of the group. In'from two to three fathoms in Ta'i-o-hae
Bay coral patches form an irregular fringing reef, composed of a few
species of coral. They have but little influence on the character of the
beach sand thrown up at the head of the bay, the greater part of which
is volcanic silt washed down from tlie liillside mixed with a little coral
sand.

The central group, which we visited, consists of the Islands of Nuku-
hiva, Ua Huka, and Ua pu. These as well as all the other islands of
the group, with the exception of the Coral Islands, are volcanic and rise
to a considerable height, the highest point of Nukuhiva being over 3800
feet, of Ua pu over 4000, and of Iliva Oa, the largest island of the
southern cluster, more than 3000.

Nukuhiva is about 14 miles in length and about 10 broad ; while
its shores are very steep on the northeastern and southern flices, with
numerous waterfalls dropping nearly vertically into the sea from 2000
feet, the western .slope is couiparatively gentle. The slope off the south
coast of Nukuhiva is steep ; within less than a mile there are depths of
from 45 to 60 fathoms over a fine volcanic sand bottom.

What is very striking at the Marquesas is the absence of coral reefs.
Here is a group of volcanic islands situated in latitude 9' south, and
in the region of the southeast trades, under the most favorable conditions
of temperature of the sea (80 ), yet there are nowhere in the group the
great barrier and fringing reefs so common in tlie Society Islands, the Fiji,
and other volcanic island groups in the Pacific. Coral reefs exist in the
Marquesas only as patches scattered here and there in protected bays.
They are indicated on the Admiralty charts at Vaeio Bay, at Hakalie

* We did not visit tlie Coral Islands, as, according to the sailing directions, they are exposed
to heavy seas, making landing dithcult.

4 "ALBATEOSS" TUOriCAL PACIFIC EXPEDITION.

tan, in Ua pn Island, also at Hanaiaj^a, Hiva Oa Island, at Anaho Bay
on the north side of Nnkuhiva, and in Comptroller Bay on the south
coast, besides at several points in Tai-o-hae Bay.

I can only attribute the absence of coral reefs in the group to the
fact that there have been no great platforms of erosion formed at the
base of the slopes of these islands. It is difficult to imagine why such
platforms do not exist here, for tlie angle of the slopes and their char-
acter are not different from that of other volcanic groups where both
fringing and barrier coral reefs occur. Owing to the greater depths
near the coast line, corals find a depth suitable for their growth only
in the closest proximity to land ; there is no opportunity for lateral
expansion, as in volcanic islands which are flanked by a wide platform
of erosion, on which the soundings are comparatively shallow or far
within the depth at which corals can grow. The absence of this plat-
form of erosion does not mean that these volcanic islands are not
eroded fully iis fast as similar islands in Fiji and in the Society group
in about the same latitude, and under similar conditions of exposure
to the tradewinds. A glance at the charts' will show how extensive
this erosion has been. The steep bluffs or the sloping faces, which
in one case flank the inner side of the reef platform, in the case of
the Marquesas simply flank the edge of the shore, but if they slough
off, they become disintegrated and worn into volcanic sand or small
masses on which coi'als can find no footing, as is also the case in the
Galapagos. This seems to me to be the probable explanation of the
absence of corals in the Marquesas ; it is confirmed by what exists in
the Galapagos^ and in the island of Mehetia to the southeast of Tahiti,
where the absence of a shore platform is most striking, the more so as
Mehetia is in a region where corals are wonderfully developed upon the
shore platforms of other volcanic islands in the Society Islands.

Round the base of the extinct crater of Mehetia there are neither
barrier nor frino-ino: reefs. Corals are limited to a small area at the

1 A. Chart 1640.

^ In the Galapagos district the absence of corals is partly due to other causes. Bull. M. C. Z.,
XXIII., No. 1, p. 69.

"Albatross'Tropical Pacific Ex

SKCTION ACROSS } MARQUESAS PLATEAU

To 2700

lif) rfay
deepCRi port of
liasiu ftantforoo

Sea Level

A) CM

Dpefff'sf pnri of ,\fos^r Bnsiri 30HH

(iencnil Lcvfl af /ifi.sh'fn pnrf of Mo.ter fiaain-.

SOUNDINGS IN FATHOMS.

THE MAEQUESAS. 5

southeast and northwest spits, where the promontories of the islands
extend seaward as shallow points, on which corals have established
themselves. It is also possible tliat the successive flows of lava from
Mehetia and the extinct craters of the Marquesas may have destroyed
the corals or prevented their obtaining a foothold. Corals occur only
in patches in the Galapagos Islands, in a still active volcanic district,
where their development should be most favored, judging from the
oceanic conditions existing there, and where tliere is no trace of any
subsidence having occurred.

Dana and Darwin have supposed that the absence of corals on these
islands was duo to their having gradually subsided, yet subsided so fast
that corals were not able to find a footing on their steep slopes.
Daua^ also attributes the absence of corals in tlie Marquesas to the
depth of water about the islands in addition to subsidence ; he says in
substance, if before the subsidence there was some extent of shallow
water round an island, it might have had very bold shores after it had
half sunk beneath the waves. The Marquesas may therefore have had
barrier reefs which were sunk from too i-apid subsidence ; others again
failed to form on account of deep water near the shore. There are, as
I have stated, no indications that either the Marquesas or Mehetia has
been subjected to the effect of subsidence, as Dana assumes.

The soundings which we took (PI. 200, stations 24, 25, 26, 27, 28)
indicate that there is a ridge gradually rising from a depth of about
2100 to a depth of about 800 fathoms, which connects Ua Huka and
Nukuhiva (Fig. 1), but existing soundings do not indicate what con-
nection (if any exists) there may be between the other islands of the
group.

It is not vmcommon to find volcanic islands with in.sig-nificant frinsj-insj
reefs, or with only patches of fringing reefs, in regions where other vol-
canic islands have well-developed barrier and fringing reefs due to the
existence of more or less wide platforms of submarine erosion. I
might mention the Home Islands (A. Chart 987), not more than 90
miles distant from the Fiji group ; both volcanic groups, the former

' Dana, Corals and Coral Islands, 3d edition, 1890, pp. 340, 361.

6

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

with very narrow fringing reefs, the latter with wide fringing or barrier
reefs.

The east coast of Madagascar has only patches of coral reefs, while
the northwest face is studded with them (A. Chart 758). Of the Comoro
Islands, Mayotta alone is protected by a barrier reef (A. Charts 2762
and 2741). Bourbon has only coral patches (A. Chart 1497), while
both Mauritius (A. Chart 711) and Rodriguez (A. Chart 715) have barrier
and fringing reefs, in the latter they are strikingly similar to the wide
reef flats of Ponapi. Similarly the Amirante Islands all have barrier
or fringing reefs, while in the Seychelles the principal islands — Mahe,
Silhouette, and others — have only comparatively imimportant fringing
reefs (A. Chart 721). I would also refer to similar conditions due to the
absence of these platforms on several of the volcanic islands of the West
Indian Windward group.' Martinique^ is specially interesting, having a
well-marked platform round the southern extremity, while the slopes
of Pelee, forming the northern part of the island, pass into a steep sub-
marine slope.

■ Grenada, H. O. Chart 1316. Grenadines, H. O. Chart 357. Dominica, H. O. Chart 1318.
St. Vincent, 11. O. Chart 1279. Guadeloupe, II. O. Chart 363. See also A. Agassiz, Bull. M. C. Z.,
Vol. XXVI., No. 1, 1894, p. 145. 2 H. O. Chart 1009.

^•'ative Ult, J Al-(i-ii.it iJAV, .MAi;guESAS.

THE PAUMOTUS. 7

THE PAUMOTUS.

Plates 4-.'i3, 201-207.

The Paumotus form a broad belt of atolls extending for nearly a thousand
miles from the southeast to the northwest. Quiros, a Spanish navigator,
first gave notice of their existence in 1606. A number of islands of the
group were subsequently discovered by French and English explorers, but
it was not until the beginning of the last century that we have any very exact
information regarding the Paumotus. The most important notices are those
of Beechey, Fitzroy, and Wilkes, and the later surveys of the French, under
whose protectorate nearly all the islands of the group are placed. It may
be interesting to repeat here the more important observations of Beechej'
and of Wilkes on the Paumotus.

Captain Beechey,' in the " Blossom," made in 1826 a most accurate sur-
vey of the Gambler group, to which but little has been added by subsequent
explorers.' The Gambler Islands (PI. 207) are interesting from a historical
point of view, as they are stated by Darwin to have been the group which
gave him the first hint for the theory of subsidence as explanatory of the
formation of atolls and barrier reefs.

Beechey's remarks on coral i.slands and coral reefs are most instructive,
and his views are far more accurate than those of many of his successors. It
is interesting to read some of his remarks on the Gambler group. Beechey
mentions the following shrubs and trees as found in the Paumotus: Sac-
charum, Achyranthu.s, Capparidia, Eugenia, Scsevola, Tournefortia, Convol-
vulus, Pemphis, Thespesia, Poron, and Lipidium.

Beechey visited no less than twenty-nine coral islands, most of which he
discovered. He noticed that the so-called central sink may be due merely to
the piling up of the sand beaches on the sea faces above the central part of

' Foster's observations on the formation of coral reefs are interesting historically, but have not the
value of Beechey"a later surveys, .John Ueinold Foster, (Jbservations made during a Voyar^e round the
World, London, 177,S.

■^ See Chart of the Gambler Group, p 133, Vol. I., Narrative of a Voyage to the Pacific and
Bering's Strait in H. M. Ship "Blossom," London, 1831, and compare it with A. Chart 1112 (PI. 207),
published in 1885.

8 "ALBATROSS" TROPICAL rACIFIC KXl'EDITIOX.

a flat island. He suggested that the lagoons of some atolls had probably
been filled by the blowing in of sand over the smnniit of the encircling
beaches, and he noticed the mode of formation of islets and islands on
the land rim of many of the atolls he visited. Beechey suggests that
openings in the reef are due to their being opposite some stream of
fresh water. He quaintly says: "The aversion of the Lithophytes to
fresh water is not singular, as, independent of its not being the natural
element of these animals, it probably supplies no materials with wliich
they can work."

He was the first to describe the outer reef platform of an atoll as well
as the lagoon platform, and he sounded a number of lagoons. He observed,
as is seen from his description of Hao, the mode of formation of sinks par-
allel to the lagoon shore. He notes that some of the surveys of Cook do
not differ from his, and that where he has instituted careful comparison he
cannot see that any change has taken place in the coral reefs since the
days of Cook, for more than sixty years. He further says that when any
differences exist they are changes readily accounted for, and generally due
to the superficial action of the wind and sea. Beechey speaks of the small
number of islands he examined where no lagoon exists. Of the twenty-
nine he visited only Aki-Aki, Nukutavake and Henderson had no lagoon.

Henderson Island is, according to Captain Beechey, who examined it in
1826, a mass of coralliferous limestone rising about 80 feet above the level
of the sea. He speaks of it as "compact, having the fracture of sec-
ondary limestone.'' It must be in its structure very similar to Nine (PI.
212), which we visited ; only the elevation of Nine is somewhat greater, and
it is a larger island. Henderson Island is about five miles long, and two and
a half miles wide in its greatest width. It is rectangular towards the north,
and triangular towards the south.^ Judging froui the chart, there must be
a well-defined terrace at the heiu-ht of 50 feet above hioh-wator mark,
leadino; to a second terrace at a heischt of 80 feet, which forms tiie sum-
mit, the flat surface extending over the greater part of the island.

Beechey observed that in the Paumotus the passages into the lagoons
were generally on the lee side of the atolls, and that the direction of the

1 See A. Chart 117C.

THE PAUMOTUS. 9

trades had a great influence in shaping the land rim of one face, while the
other was only a half-drowned reef flat, often wholly under water. He
sounded lagoons from 20 to 38 fathoms, and from such information as
he gathered inferred that there had been, according to the statements of
the natives, very little change in the depth of the passages. He noticed
the effect of the wide outer-reef platform in regulating the flow of the
sea into the lagoons over submerged parts of the rim and between
the gaps of low islands forming the land rim. He observed that the
height of the water in the Ingoons was subject to the strength of the
trades, which influenced greatly the strength of the currents and their
direction through the passages. While examining Bow Island (Hao), he
observed the nature of the bottom of the lagoon and the growth of the
coral knolls scattered throus;hout its area.

Beechev's ideas on the structure of coral reefs are interestintr, and are
well illustrated by a diagram and sketch of Pinaki (Whitsunday),' which is
accompanied by an excellent description of the island. That diagram and
sketch have been very generally copied in all books on geography, so that
Whitsunday has unfortunately obtained a wide recognition as a typical atoll.

There are scattered throughout Wilkes' "Narrative of the United States
'Exploring Expedition" many accurate observations and shrewd remarks on
the formation of coral reefs. I may especially refer to Wilkes' disappoint-
ment on landing on a coral island.^ His account of its barrenness is in
marked contrast to the poetic descriptions which have been handed down
by so many writers on coral reefs.

Wilkes^ gives also a sketch of Clermont-tonnerre, and the results of
soundings made off the east side of the atoll. At 300 feet from the edge of
the reef he obtained UO fatlioms ; at ISO feet 85 fathoms ; at 130 feet 7
fathoms. At three quarters of a mile from the southern point the ''Peacock "
sounded in 3-30 fathoms. He gives a short list of the principal trees and
shrubs, and speaks of the number of birds on the islands as incredible.
The lagoon of Raraka was sounded ; * 30 fathoms was found inside a short
distance from the entrance, where the water is from five to eight fathoms.

' Bfcchev, loc. cil., pp. 188 193. » Xop. cit, p. 311 of Vol. I.

- Loc. cit., p. 317, Vol. I. of the Narrative. * Loc. cit., p. 331.

10 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The lagoon of Ahe^ is said to be quite shallow and much obstructed by
growing corals.

A cut'' is given of what must probably be elevated old limestone rocks.
Unfortunately no locality is named ; it may be (Kauehi) Vincennes Island.

There is a good cut of Metia^ (Makatea) reproduced in Dana's " Geology
of the Exploring Expedition " and in his " Coral Islands." The ascent of
the bluff on the western face of Metia * is described : on reaching an open
space on the top a clear view of the interior was obtained. The general
shape, as far as it could be seen, was pan-like, or in tlie form of a dry lagoon.
He also says: '"The island '^ has unequivocal marks of having been uplifted
at ditt'erent periods; the cliff at two different heights appears to have
suffered abrasion by the sea." He gives a figure " of a part of the great sea
wall on the southern face of Rangiroa, with islands to the rear, taken from
a drawing made by Mr. Agate while the " Peacock " ran along the south
shore.

Lieutenant Johnson^ was left on Aratika to make some borings; the
greatest depth reached was 21 feet, the principal difficulties encountered
being " the looseness of the sand and the falling in of the coral stones." *

Wilkes also gives ^ an account of the method used by the Expedition in
surveying the coral islands. The basis of the method rested upon the
measure of distances by sound. Guns being fired alternately from tlie differ-
ent vessels, any three of them being stationary, the distances and positions of
objects could be determined from them by direct angles, or by angles be-
tween them taken from the shore, or from boats. On page 431 a woodcut
is given showing the method of surveying one of the islands. The survey
of an island '" about seven miles in length was made in three hours and
thirty-five minutes.

1 Loc. cil., p. 337. 3 Loc. clt., p. 338. ^ Loc. cit.. p. 341.

•■= Loc. cil., p. 334. * Loc. clt., p. 340. ^ Loc. cil.'. p. 342.

' Loc. cit., p. 2fi7, Vol. IV.

8 At Bow Islanfl Captain Belcher bored to a depth of 45 feet ; near Blossom aneliorai;c he passed
through a fine coralline sand. A second attempt made on the outer belt of the island faileil, as the
borer got jammed at a depth of 9 feet. Narrative of a Voyage round the World in the "Sulphur," by
Captain Sir Edward Belcher, R. N., 2 vols., 1843. Vol. I. p. 3fiC.

9 Loc. cit., p. 429, Vol. I.

1° Probably Puka-ruha. H. O. Chart 78. The woodcut differs greatly in details from the island .as
represented in the Hydrographic Chart, which is a bad copy of the original.

THE PAUMOTUS. 11

Wilkes looked upon the coral islands of the Paumotiis as showing un-
equivocal signs that they are undergoing dissolution.^ He based this opinion
on the position and size of some of the coral blocks on the top of the reefs,
which he considers — and justly, to my mind — as having formed an upper
shelf of which they are the sole remains. He was greatly struck with the
varying heights of the islands and coral reefs of the Paumotus.

I will refer to the more detailed observations of Dana in the descrip-
tion of the various islands of the Paumotus.

Next to the Maldives the Paumotu Archipelago contains the greatest
number of known atolls; then come the Marshall and the Fiji Islands.
The Paumotus extend for over 1000 miles in a southeast to northwest
direction from Manga Reva to Matahiva, and the greatest width of the
belt of islands from Anaa to Fakaina is over 300 miles in an easterly direc-
tion (Pis. 201, 202). There are in addition a number of detached islands
on the eastern flank, of the group which present no feature differing from
those of the atolls we visited. The charts of this group are somewhat inac-
curate, and, while most useful as sketches, cannot be used as are the admir-
able charts of the Fijis, of the great barrier reef of Australia, of the New
Hebrides, Solomon, and Tonga groups, or those of the Society, Cook Islands,
or Maldives, to determine the points of interest for a first examination of
the islands. To obviate this difficulty we steamed around each atoll so as to
obtain a general view of it, and when we entered the lagoon we limited our
examination to the interesting points we had noticed on skirting the land
rim close to the outer reef

The general sketch charts published by the French Hydrographic
Office are far more accurate than those which have been issued either by
the British or the American Hydrographic Office. It is true that we have a
large number of sketches of various atolls of the Paumotus made by Wilkes
in the early forties, as well as surveys by Beechey and Fitzroy and a few
sketches by Kotzebue, Bellingshausen, and Duperrey in the beginning of the
last century, but they do not compare in accuracy with later or more recent
surveys. The islands which have been sketched by Wilkes are Ahe,^

1 Loc. cit., p. 2e<>, Vol. IV.

^ I have adopted the spelling of the French Charts of the Paumotus. Depot des cartes et plans de
la marine, 985.

12 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Takaroa and Takapoto, Kauehi, Raraka, Puka-ruha, Taiaro, Marokau,
Ravahere, Napuka, Reao (commonly known as Clermont-tonnerre), Aratika,
Manihi, Takume, the Sea Gull Islands (Tuanake, Hiti, and Tepoto), Tauere,
Makatea. Hereheretue, Nukutipipi, Anu-Anuraro, and Anu-Anurimga.

Although I did not visit Fakaina, I have given a sketch plan of the
island (PI. 204), as there are, outside of Wilkes' sketches, so few of the
Paumotus properly surveyed that we have to depend almost wholly upon
the general chart of the group for illustrations of the shape and charac-
teristics of most of the atolls. Fakaina, Hao, and Mururoa are the only
islands of the principal mass of the Paumotus of which sketches are
given in some detail.

The islands of Manga Reva (PL 207) were surveyed by Captain Beechey
and d'Urville, Hao Island by Captain Cook, Bougainville, and Beechey,
while the French have surveyed, since 1874, the southern extremity of
the island of Apataki, tlie entrance of some of the harbors, as that of
Amyot on Toau Island, and Avatoru and Tiputa entrances on the island
of Rangiroa. The entrance to Takaroa, to Ahe, and. to Manihi, a part of
the atoll of Fakarava was surveyed in 1880 by the French, from the
northern pass to Rotoava and to the east a distance of about three
miles. The northern pass of Makemo was also surveyed by the French.
The officers of the " Albatross " made a running sketch of the western
shore of Fakarava (PI. 204, fig. 1) as we steamed along its western edge,
and also determined the position of Rotoava and the land to the eastward,
as, well as that of the western extremity of Rangiroa. They also determined
the position of the southwestern end of Tikahau, and corrected the position
of Matahiva as well as its outline. We also took a line of soundings from
Rotoava directly south, and then across towards the southwestern shore of
the atoll to a cluster of numerous islands situated near the central part of
the atoll. • A line of soundings was also run across Makemo from our
anchorage to the southern shore.

We came upon the Paumotus from the northeast, striking the west
coast of the island of Ahe at a distance of about ten miles. We did not
examine either Ahe or Manihi, as, from their descriptions by Dana and
the sketches given by him and by Wilkes, it was evident that they

THE PAUMOTUS. 13

would not differ from other islands of the Pauraotus which we intended
to examine. On the south face of Ahe the islands of the low land rim
are separated by a series of gaps and of cuts such as we foimd chai'ac-
teristic of Rangiroa ; the entrance into Alie differs in no way from those
of a number of other islands of the Paumotus. The entrance to the lagoon
of Manihi, although somewhat narrower than any we entered, is yet very
similar to the entrances into Hao. Ptangiroa, Tikahau, and other islands
of the group. The sketches of Tikahau and of Rangiroa, as given by
Wilkes, are somewhat incorrect; they give the idea that the land rim is
continuous, while in reality it is composed of islands and islets separated
by long stretches of reef, bare at low water. The gaps between them
allow an immense amount of water to enter the lagoon from either face
of the atoll. The description which has been given of many of the
Paumotu atolls would give one the impression that they are clo.sed and
have only a single well-marked passage. On the contrary, with the excep-
tion of a few atolls to which we shall return later, the water flows into
the lagoon fi'om either side of the atolls through numerous cuts.

It was only after an examination of the old ledges exposed in the
gaps of the northern land rim of Rangiroa, and especiall}' in the ele-
vated wall of coralliferous limestone of the weather coast, that we
obtained a satisfactory explanation of the formation of the atolls of
the Paumotus, — an explanation further confirmed after we had visited
the elevated islands of Niau, Makatea, and the other low Paumotu
Islands. It is to the cutting down of the elevations of the old ledge to a
general level, and the subsequent building up of the atolls by the material
supplied from the reef flats and from the coral slopes, that is due the
great uniformity of all these atolls.

Certainly sub.sidence could not have acted in such a uniform way, and
have lowered the level of these numerous atolls, once rai.sed to very
different heights, to the same point. We can, of course, imagine subsi-
dence to have lowered many of them, but not all, to the same level.
The cutting down by erosion and denudation and the planing action
of the sea are all factors which we still see going on at all points
of the Paumotus, and which readily explain the phenomena as we

14 "ALBATROSS" TROTICAL PACIFIC EXPEDITION.

meet them, not only in the Paumotus, but also as they are modified
by the local conditions existing in the Marquesas, in the Society Islands,
the Tonga group, and the many regions where atolls and coral reefs
flourish. In not one of these can it be said that the explanation adapted
for the structure of any one group can be applied to that of another
without some modification, and often witli very great changes. Nor can
we say that a universal law such as that of subsidence can explain the
conditions now existing in the formation of atolls and of barrier reefs
in the coralliferous regions of the Atlantic and of the Pacific. We must
seek in the many mechanical causes due to the trades, to the geological
composition of the islands, to the general geodetic and orogenic condi-
tions, to chemical action and to minute local conditions, the varied and
numerous factors at work in building up an atoll or a barrier reef.

After striking Ahe we made for Rangiroa, the largest atoll of the Pau-
motus. As Rangiroa was the first typical atoll we visited characteristic of a
supposed area of depression, it was of course with great interest that we
examined the conditions of the land rim and became acqiiainted with a tvpe
of formation so common in the Paumotus, the Ellice, the Gilbert, and the
Marshall Islands as to become monotonous at the end of a few months' sail-
ing. Rangiroa is characterized by the extreme narrowness of the land rim,
the width of the reef flats on the weather side of the atoll, and the nearly
uniform depth of the lagoon.

At Rani'iroa we obtained the first intimation of the immense amount of
water which flows in and out through the main passes, and, according to the
strength of the trades, continues sometimes to flow two or three days in one
direction, and is forced by them over the narrow part of the reef flats,
which is bare at low water, or between the gaps separating the islands and
islets which have been thrown up on the weather or lee side of the atoll.
During the strong trades both wind and seas follow the trend of the shores
of the islands, and little or no lee is found under them.

It was fortunate that our first examination of the Paumotus was made
among the northwestern atolls and islands of the group. Rangiroa, Tikahau,
Matahiva, and Makatea readily gave us the key to the structure of the rest
of the group. I doubt if an examination of the southern and eastern Pau-

THE PAUMOTUS. . 15

motus would have given us so good a basis for an explanation of the causes
which have been at work to bring about tlie existing conditions of the
islands and atolls of the group. These have so persistently been represented
as low atolls, that with such a preconceived notion strengthened by an examina-
tion of the lower islands and atolls of the group, it would have been an easy
matter to fail to see in the structure of Rangiroa, Niau, and Makatea the
survival of a state of things the history of which can easily be read as demon-
strated by what these islands teach, but which it would be difficult to
trace from a study of the lower islands alone. It would have been
comparatively simple to recognize in the outliers and remnants of the old
ledge in the low islands the same tertiary elevated limestone with which we
had become familiar in the Fiji, Tonga, and Sandwich Islands, yet we
could have formed no conception of the great orographic changes the low
islands and atolls of the group had undergone after their elevation and sub-
sequent erosion. The old ledge crops out at various points in the narrow
cuts which divide the land rim of the lagoon into a number of smaller
islands; in these secondary passes the underlying ledge, full of fossil corals,
is left exposed. In some of the secondary passes a clear channel extends
across from the lagoon to the sea side, through which water flows at high
or half tide. In other cases the cuts are silted up with coral sand blown
in from the lagoon side. In others the cut is shut off by a high sand
bank, or a bank composed of broken fragments of corals, leaving access to
the water from the northern shore only ; and finally the cuts are also shut
off on the northern side by sand and broken coral banks, the extension of the
north-shore outer beach, leaving a depression which at first is filled with salt
water and gradually silted up both from the lagoon side and the sea face, and
forms the typical north-shore land rim of the lagoon. This building up of
the land rim of the Paumotu atolls by the accumulation of material both
from the lagoon side and the sea face, is very characteristic of the atolls of
that group. It is a feature which I have not seen so marked in any other
coral reef district.

The land rim of the atolls in the Paumotus and Fiji is very stable. There
is not much movement except in hurricanes ; and there is no such regular
migration of sand as occurs on some islands in Florida. I know nothing to

16 "ALBATROSS" TEOPICAL PACIFIC EXPEDITION,

sustain Dana's' statement regarding the removal of material from the inside
of lagoons ; one need only look at all the islands and islet beaches on the
inside of the lagoon at Rangiroa, Tikahau, and Matahiva. The sea face
platform, Dana also says, is always greater than that on the lagoon side.
Certainly this is not the case in a great number of the atolls in the Pau-
motas, Society, Fiji, and Marshall Islands, where the surface area of the
lagoon flats far exceeds that of the sea face platform.

It became very evident, after we had exaniined a number of atolls, that
the underlying ledge is the remnant of a bed of tertiary coralliferous lime-
stone, which at one time covered the greater part of the area of the lagoon,
portions of which may have been elevated to a considerable height. This
limestone was gradually denuded and eroded to the level of the sea. Pas-
sages were formed on its outside edge, allowing the sea access to the inner
parts of the lagoon limestone flat. This began to cut away the inner por-
tions of the elevated limestone, forming large sounds, as in the case of Fiji
atolls, and leaving finally on the weather side only a flat strip of great width,
which has gradually been further eroded on the lagoon side and also on the
sea face, to leave only a narrow strip of land varying in height; the material
for this land has come from the disintegration of the ledge of tertiary
limestone, both on the sea face and the lagoon side. There exist in the
lagoons a number of small islets which also consist of outliers of this
same tertiary limestone in process of disintegration and transformation to
coral sand islets and bars.

The underlying ledge is not the remnant of a modern reef ; its character
is identical with that of the elevated limestones of Fiji, which are of Tertiary
age, and the rock is in every respect the same as that I observed on many
of the elevated islands of Fiji. The atoll of Rangiroa, for instance, is in a
stage of denudation and erosion very similar to that of Ngele Levu, in Fiji,
only in Ngele Levu the elevated limestone attains a height of about 60
feet, whereas at Rangiroa the coralliferous limestone ledge is from 12 to
14 feet high and about 40 to 50 feet wide at the top, forming on the sea
face of the islands and islets of the land rim a great stone-wall more or
less broken into distinct parts, a ledge consisting of elevated limestone as

1 Loc. cit., p. 300.

THE PAUMOTUS. 17

hard as calcite, full of corals, honeycombed and pitted, and undercut by the
action of the waves both on the lagoon side and on the sea face, worn into
countless spires and spurs and needles and blocks of all sizes and shapes,
separated by deep crevasses or pot-holes, recalling a similar scene in Ngele
Levu on the windward end of the lagoon. The reef flat or shore platform
of many of the Paumotu atolls is strewn here and there with huge masses,
outliers of the ledge of elevated reef rock, or torn from its outer edge.^
Similar rocks and boulders occur on the lagoon side of the islands, forming
their outer land rim ; they are either torn ofT from the lagoon face of the
outcropping ledge, or are outlying parts of the ledge which have remained
in place and have not been planed down to the base level of the reef.

The amount of water which is forced into the larger lagoons such as
Rangiroa over the flats of the weather side is something colossal, and when
we observe that there are often but a small number of passages through
which it can find its way out again on the leeward side, it is not surprising
that we should meet with such powerful currents, seven to eight knots in
several cases, sweeping out of the passages on the lee side.

The islands and islets of most of the Paumotus are fairly well covered
with low trees and shrubs and large groves of cocoanut trees.

The land rims are formed by material piled up both from the lagoon side
and the sea face, — material derived from the disintegration of the underly-
ing tertiary limestone, which crops out here and there along the sea face
and the inner shores of the lagoons. The islets and islands of the land
rim are more or less connected by outliers of the elevated limestone ledge,
attesting its greater extension in past times.

Some of the islands appear to have been formed by accretion of sand
from the decomposing ledges of the lagoon. The outer land rim sometimes
appears as if formed by sand banks driven in from the sea face and also
driven out from the lagoon side by the action of the waves. It is evident
that shallow lagoons could readily be closed by such a process and the sea
no longer have access to it.

It was with great interest that we approached Makatea, as it is the only

' I am informed that enormous outliers of elevated coralliferous limestone fully 30 feet in height
oecur on the south side of Kaukuia.

18 "ALBATROSS" TROPICAL PACIFIC EXPEDITIOIT.

high elevated island of which Dana speaks as occurring in the western Pau-
motus.' For though he mentions some others as possibly having been
elevated five or six feet, yet he considered them all, as well as Makatea
(Metia, or Aurora, of Dana), as modern elevated reefs. From the very de-
scription given by him of the character of the cliffs and of the surface of
Makatea, I felt satisfied that it was composed of the same elevated coral-
liferous limestone so characteristic of the elevated reefs of Fiji, and which,
from the evidence of the fossils and the character of the rock, both Mr. Dall
and myself have been led to regard as of Tertiary age.

As we approached the island it soon became evident that it presented all
the characteristics to which I had become so accustomed in Fiji, and upon
landing this was found to be the case. The cliflfs had tlie same appearance
as those of Vatu Leile, Ongea, Mango, Kanibara, Yangasa, and many other
elevated islands of Fiji. There were fewer fossils, perhaps, but otherwise
the petrographic character of the rock was identical with that of Fiji.

At Makatea we also first came upon well-defined terraces and lines of
caverns at the base of the cliffs indicating the line of present action of the
sea. The position of these terraces was usually more clearly seen along
the face of the cliffs at prominent points, where they were undercut much
as I have figured them for certain cliffs in Vatu Leile, Yangasa, Mango,
Fulanga, and otliers in Fiji, in my report on the islands and coi'al reefs of
that group.^

The evidence of elevation in the atolls of the western Paumotus is very
definite. Makatea is an elevated mass of coralliferous limestone similar in
all respects to masses like Vatu Vara, Thithia, and others in Fiji, having,
like some of the Fiji elevated islands, a sink of considerable depth occupy-
ing a little more than one third the length of the island. So that it is not
unnatural to look upon the area of the Paumotus, as I am inclined to do,
as one of elevation, the raised and elevated land of which has been affected
much in the same way, by denudation and by erosion, as have the masses
of elevated coralliferous limestone of Fiji. Only there seems to have been,
from the evidence thus far presented, a far greater uniformity in the height

1 Corals and Coral Islands, 3d ed., 1890, p. 193.

2 Bnll. :\I. C. Z., Vol. XXXIII., 1899; Pis. 80, 84, 92, 100.

THE PAUMOTUS. 19

of the elevation of the Paumotus. This would render the explanation I
have given less evident had I not the experience of the Fiji group to
sruide me. Evidence of this elevation is found at the two extremities and
at many intermediate points of the Paumotu plateau, at Makatea and at
Niau, elevated islands consisting of tertiary coralliferous limestone, at the
Gambler Islands, which are volcanic islands of considerable height (over
1300 feet), and at Henderson Island. Furthermore, as we shall see, there
are other islands and atolls in the Paumotu group showing traces of this
elevation, so that I am, at any rate, justified in denying that the Paumotus
are situated in an area of subsidence, and that subsidence has been the great
factor, as is maintained by Darwin and Dana, in the formation of the char-
acteristic atolls of the group.

It may be well to point out also that the western part of the Paumotus,
like the Marquesas on one side and the Society Islands on the other, are
situated upon a plateau rising from an oceanic basin which surrounds them,
with a depth of from 2300 to 2500 fathoms, the plateau itself having a
depth of 1200 to 1500 fathoms. For the differences which distinguish the
plateaus of these groups I refer to the accompanying diagrams (Figs. 1-12).

From Makatea, we visited Niau, Apataki, Tike'i, Fakarava, Anaa, Ta-
hanea, Raroia, Takume, Taenga, Makemo, Tekokota, Hikueru, Marokau,
Hao, Aki-Aki, Nukutavake, going as far east as Pinaki, when we turned
westward again to Nukutipipi.

On arriving at Pinaki we decided to give up the exploration of the
eastern extremity of the Paumotus, and not to make our contemplated visit
to the Gambler Islands, our time having been greatly curtailed by delays at
Fakarava and Makemo, from bad weather and the non-arrival of oiu' coal
supply. We therefore reluctantly turned westward again and made for the
Gloucester Islands. These, as well as Hereheretue, proved most interesting ;
they formed, as it were, an epitome of what we had seen on a gigantic
scale in the larger atolls of the western and central Paumotus. We could
see at a glance in such small atolls as Nukutipipi and Anu-Anurunga the
connection between structural features which, in an atoll of 40 miles in
length and from 10 to 15 miles in width, it was often difficult to determine.

We anchored in Fakarava and Makemo lagoons, spending a number of

20 "ALBATROSS" TEOPICAL PACIFIC EXPEDITION.

days in both these atolls. We usually timed our visits to the islands where
we could not anchor so as to spend the day, or the greater part of the day,
at these atolls, making our passages at night, and sounding whenever prac-
ticable on the way.

All the islands we examined are, without exception, formed of tertiary
coralliferous limestone, which has been elevated to a greater or less extent
above the level of the sea, and then planed down by atmospheric agencies
and submarine erosion, the greatest elevation being at Makatea (about
230 feet), and at Niau, where the tertiary coralliferous limestone does
not rise to a greater height than 20 feet. At Rangiroa it was 15
to 16 feet high. At other islands it could be traced only as forming
the shore platform, from 50 to 250 feet wide, which forms the outer face
of the Paumotus and is so characteristic a feature of the atolls of the group.
[n other parts the old ledge could be traced cropping up in the interior of
the outer land rim, or in the open cuts connecting the lagoon with the outer
sea face of the atolls. Everywhere the space between the outcroppings of
the old ledge, as I will call the tertiary coralliferous limestone, was filled
with beach rock, or a pudding-stone, or with a breccia or conglomerate of
coralliferous material consisting in part of fragments of the old ledge, and
of fragments of recent corals and shells cemented together. The appear-
ance of the old ledge and of the modern reef rock is so strikingly different
that it is very simple to distinguish the two, even where only comparatively
small fragments are found.

We did not find in the Paumotus, as in Fiji, all possible stages of denu-
dation and of submarine erosion between islands like Vatu Vara, Naiau,
Kambara, Fulanga, Ongea, Oneata, Ngele Levu, Wailangilala, and atolls
with a mere ring of surf to indicate their existence. In the Paumotus
nearly all the islands have been elevated to a very moderate height and
probably to about the same height, for the old ledge forming the base of
the modern structure' is found exposed nearly everywhere at about low
water, when it cannot be traced at a slightly greater elevation. This would
readily account for the uniform height of the islands throughout the group.

But there is another element which comes into play in this group, and
has an important part in shaping the ultimate condition of these atolls. At

THE PAUMOTUS. 21

the Fijis we have seen the submarine erosion continue until there is little
left of many of the atolls beyond the merest islet or rock to indicate its
structure. In the Paumotus, in the great atolls, which are perhaps only
the exposed summits of parts of ridges or spurs of an extensive tertiary
coralliferous limestone bed, the land rim of the atoll is, after having been
denuded to the level of the sea, again built up from the material of its two
faces, which is thrown up on the wide reef flats both from the sea face and
from the lagoon side. We do not find in the Fijis, as in the Paumotus, the
wide reef shelves which supply such masses of material from the breaking
up of the outer and inner edges of the tertiary limestone platforms, in addi-
tion to the fragments of the recent corals growing upon the flats and their
slopes, which, when dead, are thrown up on the top of the reef flats and
formed into shingle and sand to form a pudding-stone, or a conglomerate,
or breccia, with the fragments of the old ledge.

This pudding-stone, or beach rock, is found on all the reef flats of the
islands of the group. It forms great bars, at right angles usually to the
shore line, and upon the sea face of these bars is thrown up coral shingle,
both old and recent, which builds up short reaches of beaches separated by
wide flats through which the sea rushes at high water, or merely covers the
flats at low tide ; while on the lagoon side of the wide reef flats a similar
process is going on, throwing up finer sand among the beach-rock bars and
along their sides, and thus building up, little by little, at first small sand
bars, then larger bars, or islets, at right angles to the shore line, and as they
become larger by accretions from both sides, they finally form islands
from 1000 to 1200 feet long, according to the width of the reef flat,
extending from the lagoon edge of the flat to the sea face of the atoll. The
sand bars, little by little, become covered with vegetation, and at some
stages of tide appear like islands and islets situated a considerable distance
within the lagoon. Whenever the material supplied both from the lagoon
side and from the sea face is very abundant, the land rim becomes more or
less solid, the islets become consolidated into islands, separated by narrow or
wider cuts, until finally they form the larger islands which seem at first
glance to form a continuous land rim along the edge of the lagoon, but
which are often seen to be separated according to local conditions by narrow

22 "ALBATROSS" TROPICAL PACIFIC EXPEDITIOX.

cuts, which gradually silting up finally close the gaps, and merely indicate
the former separation of the various parts of the land rim.

In the lagoons of atolls of such great length as some of those of the
Paumotus, like Rangiroa, Fakarava, Makemo, and Hao, which are between
30 and 40 miles long, and others of less dimensions, considerable sea
rises under the prevailing trades. The sea and wind generally follow the
trend of the shores, both in the lagoon and along the sea face, so that
the bars of beach rock act like buttresses and collect material at their
inner and outer extremities, forming the sand bars and islets which
eventually become the land rim of the lagoon. AVhen, from local causes,
the material is not very abundant, or is washed out over the flats, there
are fewer islands, and these are often but mere islets or bars for long
reaches of the submerged land rim forming the weather faces of many of
the lagoons.

Many of the lagoons are filled with shoals or ledges awash or a few
feet above the sea level. These shoals are parts of the old ledge which
have not as yet been eroded, and the disintegration of which has gone
far to supply material from the lagoon side, for the land of the outer rims
of the atolls. In the Fakarava lagoon there are no less than thirty-six
islands and islets and ledges, parts of a former great flat, now broken up,
once existing parallel to the outer reef flat. Similar reef flats exist in ,
Tahanea, where they form a secondary lagoon with two to three fathoms of
water, extending nearly the whole length of the western face of the atoll.
There are several large islands on this flat, and at high water they would
appear, as the islands and islets of Fakarava do, as disconnected and planted
in the lagoon itself. A secondary lagoon also exists in Ravahere and one in
Anaa ; in both these atolls the reef flat extends across one extremity of the
lagoon, and does not run parallel to the longer line of the land rim of
the atoll.

The lagoons of these atolls have a general depth of 13 to 20
fathoms. In some cases they are somewhat deeper ; some of the greater
depths, to 30 fathoms or more, are probably due to orogenic conditions.
Some of the lagoons are quite shallow, as at Matahiva, as well as Pinaki,
where they are not more than two to three fathoms, and Takume, where it is

THE PAUMOTUS. 23

from five to six fathoms deep. Some of the smaller islets we visited, among
which are Tikei, Aki-Aki, and Nukutavake, have no lagoons. The former
has a small shallow sink in which fresh water collects, but the rim is only
very slightly higher than the interior. The last two islands are apparently
depressed in the centre, three to four feet below the outer bank of sand which
forms the rim (about 10 to 12 feet high) of the basin of the island ; I was
at first inclined to look upon them as examples of islands which had been
cut down to the level of the sea and subsequently been built up by beach
rock and sand in the manner described above. The existence of extensive
sand dunes on two sides of the island at Pinaki, and of large dunes (esti-
mated to be 35 feet high) on the south shore of Nukutavake, seems to
indicate the possibility of there having been a shallow lagoon occupying
the centre of Aki-Aki and of Nukutavake, and that these lagoons were
gradually filled by the sand dunes, much as Pinaki is filling now.

At Pinaki, as at other atolls and islets to the eastward, there are
fewer large trees than on the western atolls, tlie vegetation consisting
in great part of pandanus and putu trees and the usual coral-reef vege-
tation of the Paumotus ' and Fijis.

The only atoll we have seen in the Paumotus the lagoon of which
is entirely shut off from the sea is Niau. In this case the old ledge
forming the land rim which surrounds the nearly circular lagoon is about
a third of a mile in width and sufficiently high, 15 to 20 feet, to pre-
vent any sea from having access to it except in case of a cyclone, as
that of 1878, when the sea washed into the lagoon. The lagoon is
shallow, of an average depth of about three fathoms, the deeper parts per-
haps five. The sea, however, undoubtedly finds its way into the lagoon
through the cavernous rim.

Dana, and other writers on coral reefs, mention a great number of
lagoons as being absolutely shut off from the sea. I take it these
statements are due to their descriptions being taken from charts, many
of which, as in the case of the Paumotus, are very defective. For
nothing is easier than to pass unnoticed even at a short distance the wide or
narrow cuts which allow in so many cases the freest access to the sea to

1 See Dana, Curals ami Coral Islands, 3d ed., p. 32G.

24 "ALBATROSS" TEOPICAL PACIFIC EXPEDITION.

the interior of the lagoon, and yet are described as closed because they have
no boat passages. I could mention, as instances of such lagoons, those of
the atolls of Takume, Hikueru, Anaa, etc., or the weather faces of many
atolls which may be said to be closed, yet into which a huge volume of
water is poured at every tide over low parts of the encircling reef flats.
. When Dana speaks of there being no entrance to a lagoon, it merely
means that no boats can pass the reef flats ; it does not mean that the
water in the lagoon is not constantly replaced from the outside sea rushing
over the low sea reef flats or denuded parts of the reef platform. Dana^
says Margaret (Nukutipipi) has no entrance, but the reef flat is low and
submerged on the east side, allowing full access of the sea to the lagoon.
He also says^ Taiaro has no entrance; there is one. Having thus assumed
the non-existence of openings to many atolls, — Anu-Anurunga, Honden
(Puka-Puka), and others, — he bases upon their absence a number of theoreti-
cal considerations regarding the closing of lagoons,^ which naturally fell to
the ground now that the existence of passages has been proved.

The large number of flat-topped or slightly dished elevated islands of
coralliferous limestone like Nine, Makatea, Henderson Island, Tongattibu,
Vavau, Guam, Vatu Vara, and others in Fiji and elsewhere, seem to indicate
a gradation between those which are nearly flat-topped, like Nine and Hen-
derson and Guam, to others like Makatea and Eua, which are dished or
gouged by valleys, and to such islands as are so deeply dished as to appear
like elevated atolls, as Mango, Kambara, Naiau, and others.

As I have already called attention in my Report on the Fiji Reefs,'*
we have in the Lau group all the gradations between the so-called elevated
atolls and such atolls as Fulanga, Yangasa, and others, in which the uplifted
limestones are reduced to diminutive islets which represent all that remains
of an uplifted limestone plateau. Naiau (in Fiji) would soon pass into the
condition of a ring composed of limestone islets were the sea to find access
to its sink by breaking through the land rim. We might in that case have
on a small scale an atoll like Rangiroa, in which what is left of the original
elevated limestone plateau would be reduced to a low wall on the weather

1 Loc. cit., p. 199. « Loc. cit., p. .'iOi.

■i Loc. cit., p. 200. * A. Ag., Bull. M. C. Z., XXXTII. 1899, p. 43.

jAoi'oflT'caoaTAS'

■Albatross"Tropical Pacific tx

SECTION MARQUESAS CAPE MARTIN] TO RANGIROA I PAUMOTUS

Sea level

Sea.

Level.

100

1

jeorsd

too

too 1

/

?00

300 1

/

300

400 1
500 \

i 1

/ °

/ ^

+00
500

s

91

^iob-oi voiparl

1

Fig. 2. 1

1

val.pnrl Z

1 000 1 \ ;

/ .. 1

lOOO

1 ': J

adoul 000 mil fs-

i —

---,-- -y^ :.......->

< 1 I

> \

^ \rt}r]<v.vuiparl.

P \ ■
- \ '■

1500 „ \ ;

1

S^Iob.oz

1 fine car. sd

1500

^ \ ;

/

4)
<

/

a

l flio6,ox vol. pari
ZOOO \^

i

2000

2500

\35-

glob.fjz.rad

35°^

35-1 il

av

J500

mlclai _j/ "rf «•

^^^^--^

]x^P(/ r/flv

-

-■

SOUNDINGS IN FATHOMS.

3000

3100

3100

32O0

3200

THE PAUMOTU PLATEAU. 25

side, and to outliers of the elevated coralliferous limestone exposed in the
gaps of the land rim on the lee face of the atoll. The lagoon of Rangiroa
represents a huge sound, the marginal land rim of which has been denuded
and eroded to attain its present condition.

In all elevated coralliferous limestone islands it is difficult to determine if
their sink is the remnant of a former lagoon of the island, or of a sound
formed during its elevation, or if it has been formed by the action of rain
and atmospheric agencies. The amount of denudation and erosion to which
some islands have been subjected is very great, as is clearly indicated by the
small canons, pinnacles, spires, and walls of limestone, as well as crevasses
which occur in all directions over the surface of the basin or sink. The
extent to which this action has penetrated into the mass of the island is
plainly shown by the great number of caverns which crop out along the
sea face of the cliffs of elevated islands. Some of the caverns are of great
length, and extend as long galleries far into the interior of the island. It
is of course difficult, in the face of this extensive denudation and erosion,
to state positively what may be part of the ancient lagoon, or sound, and
what has been carried away by atmospheric and other agencies since the
elevation of the island.

The Paumotu Plateau.

Plates 201, 234, and Figs. UlS.

Between the Marquesas and the northwestern extremity of the Paumotus
(Fig. 2) we occupied nine stations; close to the Marquesas the depth was over
1900 fathoms, the greatest depth on that line being 2700 fathoms at Station
31, in lat. 12° 20' S., and long. 144° 15' W. The depths varied between 2451
and 2527 fathoms, and diminished to 1208 fathoms off the west end of Ahe,
and then to 706 fathoms when about sixteen miles N. E. off Avatoru Pass
in Rangiroa atoll.

We developed to a certain extent the width of the Paumotu plateau by
a line of soundings in continuation of the direction of Avatoru Pass, extend-
ing a little less than nine miles seaward, whei-e we obtained a depth of 819
fathoms. Subsequently we ran a similar line normal to the south shore

26 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

of the lagoon of Rangiroa, a distance of nearly twelve miles, into 897
fathoms (Fig. 3) ; this seems to be the depth of the western part of the
Paumotu plateau.

Between Rangiroa and Tikahau, the next atoll to the westward, we
obtained a depth of 664 fathoms.

Between Tikahau and Matahiva six soundings were made, with a depth
of 488 fathoms half a mile from shore, and a greatest depth of 850 fathoms
six and a half miles from Tikahau. The slope approaching Matahiva is
steeper than the Tikahau slope (Fig. 5).

From Matahiva to Makatea (Aurora) Island, we made six soundings :
from 624 fathoms about two and a half miles off shore to 581 fathoms about
one and one-eighth miles ofT the west side of the latter island, the depths
passing to 860, 1257, 1762, and the greatest depth being 2267 fathoms, then
2247, and rising more rapidly near Makatea to 581 fathoms (PI. 201).

Between Makatea and Tahiti we made eight soundings, beginning with
1363 fathoms, two miles off the southern end of Makatea, passing to 2238,
2363 (the greatest depth on that line), to 2224, 1930, 1585, 775, and finally
867 fathoms off Point Venus (Fig. 7).

The soundings from Makatea to Niau (PI. 201 and Fig. 8) indicate that
Makatea is an isolated peak rising from great depths and separated from the
Paumotu plateau, as we find 2238 fathoms in the direction of Tahiti, 2268
ftxthoms in the direction of the Niau plateau, and 2267 fathoms towards
Matahiva.

A line from Niau to the north of Apataki gave us a greatest depth of
677 fathoms between Niau and the southern face of Apataki, while to the
north of Apataki the Paumotu plateau drops off rapidly to over 1300
fathoms (Fig. 8).

Judging from the soundings to the east of the line from Niau to Apataki,
on the eastern extension of the Paumotu plateau are probably .situated
Fakarava, Kauehi (Fig. 4), Tahanea, Makemo, and Taenga (Fig. 6). Anaa
stands upon an isolated ridge separated by over 1700 fathoms from
Tahanea, and by 1531 from Fakarava (Figs. 4, 9); Raroia and Takume
rise from the same plateau (Fig. 6), but are separated from the eastern part
of the Paumotu plateau (Taenga) by more than 1500 fathoms.

■'Albatross Tropical Pacific Ex

SECTION ANAA TO KAl'EHI

. 1000

^ecu Levei

. 2000

. 1000

ISOO

< 7fi fiiileM

looo SECTION

RAXGIROA TO MATAHIVA

v^

3niOA^ j/i,-Tq.jnT;;>r

■'Albatross'Tropical Pacific Ex.

SKCTIOX MAKEMO TO TARUMPJ

SKCTFOX MAKATEA TO TAHITI

c ^ a;

Spg Level

SOUNDINGS IN FATHOMS.

THE PAUMOTU PLATEAU. 27

To the eastward of Makemo our soundings indicate (PI. 201 and Fig. 10)
a gradual increase in depth. Makemo and Neerou are separated by a
channel with a depth of 1221 fathoms. We find about the same depth
between Neerou and Tekokota, which with Hikueru seem to be on a shal-
lower ridge with not more than 1009 fathoms. Between Hikueru and
Marokau the depth increases to 1620 fixthoins; between the latter and
Hao it has increased to nearly 2200 fathoms. It is again over 2100 fathoms
between Hao and Aki-Aki, and over 2.300 fathoms between Aki-Aki and
Nukutavake. The latter, with Pinaki, are upon a distinct plateau with a
depth of less than 900 fathoms. So that we may state that east of Hao the
different atolls of the Paumotus rise independently, and are separated by
channels of considerable depths which are gradually becoming greater as
we go farther east (Pis. 201-203).

From Pinaki to Nukutipipi (Fig. 11), crossing the deep channel wliich
runs parallel to the general trend of the Paumotus, we find a greatest
depth of 2467 fathoms, and reach the area of red clay again.

Finally, on the line from Nukutipipi towards Mehetia (PI. 201 and
Fig. 12) we find steep slopes between the atolls, a depth of 1609 fathoms
separates Nukutipipi and Anu-Anurunga, 1890 fathoms is found between
the latter and Anu-Anuraro, and a stretch of red clay exists between it and
Hereheretue in 2524 fathoms. The area of the red clay extends towards
Mehetia, the deepest sounding towards that island being over 2400 fathoms.

In the Paumotus the islands from Hao to Matahiva trend in a general
way from southeast to northwest. But the islands to the north of a line
from Rangiroa to Makemo, except Apataki, run at right angles to that line.
They are Takaroa, Takapoto, Manihi, Ahe, Raroia, Takume, Fakaina, and a
number of the outlying islands to the eastward, as Amanu, Tatakoto. The
islands of Nakutavake, Vahitahi, and Tatakoto run in a northeasterly direc-
tion, while others, like Reao, Puka-ruha, and' Marutea, run again from
southeast to northwest.

There thus seem to be traceable a number of lines of uplieaval in the
group. Off Rangiroa, at right angles to its trend, run Ahe and Manila. A
second line at right angles to Apataki consists of Takapoto and Takaroa.
A third line off Makemo is formed by Raroia and Takume. While the out-

28 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

lying islands of Tatakoto and Fakaina run in the same direction as Amanu
off JIao, Nukutavake has the same northeasterly trend, as well as Marutea
north of the Manga Reva group, while the atolls of Hereheretue, Anu-
Anurungia, and Anu-Anuraro are on a line parallel to the principal trend of
the Paumotus from southeast to northwest. The soundings show Herehe-
retue to be an independent joeak isolated from the Duke of Gloucester
group, which may be said to rise from a connecting ridge of nearly 1900
fathoms surrounded by depths of more than 2500 fathoms.

We made more than one hundred and fifty soundings through the Paumotus
and their approaches. These have shown in a general way that the western
islands are probably all on a great plateau connected perhaps by the 800-
fathom line ; that such islands as Anaa may be on spurs or independent
smaller plateaux, separated from the main plateau by somewhat deeper water;
the same may be the condition of Raroia and Takume, and of Hao and Amanu,
while such smaller and isolated islands as Tikei, Aki-Aki, Nukutavake and
Pinaki, as well as the Gloucester Islands, rise from greater depths and are
isolated peaks. At any rate, these soundings indicate, as do the soundings
off the Fijis, that atolls do not necessarily rise from very great depths, and
that in this characteristic atoll district, atolls are found, with steep slopes, it
is true, but rising from moderate depths. The slopes of these atolls would
probably resemble in every respect the slopes of the elevated coralliferous
limestone islands characteristic of the Lau group in Fiji, where they have
not been obliterated by erosion, denudation, and atmospheric agencies.

The deepest sounding among the Paumotus was on the line to the north-
ward of Hereheretue in the direction of Mehetia, where we found a depth
of 2524 fathoms, and a continuation of the red clay characterizing the
soundings since we left Pinaki. In nearly all the soundings among the
Paumotus, even at moderate depths not far from the atolls, we brought up
manganese particles or small manganese nodules. The last haul, made in
deep water on the way from Hereheretue to Mehetia in 2440 fathoms, brought
at least half a ton of manganese nodules, the bottom being red clay.

We steamed about 2500 miles among the Paumotus, and although we
had not the advantage of the accurate surveys of the English Hydrographic
charts, which made the exploration of Fiji so easy, yet from the structure of

VlLeATROSS'TROPICAL PACIFIC Ex

Si;(Tl()\ AA'AA TO TAKUMK

SKCTIOX MAKATEA TO APATAKI

-Vf'rt /yr»

>/■

■^

: wvJi ■

\yy.^\J

n ■

. 100

: \ :

<

: ]k1

. JOO

\coKsam

. : . ,

IC

,' '^ \

. 300
. *Off

. 500

1

<

<

Z

\ <

: \<\

; ! ^ '

' < i

J , COK.

1 D V
1 h

J

' pier. 02.

; a8'6

cor.san

i\ /

\

ic/lob.oz.

. 1000

1

i

^'^° plo,

i

-

1500

\

1

Fig. 9.

Cjtob 02

^ gloli.oz

SOUNDINGS

2000

'S'p a A <? r p /

jaooo

2500

^.^j^^.v^.cy.^y.i wi i iji ou crtoj', jcL iruiu tiie Structure ol

i>tA'/rf(

"Albatross" Tropical Pacific Ex,

SECTION MAKEMO TO PINAKI

00

zoo

300
♦00
500

ISOO

red rlnv

THE PAUMOTU PLATEAU. 29

these atolls it was a comparatively simple task to get a fairly good idea
of them. We have seen nothing in this more extended examination of the
group tending to show that there has anywhere been subsidence. On the
contrary, the existing condition of the atolls of the Paumotus cannot, it
seems to me, be explained on any other theory except that they have been
formed in an area of elevation extending from Matahiva on the west
to Pinaki in the east, and from the Gloucester Islands on the south to
Tikei on the north, although the islands in the line of Manga Reva to
Tahiti are separated from the other Paumotus by a deep channel, nearly
200 miles wide and more than 2400 fathoms in depth, with scattered islets
and atolls extending from Manga Reva to Pinaki, and northward to Puka-
ruha and islands beyond, which are not connected with the extensive plateau
upon which the greater number of the Paumotu Islands to the westward of
Hao rise.

The character of the I'eef corals of the Paumotus is very different from
that of other coral reef regions I have seen. Nowhere have I seen such a
small number of genera, so many small species, and such stunted develop-
ment of the corals. The outer reefs in from 3 to 15 fathoms of water are
composed almost entirely of dense masses of Astrseans, Pavonia, and of
several species of Madrepora and of Pocillipora.

A yellowish green nodular species of Millepora is very common between
the surface and three fathoms. On the shallow reef flats are found the fol-
lowing corals arranged in the order of the frequency of their occurrence, —
several species of Madrepora, Porites, Goniastrsea, Astrasa, Pocillipora, Alveo-
pora, Fungia, Mussa ; no Maeandrinae wei'e found, and, what is specially note-
worthy, no huge heads of any of the species of corals mentioned above are
to be seen. This is in striking contrast to the colossal masses of so many
species of corals which characterize the physiognomy of the Great Barrier
Reef of Australia and of the West Indian region. The general absence
of the large fleshy Alcyonaria of Australia is very marked in the Paumotus,
so far as our experience shows, and there are but few Sponges to be found
among the corals. Gorgonians and the like are also infrequent, coming
up only in our trawl hauls. Plexaura was found on a shallow reef flat
in the lagoon of Makemo, where Allopora is quite common in from 12 to

30 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

13 fathoms. Tubipora was brought up from deep water (742 fathoms)
off Marokau Islaud. The bathymetrical Hmit of the reef-building corals
seems to be about 20 to 22 fathoms.

Nowhere have I seen such extraordinary development of incrusting
Nullipores as on the sea edge of the shore platforms of some of the
Paumotu atolls, where they build up to a height often of four feet to form
the outer edge of what may be called a secondary barrier reef so fre-
quently seen along the sea reef faces of the Paumotus. Incrustation by
Nullipores gives the reef platform a decided peach or pinkish or orange
red tint in addition to that of the patches of Pocillipora growing upon the
very edge of the platforms.^ The whole platform thus has a very decided
hue, but most marlced and brilliant on the raised edge of the sea face.

The Tridacnas of the Paumotus are not more than six to eighteen inches
in length, — dwarfs compared to the giant species of the Queensland coast.
It is only when we come as far west as the Gilbert Islands that we again
strike the giant Tridacna, which has a special value to the natives of the
groups adjoining the Gilberts. They use the thick part of the shell near
the hinge to make mat-beaters, and the harder and tougher parts of the
curved part of the shells they shape into axes and knives.

But little seems to be known regarding the reproduction of the pearl
oyster, and thus far all attempts at planting and artificial reproduction or
regulation of fisheries have proved unsuccessful. Certain islands are after
the lapse of a couple of years thrown open again to pearl-divers, and this
close season has thus far proved successful in checking the destruction of the
pearl by overfishing. But a single season like the present one at Hikueru,
where the greater part of the fishing population of the Paumotus is assem-
bled within such narrow limits as the Hikueru atoll to collect pearl shells,
must be a great strain on its productive capacity.

On pearl shells said by the natives to be six years old we found
growing stems of a species of Madrepora and one of Allopora, each fully
eight inches in length.

The Echinoderms we collected in the Paumotus all belong to genera and
species having a wide geographical range, the majority extending from the

' See Dana's description of this on the Ahe platform, loc. cit., p. 201.

"Albatross Tropical Pacific Ek

SECTION XUKUTIPIPI TO PINAKI

Sfa Level

Sea Lflvei

100 .
«00 .
300 .
400 ■
SOO

2500 I

\

1

100

eoo

300
400

500

i

■pier- ;

—

;' Z

^

1 =^

^. 1

Fig

11

looo

D '•

i

Z ;

<- ;

-- 230 Miles

^,.. >-

35'4,

\tlU)h.

1500

'

\

•^^°) Qbb.oz

2000

35'*lre(i tlax

^"^^d__-^— -—

35'

3^

'■^d clay

red c/.av

35 -A

/red ciav

redciay

2500

SOUNDINGS IN FATHOMS

30 "ALI

13 fathoms. Till
off Marokau Islai
seems to be abo
Nowhere have
NuUipores as on
Paumotu atolls, w
the outer edge c
quently seen aloi
NuUipores gives ■
red tint in additii
very edge of the
hue, but most ma:

The Tridacnas
in length, — dwar
It is only when w
strike the giant 1
groups adjoining
the hinge to mal^
curved part of th

But little seen
oyster, and thus f
regulation of fishf
the lapse of a cou
close season has th
pearl by overfishii
where the greater
bled within such i
must be a great

On pearl shel
growing stems of
eight inches in le

The Echinoderi
species having a w

1 SeeE

Albatross'Tropical Pacific Ex

SECTION TAHITI TO XrKL'TIPlPI

SOUNDINGS IN FATHOMS

THE PAUMOTU PLATEAU. 31

Panmotiis to Australia, to the East Indies, and even farther to tlie west, to
the east coast of Al'rica. Among the genera we collected were Parasalenia,
Metalia, Heterocentrotus, Echinometra, Echinaster, Culcita, and other genera
having a very general distribution in the tropical Pacific.

Of birds the number of species is also small ; a babbler, a pigeon, a
curlew, snipe, a small parroquet, a kingfisher, are the principal types, in
addition to the terns, boobies, frigate birds, petrels, and tropic birds, all of
which spread over the Pacific.

The Large Birgus (cocoanut-tree crab) is abundant on some of the islands
of the Paumotus.

As far as we observed, the temperature of the lagoons at the surface is
identical with that of the sea outside of the atolls, and at .a depth of about
500 fathoms a temperature of 40° F. was recorded.

We made a number of surface hauls, as well as intermediate hauls with
the tow-nets, but obtained very little animal life in the Paumotus. The
poverty of the surface pelagic life and down to 300 fathoms is remarkable.
I do not think I have ever sailed over so extensive an area as that of the
Paumotus and observed so little surface life ; on calm days, under the most
favorable conditions, nothing could be seen with the naked eye, and at night
there was little or no phosphorescence. Inside of the lagoons our hauls
were equally barren.

The same paucity of animal life seemed to extend to the deep-water
fauna. All the hauls we made off the islands, in from 600 to 1000 fathoms,
usually the most productive area of a sea slope, brought nothing, or so little
that we came to grudge the time spent in trawling on the bottom, as well as
towing on the surface or near it, — a great contrast to the conditions in the
Atlantic in similar latitudes, and very difierent from our anticipations.

For these reasons we did not attempt to make a trial of the deep-sea
pump while in such unproductive areas; and unfortunately while we were
in the region of the equatorial currents the weather conditions were not
suited for a trial of the apparatus.

The vegetation of the land rim is composed entirely of small trees and
low bushes, and it is only on the larger islands that they have been cleared
and cocoanut trees have been planted in their place.

32 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

An atoll like Rangiroa, and similar islands in the Paumotus, supplies
an abundance of food for the few natives living upon it. In fact, there are
not enough natives in the group to collect the copra and prepare it for
export.

The occurrence of young cocoanut trees on the isolated islets and bars
formed on the weather side of the reef flats of many of the atolls would
seem to indicate that cocoanuts can be carried a great distance and take
root. Though Dana, while acknowledging that the cocoanut is well adapted
for marine transportation,^ is of the opinion that " there is no known evi-
dence that an island never inhabited has been found supplied with cocoa-
nut trees," yet it is also evident that some of the atolls of the Pauniotus and
Marshall Islands as well as other regions are suflBciently near and so placed
with reference to the favorable transportation of cocoanuts by the trades,
that it seems most probable that the cocoanuts have been successfully
transported by the ocean from one atoll to another. So that cocoanuts
probably do not form an exception to the extensive transportation by marine
agencies of the many plants which characterize the scanty vegetation of the
Paumotus and other Pacific islands, — vegetation which becomes more luxu-
riant in proportion as we go west.

Dana^ has already called attention to the small number of plants
which characterize the Paumotus ; the two most characteristic trees and
shrubs being a Pisonia and a Sctevola, a fleshy plant with large leaves which
grows well on the sea face of the atolls in the poorest coral soil and exposed
to the full strength of the winds, and usually forms the outer belt of pro-
tective vegetation of the plantations. Mangroves do not play an important
part in the vegetation of the Paumotus.

1 Loc. cit, p. 327.

2 A list of the principal plants has been given by Dana (Joe. cit., p. 326), " not more than twenty-
eight to thirty species."

EANGIROA. 33

Rangiroa.

Plates 4-19, Wl, 202 ; 20i,figs. 3, Jp ; 205, fig. 3 ; and Figs. 2, 3, 5.

After striking Ahe we made for Rangiroa, skirting the northern shore.
Rangiroa' is somewhat pear-shaped (Pis. 201, 202; 204, fig. 4). Its
broadest part is towards the northwestern face. The northern land rim is
thickly wooded. The irregular arc forming the southern face of the atoll
is edged by the great wall of elevated reef rock ; there are but few
islets and islands on the sea face of the wide reef platform, which extends
far into the lagoon.

About five miles eastof Tiputa Entrance (PI. 204, fig. 3) there are masses
of large coral rocks and boulders " at the foot of the high sand beach, which
cover the shore platform for a considerable distance. Steaming parallel with
the shore, we find these reaches of boulders alternate with clear flats of
the shore platform. This is about 250 to 500 feet in width from the ba.se
of the steep coral sand beach, which varies in height from 8 to 15 feet.
Occasionally the outer platform can be seen to extend in towards the lagoon
and to form a shallow pass from it to the outer sea across the narrow land
rim forming the northern side of the Rangiroa atoll. The northern land
rim is well wooded with masses of shrubs and low trees, and with tall
cocoanut trees rising to a height of from 25 to 40 feet.

At Tiputa Pass we obtained our first glance into one of the large
Paumotu atolls. The entrance is a little over a cable length wide (PL 204,
fig. 3), and a strong current flows out during ebb- tide, running, it is said,
from seven to eight knots per hour. The outward flow is regulated by the
strength of the trades; if they force much water over the weather side of
the reef, it continues sometimes to flow out for several days in succession.
On the interior of the western side of the pass a couple of small islands (PI.
204, fig. 3), Nui Nui, extend, of which the base is, as we shall see, made up
of tertiary coralliferous limestone covered over in part with recent stratified
beach rock or coral breccia and conglomerate.

' I give an account of each island and of the various groups we visited in the order in which we
examined them.

* Dana mentions such large boulders as occurring at Raraka, Kauehi, Manibi, and Aratika.

3

34 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

Between Tiputa and Avatoru Pass (PI. 4, fig. 1) the outer islands are
flanked on the sea side with steep coral sand beaches alternating with
reaches of large boulders (Pis. 4, fig. 2; 13, fig. 1) extending on the
inner face of the shore platform to the foot of the sand beach or reaching
across the low cuts into the lagoon (Pis. 8 ; 9, fig. 1 ; 12, fig. 2 ; 13, fig. 2).
When the coral sand beaches are high, the boulders on the platform are
usually absent, having been ground up into fragments to form the sand
beaches or the coral shingle beaches so characteristic, as we found later,
of the outer beaches of the atolls in the Paumotus (PI. 4, fig. 2), and
which often run unbroken for miles on the lee side of the atolls.

The reaches of old reef rock on the outer beaches ai'e mixed with recent
stratified beach rock (PI. 8, figs. 1, 11), or with a conglomerate or breccia of
corals, consisting of recent coral fragments and of fi'agments or masses of
the underlying tertiary coralliferous limestone, so that, unless one has had
some experience with the coral rocks composing this heterogeneous mass, it
is difficult to make out its composition, and it would be most natui'al to
assume that the conglomerate or coral breccia was composed only of frag-
ments of recent corals more or less weathered, cemented together, after
having been piled up on the underlying tertiary coralliferous reef rock.

Avatoru Pass (PI. 4, fig. 1) is nearly a quarter of a mile wide and more
than half a mile long, with a depth ranging from 15 fathoms at the outer en-
trance to three or four fiithoms at tlie bar (PI. 205, fig. 3) on the inner side
of the pass, which deepens rapidly to 9 or 10 fathoms towards the interior of
the lagoon. The bar is more or less connected with the spit which extends
from the southern point of Brander Island (Motoufara). On steaming in we
found a strong current of from four and a half to five knots running out of
the lagoon. In the pass itself are corals growing in profusion down to 9 or
10 fathoms, then thinning out gradually to 20 fathoms. They also grow
abundantly on the inner lagoon faces of the islands forming the outer land
rim of the atoll, and extend into 5 to 9 fathoms. On the islets which
occur in the lagoon (PI. 205, fig. 3), such as Brander (PI. 12, fig. 1) and
Mohican Island (PI. 7). corals are found on all the slopes extending
into the deeper water of the lagoon from two to three feet to 8 or 9
fathoms. The inner extremity of Avatoru Pass is cut in two by Brander

RANGIROA. 35

Island ; to the west of it is a narrow passage not more than a tenth of a
mile in width, and with about six fathoms. The slopes of the sides of the
pass are steep, and the current rushing through it is often so strong that it
is impossible, at certain stages of the tide, to attempt to steam against it.
About six miles to the east of Avatoru Pass is another deep passage much
narrower and somewhat more shallow (Tiputa Pass, PI. 204, fig. 3).

The first appearance of such an atoll as Rangiroa was very different from
that of any atoll I had thus far visited. The lono-line of narrow low islands
covered with cocoanut trees (Pis. 4, fig. 1 ; G) forms the only visible land
of the atoll ; extending eastward and westward as far as the eye could reach
was presented an aspect very different from that of the atolls of the Fijis,
and I was STcarcely prepared for this great difference, in spite of the descrip-
tion given of them by Beechey and Dana, though the account given by
Lesson of the belt of low sand i.slets thrown up on the barrier reef, and
covered with cocoanuts and low shrubs, surrounding the volcanic i.slands of
the Society group, had prepared me for what I saw in the Society Islands.

At a first glance it would seem as if the outer land rim had been formed
from tlie disintegration of the material thrown up on the reef platform,
forming either a coral shingle or a coral sand beach. Upon the outside
shore or in the reaches stretching across the narrow land rim to the lagoon,
but few boulders or negro-heads are left to indicate the former position of
the old land formed of tertiary coralliferous limestone, the greater part of
which has been eroded to below low-water mark or thereabout, when the
process of building iip again commenced, — a process which has not been
recognized by those who have attributed to subsidence the existing con-
ditions in the Paumotu atolls.

In atolls of such a size as Rangiroa, nearly 45 miles long and from
12 to 14 miles wide, the conditions become very different from those
which affect smaller atolls. The prevailing southeast trades sweep nearly
parallel with tlie longer axis of the atoll, and naturally considerable
sea is constantly washing the bars, knolls, and islets found in the large atolls,
acting upon them in many instances, according to their position in the
atoll, much as if they were exposed to the full force of the seas which break
upon the outer sea-shores of the i.slands on the land rim of the lagoon.

36 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Brander and Mohican Islets (PI. 205, fig. 3), which project partly across
the western side of Avatoru Pass, and Nui Niii Islet, which holds the same
position to Tiputa Pass (PI. 204, fig. 3), show the whole proce.ss of disinte-
gration and ei'osion of the old tertiary coralliferous limestone to below low-
water mark. During this erosion it has not been planed off uniformly ;
some parts have been more easily washed away, leaving ledges and ridges
of the old rock, and the spaces between tliem have been filled by the
formation of the recent beach rock, breccias, and conglomerates (Pis. 8,
fig. 2 ; 9, fig. 1; 11). The former greater extent of these islands and
islets is indicated by the prolongation lagoon ward of the inner platform,
on which are still found here and there boulders of the old reef rock
(Pis. 9, fig. 2; 13, fig. 2), resting upon it, associated with boulders of the
modern beach rock gradually passing into the modern reef flat.

The vegetation on the lagoon side of the outer land rim is usually more
luxuriant (PI. 6, fig. 1) than on the sea face, and immediately behind the
highest part of the beach slope (PI. 5), where the shrubs and bushes and
trees are exposed to the more violent winds which sweep in from the sea.
It is remarkable how uniformly the winds and seas follow the outline of
the lagoon, making it quite difficult, from the prevailing swell, to effect a
landing, except under very favorable conditions, on the sea face of the lee
islands of an atoll.

The bottom of the lagoon at our anchorage in 9| fathoms consisted
of incrusting NuUipores and coralline Algee, forming, as a general
rule, a hard coating upon the bottom. Similar bottom was found
everywhere in the lagoon on the line from Avatoru Pass to Tiputa Pass,
and on the line carried across the lagoon by Lieutenant Rodman from
our anchorage to the weather side of the atoll (PI. 204, fig. 4). A few
shoals were found, and an islet (PI. 19) similar in its structure to the islet
west of Mohican Island. The soundings varied from 14 to 17 fathoms
(PI. 204). The bottom consisted entirely of hard Nullipore growth.
Nothing came up in the boat dredge, and the depth was quite uniform.
The same hard Nullipore bottom appears to cover the bottom of the lagoon
wherever there are no coral patches. Corals occurred in the lagoon in exten-
sive patches in from two and three to 10 fathoms of water, both along the

RANGIROA. 3 1

lagoon fiice of the reef platform on the weather and lee sides ot" the lagoon
and on the slopes of the islets found in the lagoon.

On the lagoon side of the lee land the steep beach in places is made
up of fragments of coral more or less weathered, and forming what I
may call coral shingle (Pis. 6, fig. 2; 9, fig. 2). "When examined, the
shingle is found to be composed of fragments of recent species of corals, of
fragments of beach rock, of pieces of coral breccia or conglomerate mixed
with fragments of the old tertiary reef rock or corals disintegrated from
it. The breccia and conglomerate on the lagoon and sea face (Pis. 5, 8,
11) also are made up in part of modern material and in part of fragments
of the old reef rock torn by the waves from the edges and sea face of
the old platform and thrown up on the beach in benches.

On crossing the island to the east of Avatoru Pass, we came upon the
different stages of its growth as first formed by the disintegration and
erosion of the old tertiary ledge, then of its fragments thrown up towards
the interior, mixed with those of recent corals growing at that point. Near
the gendarme's house we came upon a ledge of old reef rock (tertiary cor-
alliferoas limestone) in dtit about seven feet above high-water mark. In
the central part of the island, which varies in width from 800 to 1200
feet, are found large loose masses of recent beach rock, corals, and old reef
rock, together with finer and coarser blocks of coral. In the depressions
near the edge of Avatoru Pass and in some parts of the centre of the
island we come upon the ancient reef rock in situ. At a point near the
entrance to Avatoru Pass, on the east side, a projecting ledge consisted
in part of recent conglomerate and in part of ancient reef rock, which
had been eaten away to form the adjacent beach. On the sea face the
slope of the outer beach was covered with fragments of old reef corals
and coral rock which had been thrown up, mixed with the worn fragments
of recent reef corals, forming a gray shingle on the beach nearly 16 feet
high. In fact, the same conditions which exist on the lagoon face exist
on the sea face of the island.

Isolated Astrajans are growing on the old reef rock plateau, which is
planed off" to a general level, and honeycombed and pitted and grooved and
covered with sharp points projecting from the surface of this flat ledge.

38 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

On the south shore (the lagoon shore) of the outer island this ledge projects
in an irregular outline from the shore, and in many places is completely
hidden by the overlying stratified recent beach rock or the recent breccia
and conglomerate. I was informed that at Kaukura there were great
outliers of old reef rock fully 17 feet above the general level of the lagoon
plateau.

A section made across the land rim east of Avatoru Pass from the lagoon
side to the sea is quite simple. Starting from our anchorage in 9| fathoms
at a distance of about half a mile from the shore, the water shoals very
gradually to three or four fathoms, where we came across patches, some of
considerable size, of Porites, of Madrepores, and of Pocillipores, growing
either on the slopes of the outcropping reef flat or on its surface.
We then came to the base of the steep coral sand beach or coral shingle
beach from six to eight feet in height, at the base of which crops out here
and there the recent stratified beach rock or conglomerate.

The lagoon beach to the east of Avatoru village is an excellent example
of the character of an inside beach of one of the larger atolls (PI. 6, figs.
1, 2). Tlie beach is steep, with a bench at a height of from five to six feet ;
below it the slope is covered with moderately fine sand made up of coral
and broken shells. The upper part of the shelf above the bench consists
mainly of broken shells, large fragments of recent corals, more or less
worn, and of fragments of old reef rock and old reef rock corals, the
latter derived from the disintegration and erosion on the lagoon side of
the edges of the same platform which crops out as the reef platform on
the sea face, and forms the underlying base of the lee land of the atoll.
This platform varies greatly in width ; usually it is much narrower on the
sea face of the land rim, being sometimes not more than 75 to 150 feet
wide (PI. 11), while on the lagoon side the old platform is at times more
than a mile wide. The shingle of coral and shells is weathered and thrown
up to the very top of the beach from seven to eight feet above low-water
mark ; it consists of pieces of coral shingle varying in size from a walnut
to that of one's fist, and on the slope of the shelf of pieces varying from a
half to two inches, intermixed with more or less coarse coral sand. At the
foot of the beach slope, near low-water mark, both above and also below

RA^GIROA. 39

it, crop out bands of recent beach rock (PI. 9), stratified and dipping at a
slight angle towards the lagoon ; between the patches of beach rock are
heads of old reef rock, either as boulders which had been separated from the
lagoon edge of the old reef rock ledge and thrown up on the beach slope, or
still attached to the ledge, large pieces of which occasionally crop out inland,
but usually so hidden and covered by the surrounding fragments of recent
beach rock and fragments of corals that it is difficult to decide whether they
are part of the ancient reef i-ock ledge or liave been thrown up by the sea
from the lagoon face of the old ledge of the island.

From its highest point the beach slopes inland, and forms the outer dam
of a shallow sink in which fresh water collects. This lagoon sink (PI. 205)
is better developed in other islands, and will be described elsewhere. In the
rear of the village, to the eastward, the sink becomes a small shallow pond
which furnishes a large part of the fresh-water supply of the natives. On
the northern side of the sink the ground rises again, is undulating, and is
composed mainly of beach rock, the interstices being filled with coral shingle
and sand, which extends to the southern face of the high coral sand and
shingle beach facing the sea. The top of the outer sea beach is in places
fully 15 feet high, and is, like the inner lagoon beach, composed of coral
sand at the lower part of the slope, and of coral shingle towards the top.
The shingle extends inland in a comparatively gentle slope for quite a
distance, and finds its way between the cocoanut and low trees and shrubs
forming extensive broad lanes entirely devoid of vegetation. Isolated shrubs
often begin to grow on the sea face of the outer beach ; they increase some-
what towards the top of the beach, and form usually quite a thick growth
at or immediately behind the summit. The vegetation consists of many of
the same plants found on the Fiji reefs, and which are as a whole character-
istic of all the Pacific coral reef islands.

At the base of the outer beach extends the shore platform (Pis. 8, 11, 12),
the underlying bed of which consists of old tertiary coralliferous limestone
more or less concealed by stretches of recent beach rock. The shore plat-
form at this part of Kangiroa varies from 75 to 150 feet in width, and is
flanked on its very outer edge by a ridge of Nullipores and of Pocillipores ris-
ing from two to four feet above the general level of the shore platform, which

40 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

thus forms a shallow shik, the outer NuUipore edge forming as it were the
diminutive barrier reef of a shallow and narrow lagoon on the outer part of
the shore platform (PI. 4, fig. 2). The outer wall and outer edge of the plat-
form are cut into by deep gullies, into which the breakers rush with great
violence, forcing the sea into the lagoon area of the shore platform, and at
contracted spots throwing up huge columns of water in the air.' There
is usually a considerable current formed in this platform lagoon, towards
the nearest lowest part of the Nullipore ridge.

The shore platform is nearly devoid of growing corals. A few small
patches and heads are found here and there in the platform lagoon ;
towards the outer edge they become somewhat more numerous, and on the
sea face or the summit of the Nullipore ridge they often cover quite large
areas. The inner part of the platform lagoon is often covered for long
reaches with masses of recent beach rock, or masses torn off from the Nulli-
pore ridge which finally have become isolated and undercut by the encroach-
ment of the deep gullies into the shore platform. These deposits often
completely conceal the underlying old tertiary reef platform. The islet
about 2^ miles south of Mohican Islet shows this well ; there huge masses of
modern reef rock and beach rock have been forced by the waves of the
lagoon over the old reef rock and into the spaces between the ridges of this
rock wliich constitute the substratum of the islet.

Mohican Islet (PI. 7, fig. 2) is also composed of old reef rock which has
gradually been decomposed and eroded to the level of the lagoon, in which
it forms a flat of considerable size ; on Brander Island there is considerable
building up going on from the washing up of the ledge sand into bars and
islets and from the formation of recent beach rock on the underlying
plateau of old reef rock, thus preventing the further disintegration and
erosion of the island. On the lagoon slopes of both these islands corals are
growing in from one to five fathoms or more, but they diminish rapidly
after six fathoms.

In the channel to the west of Brander Island corals grow as far as nine
to ten fathoms ; they are mainly Madrepores, Porites, and Astrieans.

Following the shore line of the lagoon from Avatoru to Tiputa Pass, we

* See ihe figures of the blow-boles of Tongatdbii (Pis 1 17, 118).

EANGIROA. 41

found the bottom clear of corals in from nine to ten fathoms. It was
only between four to six fathoms that they began to appear in patches.
They were mainly rather small heads of two species of Astrteans.

At Rangiroa I saw for the first time a feature which turned out to be
very characteristic of the structure of the Paumotus as well as of the Society
Islands, and explained in a very clear way the mode of formation of the
outer land rim islands upon the sea face of the platform of the barrier reefs
surrounding the volcanic islands of the Society Islands, or forming the rims
of the Paumotu atolls. I had noticed, as we first steamed along the outer face
of the Rangiroa atoll from the eastward of Tiputa to Avatoru Pass, that the
high outer beach was here and there greatly depressed, and in some instances
the depression was suflicient to open out a view into the interior of
the lagoon across a shallow passage, through which in some cases water
was flowing from one face of the island to the other, in others the shallow
channel reached but a short distance into the island either from the sea
face or the lagoon side. These depressions (Pis. 9, 10; 13, fig. 1) were
usually indicated on the sea face by stretches of boulders extending on
both sides ; and as these were disintegrated they gradually disappeared
both to the north and south of the openings, having gone to build up the
coral sand and shingle beaches of the sea face of the outer island. There
were no less than five such cuts in the island between Avatoru and
Tiputa Pass, dividing the island into parts connected at low tide only, and
separated at high water by narrow channels, from 75 to 100 feet in
width and with one to three feet of water (Pis. 8-11). The first cut to
the east of Avatoru Pass was Y-shaped, the main branch extending
across from the lagoon to the reef platform nearly in a straight line,
the other bi-anch forming a cul-de-sac extending about two thirds of
the way across the island from the lagoon face. A high steep coral sand-
beach forms a sort of dam across the opening of the cut on the lagoon side
(like that of PI. 13, fig. 2). The greater part of its channel has been cut
through beach rock and low masses of coral fragments and a conglomerate
composed of pieces of recent corals and of corals and smaller fragments
washed out from the old ledge platform, which is exposed at several points
at the bottom of the main cut.

42 ■ "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

A low coral sand beach is tlirown up across the lagoon side of the second
channel ; this only stops access of the water at half tide, .and forms a series
of shallow pools which run across the depression for a distance of perhaps
1000 feet fi-oni the lagoon side towards the sea face (as in PI. 9, fig- !)•
The pools open into the lagoon through narrow channels. The central part
of the depression also exposes, as in the case of the first cut, the old reef
rock ledge, and it is topped with recent beach rock and conglomerate
and worn fragments of recent corals and of pieces of the old ledge.
The sea face of the cut is quite narrow, passing between the extremities
of a steep coral sand and shingle beach which will shortly connect across
this narrow channel and completely block access of the sea into the cut.
The same thing will in its turn take place across the lagoon end of the cut
(PI. 9, fig. 2), so that when access of the sea is completely shut off both on
the lagoon and sea face there will remain in the cut near the centre of the
island only a shallow pond, which will in its turn be gradually filled with
sand blowing over the high beaches from the inner and outer faces, and
eventually form a part of the island, to be little by little covered by the
vegetation usually found on reef islets. In this manner many of the sinks
of the Paumotus have been formed. At the second cut the reef flat plat-
form, viz., the old ledge platform, is fully 250 feet wide, and has been
planed off, as it were, having a slight rise towards the base of the sand-
beach. The rollers lose much of their force comina: in over the outer
edge of this ])latform, which is slightly raised and falls off rapidly into deep
water.

The third cut was partially closed both on the lagoon and sea faces,
leaving but little access to the water except towards high tide. The
shingle across the passage was as high as the shingle on either side of the
passage.

The fifth cut is shut off on both faces, on the lagoon side, by a coral
shingle bank of about four feet in height, with a brackish pond near the
lagoon side of the island. In the cut parts of the old ledge were exposed,
and like the others it was cut through a superstructure of recent beach
rock and conglomerate and masses of recent corals and fragments of old
ledge. The passage was about 30 to 40 yards wide. On the sea face the

EANGIROA. 43

opening of the cut was filled with fragments of beach rock and an agglom-
eration of fragments of large rocks and masses thrown up from the reef
platform.

At the third cut there is a high dam, composed of coarse coral fragments
and sand, from five to six feet high, placed directly across the lagoon open-
ing, with a narrow channel leading into the lagoon from a large pool behind
the dam, about 60 feet wide and not more than six inches in depth. The
channel is partly dry in the middle, and covered with fragments of coral,
as are the sides. On the sea face and on the lagoon side the old ledge rock
is cut through, and a conglomerate composed of old and recent corals is ex-
posed on the flanks of the cut. Across the centre of the cut, on the sea face,
a bank has been thrown up, similar to the beach to the east and to the west
of the cut, leaving a channel on each side and not quite closing the sea
entrance. The channel is deeper on the west side of the central beach.
The old ledge is exposed about 150 feet to the south of the sea beach, and
is topped here and there with a conglomerate composed of recent and old
reef rock. The mixture of this old and recent material makes the deter-
mination of the composition and age of any particular stretch of reef rock
somewhat complicated.

Across the lagoon side of the fourth cut extends a dam directly across
the channel. This was a shallow depression perhaps 50 feet wide, filled
with fine sand to about 100 yards of the outer beach, where the old
reef rock ledge cropped out. The sea face channel was open. The sea
platform was cut by the sea into numerous tide pools ; the rocks and
boulders above the reach of the breakers were pitted and honeycombed
in all the cuts which were wholly or partly shut off, showing that for a
considerable time no currents had passed over them. The sides of the cut
indicated that it was made up, as are the other cuts, of a conglomerate of
broken masses of both recent and ancient corals, and fragments of modern
beach and old ledge rock.

The sea face of Rangiroa consists of a steep, coarse coral sand beach
made up near the summit of coral shingle, the fragments of which are from
two to three inches, with finer material at the base of the beach. This beacli
is flanked for a distance of 75 to 100 feet by a mass of fragments of old reef

44 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

rock thrown upon the shore platform, many of them of great size (PI. 11).
Two masses were measured, one 18 feet long by 5 wide, and varying in
height from 6 to 7 feet; another nearly cubical mass measuring 9 feet.
These masses are detached during storms or b}' high seas from the sea face
of the old reef ledge and hurled towards the shore, where they are gradually
broken up into smaller masses (Pis. 8; 12, fig. 2), and eventually ground
into the high coral shingle (Pis. 5 ; 12, fig. 1) and sand beaches of the sea
face ; or are outliers of the old ledge platform.

The old reef rock ledge exposed in the cuts (PI. 9, fig. 1) can be traced
all the way across the land rim till it merges into the old ledge of the sea
face flat (PI. 8, fig. 2), and with its extension on the lagoon side, which can
be traced reaching into two to three fathoms. On the lagoon side similar
masses, but smaller (PI. 9, fig. 2), have also been thrown up after being de-
tached from the outer edge of the lagoon platform, or they are left as on
the sea face standing as remnants still connected with the ledge of the old
reef rock of tertiary coralliferous limestone. Some of these ancient masses
projected in the bushes beyond the line of vegetation. It was of course not
always possible to determine whether they were parts of the old lodge or
loose boulders more or less covered by the surrounding fragments of loose
corals. When below low-water mark their connection with the old ledge
was concealed b^' the mass of beach rock and fragments of conglomerate
surrounding the lower parts.

Nui Nui Island, off the lagoon entrance of Tiputa Pass, is, like Mohican
Island, composed of ancient reef rock ; the extremities are being gradually
cut up into masses and smaller boulders, and finally spread out into the
coarse sand flat. The destruction of the islands and islets off the lagoon
side of Tiputa and Avatoru Passes (Pis. 7 ; 12, fig. 1) shows plainly how
much material has been removed from the inner ledges of the lagoon, gradually
reducing them to the water's edge, and finally, by the action of the waves
and currents, as well as the solvent action of the sea, gouging out the
inequalities of the lagoon, deepening it little by little, — agencies which
have been at work steadily since the last period of elevation of the tertiary
coralliferous limestones, when the area of the exposed limestones was not
only far greater than it is at the present time, but when the land probably

EANGIROA. 45

rose to .1 somewhat greater height than that of the highest tertiary
limestones found in the Paumotus.

Wherever we examined the bottom of the lagoon we found it generally
quite barren of animal life, and covered with a hard Nullipore bottom and
coralline Alga3. Fish were quite abundant in the lagoon, and on the flats; in
two to three fathoms, corals and other invertebrates flourished. The patches
of corals were generally most abundant on the slopes of the ledges and flats
in from three to five fathoms.

The land rim surrounding Rangiroa is quite narrow ; the islands of the
land belt are not more than 1000 feet wide, and in many places less than 500,
and they are limited to the northern and western sides. The islets of the
northern side are wooded. On the southern side (PI. 204) the land belt is
reduced to a few wooded islets (Pis. 13, fig. 1; 14), the long reaches between
them being composed of a wall of old reef rock from 10 to 14 feet in height.
It forms the culminating point of the windward sea face platform of the old
ledge, which varies in width from 250 to 500 feet, and of its lagoon ex-
tension, which can be traced for a mile to a mile and a half as it slopes
gradually into eight to ten fathoms of water ; the lagoon slope is covered
with patches of coral.

The little islet of Paoi, on the way to the south shore, is an elevated old
reef ledge with many fossil corals (Pis. 18, fig. 2 ; 19). It is about 12 feet
high, and it, as well as Tiarari to the southward, and the few ledges we found
scattered through the lagoon, are the remnants of irregular peaks or ridges,
or spurs of the land once covering the area of Rangiroa, which have been
planed down and eroded at the same time as the higher parts of the belt of
land comprising the northern and southern ridges of the atoll.

On Plate 204 I have given the Ime of soundings run across the lagoon
ot Rangiroa by Lieutenant Rodman. It will be noticed that the deepest
part of the lagoon is near the northern land rim of the atoll, and that the
floor of the lagoon has a very uniform depth ranging from 10 to 16 fathoms,
the central part of the lagoon varying from 14 to 16. The slope of the
lagoon flat extending north from the southern land rim is much flatter than
the lagoon slope off the northern land rim, where it runs rapidly into ten
fathoms ; while the lagoon reef flat of the south shore extends more than

46 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

two miles before we obtain a depth of over five fathoms. The lagoon
slope of the old ledge as it extends eastward from the southern land belt is
quite shallow (Pis. 15, fig. 2 ; 16). About two miles from the south shore the
lagoon is not more than two to four fathoms deep, and the surface is covered
with huge patches of corals, mainly Porites and Astraeans, as well as Madre-
pores and Pocillipores, at a depth corresponding to that where flourish the
corals on the north side of the lagoon, both to the west and east of Avatoru
Pass. We landed on the south side of Funuarua Island, the largest of the
islands on the windward face of the lagoon (PI. 16, fig. 1). This island we
found, like those on the land belt of the north side, to be in reality a
chain of islands and islets, separated, like them, by cuts, only the cuts were
much more marked, and the process of formation of the islands of the land
belt was much more apparent than on the north side. At our landing-place
we found a cut fully 200 feet wide running directly across the island (Pis. 15,
fig. 1 ; 16, fig. 2) from the lagoon side to the great wall of ancient elevated
reef rock which shuts it off completely from the southern or windward side.
This wall was fully 12 feet high (Pis. 15, fig. 2 ; 17, fig. 2 ; 18, fig. 1), and
is the remnant of the ancient coralliferous limestone ridge which flanked the
southern side of Rangiroa, and which Dana^ described (vicariously) while
coasting along the southern face of Rangiroa in the " Peacock."

This old ledge is deeply pitted and honeycombed and eroded into all
kinds of fantastic spires and pinnacles (Pis. 15, 17 ; 18, fig. 1) and walls (PI.
14, figs. 1, 2) cut through by crevasses extending from low-water mark to
the summit, which is more or less covered by the high sand beach accumu-
lated behind it on the lagoon side. This beach completely conceals the
extension of the old ledge (PI. 16, lig. 2) under the island ; it has been
formed from the disintegration on the lagoon side of the extension of the
ledge (PI. 15, fig. 1), and has been piled up to a height of from 10 to 15
or even 18 feet against the great sea wall of old reef rock which extends
almost unbroken from the northern point of Rangiroa to its southwestern
end.

The island we examined (Funuarua), as well as the islands and islets
to the westward, are all built up at right angles to the trend of the coast.

1 Dana, loc. cit. pp. 20,!, 369.

RANGIROA. 47

Funuarua is perhaps 1000 to 1200 feet wide ; the smaller islands near it
gradually become narrower as we pass to the westward, forming shorter
and shorter dams separated by channels varying greatly in width and in
depth (from one to two feet).

The larger and higher islets, covered with bushes, low trees, and cocoa-
nuts, gradually pass into smaller and lower islets with less and less vegeta-
tion, until we find, as buttresses to the sea wall which separates all these cuts
from the sea face, mere sand bars extending into the lagoon (PI. 14). To
the northward are a few islands and islets, centres of such sand accumula-
tions, where the great sea wall and its extension into the lagoon is hidden
by the butt of the sand bars accumulated against it. The great sea wall
is inore or less cut into fragments, and open here and there to the passage
of breakers which roll in upon the wide ledge fiat which skirts the whole
southern face of the atoll, — a fiat fully two to two and one half miles wide
from the sea face to the two-fathom line on the lagoon side. A short distance
from the wall on the hrgoon side one can see the white line of breakers rising
above it and losing itself through the openings on the reef fiat, or appear-
ing in the cuts between the islands as a white line on the top of the dark
wall of the cul-de-sac. From the last island which we could see to the west-
ward (Taeroere) there is also a long stretch of this bare wall with here and
there a sand bar buttress on the lagoon reef fiat.

In the large cut we examined we could trace the extension of the old
reef rock toward the lagoon as a more or less distinct slope of the great
wall until it became lost in the centre of the cut; then only occasional rocks
jutted out here and there above the water line to disappear and pass into
the slope of the lagoon ledge (PI. 16).

On the sea face of the wall extends a reef flat platform fully 450 feet
wide in places, the surface of which is deeply pitted and honeycombed and
planed off to a general level (Pi. 17, fig. 1). On the outer edge, which is
somewhat higher than the depressed edge near the base of the great wall,
Pocillipores grow in abundance, and the whole of the platform is more or
less protected by a growth of encrusting Nullipores of a pink or brown
color. The Nullipores appear to thrive best on the raised outer edge of the
reef platform. With the incoming tide the water rushes into the secondary

48 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

platform lagoon through the deep cuts wliich indent the outer edge of the
reef platform, and creates a current of considerable strength parallel with
the shore line. A few large masses of reef rock were scattered upon the
face of the outer reef platform. There was little animal life in the pools on
the reef flat.

The base of the outer slope of the great wall varies in width from 100 to
200 feet; the top, the height of which i-anges from 10 to 14 feet, is per-
haps 50 feet wide, and the buttresses are well marked for 100 to 350 feet.
These buttresses of old reef rock could also be traced across the base of the
islands (PI. 14). •

Steaming to the westward of Avatoru Pass, we kept close to the land rim ;
this retained the general characters it possessed to the eastward, a succes-
sion of sand beaches and ledges and a wide shore platform. The land rim
consists of a long narrow island, which finally tapers off into a series of
islands placed iipon a nari'ow outer reef, the horn of which is quite sharp at
the northwest point, and forms on the western extremity a long reef flat
covered with low islands and islets. Tlie corrected sketch of the western
part of the island, given in PI. 204, is very different from that outlined by
Wilkes. After rounding the northeast corner of Rangiroa, we came upon
a series of gaps in the island very much wider than those we had seen
between Avatoru and Tiputa Pass. The old ledge was exposed here and
there in the gaps between the islands and islets, as well as on the sea face of
the islands. The gaps were of varying width and depth. In some cases
the beach I'ock had been piled up in irregular low heaps so as to leave no
access into the lagoon except to high seas. In others there were shallow
irregular channels allowing a more or less free access to the sea, while in
other cases the gaps were shallow channels with a depth of from one to three
feet at low tide, allowing the water to flow across the outer lagoon flat.

After we passed the northeast point of the atoll the outer islands became
smaller and separated by wider gaps, exposing to view the whole width of
the shore platform and of its extension into the lagoon flat. The islands
thus far were for the most part covered with shrubs and cocoanut trees,
but we now began to strike low sand bars and islets ([uito bare of vegeta-
tion. These bars extended at right angles to the shore line across the

EANGIKOA. 49

lagoon flat, the highest point nsually being on the lagoon side of
the flat.

' The formation of sand bars and islets at right angles to the trend of the
outer reef flats is a most characteristic feature not only of the Pauinotus but
of other atolls in the Pacific. These bars or islets are mainly the results of
two causes: the rushing of the water into the lagoon, and the wash of the
trades along the lagoon face of the land rims. The accumulations of coral
shingle and boulders derived from the decomposition of old ledge and
modern reef conglomerate act as jetties across the face of the reef flats.
The material worn from the flats, both on the sea face and on the lagoon
side, is thus deposited on the flanks and extremities of the jetties. The
sand bars and islets thus formed often jut as long spits far into the
lagoon, and the beaches flanking the spits form a series of loops connected
at the base or leaving gaps for the passage of the sea in and out of the
lagoon. The material for these sand bars and islets is evidently derived from
the disintegration of the lagoon reef flat and is thrown up by the waves as
sand to form these bars and islets ; they gradually increase in size and be-
come at first covered with scanty shrubs and finally with cocoanut trees.
That seems to me to have been the history of the formation of the land belt
on the lee side of Rangiroa. Local conditions of winds and tides and cur-
rents, as well as position in the outer belt of the atoll, all tend to make
certain points centres of accumulation and of rapid building up of islands
and islets, while at other places there is maintained a fair equilibrium be-
tween denudation and erosion and building up, and at other points all pos-
sible combinations of these two states. These conditions have, of course,
commenced to act on each atoll at somewhat different times, and have re-
sulted in modifications which will be noted in the description of the various
atolls. The changes all date back to the time when the original land flat,
or low ridge of elevated tertiary coralliferous limestone, which occupied the
area of tlie atoll began to be cut down to the level of the sea, and formed
finally on the sea face of the atoll the great shore platform which charac-
terizes the Paumotu atolls. The cutting down of the summits of the ridges
of the land rim, and of the islands or islets or bars in the lagoon to the same
level, supplied material for filling up in part the adjoining depths of the

50 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

lagoon, or the materials were piled up as islets on the outer flat, or carried
away across it, or washed out in solution; the disintegration of the land
rim by the waves and the solvent action of the sea all tending to deepen the
lagoon and to clear it of islands and bars and ledges. In the larger atolls
especially they are cut to a general level from which only here and there
islets and bars rise to attest the former existence of larger areas of land
within the atoll, as will be shown in the description of atolls like Taha-
nea, Anaa, Marokau, and Ravahere, and of atolls in the topography of
which islands, islets, and flats play an important part.

To the southeast of the northwest point of Rangiroa, the great wall of ele-
vated ancient coralliferous rock begins, extending towards Taeroere Island,
which we had seen, with the wall extending towards it, from the island of
Funuarua. On the south side the reef flat is of great width, varying from one
to two miles and more. The wall rises from the shore platforni itself, from
300 to 400 feet wide, to a height varying from 8 to 15 feet.' At various
distances behind the wall, and in the rear of the larger islands and islets
which are more or less covered with vegetation, and which abut against the
wall, are bars and islets of sand forming on the inner edge of the lagoon
reef flat and extending towards the wall, until they finally form a buttress
or a narrow island behind the wall, which closes more or less the gaps inter-
vening between the lines of bars and islets and islands built up on the outer
land belt of the south shore near the northwest point. Some of the bars have
very scanty vegetation ; as they grow larger, this increases ; a few cocoanut
trees occur, and the larger islands, occupying the whole width of the land belt,
are well covered with vegetation and cocoanut trees. On the southwest side
the gaps between the islands become of great width ; some of them are several
miles across. The great wall is the most prominent feature, and runs appar-
ently without a break, not only across the gaps but also across the butts of
the islands. In some places the sand beach which has accumulated behind
the wall encroaches gradually upon the sea face of the wall itself and con-
ceals it so that spurs of the wall only crop out here and there on the face of
the beach. The contrast between the brilliant white sand bars standing out
against the green water of the shallow edge of the lagoon and the sand

^ Dana has described what I take to be similar tertiary limestone from Honden and Manihi.

RANGIROA. 51

islands piled up behind the wall on the lagoon flat is very striking; the
dark ragged points, the spires, the columns, the buttresses and walls stand-
ing out prominently from the light background. Thundering upon the
outer shore platform fall the huge rollers, which break at the base of the
wall and spend themselves on the platform, or at high tide throw the water
flir over the top, or force it through the openings between the undercut
and honeycombed columns and spires of which the wall is made up.

There is a strong current making towards the lagoon through the gaps
where the rollers force their way in, and also in the gaps between the islets
wherever there is a passage for the sea, which is driven by the trades against
the weather side of the atoll. Where there is no pass we found upon the
shore platform, which is furrowed into a diminutive barrier reef and its
lagoon, a similar current flowing westward in the direction of the pre-
vailing winds. The decomposition and disintegration of the great wall sup-
plies a certain amount of coarse sand which is thrown up on the top of the
great wall and tends to conceal it; in addition sand is supplied from the
lagoon side flat, to form the high sand beaches which extend beliind
the sea wall and form the ridges of the higher islands or islets, which rise to
a height of perhaps 18 feet, or else form the high and steep sand beaches of
the islands to the east of Funuarua ; on the face of these project here and
there buttresses of the wall, at the foot of which are piled up masses of old
reef rock torn from the outer raised edge of the shore platform and thrown
up at the base of the sand beach.

To the eastward of the nucleus of islands and islets of which Funuarua is
the centre, we could see, as we steamed away, extending to the easternmost
point of the island, islands and islets similar apparently in all respects to
those we had examined.

In comparing the desci'iption given by Dana of the great wall occupying
the southern face of Rangiroa with what we saw, it is impossible to make
them agree. Dana speaks of the absence of islands on this face. It does
not seem probable that there should have taken place in sixty years such
extensive changes as are suggested by the description of Dana. The natives
whom I questioned assert that the condition of things which we found was
practically what it has been with very minor changes. It is probable that

52

"ALBATROSS" TROPICAL PACIFIC EXPEDITION".

at the distance at which the "Peacock" sailed, slie might have seen only
the bare jDart of the southwestern part of the atoll. But as Dana's
description is not ba.sed upon his own observ;ition, too much reliance should
not be placed upon what he states on the authority of others.

t (

Old Ledge Dam and Spur, Lagoon Side ok West Coast of Hangiroa.

Tikahau.

Plates SO, figs. S-^ ; 201, W2 ; Wi., fig. 4-

On approaching the west side of Tikahau, we found it much like the west
coast of Rangiroa, broken up into islands and islets (PI. 20, fig. 2) separated
by gaps, some of them of considerable width, with here and there reaches of
the old ledge cropping out in them, and in one place a part of the ledge was
standing in the gap as a honeycombed, pitted, and undercut mass of columns
of irregular shape, similar to the great sea wall ledge on the south shore of
Rangiroa. We could see several islets covered with trees in the interior of
the lagoon, as well as rocky ledges similar to the ancient wall ledge on the
outer land belt mentioned above (PI. 20, fig. 3).

The entrance to Tikahau is in a gap on the western side, between low
islands covered with cocoanut trees. The entrance is, like that of the
passes into Rangiroa, flanked with ledges and islets. The structure of this
atoll is in every way identical to tliat of Rangiroa, the sea faces of the
island belt being high sand beaches alternating with exposed ledges. The

TIKAHAU. 53

height of the cocoanut trees seems to show that the elevation of the island
belt, like that of Rangiroa, varies but little. Its islands and islets are
covered with similar vegetation. They are separated by gaps and open
passages, like those at Rangiroa, where the old reef ledge is exposed.

Tlie island belt must have been formed, like that of Rangiroa, by the
throwing up of the sand as dunes or bars and sand islets, upon the inner face
of the lagoon flat behind the sea wall of the old ledge. From the smaller
size of the lagoon and the proportionally greater mass of available material
as sand, the islands and islets formed a more solid land belt concealing the
greater part of the old ledge wall or leaving only a few patches of it exposed.
The building up of the land belt from the lagoon side in all directions is
quite marked in Tikahau. It is still more marked in Matahiva, and culmi-
nates, as we shall see, in the filling up of some lagoons in the smaller atolls,
as Whitsunday for instance. On the west side of Tikahau there are only a
few points where the ancient reef rock ledge is exposed ; it has either been
cut away or the inland buttresses are buried in the lagoon sand formed upon
the lagoon flat, so that it crops out only occasionally, usually in the gaps, and
rarely across the face of an island. The outer shore platform is from 150 to
300 feet in width, and the inner lagoon reef ledge from 600 to 1000 feet
or perhaps even more.

Tikahau is elliptical in outline, nearly fifteen miles long and ten miles
wide. The position of the southwestern part of the atoll is about
three miles more to the westward (Pis. 201 ; 204, fig. 4) than is indicated
by Wilkes's sketch in H. 0. Chart 85.

The southwestern and western face of the land rim is also, as we
saw it, far narrower than is indicated on Wilkes's sketch, consisting of
a narrow reef flat, bare at low water (PI. 20, figs. 2, 4), with only five
small, widely separated islets on the submerged rim. The western part,
as we observed it (PI. 204, fig. 4), differed greatly from the drawing given
by the U. S. Exploring Expedition. On the west side of the atoll the sea
had access to the lagoon through many wide and shallow openings separating
the islets forming the land rim.

It will be noted that the entrances to Tikahau and to Matahiva
are on the western face of these islands, while the entrances to Rangiroa

54 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

are on the north side. This may be due to the fact that the land belts
of the former atolls are rapidly building up from the lagoon side, the
tendency of the prevailing winds being to keep an opening clear on the
western faces.

Matahiva.

Plates 20, fig. 1 ; 201, 202; 204, fig. 4-

Matahiva, as seen about four miles off from the southeast, appears
well wooded, with cocoanut patches and an outer belt of vegetation of the
usual type characteristic of the Paumotu atolls. We could see traces of
the old ledge cropping out here and there, separated by sand reaches
which seem to have overwhelmed the ledge. There appear to be very
few large breaks on the eastern face of the island. I was informed by the
gendarme at Rangiroa, and by Mr. Edward Bonnefin, a former resident
of Matahiva, and now of Makatea, that the lagoon of this atoll is very
shallow, full of ledges and islets, and that one can get about in the
lagoon only in a flat boat. From what we could see steaming around
the island it is evident that the passes and cuts once separating the
islands and islets, similar to the single opening now left, through which
boats enter the lagoon (PI. 20, fig. 1), have been, as in other atolls of
the group, gradually closed by the sand blown along the inner shore of
the lagoon derived from the breaking up of the ledges of the interior ;
the sand blowing on the lagoon side of the outer edge of what is left
of the ledge, and gradually overwhelming it, the rapidity of this work
depending upon the amount of ledge rock exposed to the action of the
wind and sea inside of the lagoon.

As we steamed around Matahiva, the outer reef platform seemed to
be much wider than we had seen it either at Rangiroa or Tikahau ;
it varied from 200 to 300 feet in places, judging from the position of
the breakers relatively to the sliore coral sand beach.

Between the more or less continuous ridges of the old ledge, running
diagonally or at right angles to the beach, wide patches and reaches of sand
extend. From the greater width of the shore platform of this the western-
most island of the group more material is supjjlied on the sea face, and thus

MATAHIVA. 55

a higher coral sand beach is thrown up, and rapidly closes the cuts and
passes leading from the sea face to the lagoon as we had traced it on Rangiroa.

Great care should be taken to call a lagoon closed only when, as in
the case of Niau, the outer ring of land surrounding the lagoon is en-
tirely solid. Many atolls are called closed which, while having no
boat entrance, yet have many very shallow cuts and passes between the
islands and islets of the outer land rim, through which at nearly all
stages of the tide a large amount of w^ater passes, and is forced in
from certain directions by the prevailing winds.

On the beach of the northeastern shore a table-topped rock of old
ledge deeply undercut was a prominent object. Part of the shore ledge
undoubtedly consists of beach rock and modern conglomerate piled up
or formed between portions of the old ledge left standing, as on the north
face of Rangiroa, but the bulk of the ledge is made up of old elevated
reef rock ledge.

Matahiva is densely wooded, and much coral sand has been blown in
between the trees from the outer beaches. At the boat entrance into
Matahiva the old reef rock is well exposed on both sides, and through the
narrow pass we could see two wooded islets in the rear of the gap fringed
in part by the old reef rock ledge.

The coral sand beaches of Matahiva were from six to eight feet high,
and the remnants of the old ledges forming the summit of the land and
more or less overwhelmed by sand were from ten to twelve feet. The sea
was breaking heavily on the wide platform of the southwest point.

The condition of Matahiva as well as of Tikahau seems to indicate
atolls which are gradually filling from the sand blown into them, both
from the decomposition of the ledge of the outer beach and outer reef
platform, and from the sand of the lagoon side derived from the disin-
tegration of the islets and ledge flats, as well as from the material de-
rived from the lagoon shore platform.

The sketch of Matahiva given by Wilkes on H. 0. Chart 85 is not
correct. The atoll is triangular in shape (PI. 204, fig. 4), about seven
miles in length, and its position is nearly six miles more to the west-
ward than is indicated on the Hydrographic Chart.

56 "ALBATEOSS" TKOPICAL PACIFIC EXPEDITION.

Makatea.

Plates M-32; 201, 202; 205, fig. 1; and Figs. 7, 8.

Makatea is perhaps the most interesting of the Paumotu Islands, as
its structure gives us, in connection with Niau and Rangiroa and other
atolls of the Paumotus, the key to the structure of the whole group.
It is an elevated coralliferous limestone island, the highest point of
which is about 230 feet, flanked on the northeast and eastern sides by
perpendicular cliffs (Pis. 24, 25, 27) which are especially prominent on
the northern and northeastern point of the island as well as on the
easternmost point.. The southern face of the island slopes quite
gradually, and shows the lines of the terraces (PI. 29) which once
characterized the island before the extensive disintegration and denu-
dation which has reduced it to its present dimensions took place.
The terraces disappear on the western face of Makatea (Pis. 22, 23),
where they run into the steep wooded slope which characterizes that
side of the island. Makatea was visited by Dana, and he has given
a sketch of its appearance as seen from the sea facing the west
coast,' as well as a description of its principal features. The island
is four and a half miles long, and its greatest width a little over a mile
and a half^ (PI. 205, fig. 1).

The island of Makatea is irregular in outline (PI. 205, fig. 1). The
southern part of the island is more or less rectangular ; the northwestern
angle extends into an elongated point tapering somewhat towards the
northern extremity of the island ; the northeastern fiice is concave ; its
western face runs nearly north and south; the southern face is convex,
and the eastern face, the shortest, runs, like the western face, north and
south. Its greatest width extends from the southeast point to the east
face.

The southern and eastern faces are flanked by a sand beach,
and on the western face two coral sand beaches, separated by low ver-
tical bluffs belonging to the first terrace, occupy the greater pai-t of

1 Dana, J. D., Geology of U. S. Exploring Expedition, p. CT; Corals ami Coral Islamls, p. 193.
■•^ H. O. Chart 83 gives a good sketch of Makatea, though on a small scale.

MAKATEA. 57

the west coast (Pis. 23, 24 ; 26, fig. 2), running along the base of the
steep western slope of Makatea. The western extremity of the south
coast is also flanked by low limestone bluffs, and a narrow reef plat-
form extends from the southeastern point along the western face to
the northern point of the island, perhaps 400 feet at its widest point,
and gradually disappears as it passes around the northern point into the
face of the cliflfs of the east side of the island.

Makatea, as seen coming from the west, rises abruptly (PL 21, figs. 1, 2)
from the sea. The northern part of the western face consists of vertical
cliffs composed of elevated tertiary coralliferous limestone (PI. 22), deeply
cut by vertical fissures, some of them of considerable depth, extending
nearly the whole height of the cliffs (PI. 25) ; these are from 120 to 150
and even 200 feet in height. At the northern end of the i-sland they
are capped with a rounded summit probably 30 or 50 feet higher than the
crest of the highest cliffs (PI. 22, fig. 1). The rounded summit falls off
equally on both sides, to rise to a low, sliglitly pointed hill which stands on
the northern edge (PI. 21, fig. 3) of what looks from the sea like a marked
depression or sink, the southern extremity of which is marked by a low
conical hill (PI. 21, fig. 2) rising slightly above the line of vertical cliffs
which occupy the northern half of the southern part of tlie island. This
line of cliffs, covered in great part by vegetation, is considerably lower
than those of the northern extremity (Pis. 23 ; 26, fig. 2), and they are
separated by a more or less abrupt slope formed by the crumbling of the
limestone cliffs . of that part of the island, mainly from the falling in of the
first terrace. From the southern summit the island slopes south very
gradually, and along the face of this long slope two terraces are plainly in-
dicated. The base of the second terrace can be traced far towards the
middle of the island (PI. 23). From the southern point northward
the island is flanked by a steep coral sand beach running up in places
close to the line of the cliffs or to the line of vegetation (Pis. 23, 24, 25 ;
26, fig. 2); and both it and the narrow shore platform of the west face,
which is bare at low water, disappear near the northern point.

The first terrace is from 20 to 25 feet high and the second about 30
feet. Along the face of the vertical cliffs lines of caverns and deep

58 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

recesses extend at certain levels, indicating probably the position of the
former terraces, which can be traced somewhat indistinctly on the eastern
face of the island (Pis. 22, fig. 2 ; 23, 25). On the northwest side these
lines of caverns would indicate no less than five terraces or periods of
elevation (Pis, 27, 28); the caverns of the higher levels having in their
time probably held the same relation to the sea which those at the base
of the cliff (Pis. 22 ; 26, fig. 1 ; 28, fig. 2) hold to the present sea-level. On
the northwest face the vertical furrows and great bands of stalactites and
lines of caverns (Pis. 23, 27, 28) and of former levels of shore under-cutting
are most plainly to be seen along the central and northern part of the north-
west side of the island. At the northern point, where the shore platform
disappears, the base of the cliffs is deeply undercut (Pis. 22; 26, fig. 1).

Steaming around the north point, the line of high vertical cliffs is con-
tinued along the east face ; they are deeply undercut at the base, with
vertical fissures and lines of caverns, only far more prominently marked than
those on the northwest side. As we rounded the northern point, we could
trace on the east side, as on the west, the extension southward of the slope
of the rounded summit towards the northern edge of the sink occupying the
central part of the island. The cliffs on the east side are not only higher,
but also more uniform in height than on the northwestern face (Pis. 27, 28).
The village on the east side (PI. 21, fig. 1) is at the base of a slope formed
by the crumbling of the first and second terraces, and at the point where the
vertical cliffs are somewhat lower than those to the north and south of the
village. At this part of the island there is again a narrow shore platform,
which however does not extend far to either side of the village, and dis-
appeai's again. On the face of the vertical cliffs of the east side the lines of
four terraces are clearly indicated, and along the slopes of the rounded
summit the fifth and perhaps the sixth terrace can be traced.

The coral sand beach of the west face of the island (Pis. 23-25 ; 26, fig. 2)
is about twelve feet high, and the shore platform varies from 200 to 400
feet in width, is slightly raised at the outer rim, with deep channels at right
angles to the face, extending sometimes from 10 to 30 feet towards the
beach, or forming the merest indentations of the raised outer edge of the
shore platform.

MAKATEA. 59

The landing-places at Makatea and at Tike'i show beautifully the little
inlets, finger-like cul-de-sacs, which the sea has cut or wliich have grown
out seaward from the edge of the reef platform. Into some of these
larger inlets boats can be run and a landing effected. Nine has perhaps
the best examples of these corrugations of the edge of the reef platform,
affording an excellent landing on the inner part of the reef platform.

The reef flat is covered with incrusting Nullipores, and these constitute
the greater mass of the rim. The width of the small channels cutting at
right angles into the reef platform varies greatly ; their sides are frequently
perpendicular, the depth from a few feet to two or three fathoms ; or the
sides may arch over, nearly bridging the channels in places ; the sea rushes
with considerable force into these gullies, which, according to their posi-
tion and size, form blow-holes where the sea or spray is thrown up with
considerable force.

From the outer edge of the reef platform the slope to six or seven
fathoms was quite gradual, and beyond that somewhat steeper. Pocillipores
and scattered corals were common on the exposed rim of the shore platform,
crowded with Nullipores in the intervening spaces. Corals, mainly small
heads of Madrepores, Pavonia, and Porites, grew in great abundance on the
slope to eight fathoms ; there the corals began to decrease, both in size and
number, and although they extended often to 20 or even 22 fathoms, the
patches were separated by wider and wider lanes and patches of coral sand.
The reef flat or shore platform (Pis. 24, 25; 26, fig. 2) is a part of the
base of the first terrace, which has been planed down to below low-water
mark, and is deeply pitted and honeycombed. On the west face we collected,
from the first and second terraces, fossils similar in every respect to those
from Fiji, which have been determined by Mr. Dall and myself as tertiary.
We also collected many fossils on our way across the island, principally
in the deep cuts and caverns of the vertical cliffs on both faces of the
island.

To the south of the village, on the east side (PI. 21, fig. 1), there are
four distinct lines of undercutting, and huge stalactites running from cavern
to cavern on the vertical faces of the cliff!?. The lines of the caverns of the
second and third terraces are best marked in the cliffs to the north of the

60 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

southeast point (PI. 27), and at the southeast point these lines become broad
belts (PI. 28), deeply sunken, while to the south of it the cliffs, which now
are becoming less in height (PI. 29, fig. 2), are undercut mainly at the first
terrace, and the face of the cliffs is cut into prominent buttresses (PI. 28,
fig. 1). These gradually pass into the face of the second terrace of the south
point, where they crop out only here and there through the dense vegetation
(PI. 29, figs. 2, 3) and at the base of the first terrace rmi across the slope of
the steep coral sand beach which separates them in the shape of wide wedges
(PI. 29, figs. 1-3) ; the base of these buttresses has to a great extent been
eaten away, or ground into coral sand.

Tliat the lines of caverns indicate the former lines of terraces is easily seen
in the passage of the vertical cliffs of the east coast, where the terraces are
only indicated by lines of caverns, into the terraces themselves (Pis. 27-29).
This is well shown at the southeim point, where the line of the second and
third terraces gradually recedes from the face of the vertical cliffs and passes
into the walls of the terraces behind the talus indicating their base. The
mode of formation of the talus is also well seen along the south point, where
tlie first terrace is gradually eaten away and its material ground into a steep
coral sand beach. The sea, by breaking into the face of the cliffs of the first
terrace, forms a series of buttresses at right angles to the reef platform, be-
tween which run short sand beaches. As we approach the south point, the
buttresses become smaller and smaller, and the sand beaches longer, till the
first terrace only consists of a series of apparently independent buttresses
separated by sand beaches.

The path back of the beach which leads from the centre of the west side of
Makatea across to the east face of tlie island runs in a great crevasse at
right angles to the trend of the bluffs. It finds its way up between high
walls rising on each side from 20 to 30 feet (PI. 30), until it reaches the
top of the bluff, where it enters a small canon with walls about 12 feet high,
running level for a distance perhaps of an eighth of a mile, then a gentle
descent begins into the sink occupying the central part of the island. The
sink falls away from the foot of the slope of the highest point at the north-
ern end of the island towards the south, where the lowest part of the sink
is fully 50 to 75 feet lower than the surrounding rim of the cliffs. The

MAKATEA.

61

lowest part of the sink along the path leading across the island from west
to east is probably from 30 to 50 feet lower than the rim, the deepest part
being nearest the eastern face. The path winds its way between huge
masses of limestone (Pis. 31, 32), forming needles and spires, and on each
side are found deep crevasses or pot-holes or small sinks. Some of the
pinnacles are fully 20 feet high (PI. 32, fig. 1), and some of the narrow
crevasses equal them in depth.

The surface of the exposed rock is everywhere pitted and honeycombed
and weathered, much as we found it at Ngele Levu and other points in Fiji.
The intervening spaces are
covered with thick vege-
tation. The same sort of
scenery runs across the
island from west to east,
patches of vegetation al-
ternating with spires and
pinnacles, or huge masses
forming indistinct cyclo-
pean walls, alternating
with deep crevasses, small
caverns, pot-holes, or di-
minutive caverns running
in all directions. On strik-
ing the summit of the
cliffs of the eastern face of Makatea, the path leading down the slope to the
village runs between walls from 30 to 40 feet high, and on each side the
cliffs are honeycombed with caverns and crevasses even to a greater
extent than on the west face.

Near the foot of the cliffs on the east side, at the ba.se of the second
terrace, a large cavern is found, which is said to run towards the northern
point and come out on the shore cliffs at a distance of more than a mile and
a half. Other caverns honeycomb the eastern part of the island, as can be
seen from the sea from the number of tho.se wliich crop out on the cliffs of
the eastern face of the island. On the east face, in the bight where the

Entrance to Cavern, East Face of Makatea.

62 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

village is situated, extends a narrow reef platform cut out of the cliffs of the
first terrace, similar in every respect to that off the Avest coast, but perhaps a
little wider, with a higher rim and deeper fissured edge. There is no great
high sand beach back of the reef platform on the east shore as on the west
side ; it abuts against the remnants of the slope of the first terrace.

On the east face, to the south of the village, the reef platform disap-
pears; its occasional presence is only indicated here and there by a few small
sand beaches at the foot of the line of caverns.

On the face of a vertical cliff immediately south of the village four
periods of elevation are most clearly indicated. The edges of the caverns
were thickly covered with lines of stalactites running along the face of the
cliffs, and giving them the appearance of gray basaltic rocks.

It is evident that the sea has not had access into the interior of the sink,
if it ever had any, after the elevation of the second terrace. It is most
difficult to decide whether such sinks as those of Makatea and Niau are the
remnants of sounds or of atolls, or merely sinks representing huge " banana
holes," as they are called in the Bahamas, or " sounds," as they are termed
in the Bermudas. The great sink at Nassau^ has nothing in common with a
lagoon, though if the sea were to cut into it we should have a sound having
all the appearance of a lagoon, as have the sounds of the Bermudas, yet
each owes its origin and present condition to very different causes. The
crevasses, pot-holes, spires, pinnacles, and the pitting and honeycombing of the
sink of Makatea clearly indicate an enormous amount of erosion and of
denudation ; and the existence of the endless cavei'ns in the body of the
island - also shows how long this disintegration has been going on, to honey-
comb as it were the whole of Makatea on so large a scale. Furthermore,
this disintegration and erosion has gone on so long that if the sink is the
remnant of an ancient lagoon existino: in Makatea before the second terrace
was elevated, it has been subsequently so modified by atmospheric agencies
as to completely obliterate all that characterizes an atoll of modern times,
formed in the existing period. The comparatively flat floor, the gentle slopes

1 Bull M. C. Z., XXVI. No 1, n. 10, fig. 3.

- Similar caverns arc known in nearly all the limestone islands of Fiji, Tonga, the Cook group,
Guam, Niue, Ocean and Pleasant Islands in the Pacific, as well as in the Atlantic, at the Bermudas,
Bahamas, Cuba, and other limestone islands.

MAKATEA. 63

of the lagoon platforms, the ledges and islets of the inner lagoon, the exist-
ence of beach rock ledges, of conglomerate ledges, — all these characteristics
of the modern atoll are nowhere to be traced in the sink of such an island
as Makatea. In fact, we can explain far more readily its existence through
atmospheric agencies and other factors which we know to act upon lime-
stones, after the island had been elevated, or during the course of its
elevation.

Dana' has well described the appearance of Makatea while crossing the
inland basin. He also states " that the rock of the elevated portion of the
island of Makatea " appears to correspond to the interior of the original
lagoon of the island, and exemplifies the kind of rock-raaking which is going
on in most of the coral island lagoons." This does not seem probable to
me. The material composing the pinnacles, spires, or ledges of the central
sink does not differ from that found on the fossiliferous cliff faces of any
of the elevated coralliferous limestone islands of the Paumotus and others
which have no lagoon, such as Guam, Nine, the Tonga Islands, and Fiji.
The material of the bottom of the lagoon generally contains comparatively
few corals and other invertebrates, and consists mainly of sand or ooze
made up of fragments of Nullipores and corallines.

It seems to me as if Dana^ had laid too much stress upon the absence of
fossils in interior basins, as when he characterized these basins as eminently
the places for making non-fossiliferous limestones. While it is true that on
the lagoon beaches shells and other invertebrates are ground into fine
material, yet at a very moderate depth the calcareous mud of the bottom of
the lagoons is often filled with shells, Echini, Crustacea, and other inverte-
brates, and if fossilified would form anything but a limestone barren of fossils.
In many shallow lagoons which are in an eminently marshy condition
(as stated by Dana*), and have become so small and shallow that corals and
large shells have all disappeared, the bottom is covered by the finest kind of
calcareous mud. But this mud is not necessarily devoid of fossils; on the
contrary, we should infer very much the opposite, from the mass of small
marine shells found on the shores of the lagoon of Niau and of San

> Loc. cit., p. 193. ' Loc. cit., p. 389.

2 Loc. cit., p. 386. < Ibid.

64 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Salvador, and on the lagoon shores of Maraki, all of which would supply a
mass of small shells as fossils in fine calcareous mud, as characteristic of
the interior of lagoon deposits, with here and there corals, or, finally, a mass
of corals in the larger lagoons to which the sea has full access.

As I have already suggested, I am inclined to look upon the basin of
Makatea not as the remnant of the lagoon of an elevated atoll, but as a
sink produced by atmospheric agencies acting for a long period upon a
comparatively flat plateau of elevated coralliferous limestone. The deepest
part of the sink may have been formed as a sound when the third terrace
was broken through and the seacutaci'oss towards the north end, leaving that
remnant to attest the elevation taking place at the time of formation of the
third terrace. Similarly the limestone islands at Fiji are often eaten away
at the lowest terrace, leaving fragments of higher terraces untouched, which
can be seen in some of the higher islands of many lagoons.

The elevation of the Makatea plateau has taken place too rapidly to allow
a connection to be formed between the central sink of disintegration and the
deep cuts made by the sea on the flanks of the island, — cuts like those
which form the diminutive valleys and crevasses which extend towards the
centre of Nine at right angles to the beach line. The elevated plateaus of
such islands as Tongatubu, Vavau, Eua, Nine, and Makatea, which are fur-
rowed by valleys, or sinks, or areas of drainage, are in marked contrast to
such atolls as Fulanga, Ongea, Yangasa, and others in Fiji, — atolls which
must at one time have been similar elevated plateaus into which the sea has
eaten channels which, communicating with the central sink, very soon eroded
the central part of the mass to form sounds or lagoons.

Niau-

Plates 33-36, Wl, W2.

The island of Niau is the only one of the larger atolls of the Paumotus
in which there is no entrance into the lagoon, which is merely a shallow
salt-water pond. The atoll is nearly circular, about four miles in diameter ;
its land rim is well wooded.

NIAU. 65

Coming upon Niau from the westward, two low terraces are plainly
marked at the northeastern point of the island (PI. 33). As we ap-
proached Niau, we could see along the beach spurs or buttresses of the
old ledge projecting out from the sand beach, extending at right angles across
the shore edge of the reef flat. The lagoon is absolutely closed to the
access of the sea, except as it percolates through caverns and fissures of the
land rim. It is about three and a half miles across, and it is from 12 to 18
feet deep. The slope from the edge of the lagoon is very gradual. There
are large mullet living in it, and the shores of the lagoon are Covered with
the dead shells of small marine bivalves and gasteropods, which, as was
the case in the lagoon of San Salvador, were diminutive examples of larger
marine species occurring on the reef Hat. The land rim separating the sea
from the lagoon (or sink) is fully 25 feet high, and perhaps half a mile wide.
The inner slope of the land rim dips slightly towards the sink. It is com-
posed of the same old ledge rock which crops out all around the island, and
can be seen forming the outer wall composed of rounded buttresses, more or
le.ss widely separated (PI. 33) by reaches of coral sand, forming small beaches
composed of material varying from fine coral sand to coarse coral shingle.
The beach of the sea face is quite wide, fully 40 to 50 yards. It rises steeply
from the inner edge of the reef flat, wliich has been dug out and planed off
to low-water mark from the first terrace of the old ledge (Pis. 33 ; 34, fig. 2).
The sea rim of the reef platform is slightly raised, Nullipores and Pocillipores
growing luxuriantly on it, with deep fissures extending far into the platform
from one to twenty feet in width and from a few inches to three fathoms
in depth (PI. 34, fig. 2). Many of these fissures form small inlets for boats
and canoes, which the natives are quick to make use of in landing and
reaching the diminutive lagoon flat inside of the fringing reef rim of the
reef platform.

Pocillipores, Porites, Astrasans, Millepores, Madrepores, and Pavonia grow
in abundance from the edge of the reef platform, taking their greatest de-
velopment in from three to seven fathoms. None of the corals are large,
the heads are small ; and at 20 fathoms, about 100 yards from the outer
rim of the platform, there are no living corals ; nothing but coral sand is
found, with here and there a patch of corals in slightly shallower water.

66 "ALBATKOSS" TROPICAL PACIFIC EXPEDITION.

The reef flat on the west side is from 100 to 150 yards wide ; its founda-
tion consists of coralliferous limestone of the old ledge rock ; but along the
higher parts of the beach the old ledge rock is often topped with a bed of
conglomerate made up of beach rock, fragments of pieces of broken coral,
and of old ledge rock (PI. 33), the whole cemented together. This material
hides the higher parts of the underlying ledge rock ; ^ it can, how-
ever, be seen cropping out again wherever the upper part of the old
ledge buttresses has not been obliterated, and on the top of the land rim
back of the beach (PI. 34, fig. 1). All the way across the land rim from
the beach to the lagoon the old ledge crops out in the vegetation and
rises in small blocks and pinnacles. On the lagoon side the old ledge is
fully as well exposed as on the sea face of the atoll (PI. 35). There
are no corals in the lagoon, and sea water probably percolates through
the porous rock of the land rim. It is rarely washed over the high land
rim of the atoll except in a hurricane, as in the cyclone of 1878, when the
lagoon was to a certain extent filled with sand and coral fragments washed
in by the sea. The density of the water in the lagoon is 1.021G at
28° C. The water is very salt.

Wherever the old ledge cropped out, either on the sea face of the atoll,
the summit of the land rim, or on the lagoon side, it was pitted and honey-
combed and covered with diminutive spires and points, as is all the old ledge
rock of Makatea; in fact, it was like it in all respects, full of tertiary fossils,
and was not composed in any way of recent material except in those places
where the conglomei'ate mentioned above had been formed and deposited on
the surface of the old ledge rock or between its buttresses.

At Niau, as is the case at Rangiroa, we find the beach sand is gradually
encroaching upon the old ledge, covering it in places, until finally it will
obliterate it along the sea face, and eventually the sand will completely hide
the old ledge both on the land rim and lagoon side. With the decomposi-
tion and disintegration of the reef platform, the undercutting of the old
ledge, and the grinding up of the fragments and blocks of dead coral, more
material is constantly supplied to build up a higher and higher coral sand

1 This conglomerate or beach rock has also comparatively recently been elevated to a height of from
six to einrht feet above hijrh-water mark.

NIAU. G7

beach, which will encroach on the land rim, and finally advance as dunes
do, and little by little fill the lagoon.

It is difficult to say whether the lagoon ever has been the lagoon of an
atoll or has been formed as a sink. Both explanations are plausible. The
land rim, while solid and unbroken at present, may at one time have con-
sisted of several small islets surrounding a shallow sound, separated by low
gaps which have gradually been filled from the coral sand material supplied
from both the sea face and the lagoon side of the atoll, as we have seen it to
take place in other atolls in the Paumotus, or it may have been a
flat patch of elevated limestone the central part of which has been
gradually eroded or dissolved out into a sink by atmospheric agencies
assisted by the solvent action of the sea percolating through the land rim.
That the sea has had access to it, and that it has been shut off for a
long period of time, would seem to be proved by the presence of the
diminutive race of marine shells living in the lagoon, and the presence
of Lagena-like Foraminifera in the lagoon sand. The mud of the bottom
of the lagoon is very fine ooze, consisting of decomposed ledge rock sand.
Algae are growing in great abundance on the shore flat of the lagoon.
Disintegrated corals from the old ledge and fragments of it are found
along the lagoon beach.

The shore platform forming the reef flat of Niau shows most plainly
(PI. 33) the manner in which the old land rim has been planed away by
submarine erosion, from the outer edge of the reef flat to its present
position, leaving on the edge of the land rim buttresses of the old
ledj^e runnintf at right angles across the coral sand beach and lower
outliers of the same upon the reef platform, the space between some
of these buttresses and outliers being filled with modern reef rock.
The same process can be observed on the west shore, the southern
extremity of Makatea, the south shore of Rangiroa, and many other
atolls in the Pacific, but the changes which have taken place are
specially evident at Niau.

On the southern shore of Niau (PI. 34, fig. 3) the land rim faces
upon deep water, and there the low cliffs have merely been under-
cut, as no platform could be cut on that face of the island.

68 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Apataki.

Plates 37, 39 ; 40, fig. 1 ; 201, 20^.

The southern part of Apataki is the only one which has been
carefully surveyed ; the chart shows the reef flat extending between
Motu ruvahine to Pakaka Passage,' with an island on the southeastern
point of the atoll connecting by a narrow reef flat, more or less bare
at low water, with the islet of the southwestern point, where the
reef flat becomes wider and is surmounted by reaches of a high
sand beach forming the bank between Seignelay Point and Pakaka
Pass. This sand beach passes into the low land rim forming the
southern boundary of Pakaka Channel. On the lagoon face of the pas-
sage are situated two islets similar to those found across the entrance
in other lagoons of the Paumotus, such as Avatoru Pass, Tiputa
Entrance, and many others.

The island of Apataki is rectangular in outline, with a somewhat pointed
southern face. It is about seventeen miles long, and extends from north
to south. On the lee side there are a number of entrances which are
available only for small schooners. We examined the lagoon of Apataki
in the vicinity of Pakaka Entrance, and steamed along its western and
northern faces. The land rim of the southwest face of Apataki is broken
into numerous islands and islets separated by gaps and cuts of varying width
and depth, in many of which the old ledge is exposed (PI. 37, figs. 1 and
2). The lagoon sides of the islands and islets are flanked by sand reaches
and shingle beaches, while near the sea face they pass into lines of small
boulders or larger blocks. There are many ledges exposed in the lagoon.
Those we examined near Pakaka Entrance are more or less covered on
the weather side with sand or shingle beaches. On some of the sandy
islets a few cocoanut trees have obtained a footing.

On the north side of Pakaka Pass a high coarse coral shingle beach
has been thrown up, while on the south a low point marks the entrance
(PI. 38, fig. 3). To the north of the passage the land rim is broken by

^ Depot des cartes et plans de la mariue, 3577.

APATAKI. 69

numerous gaps, with shallow cuts giving more or less free communication
between the waters of the lagoon and the sea (PI. 38, fig. 2).

We ran at a slight angle to the northern face of the land rim of Apataki ;
it possessed the same general character as the land on the west side.
The stretches of unbroken land rim were, however, longer, the low reaches
connecting them much less numerous, and there were comparatively few
outcrops of old ledge.

The north face of Apataki, as far as we could see steaming along, is fairly
well closed up by a series of low islets and islands similar in every respect to
those we had seen thus far, the beaches made up of coral sand with old ledge
boulders and occasional old ledge outcrops.

One of the islands of the land rim to the north of Apataki Entrance
has all the characteristics of the land rim of Rangiroa near Avatoru Pass.
It is marked by a steep white coral sand sea beach, passing into coarse
coral shingle (PL 38, fig. 1) in its most exposed places, with beach rock
boulders cropping out at the base of the steep beach, or conglomerate
boulders covering a part of the old ledge reef platform ; this has a raised
rim of Nullipores and Pocillipores, and a diminutive reef platform lagoon
channel. The top of the high beach runs in loops into the bush vege-
tation, which at first is very meagre, but becomes quite thick beyond
the summit rim of the beach, where cocoanut palms cover the land rim.

The shore platform of the lagoon is marked by two slight but distinct
steps; these would seem to indicate a very recent elevation of 12 to 18
inches on the lagoon side. The long stretches of sand flats in the gaps
and cuts which separate the lagoon from the sea (PI. 37, fig. 2) are only
decomposed ledge flats like the flats on the lagoon side of the land rim
(PI. 39). On some of these are still left the boulders or scattered rocks
and corals which once formed part of the old reef ledge (PI. 37, fig. 2).

The bottom of Pakaka Pass (PI. 38, figs. 1, 3) is covered by very
fine masses of corals, heads of Astraeans, Porites, and the like, extending
down to 17 fathoms. On the island to the north of the pass, near the
entrance point, back of the high shingle beach facing the pass, is found
a small sink of brackish water. On the opposite island the shingle beach
at the face of the pass is from seven to eight feet high, and the outer

70 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

beach of that island is a steep sand beach topped with small coral shingle
(PI. 38, figs. 1, 3). To the south of the island a wide gap forming a
shallow passage towards the sea is covered with fine coral sand silt, and
shut off" from the sea by a wide sand bar. An islet and a couple of
sand banks flank the side of the flat, which opens out broadly into ledge
flats extending far into the lagoon.

On the lagoon side the beach rock consists of a conglomerate of recent
beach rock and corals, as well as fragments of the old ledge and its
component corals.

The old ledge crops out in the lagoon about three quarters of a mile from
the wharf in Pakaka Entrance (PI. 34, fig. 3), its disintegration supplying
the materials for the beach on the lagoon face, and for the low dunes three
to four feet high, blown up occasionally on the lagoon side of the land rim
(PI. 39, fig. 1). The lagoon is less well closed than that of Rangiroa,
where there are high white sand as well as gray shingle beaches on the
sea face of the islands and islets of the land rim. The reef flat on the
sea face is quite narrow, not more than 75 to 100 feet wide, and negro-
heads of old ledge are scattered along the platform at the foot of the
beach (PI. 37, figs. 1, 2).

On the lagoon face of Apataki the sand beach is low, not more than one
to three feet in height. It is made up of fragments of recent corals and
of broken shells. The highest islands of the land rim near the pass are
not more than seven to eight feet. The beach on the sea face is steep
(PI. 39) ; old ledge corals as well as recent corals are thrown up to-
gether, and form, as at Rangiroa, a more or less coarse shingle.

Dr. Moore collected on the Apataki reef flats Pocillipora, Millepora, Pon-
tes, and Madrepores. An islet on the flats to the north runs nearly across
the entrance of Pakaka ; it is about three feet above high-water mark, and
made up of disintegrated old ledge rocks. Inside of the lagoon here and
there a long narrow ledge of old reef rock crops out, similar in all respects
to that seen in Pakaka Pass (PI. 38, fig. 3). Similar ledges also occur on
the lagoon side of the low reef flats, with occasionally a large negro-head
(PI. 39, figs. 1, 2). The land rim is an alternation of islets and low sand
flats, with beach rock ledges on the narrow reef flats connecting the islets.

TIKEi. 71

At one point we saw a great accumulation of large old ledge rocks with a
regular pavement of smaller boulders piled up on the reef flat in front of
them ; this line of old ledge boulders extended fully one and a half to two
miles. These large boulders are evidently a part of the old ledge still
in place which crops out on the sea face of the island.

The island at the north end of the atoll shows the same features char-
acteristic of the islands we had seen thus far near Pakaka Pass, and others
on the weather rim ; being somewhat more exposed to the action of the sea,
the shingle beach is fidly from eight to ten feet in height ; occasionally a
large head of old ledge crops out at the foot of the beach, and its remnants
are the scattered boulders occurring on the flats, extending towards the
lagoon beach of the land rim. A second islet not more than twelve inches
high is made up of beach rock consisting of fragments of recent corals and
of fragments of the old ledge, as well as boulders of the same material ; it
extends to the edge of the flat sloping into the deeper part of the lagoon.

Tihere Entrance is a short pass through a narrow part of the reef flat, pre-
senting no special feature.

Tikei.

Plates Ifi, figs. 3-4 ; 4.1-U, ^01, 203.

Tikei was discovered by Kotzebue in 1815. It is circular, about ten
miles in circumference, and is an elevated coralliferous limestone island.
The central part of the island is occupied by an indistinct sink, which rep-
resents a stao-e of denudation and of erosion somewhat more advanced
than that of Niau (PI. 44). The island is so well covered with vegetation
and with decomposed coralliferous limestone material (PI. 43) that it is diffi-
cult to trace the outcrops of the old ledge. These, however, we came upon
in the small outlier rising from the pool (PI. 44) which occupied the lowest
part of the shallow sink of Tikei. There is no lagoon proper, and the denu-
dation of the old ledge has taken place to such an extent that the sea finds
access to this shallow sink, which differs from that of Niau only in depth and
in the height of the bank, which in the case of Niau prevents inroads of the
sea, while at Tikei it has access to the central sink through the shallow

72 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

passages crossing the northern beach and which reach far in towards the
centre of the island (Pis. 41-43).

The reef platform of the island is from 50 to 150 feet wide (PI. 43,
fig. 4) ; it consists of old ledge planed off on the northwestern face, while on
the other side the platform is covered by a mass of boulders all consisting of
old ledge rocks thrown up in part from the edge of the reef flat after being
torn off, or in part from the disintegrated old ledge itself (PI. 40, fig. 2).
This extends inland to the termination of the bight or shallow wide gap
(PI. 41, fig. 1) leading to the sink of the central part of the island (PI. 44);
channels lead from the bight to the innermost parts of the sink, thus con-
necting it with the sea face of Tike'i (Pis. 42, 43).

The sea face beach of Tikei is high (PL 40, figs. 3, 4), from 10 to 12 feet.
It consists, as at Niau and Rangiroa, of coral rubble or shingle on each side
of the part of the reef flat covered with old ledge boulders. The bight or
low gap is crossed by the mass of boulders mentioned above ; they extend
from the sea face of the platform a short distance inland in the gap. Behind
the boulders, on the inner face, has been thrown up a low rubble beach
(PI. 41, fig. 1) composed of smaller fragments of recent corals and old ledge,
almost closing the mouth of the gap, which is about 500 feet wide and
extends fully 1200 feet inland, forming a cul-de-sac (PI. 42), from the
extremity of which lead the shallow channels (Pis. 41, fig. 2 ; 43), connect-
ing at highest water with the sink which occupies the position of a lagoon
in this island (PI. 44).

The central part of the island is low, full of shallow sinks (Pis. 43, 44),
connected evidently with one another in the rainy season ; all leading into
the main sink, an irregularly shaped depression about a third of a mile in great-
est width, with a pool of brackish water in its deepest part from 40 to 50 feet
long and about 25 feet wide (PI. 44). In the centre of the pool there was
an outcrop of the old ledge (PI. 44). The floor of these swampy sinks and
channels was covered with Algte (Pi. 43) ; at high-water stages the main sink
must have been fully half a mile in length and from 500 to 600 feet wide.
The lichens covering the flat resemble those found on the marshy flats of
the Florida reefs.

Here and there we came upon patches of recent conglomerate beach

TIKEI. 73

rock which had been deposited on the underlying old ledge between its
outcrops; but the greater part of the beach rock conglomerate had been
disintegrated and reduced to isolated fragments, which in their turn had
become worn and weathered to fine sand (PI. 42).

In the central pool, as well as in the smaller pools of other sinks, we
found mullet, probably the same species as that living in the lagoon (or
greater sink) of Niau, the former being not more at any time than four
to five feet in depth, the latter at least 12 to 15. The Tikei sink com-
municates more freely with the sea than the Niau lagoon, separated as it
is from it by a wall of nearly half a mile in width and fully 25 feet high.

The shore platform is full of pot-holes of all sizes, containing the
pebbles of harder corals which formed them. The edge of the reef plat-
form is deeply indented and scalloped by channels varying in width from
a few inches to several feet, and some of them large enough to be used
as boat passages for landing. The points between these channels rise con-
siderably above the general level of the reef flat. They, as well as the
reef platform, are covered with Nullipores and other calcareous Algte,
which appear to thrive best in the full force of the breakers. They rise
sometimes as knolls fully four feet higher than the general level of the shore
platform. The depth of the channels varies from a few inches to two or
three fathoms, frequently the projecting irregularities of adjacent sides be-
come soldered together, forming bridges imder which the surf is forced,
and is projected behind these connecting bars in columns of spray or water
varying in height according to the size of the opening left. These bridges
frequently form a continuous floor for a considerable distance. When the
force of the surf is too great, they are broken off, as well as the higher
knolls or projections which have been built too far out into the breakers
and are thrown up on the reef flat as boulders, often of great size, at the
base of the sand or shingle beach, to be ground into sand.

As seen looking down upon them from the ship, these indentations
look like so nianv huge fingers extending into the edge of the mass of
the reef platform ; and in certain lights they look like light or dark blue
passes or cuts, standing out in marked contrast to the orange-red masses
of Nullipores and Pocillipores into which they have eaten.

74 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Kauehi.

Plates 45, 201, W3.

Kauehi was discovered by Captain Fitzroy in the "Beagle" in 1835.
It is nearly circular, about twelve miles long from north to south and nine
miles at its greatest width. The sketch given by Wilkes ^ is somewhat
different from the outline of Kauehi given by the French Hydrographic
charts,^ which are somewhat more accurate. There is no entrance on
the windward side, as is marked by Wilkes, and the lee face land
rim is covered by a far larger number of islands than are indicated
by him. We did not enter the lagoon, merely skirting the lee face of
the island.

Kauehi is marked for the extent of the weather land rim, covered by
islands and islets. With the exception of a short stretch on the south-
eastern land rim, it is more or less protected from the trades by the atoll
of Raraka lying to the southeast ; the southeastern face of Raraka, as
sketched by Wilkes,^ plainly shows the effect of tlie prevailing winds on
the character of the land rim, which is a wide reef flat in great part
submerged and devoid of islands.

Along a part of the north shore of Kauehi we came upon a stretch
of about a mile which was simply a mass of large boulders of old ledge rock
(PL 45, fig. 3) spread at the base of the low beach line forming the land
rim of this atoll, which is very narrow, so that steaming along we could
looli far into the lagoon over the low land rim (PI. 45, fig. 1), and could
see in the interior a number of ledges. Along the northwestern side
we came upon a cluster of large boulders of the old reef rock scattered
along the lagoon face of the reef flats. In the gaps and opposite them
the old ledge is pretty well disintegrated (PI. 45, fig. 2), forming here
and there small islets on the reef flats and beyond, the lagoon reef
flats being often very wide (PI. 45, fig. 1), and the bare flats exposed
to the action of the sea from both sides. Sand bars also occur on the

1 H. O. Chart 280.

2 Depot des cartes et des plans de la marine, 1716.
8 H. O. Chart 280.

KAUEHI. 15

wider flats where sufficient material is supplied from the flats on the
lagoon side.

We steamed by the large boulders of old ledge rock figured by
Dana, which he considers as boulders thrown up from the outer edge.
I am inclined to consider these huge undercut masses, many still at-
tached to the reef platform, as outliers, or as part of the old ledge
rock forming that platform ; the moi'e so, as a little farther on the
same beach we find outcroppings of the old ledge running from the
edge of the land rim across the greater part of the beach, — outcrop-
pings which could not be a part of the outer edge of the reef platform.

The old ledge again crops out on the island to the north of the
entrance to Kauehi. This island is perhaps ten to twelve feet high, and
the old ledge puts out diagonally across the face of the beach from its
highest point a series of spurs separated by short reaches of sand.

On the west side of Kauehi there are a great many low gaps be-
tween the islands and islets of the land rim opening freely into the
lagoon, into which the sea washes. According to the position of the
islands, the presence of old ledge or of boulders, either of recent corals
or of old ledge, or of recent conglomerate formed of both, the beaches
of the sea face are made up of coral sand of various degrees of fine-
ness, or of coral shingle of varying size. The edge of the land rim
is, as usual, flanked by a narrow belt of shrubs, which protects the
land rim against the pi'evailing winds.

The entrance to Kauehi is very similar to the entrances into other
lagoons, — an opening with deep water between two low headlands,
flanked on the lagoon side by reef flats and islets or sand bars. Kauehi
is said to have on the east side a secondary lagoon similar to those which
we shall describe for Marokau and Ravahere, as well as to the second-
ary lagoons of Tahanea and Anaa.

76 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Pakarava.

Plates i6-60; 51, fig. 2; 5S,fig. 1 ; 201, S03 ; 20^, figs. 1, 7.

We spent some time in the lagoon of Fakarava. This atoll and Makemo,
Hao, and Rangiroa are the four largest atolls of the group, Rangiroa being
somewhat the larger. Fakarava is about thirty-two miles long, ten miles
wide, and rectangular in form. It runs from southeast to northwest; there
are two ship passages, one on the northern face and the other on the south-
ern face of the atoll. The northern passage and the northern part of Faka-
rava have been surveyed by the French,^ and the officers of the " Albatross "
made a running survey of the western face from Ngarue Pass to the south-
ernmost point of the atoll. On the lee side the atoll is fringed by large well-
wooded islands, while on the weather side there is a wide reef flat on which
small islands are found on the inner edge of the reef flat ; on the northern
face to the westward of Ngarue Pass a series of larger islands also forms the
land rim. What is very characteristic of this lagoon is the large area which
is studded with islands and islets, showing that probably a great part of the
atoll of Fakarava was once a wide flat,^ composed of coralliferous limestone,
which has little by little been denuded, dissolved, and cut down to the
existing level. With the prevailing southeasterly trades a considerable sea
runs on the lagoon side of the west coast of the atoll, which is raked
diagonally by tlie trades from one end of the lagoon to the other. The
same is the case with nearly all the larger lagoons which trend in a north-
westerly direction, like Hao, Makemo, and Rangiroa, as well as with lagoons
of somewhat less dimensions like Apataki, Arutua, Kaukura, and Tahanea,
as well as others of smaller dimensions, all of which are swept by the prevail-
ing trades.

The width of the western reef platform is not much greater than that of
the land rim on the lee side, showing plainly that the existing condi-
tions are such as to favor the piling up of material on the lee side, while it
is carried off on the weather side. It is evident, from the position of the
islands on the lee face of Fakarava, that where the trend of the land rim is

' PI. 204, fig. 7.

- IVobablv similar to the great flats of the lagoons of Anaa and Tahanea.

FAKAEAVA. 77

such that additional islands are formed on the inner face of the lagoon
from the deposition of drifting material, we should have (supposing that the
reef flat has been gouged out to a moderate depth by the action of the sea)
a secondary lagoon, comparatively narrow, formed between the lagoon face
of the flat and the interior line of islands thrown up more or less pai'allel
to the inner lagoon face of the land rim.

When off the north end of Fakarava it appears like a long continuous
island with the usual fringe of low bushes and shrubs sheltering the cocoa-
nut palms. On the western side of the lagoon there are many islets, but
few rocks and ledges are exposed at low-water mark on the eastern side
of the north passage, and the. same condition continues southward along
the eastern lagoon face.

On the north side of the entrance of Fakarava — Ngarue Pass (PI. 46,
fig. 2), which is half a mile wide — the old ledge crops out in places, and
there is a long bare point on the south side of the entrance. In the pass
there is from 5 to 7 fathoms of water, and once inside the lagoon the slope
drops rapidly into 17 to 19 fathoms (PI. 204, fig. 1). On the way to the
anchorage off Rotoava we passed several outcrops of the old ledge (PI. 47,
fig. 2), indicated as shoals on the charts. Two are three and even five feet
above high-water mark (PI. 58, fig. 1). Several flats make out as spits from
the land rim on the lagoon side, showing the former lagoonward extension of
the land. The shore line of this atoll has gradually been shifted and changed
by erosion and disintegration and solution into the lagoon flats and shoals.
All of these are generally composed of old ledge rock planed down from
various causes to their present level.

The old ledge crops out on the sea face at several points, and is seen to
run out from the top of the beach in wide buttresses upon the reef platform
at right angles to the general trend of the surf. At other points the surf
has cut down the old ledge to the level of the reef platform, or the sand
and shingle forming the sea beach have overwhelmed the remaining low
buttresses and concealed their presence (PI. 51, fig. 2).

In the lagoon the sea breaks with considerable force, and the outcrops of
the old ledge are separated by sand reaches, or even by short stretches of
recent beach rock (PI. 49). There are in the lagoon a great many ledges,

78 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

shoals, islands and islets, most of which are outcroppings of the old ledge
or are underlaid by the old ledge (PI. 47, figs. 2-4), which has been partially
covered by beach rock or recent conglomerate or blocks of dead corals.
Some of these ledges and shoals rise to nearly the same height — five to
seven feet above high-water mark — as the islands found in the lagoon
(PI. 47, fig. 1).

The island forming the land rim at Rotoava varies in width from 900 to
1200 feet ; it rises very gradually from the lagoon shore, where the beach
is from four to five feet at high water, towards the top of the beach on the
sea face. Its highest point is from 250 to 300 feet from the outer edge of
the ledge platform, which is itself quite narrow, only from 50 to 75 feet wide ;
then conies the steep beach ftice of coral sand or of shingle of broken coral,
next a slight depression, an outside beach of a lower level — a sort of break-
water, as it were — followed by a gradual rise to the highest point of the
outer beach (PI. 51, fig. 2). From the edge of the outer depression com-
mences the fringe of the characteristic Paumotu atoll vegetation which acts
as a shelter for the cocoanut trees (PI. 50).

On the lagoon side the shore platform is in great part made up of beach
I'ock and recent conglomerate, which has covered the old ledge and its
shore outcroppings at most places (Pis. 46, fig. 3 ; 49). The lagoon plat-
form is from 60 to 100 feet in width, but often juts far out into the lagoon
in isolated patches (PI. 58, fig. 1). The platform slopes gradually into six
or seven fathoms of water, the slope and flats being full of coral patches,
some of which extend as far as our anchorage.

Modern beach rock (PI. 51, fig. 2) and conglomerate are also deposited
on the sea face at the base of the steep beach on the top of the old ledge.
Here and there the old ledge crops out from the beach rock at some point
high upon the sea face of the beach, beyond the reach of the point where
recent conglomerate is formed. The narrow sea-face platform is exposed to
the full force of the breakers, which pound with their whole swing upon the
raised outer edge of Nullipore knolls (PI. 51, fig. 2). These are constantly
broken off and forced up towards the base of the sea beach along the shore
platform, and go to add to the mass of coral rubble which is constantly being
rolled and ground into shingle or sand (PI. 50). Together with the

FAKAEAVA. 79

Nullipore knolls are found ujasses of Pocillipores, which here, as elsewhere
in the Tropical Pacific, seem to flourish remarkably well in such an exposed
habitat as the outermost edge of the reef platform.

On the lagoon side in many places a low sand beach, at the outside three
to four feet in height, has been thrown up, inside of which runs a long trench
or depression, the bottom of which is at about the level of the water in the
lagoon at half tide, and is more or less full of brackish or fresh water accord-
ing to the season of the year (PI. 48). Similar trenches or sinks filled with
water are found in many of the Paumotus ; they vary greatly in shape
according to their position. If occurring along the lagoon face of a narrow
island, they are mere trenches, but may become sinks or pools or even small
ponds of considerable size, if they have been formed by the isolation of a
wider tract of low land, such as at the extremity of an island near a pass,
where the land usually widens out. Such pools have been described at
Rangiroa (PI. 204), on the south of Avatoru Pass, and are known in many
other atolls in the Paumotus, in the Ellice and Marshall Islands, which are
described as having ponds or sinks filled with more or less brackish water.'
Dana has described them as occurring at (Manihi) Waterlandt, so named
from the presence of a number of such trenches and pools or sinks. One of
the sinks to the south of the village of Rotoava must be fully four feet deep
and at least 200 feet long by 30 wide.^ These sinks, when of considerable
length and width or depth, have been described as secondary or subsidiary
lagoons. I shall have occasion to describe their formation in other atolls
where their structure is more easily seen than in Fakarava, as in the lagoons
of Likieb and Jaluit.

The effect which the violent surf has in modifying the mode of growth of
corals is very striking, and it would often be difficult to recognize in the
spreading mass found on the outer reef flat the delicately branching
species characteristic of the lagoon. Everything living on the sea face

The long sinks more or less parallel to the shore of the island are formed hv the throwing up of
a low beach sand dam, behind which water collerts. At one of the points we really have an atoll
within an atoll, formed by the ring of islets and sand bars cutting across the shallow reef flats of the
point. This we shall find developed on a larger scale in other atolls not only of the Paumotus, but also
in the Gilbert and IMarshall Islands.

'^ Dana (p. 324) mentions a sink in Aratika 50 feet in diameter.

80 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

platform seems to adapt itself to its conditions. Holothurians are found
only in deep pools worn out of the flat or protected by masses of boulders.
Every boulder is full of boring annelids, moUusks, Crustacea, and sponges,
which one would seek in vain on the exposed face of the reef flat, but which
are abundant in the quieter waters of the lagoon. Echini, Ophiurans and
Holothurians, which are buried in deep holes on the sea reef, live quietly
exposed to full view on the lagoon side. Of Echini, those with massive spines
like Heterocentrotus seem to be able to withstand the force of the surf; and
they as well as the peculiarly protected Colobocentrotus, the spines of which
are merely a close pavement covering the test and strong enough to with-
stand the full shock of the largest rollers breaking on the edge of the reef
flat, seem to prefer the sea face of the atoll to the lagoon side, where in fact
they do not occur.^

The outer edge (the sea face) of the reef platform is from one to two feet
higher than the general level of the platform itself, and in some places even
three feet (PI. 51, fig. 2). This forms a wide channel between the outer NuUi-
pore edge and the foot of the beach, and in this rudimentary lagoon a strong
current is formed by the surf driving the water on to the platform through
the channels and gaps left between the Nullipore knolls. On a wide reef
platform a regular barrier reef with a diminutive lagoon would be formed,
as at Anu-Anurunga and Hereheretue. This reef lagoon may be compared
to the long narrow sinks formed on the lagoon side of the land rim by
the throwing up of sand beaches in a line parallel to the land rim.

We examined about five miles of the lee side of the lagoon to the south
of the village, and found it identical in structiu-e with that westward of
the village, patches of beach rock cropping out at short intervals for a
couple of hundred yards, and again separated by coral sand beaches rising
to a height of not more than three or four feet. Here and there we came
upon an outcrop of old ledge running at right angles to the beach, en-
croaching more or less diagonally upon the face of the beach, or upon some
outlier of the old ledge, part of the outer platform of the lagoon.

The underlying old ledge is generally concealed by beach rock or by

1 I was greatly surprised to find Echinoneus alive on the outer reef platform, buried in cavities of
the rook.

FAKAEAVA. 81

recent conglomerate on the sand beaches and flats. Along the lagoon
side there are wide platforms of beach rock dipping slightly towards the
lagoon, extending out from the shore in points or flats from 600 to 700
feet in width. A number of shallow patches of the same are found in from
six to seven fathoms, rising nearly to the surface, the sides overgrown with
corals and I^uUipores, the corals being mainly Madrepores, Pocillipores,
and a few small heads of Porites. The NuUipores and coralline Algse
are of all coloi-s, from white to yellow, pink, or orange.

We made a series of soundings at right angles to the lagoon shelf,
passing very gradually into 17 fathoms at a distance of about 2500
feet. At 200 feet from the shore we were in 5 fathoms, obtaining
8 fathoms at 500, 12 fathoms at 1000, and 16 fathoms at 2000 feet. The
bottom of the lagoon was sandy, consisting of decomposed beach rock and of
old ledge rock, with patches of NuUipores. We collected large pearl oysters
on which were growing two species of Madrepores, one seven inches long,
the other four ; the shells were said by the natives to be about five years
old.

A line of soundings running in a northeasterly direction across the
lagoon of Fakarava, about half-way from the eastern edge to the islands
inside, developed from 22 to 24 fathoms. Fakarava is marked for the great
number of islands in the northern part of the lagoon (PI. 204). Those we
visited are situated about half-way across the lagoon, rather nearer the reef
in a northerly and westerly direction, varying from one to five miles from
the edge of the reef (PI. 47, fig. 1). The island group consists of a cluster
of ledges, of shoals, of sand banks, of islets and islands, more than forty
in number (PI. 46, fig. 1), all of which were visible from the point of
the island where we landed (PI. 47, figs. 3, 4). The islets just described
extend close to the north coast (PI. 204, fig. 1). They are scattered in
an elliptical area of from four to five miles in diameter. On some of the
higher sand bars a little vegetation is found, and as these islets and shofils
increase in size they are better covered with shrubs, and an occasional
cocoanut tree is found on the larger islets.^

' On the isolated islets having cocoanut trees, the nuts must have drifted there and found a foothold,
for we can trace all the stages from a single small young tree to a cluster of eight or ten, on islets
well isolated from the larger ones on which cocoanut trees have long been planted.

6

82 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

On the northwestern land rim there are a number of small islets con-
nected by sand bars on the lagoon side, and running somewhat diagonally
towards the reef flat edge, the edges of these bars are separated by
negro-heads or bands of beach rock at right angles to the coast line.

On a nearer view of the cluster of islets inside the lagoon, we could
see that many of them were separated by comparatively deep water from
the outer reef flat, which is fully half a mile wide. We could see the old
ledge outcrops on many islands (PI. 47, figs. 1, 3), as well as those of
beach rock and of recent conglomerate, flanking many of the sand bars
and sandy islets or keys. The lower part of it near the foot of the
beaches is covered with a recent very coarse conglomerate of shells and
corals (PI. 47, fig. 2). On one of the islets the old ledge projects promi-
nently at the eastern extremity, the inner extension being covered with
sand. On many of the islands the ledges are composed of beach rock and
conglomerate which has concealed the old ledge rock cropping out at
many of the other islands. The conglomerate has also extended over
the shallow parts of many of the flats adjacent to the islands. As we
steamed south, the old ledge was again observed on the western face of
many of the islets, standing like a raised wall, more or less broken, pre-
senting on a small scale the elevated wall we had seen at Rangiroa (PI.
4G, fig. 1). After leaving the cluster of islets, which became gradually
more widely separated as we steamed south, we found only a wide reef flat,
on the edge of which are large boulders of beach rock or of old ledge.

The few soundings we made indicate quite deep water between the
cluster of islands and the outer reef. The islets are covered with vege-
tation just as are the islands of the land rim flat (PI. 47, figs. 3, 4).

This group of islands, ledges, and shoals is a part of a wide ridge
more or less parallel with the basin of the lagoon, of which the higher
parts alone remain as islands and bars which have not been eroded or
carried off in solution. The reef flat on the sea face of the eastern land
rim is full of pot-holes more or less filled with gravel ; these pot-holes
are some of them circular, others elliptical or run together as long and
deep furrows. The action of the current inside the NuUipore knolls is
to scour out a channel along the outer face of the reef platform. This

FAKAEAVA. 83

is one of the richest collecting grounds we have met, though many reef
flats in other islands of the group similarly situated are comparatively
poor in animal life. The finger-like scalloping of the outer edge of the
reef platform is also well indicated at Fakarava.

The bottom samples of the lagoon, wherever collected, indicate the
presence of coral sand made up of Nullipores, of corallines, and of frag-
ments of corals reduced to minute pieces by boring sponges and Algce, of
broken parts of echinoderms and mollusks as well as Foraminifera.

On the lagoon side of Fakarava near the village of Rotoava, in from
two to three fathoms of water, are numerous fine patches of corals com-
posed of Astrseans, Porites, Goniastrasans, and Madrepores. In somewhat
deeper water these patches become larger and run out into 8 to 10
fathoms. The same condition exists on the slopes of the shoals, sand bars,
and islets, the corals appearing to be most flourishing in from 5 to 9 or 10
fathoms. As we passed out of the Ngarue Pass, we could see in the pass
and on the outer slope, down to 17 or 18 fathoms, a fine growth of large
masses of corals, which rapidly became separated by wider and wider
patches of fine white sand, till the coral patches disappeared completely in
from 20 to 22 fathoms.

Skirting along the north shore of Fakarava, the land rim islands are
flanked by long stretches of sand beaches. Long reaches of coral rag
shingle extend along the eastei'n face of the island. These sometimes form
high beaches, and between them low channels have been cut, such as we
found back of the villao-e of Rotoava.

The west side has not been built up as much as the other, and the
material washed over the western flat has formed the wide reef flat of
the weather side. The sand bars and sand islets are always on the lagoon
side of the flat where islands are ultimately developed ; lines of beach
rock or of coral boulders or fragments of the old ledge run across the flat,
generally at right angles to the outer edge, with larger boulders or negro-
heads of old ledge or beach rock or recent conglomerate on the outer edge
of the sea face of the reef flat, across which here and there wide gaps, some-
what deeper than the rest of the reef flat, allow the water freer access to the
lagoon than elsewhere.

84 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

On the southwestern point of Fakarava we passed a tine old ledge reef
platform covered with Pocillipores, considerably higher than the inner flat,
and higher again on the lagoon side, with raised sand bars full of small
gulleys running at right angles to the sea line. About two miles north of
the southwestern point, the old ledge is standing as a sort of broken wall
about two feet high ; it is more or less cut into by the sea, and large
boulders have been broken off from it on the sea face and thrown up on the
reef flat of the western face behind the raised edge, rising fully five to
seven feet, as in Rangiroa.

On the south side the land rim is formed by large islands near the south
pass and a low reef extending to the islets on the east side. In the middle
of the lagoon, about due north of the south pass and near it, there is a well-
wooded islet.

Anaa.

Plates 51, fig. 1 ; SB, 53, Wl, 203.

Anaa is about twenty miles long and six miles wide ; it is elliptical ; its
general trend is from the southeast to the northwest. It receives its name,
Chain Island, from the very regular dimensions of the islands forming its
land rim, so that a plot of it resembles a long bracelet with links of nearly
uniform size. The islands are well covered with cocoanut groves, and, al-
though there are many gaps between the islands and islets, there exists
only one very indifferent passage for boats into the lagoon.

On the northwest shore of Anaa are fine outcrops of the old ledge
running at an angle to the shore line and separated by sandy beaches.
On the north side exists an inner line of islands (PI. 51, fig. 1) dividing the
lagoon into two very distinct parts.

At the northwest point of Anaa there is a comparatively deep lagoon, a
secondary channel extends parallel with the shore line, from the base of
the outcropping old ledge to the Nullipore and Pocillipore edge of the reef
flat. This canal runs for quite a distance parallel with tlie coast line, and
expands into a large bay forming the pass or cut between two adjoining
islands (PI. 52, figs. 2, 3). The reef flat then becomes quite wide, — 500 to
600 feet. All the way from the west shore to the landing bight there are

i

TAHANEA. 85

fine outcrops of the old ledge, buttresses reaching nearly to the water's edge
across the sand beaches, and separated by coral sand beaches or by coral
rag shingle beaches (Pis. 52, fig. 1 ; 53, fig. 1).

To the south of the inner line of islands extends an immense flat covered
only with a few feet of water (Pis. 52, fig. 2 ; 53, fig. 3), the whole flat shin-
ing brightly in the sun as a light green sheet, in contrast to the darker
greenish blue band of deeper water extending towards. the south. This flat
covers so great a proportion of the lagoon tliat its greenish light, reflected
against the clouds, can often be seen long before the atoll itself looms in sight.
Other shallow lagoons are also detected in this Tnanner. The greater part of
the lagoon is quite shallow, not more than from one to two fathoms in
depth. A great many sand bars are found all through the lagoon.

This atoll is intermediate in structure between such an atoll as
Fakarava, which has a comparatively deep lagoon full of islands, and a
solid island or an island with an insignificant lagoon or sink, such as Tikei.

The northwestern part of Anaa will soon be filled with islets ; in that part
of the lagoon sand is constantly piling up inside on the lagoon side, and on
the sea face reef coral shingle beaches are thrown up (PI. 53, fig. 2). At
a distance the bight where the boat pass is situated looks like an inlet
to the lagoon between the islands, but the lagoon is shut oflf by a wide
flat, the extension of the reef flat to the east of the secondary lagoon.

On the east, as well as on the west side of the atoll, are alternating
low and high gaps. On the east face the old ledge crops out in a series
of high spurs running diagonally across the face of the beach.

Tahanea.

Plates 54, 55, 201, 203.

Tahanea Island is about twenty-five miles long, it is irregularly elhptical,
and perhaps ten miles at its greatest width. On the north side within a
distance of about two miles there are three entrances for small vessels into
tlie lagoon. Tlie land rim on the north side is well wooded, while on
the southern face the islands are generally bare.

86 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

We struck the central part of the western face of Tahanea, and
found the interior of the lagoon dotted all over with islands or ledges,
the islands flanked with spurs of old ledge outcrops, and the ledges running
diagonally across the middle and southern part of the lagoon. Parallel
with the south face runs a remarkable secondary lagoon, about one mile
wide at its widest part, formed on the sea face by the broad reef
platform, fully 1000 feet wide, and on the other side by a series of
islands rising from an inner reef flat as wide, if not wider, than the outer
flat, and separated by a deep channel, in places from two to three fathoms
in depth (Pis. 54, figs. 2, 3; 55, figs. 2-4). The depth of the channel
greatly varies ; it shallows both at the eastern and western ends, where the
secondary lagoon narrows, and eventually, at the northern end, terminates
in an island (PI. 54, fig. 1), which blocks the cul-de-sac of that part of
the lagoon where the outer reef flat is not more than from 50 to 100
feet wide. The islands to the east of the secondary lagoon are gener-
ally well wooded (Pis. 54, fig. 3 ; 55, figs. 1, 2, 4). From the topsail
yards no extensive clear space could be seen in the lagoon, the islets
and islands occurring apparently throughout the whole lagoon. The old
ledge seems to be exposed all along the south face, and is flanked by a
comparatively narrow reef platform, edged by Pocillipore and Nullipore
knolls (Pis. 54, fig. 3; 55, figs. 3, 4).

The secondary lagoon is cut up by ledges in all sorts of ways ; these
same ledges send spurs into the main lagoon, where there are innu-
merable single rocks and ledges and islands and islets making irregular
divisions of the lagoon, more or less shut off" from one another (Pis. 54,
55). Numerous sand bars form low islets and islands on the inner side
of the reef platform. The outer reef flat is from 800 to 1000 feet
wide (Pis. 54, fig. 3 ; 55, figs. 2-4). At the southwestern horn, where
the secondary lagoon ends, islands and sand bars again appear on the
lagoon side of the outer edge of the reef platform of the atoll. These
islets are from eight to nine feet high, with coral sand beaches on the inner
or lagoon side (PI. 55, fig. 3). A few boulders are thrown up on the
reef flat, of which the outer edge is well gouged out in the finger-like
channels and scollops running at right angles to the sea face of the reef

T AH AXE A. 87

platform. On the west face we could see that the islets of the reef flat
were placed on the inner lagoon edge, at an angle with the shore line ;
we could also readily trace the sand beaches of the lagoon end of the
islands, as they gradually pass into the shingle beach characterizing their
sea face extremity (Pis. 54, fig. 1 ; 55, figs. 2, 4). These islets and islands,
thrown up either from the outside face or from the inside face, alternate
with one another, but all have shingle beaches on the sea face ex-
tremities and coral sand beaches on the lagoon side ends. The shingle
beaches are gradually forced towards the lagoon side, where they meet
the sand bars pushed seaward by agencies from the lagoon side, or
vice versa (PI. 55, fig. 2). The currents, both running in and running
out, gradually accumulate more and more sand, cover the beach rock
boulders and shingle, and spread over the reef flat, and finally form
a bar extending quite across it. If the depth of water between the
outer and inner edges of the reef flat is too great, two separate islands
are formed which wall become joined when the channel between them
has been filled or bridged over in part, when the whole of the exposed
flat, either on the lagoon .side or the sea face, has been completely cov-
ered by shingle or sand and has formed a continuous island from the
lagoon edge of the reef flat to its sea fixce (Pis. 54, fig. 3 ; 55, figs. 2, 4).

All along the south shore the reef flat or the land rim is so low that
at the least sea, water must be driven through the gaps separating the
reef flat islands (Pis. 54, 55). In the lagoon the old ledge has been
planed off to about high-water level, so that but little material is now
supplied from the disintegration of the numerous shoals and ledge flats left
in the lagoon ; the greater part of the material is derived from the lagoon
edge of the outer reef flats or from some of the higher ledges left in the
lagoon.

Young cocoanut trees grow on some of the smallest and lowest sand
islets when not more than one to two feet high, while on larger and higher
i.slets they are more numerous, and by the time the islands extend
across the outer reef platform they are well covered with the char-
acteristic coral reef vegetation, as well as with cocoanut trees (Pis. 54,
fig. 2; 55, figs. 1, 2).

88 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

On the northwestern face of Tahanea we find here and there a stretch
of a secondary lagoon similar to the one described on the south shore, but
not more than 20 to 25 feet in width. At the horn of the northwestern
point are fine patches of beach rock covering the old ledge, and coral
shingle, and black shingle thrown up on beach faces from six to seven
feet high (PI. 54, fig. 1).

After passing the northeastern point, going southeast, we saw a
beautiful effect of the blending colors of the line of breakers, of the
dark masses of rocks and boulders, and of the sky line without any
special line of demarcation. We could see the flash of the columns of
white breakers, like the explosion of a torpedo, thrown high up in the air
against the gray sky, bringing out on the horizon a sharp line of dark
spots which were the boulders and rocks covering the reef flats.
Along this part of the atoll the reef flat is from 200 to 250 feet in width,
the lagoon edge being formed by an irregular belt of sand bars or of
beach rock shingle ; the central parts of the flat are covered with end-
less shingle bars at right angles to the trend of the sea face.

The north face of Tahanea is low, narrow, with here and there a
broader island, say 800 to 1000 feet, running diagonally across the
narrow land rim of the north side, and connecting more or less, on
the lagoon side, the numerous ledges in the channel which separate
the outer reef flat from the wide inner reef flat, on which these broad
islands have been thrown up.

Outcrops of the old ledge are not uncommon close to the narrow
outer reef flat of the north shore.

Towards the northern point of Tahanea the atoll is edged with a some-
what narrow reef flat awash, not more than from fifty to one hundred feet
in width ; for six to seven miles the north shore land rim is low and narrow,
with only here and there an islet or ledge within the lagoon. On the face
on which are the entrances into the lagoon somewhat higher islands have
been formed, with rather more vegetation than is usual in the Pauniotus ;
these islands are all faced by extensive coral sand beaches on the lagoon
side. More or less parallel with them on the interior of the lagoon are
scattered numerous sand bars and sand patches, many of them rising into

TAHANEA. 89

islands north of the western entrance, with a wide lagoon flat and many
rocky ledges extending- from a mile to a mile and a half into the
lagoon.

The formation of all these islands, more or less at right angles to
the line of the outer reef flat, is probably due to the currents which
run parallel to the lagoon face of the flats, caused by the hauling of
the prevailing winds along the coast lines of the atolls. These currents
carry more or less sand, and meeting an obstacle, this acts like a jetty,
some of the sand is deposited, and thus a diminutive sand spit is
formed which, little by little, forms a series of sand points projecting into
the lagoon. The spits increase from either side, froui whichever direction
the wind may draw, and thus the reef flats are in the first place widened,
and in the second place partially covered with sand, leaving the sea free
access to the lagoon only through the gaps between the spits and over
the sea face of the reef flat, wherever the beach rock or recent
conglomerate or coral shingle spread over the old ledge has not
been covered with sand. These sand buttresses thus form the begin-
nings of small low sand islands on the lagoon face of the atoll ; as
they increase in size, they gradually join similar accumulations of
beach rock or coral shingle, thrown up in a similar but in a much
more active way, on the sea face of the reef platform.

This phenomenon is well illustrated on the islands and islets to the
south of the north point of Tahanea, where not only their growth can
be distinctly traced, as has been described, but where also the manner
in which they become clothed with vegetation can be equally well fol-
lowed. The ledges and the shoals in the lagoon supply the material for the
inner sand spits. On the line of reef flats and on the sea face, the breakers
grind the material on its edge and supply the coarser material for the
shingle beaches, which may be thrown up to a height of from two to three
feet.

As fixr as we could see to the eastward, the conditions of the eastern
shore did not seem to differ from those of the northern and southern parts
of the atoll which we e.xamined.

90 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The Raveskoi Islands.

The Raveskoi Islands consist of three small atolls — Tuanake, Hiti, and
Tepoto — discovered by Bellingshausen in 1820.

Tepoto.

Tepoto ' appears, as seen facing the southeast, edged with high coral sand
beaches with a few boulders scattered at their base. According to Wilkes's
sketch this small atoll is about two miles in diameter, nearly circular, with
a land rim on the northern part of the atoll, and a bare reef flat flanking
the southern face of the atoll.

Tuanake.

Plates 201, 203.

Tuanake appears to have a very narrow land rim, — narrower per-
haps than in any atoll of the Paumotus we have seen thus far. On the
south side the atoll consists of an extensive flat filling that angle of
the lagoon and extending far into it as a huge spit. There are three
very prominent islands on thq flat connected by beach rock ledges. On
the sea face the shores of the islands of the land rim are edged with
rocky ledges, alternating with short coral sand beaches, while on the lagoon
side they are bordered by coral sand beaches only. Tuanake " is, according
to Wilkes, rectangular in shape, with tlie land rim on the eastern, northern,
and western faces. The atoll is nearly four miles across.

Owing to thick weather suddenly coming on, we were unable to examine
Hiti. WiUtes describes it as also rectangular, and it differs from Tuanake
only in size. The atoll is about two and one-fourth miles across.

1 H. O Ch.ait 83. 2 Ibid.

TAKUME. 91

Takume-

Plates 56, 57; 58, fig. 2; ^01, 203, 205.

Takume is marked for the great number of the islands and islets which
form the land rim on the lee side, from forty-five to fifty, a far greater num-
ber for that length of face than we have seen anywhere in the Paumotus.
On atolls, which, like Takume,^ run from the southwest to the northeast the
land rim is mainly on the lee side and only partly on the weather side ; on
atolls which run in the opposite direction the land rim is usually best devel-
oped on the northern and eastern faces, which may be considered the lee
side, the southwestern extremity being usually bounded by low bare reef flats
with but few islands and islets. This atoll is about twelve miles long, quite
narrow, not more than two and a half to three miles at its greatest width.
A large island occupies the greater part of the northern point of the atoll ;
its weather face is one long line of low reef flats hardly bare at low water.
This atoll has always been described as a splendid example of a closed atoll
without an entrance. If it is intended by that to denote that boats cannot
enter the lagoon, such is really the case ; but the amount of water which
pours in over the weather side of this atoll is something enormous, and
numberless passages on the lee side allow free exit to the water, which is
driven into the lagoon over the weather reef flat. We steamed around
this atoll, and from its elongated and narrow shape were able to take
excellent views of the two sides of the islands and islets both on the lee
and weather face of the atoll.

The southwestern point of Takume is formed by a reef flat extending
east from the southernmost island. It varies in width from 100 to more
than 300 feet. The island terminates in a high steep beach covered by coral
shingle, at the base of which crops out the old ledge. On the other side of
the southwestern horn the inner limits of the reef flat are indicated by a line
of sand bars, and adjoining islands of the western face are separated by gaps
more or less wide, similar to those we described at Rangiroa, in which the
old ledge crops out. The surf washes freely into the lagoon over the east

1 H. O. Chart 83, sketch by Wilkes.

92 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

face, where there are but three small islands with sand bars on the shallow
submerged reef (PI. 57, figs. 1, 4).

On the central part of the west shore there is a wide reef flat partially
covered with beach rock scattered over the surface of the old ledge in innu-
merable boulders, especially near the sea face. Gaps of varying width
follow one after another in quick succession as the separate islands make
their appearance along the western face of the atoll. Many of the gaps
are not more than 30 or 40 feet wide. The sea face of the islands is
usually flanked by coral shingle beaches, while the lagoon beaches con-
•sist of coral sand (Pis. 56, figs. 2, 3 ; 57, fig. 2). Bars of sand seem to be
forming both on the lagoon side and in the cuts, the sand piling up on
the lagoon edge of the flats (PI. 56, fig. 2). The island at the southwest
point has a high shingle beach (at least six to seven feet), the other islands
to the north have low shingle beaches (Pis. 57, fig. 2 ; 58, fig. 2), not
higher perhaps than three to four feet.

A wide reef flat extends on the lagoon side of the islands, more than a
third of a mile in width (PL 57, fig. 4), and at the northern extremity of
the atoll, this flat is covered by a large island occupying its horn, and fully
1000 feet wide (PI. 56, fig. 1).

At the base of the shingle beaches of the islands, on the western rim
of the atoll, are accumulated masses of large boulders (Pis. 56, figs. 1, 2 ;
57, fig. 3 ; 58, fig. 2), many of them beach rock or recent conglomerate ;
other boulders are outcrops of the old ledge which forms the underlying
base of the atoll, and which have not been concealed by the mass of recent
material thrown up on the surface of the outer platform.

The whole of the shore of the north point is thickly covered with
large boulders, many of them undercut on one side, forming so-called horse-
heads, — parts of the old ledge still attached to old ledge reef platforms.
The tinted Nullipores and red or pink and blue Pocillipores color the knolls
forming the outer raised edge of the reef platform. On the northern part
of the east face the reef flat is wide, fully 1500 feet from the base of the
shingle beach flanking the northern island, and slightly dished (PI. 56,
fig. 1), it is full of sinks and pot-holes. At the base of the shingle beach
run .stretches of beach rock, recent conglomerate, and outcrops of old ledge.

TAKUME. 93

On the west side the reef flat shows but little tendency to dishing ; it has
a more uniform slope from the base of the shingle beach to the outer
raised edge of the reef platform.

At some jioints the old ledge must be at some distance below the sea
level, judging from the size of the beach rock and recent conglomerate
boulders which have been thrown upon the outer reef flat.

On the east face there are but three wooded islands, and a number of
rocky islets and sand bars (PI. 57, figs. 1, 4), all placed on the lagoon side of
the outer flat, which is fully 2000 feet wide, and is more or less dished and
gouged out into long canals and pot-holes. Numerous boulders consisting
of beach rock and recent conglomerate, as well as old ledge, crop out in all
directions upon this flat ; they are weathered into all possible shapes and
sizes, from a large boulder to the smaller fragments which supply the
material for the shingle beaches and bars. On the more open part of the
east face the reef flat becomes narrow, especially near the central part of
the island, where it is not more than 200 to 300 feet.

On the island and islets of the east side of the atoll cocoanut trees, often
single, are growing at all points where land is making. Young cocoanut
trees have here, as elsewhere in other lagoons, evidently been transported
by the sea on the smaller sand islets ; they have not been planted.

On the outer edge of the reef flat there is the same raised edge of knolls
of Nullipores growing at the extremity and between the narrow and deep
cuts which encroach upon the outer edge of the reef flats. Many of these
large knobs seem ready to be torn off by the next high sea, to be then
thrown among the rocks and boulders and horse-heads studding the outer
reef flat.

Many of the islands and islets are, as at Anaa, quite a distance from the
outer edge of the reef flat, well on the inner lagoon face of the flat.

The lagoon is comparatively shallow, not more, on the average, than
from five to six fathoms.

As we left Takume, this shallow lagoon also showed us the same reflection
in the clouds which we had noticed on approaching Anaa, and other large
atolls with shallow lagoons and with wide reef flats.

On the reef flat of the east face the old ledge forms the underlying

94 " ALBATROSS " TROPICAL PACIFIC EXPEDITION.

base ; it is honeycombed and pitted where exposed to tlie action of the
sea and weather, and where the modern beach and conglomerate boulders
have been swept off or eroded from its surface. The east face, south of
the islets, is a reef flat bare at low water, .with a great many shallow gaps
through which water flows into the lagoon even at the lowest tides.

Takume is, like other atolls of the group, a narrow pear-shaped ridge, widest
opposite Raroia, its lagoon gouged out in part by the action of the sea, or in
part shut off from the sea by sand banks and shingle beaches formed in the
lagoon on the reef platform.

At dusk, when laying to off the south point of Takume, we could see the
whole atoll stretching to the northward as plainly as if it had been charted
out. The line of numerous wooded islands and islets flanking the western
face of the atoll extends about fourteen miles in a northeasterly direction in
a large arc somewhat convex to the west, while on the east face parallel
with these runs the low bare reef flat with its three small islets separated by
the shallow and narrow lagoon of the atoll. The reef flat is widest near the
northeast horn ; the southern coast forms a curve which gives to the atoll
a slightly pear-shaped outline.

Lookino- across the narrow lagoon from off the east face, the wide bare
reef flat separated by the .shallow water from the islands and islets of the
western face presented all the appearance of a narrow secondary lagoon, only
somewhat wider, such as we have described for Anaa and other atolls of the
group.

Raroia.

Plates 201, 203.

Raroia Island, like Tahanea, was discovered by Bellingshausen. It is
very lightly wooded on the east side, but the west and north sides, along
which we skirted, are well covered with vegetation. This atoll and Takume
to the north of it have a soutli westerly to northeasterly trend (Pis. 201, 203), a
direction opposite to that of all the islands of the Paumotus we have thus far
examined.

Raroia is about twenty miles long ; it is a narrow, elliptical, somewhat
pear-shaped atoll, not more than six miles at its greatest width, in the

RAROIA. 95

northern part of the atoll. It and Takume are remarkable for the number
of islands which are found on their western face. The larger islands of the
land rim of Raroia form the northern and southern horns of the atoll.

Along the west coast of Raroia there are very large boulders scattered
all along the shore, seemingly larger than any we had seen before. As we
approached the beaches towards the northwest point, the shore ledges became
more apparent. There is but little sand above them, and everywhere large
boulders were scattered about.

The islets on the opposite face of the lagoon, as seen across the lagoon,
have their sandy beaches on the lagoon side, and those on the west face have
similar sand beaches on the lagoon side, passing gradually into the coral
shingle beaches facing the sea and with a narrow reef platform bordered by
long reaches of old ledge rocks. Across the low gaps in the islands we
could see also the light green strips of the narrow lagoon platform. The
islands and islets on the west side all appear to be placed more or less
at an angle across the outer rim flat. At the west point there is a long
line of small sand bars on the inner edge of the lagoon flat, some of them
islets high enough above tide lines to be covered with a scanty vegetation.
The reef flat extending around the northwest point of the atoll is wide,
and its sea face is flanked by a low bank of coral shingle. On the lagoon
side of the flat rise a series of islets and islands more or less at right angles
to the sreneral trend of the shore.

The old ledge crops out at the base of the coarse shingle beaches, and runs
out in low buttresses more or less covered by sand or coral shingle. On the
reef flat many boulders of old ledge are scattered.

The east face of the atoll, as far as we could see it, is quite bare of
islands, the bare or partly submerged ledge, according to our pilot, resem-
bling in every respect that of Takume. The outer islands gradually diminish
in number from the north side towards the east and south, while on the
north end they are quite closely crowded. The islands, as is usual, are
placed at right angles, or nearly so, to the general trend of the shore line.
This structure is of course ultimately lost sight of where adjacent islets have
united into a larger island. In some cases the process of consolidation has
been repeated often enough to make an island several miles in length but

96 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

only a couple of hundred yards wide at tlie outside. We find on the
islets the usual coral shingle on the sea face beaches and coral sand on the
lagoon side. The shore platform is from 100 to 200 feet in width, and is
edged by high Nullipore knolls ; it slopes quite sharply from the base of the
shingle beach to the sea face. The boulders and ledges at the base of the
shingle beach are made up of beach rock and recent conglomerate which at
one time must also have covered the greater part of the old ledge reef flat.
But the material which covered the sea face of the old ledge has all been
washed away and has been deposited either as boulders at the foot of the
beach where the beach rock still crops out, or has been ground into the coral
shingle forming the shingle beaches, or has together with the smaller rolled
coral fragments supplied the material for building up the sea side of the
islands of the outer rim of the lasjoon.

A similar condition of things has been described at Fakarava and on tlie
north side of Rangiroa.

On the west face the gaps separating the islands are often quite wide,
and from the color of the water passing through them a large quantity of
water must pass in and out at every tide ; or else the gaps may be closed
either on the lagoon side or on the sea face by shingle banks or sand bars,
forming thus diminutive bays opening, as the case may be, towards the
sea or communicating freely with the lagoon.

About three or four miles north of the West Pass there is a long line of
huge boulders of beach rock, some of them of colossal size ; one of them must
have been eighteen by twelve feet and nearly as high (twelve feet). They
formed a striking dark mass at the base of a narrow beach, with a narrow
reef platform of yellowish rock edged with a brilliant band of pinkish and
orange Nullipore and Pocillipore knolls slightly raised above the level of the
edge of the reef platform. Where the boulders were still a component part
of the stratum of rock overlying the old ledge, close to the base of the beach,
they are more or less undercut.

All the islands on the east end show fine coral sand beaches on the
lagoon side and beach rock boulders and coral shingle on the sea face.
Occasionally we come across a stretch of beach or coral shingle from five to
six feet high.

RAROIA. 97

We find the same digitating channels worn into the sea face of the reef
platform, cutting the outer edge into knolls which are gradually undermined
at the sea face of the reef platform, and finally are broken off in large
masses ; these are thrown up on the ledge flat and broken up little by little,
according to their size and their more or less exposed position on the plat-
form, and also accoi'ding to their composition of hard old ledge or of more
easily disintegrated beach rock or recent conglomerate.

The entrance on the west side of Raroia is fully 1200 feet wide, a
strong tide rip running diagonally across the mouth of the passage according
to the stage of the tide. The passage is flanked by a high and steep shingle
beach on one side, while on the other there is a low, long coral sand spit.
Tlie west side is raked by the wind, the sea following the shore ; while the
east side is butted by the wind and sea, which clear the reef flat of all loose
material ; as the platform passes into the lagoon and comes under the influ-
ence of the lagoon wind and sea following the shore, it is again covered by
islets and bars. Opposite the gap forming the entrance we could see on the
other side of the lagoon a few islands both to the north and south.

Soutli of the entrance the land rim is more continuous, less cut into
islands, with long stretches of shingle beaches, and with small boulders of
beach rock at the base of the beaches, with here and there larger masses. The
shingle beaches are steep, from six to seven feet high. A section, from the
outer sea face of the reef platform to the top of the sand or shingle beach,
shows a reef platform of old ledge from seventy to one hundred feet wide,
edged with a growth of Nullipores rising from one to three feet above the
outer level of the fiat and running out in a digitate form. At the base of
the beach crops out a ledge of beach rock, which at one time must have cov-
ered the greater part of the gld ledge flat, but which has been washed away,
and supplied as elsewhere the material for the beaches and the building up
of the seaward part of the land rim islands.

The stretch from the southwest point to the southeast point forms a

great bight, similar in all respects to the stretches to the north on the west

face of the atoll ; the whole seems one long continuous stretch of land

rim without gaps, with a high beach of coral shingle, and a beach rock ledge

at the foot of the beaches.

7

98 "ALBATROSS" TROPICAL PACIFIC EXPEDITION,

Taenga.

Plates 201, 203.

Taenga is triangular in shape, about ten miles long and five at its
greatest width.* The land rim is situated mainly on the faces of the
northern extremity of the atoll. The whole eastern end of the northeastern
and southern faces consists of low reef flats, bare at low water. There is a
narrow passage for small vessels on the southwest side of the atoll.

As we steamed westward along the greater part of the northeast shore of
Taenga, we skirted along the face of a large island which occupied the north-
western horn of the atoll. At the eastern and southern extremities the
islands are separated by wide gaps, and their shores flanked by high coral
sand beaches, with many reaches of huge boulders.

The shore of Taenga to the east of the northwestern point is low and
lined with huge boulders of beach rock. There is no coral shingle at this
point, and on the islands of that part of the land rim the old ledge is hidden
by modern beach rock. The reef platform where the old ledge is exposed is
quite narrow, and is covered with red Pocillipores and pink and orange
Nullipores. As far as we could see into the lagoon there are no islets to the
south, but on the western face there are a few.

At the southwest end of the lagoon the land rim is very low and narrow,
and at the southwest point passes into a rocky promontory, with masses
of large boulders piled upon the inner edge of the platform. On the west
face of the lagoon the island forming the northwest point is unusually wide,
fully 1200 to 1500 feet, as shown by the long gap cut across the island ; this
cut must be quite deep, judging from the color of the water, and must be an
excellent boat passage. It is edged on the sea face for quite a distance in
towards the lagoon by a high coral shingle beach.

Tiie boulders of the beach I'ock ledge are more or less loosely cemented
together, and some of them near the base of the beach are still connected
with the underlying beach rock ledge.

On a part of the west face of the atoll an extensive sand bar runs behind
the low shingle and boulder bars of the reef flat. The islands and islets on

1 Peppt des cartes et plans de la marine, 1716.

MAKEMO. 99

the reef flat of the west face extend nearly to the southwest point. North
of the southwest point and to the eastward, shallow gaps cut across the land
rira, and water passes freely through the gaps between the bars into the
lagoon across the southern face, and the eastern part of the northeast face
of the atoll. The whole face of the atoll from the eastern to the southwest
horn is open to the full force of the prevailing trades.

Makemo.

Plates 59-65; 75, fig. 4; 201, 'B03, SO^.

The atoll of Makemo is about forty miles in length, its greatest width
not more than six or seven miles. We entered the lagoon through the
channel on the northeastern side of the island, near the eastern extremity.
The whole south face of this atoll is nothing but a series of rocky bars
exposed at low water, with here and there an isolated island thrown up on
the reef flat. The reef flat of the land rim of the southwest face of
Makemo forms a great arc ending in a sharp horn at the southeast point of
the atoll. The western part of the north face is convex; it then becomes
concave, the land rim trending to the southeast as far as the northeast pass,
when the face of the land rim makes a sharp angle and runs nearly due
east to the southeastern point.

On our way to Takume we passed the northwest point of Makemo ; it
has a wide outer reef flat. The sea edge is higher than the platform flat,
with a depression running along the Nullipore edge, forming a narrow
platform lagoon. At the northwest point there is a high coral shingle
beach ; the land rim is narrow, with many low gaps over which one can
see into the lagoon. The islands on the west face of the atoll are thrown
up from the sea face.

The northwest pass is wide, flanked on the east side by a well-wooded
spit with a steep coral shingle beach, and on the west by a low sand spit,
partly covered with large boulders of beach rock and edged by a line of
smaller boulders of recent conglomerate.

On our return from Takume we struck Makemo about twelve miles north
of the northeast pass, where it presents the usual appearance of other

100 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Paumotu islands. Sand beaches are thrown up on the inner lagoon side of
the narrow low islands ; these vary greatly in length, and the gaps separat-
ing them vary also much in width. The gaps are frequently walled off on
the sea face by coral shingle beaches, or only partially so, allowing the sea
access to the lagoon through very shallow passages dotted with shingle
and rocks and sand bars, forming most irregular canals likely to be closed
at any time (PI. 61, fig. 2). Or the gaps may be similarly closed on the
lagoon side by the formation of sand bars and beaches across the openings
(PL 61, fig. 2), as we have described them at Rangiroa, between Avatoru
and Tiputa Pass.

On such steep faces as the sea faces of the Paumotu atolls, the corals
living on the outer slope are limited to a very narrow belt, which expands
at the passes and spreads into a luxuriant mass over their bottom. In some
atolls, judging from the amount of coral shingle derived from the old ledge,
they supply but a comparatively small amount of the material which goes
to build up the islands and islets and sand bars of the outer rim. In many
of the lagoons the corals form very extensive patches, and together with the
disintegration of the shoals and ledge flats of the interior, supply, when
dead and ground to pieces on the beaches of the lagoon, a large amount of
material for the building up of the land rim from the lagoon side. Of
course this proposition is not of universal application, as the luxuriant
growth of corals on the sea face depends upon a number of local conditions
and combinations of conditions which must be taken into account at each
atoll. It is not always on the weather side that corals flourish best, but on
the lee face of a reef, as, for instance, at Tahiti, where the corals tevke their
greatest development on the lee shore of the island ; and that, on the whole,
is usually the case in most of the districts I have examined, the lee sea face
presenting the healthiest development of corals. Yet from the constant
destruction of these going on on the sea face of the weather side, they
supply a far larger amount of material for the making of the land rim than
the corals which are growing undisturbed on the lee face. As far as acces-
sions are due to Nitllipores and corallines, their action is very different from
that of the corals ; inside of the lagoon their tendency is to coat every
fragment of loose coral, and cover it with a harder coating, to prevent

MAKEMO. 101

its further decay and disintegration ; at the same time soldering adjoining
pieces into a compact paving which eventually forms the great shore reef
flats and shoals of the lagoon of an atoll. Or the corallines grow in huge
masses on the bottom of the lagoon, and when dead and disintegrating
cover the floor of the lagoon with a viscid calcareous mass which, mixed
with fragments of shells and other invertebrates or pieces of dead coral,
makes a recent fossiliferous mass resembling more or less coarse chalk.

On the northeast face the islands are narrow (PI. 60, figs. 1,2); the
land rim is generally not more than 500 to 600 feet in width ; the
beaches are steep (PI. 59). All along the sea face shores of the Pauniotu,
where we find high coral sand beaches the boulders and shingle have been
completely ground to pieces, and the old ledge is well cleaned and left
exposed on the reef flat platform (Pis. 62, fig. 2 ; 65, fig. 1) ; where shingle
predominates there are usually lines of boulders at the foot of the shingle
beach, covering the reef flat in part (PL 59, fig. 2) ; and where there are
masses of large boulders the land rim is low, the material for elevating it
to the height of the rest of the land rim, either as a coral sand or a shingle
beach, remaining piled up in masses of boulders along the low line of reef
flat or upon the old ledge reef flat (PI. 62).

On the northeast face of Makemo the outer platform is narrow. The
outer edge is protected by masses of highly colored Nullipores and Pocil-
lipores (Pis. 59, fig. 1 ; 60, fig. 2 ; 62, 63). The northeast shore is protected
by narrow shingle beaches (PL 62) and small masses of beach rock. There
are long reaches of this, forming a sort of hedge of beach rock and of recent
conglomerate boulders (PL 63, fig. 2) in the rear of the narrow reef flat of
the old ledge, of which an outcrop runs here and there across the beach and
is lost in the mass of the outer belt of vegetation (PI. 64). For a long dis-
tance the land rim consists of long narrow islands edged by a coral shingle
beach from five to six feet high (Pis. 59, fig. 2 ; 62) ; and as we pursued our
course the outer shingle beach gradually increased in height to seven or
eight feet, and in soTne places to nearly ten feet. There is no lee on the
northeast side of Makemo ; the whole shore is raked by the trades.

The high shingle beach stretch is followed by a low coast protected by
a ledge wall and masses of boulders. Here and there a small island covered

102 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

with low vegetation, and followed by numerous islets, connects the separate
reaches of masses of boulders. None of the boulders on the northeast face
are large. To the south of Makemo Pass the islands continue small and
low, and are covered with low shrubs. The northeast pass of Makemo has
on one side a steep shingle beach (PI. 59), and on the other a long low sand
spit, which on the sea face passes gradually into a high shingle beach fully
13 feet in height. The land rim to the east of the pass is well wooded
(PI. 75, fig. 4) for a short distance, but soon it becomes low, and consists
of a series of small, low islands, connected by the reef ledge of beach rock
or by a few small boulders. Across the lagoon the horizon was clear, and
only a single island could be seen in the distance on the south face.

While at anchor in 13 fathoms we brought up in the dredge two species
of Madrepores and masses of broken fragments of corals, mainly Madrepores,
cemented together by Nullipores, worm tubes, and algae, and filled with mol-
lusks and worms and other boring invertebrates. Deep water runs close to
the shore in the lagoon wliere we were at anchor, and everywhere are
patches of corals to be seen, — no less than ten in our immediate vicinity.
To the north of our anchorage the lagoon platform is very narrow, while
near the pass it runs out into the lagoon in wide flats and long spits covered
with patches of beach rock.

In the passage there were fine masses of coral visible everywhere along
our course as we entered the lagoon. The bottom was covered with huge
patches of algae and of coralline algiB.

On shore near our anchorage we found in one of the gaps a fine exposure
of beacli rock, and of recent conglomerate made up of fragments of beach
rock, recent corals, and of fragments of old ledge (PL 61, fig. 2). This sec-
tion was taken near the base of the sea face beach, in a small canon, as it
were, forming the channel through whicli at high tide the sea is washed
into the gap and passes into the lagoon. It exposes admirably the old
ledge forming the base of the reef flat platform overlaid in part by the
beach rock conglomerate. The old ledge has been planed off and covered by
a thick bed of recent conglomerate, which has been washed away from |^the
greater part of the surface, leaving only here and there an outcrop of the
old ledge, or a horsehead, the upper part of which is beach rock conglom-

MAKEMO. 103

erate, resting upon a pedestal of old ledge rising above the general level of
the outer platform (PI. 65, fig. 1). The conglomerate ledge at the foot of
the beach only exposes here and there the old ledge rock at its base, or it is
seen occasionally cropping out as an outlier in the midst of the conglom-
erate bed covering its inner face.

The reef flat near Makemo Pass is not very wide (PI. 59, fig. 2),
and pitches quite steeply towards the high many-colored Nullipore edge,
which in many places must be fully three feet higher than the reef flat
(Pis. 60, fig. 2 ; 62 ; 63, fig. 1). For a distance of nearly twelve miles the
reef flat cannot be more than 50 to 70 feet in width, and there is, as at
the northwest point, parallel to the shore line, a deep sink ditch, between the
outer raised edge of the reef flat and the line of old ledge outcroppings
which run out at right angles to the beach (PI. 62, fig. 2). There is a
high coral shingle beach at the back of the beach rock conglomerate, made
up of recent coral heads and fragments of old ledge, which extends at the
foot of the shingle beach in more or less broken stretclies, separated by out-
crops of the old ledge rising above this recent conglomerate. Innumerable
pools are left at low tide along the slope of the reef flat (Pis. 59, 60, 62, 63),
filled with Holothurians, sea urchins (Hipponoe), covered with fragments of
dead Nullipores, or corallines, with others crowded with Echinometrae ;
black Diadematidai and Echinothrix are sheltered under projections of the
ledge or in pools protected by boulders. It is difficult to see how these
black Echinoderms have derived any advantage from living on this outer
reef flat, where they stand in nearly as strong a contrast on the light yellow
rock flat, as they do in the interior of the lagoon, against the white Nullipore
and coral sand upon which they equally congregate.

Fragments of broken corals, ground or worn into the shape of flat or
rounded pebbles of all sizes, are thrown in the cracks and between the
boulders of the conglomerate or old ledge rock, and gradually become
cemented together, forming a coar.«e puddingstone, composed of all the
various sorts of materials which go to make up the sea face of a coral
reef (PI. 65, fig. 2).

The beach near the entrance to Makemo on the northeast side is a high
coral shingle beach, fully 14 feet in height. Much of the shingle is thrown

104 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

over the highest point of the beach and rolls inland (PI. 59, fig. 1). At the
base of the beach the shingle ha.s been ground to fine coral sand. From the
base of tliis extends the rather narrow reef flat from 50 to 75 feet wide ;
this is somewhat dished, forming an irregular ditch flanked on the sea face
by a wall of Nullipore and Pocillipore knolls in places fully four feet higher
than the reef flat sink (PI. 60, fig. 3). The large island on the north side of
Makemo Pass is from 1000 to 1200 feet in width.

A line of soundings was made in the lagoon by one of the officers (Mr.
Kempff). He brought back a number of samples of the bottom ; they are
most uniform in character, consisting of coral sand, coral fragments, broken
shells, plates and spines of sea urchins, fragments of Nullipores. coralline.s,
Orbitolites, and other Foraminifera. The greatest depth thus far found while
surveying in the lagoon is 16 fathoms. A great many islets, shoals, bars,
and ledges are to be seen cropping out in all directions.*

We went in the steam launch across tlie lagoon towards the nearest point
of the south side ; we made a few sounding.s, onoino; over, in from eight
to ten fathoms; we usually found hard bottom, with Nullipore and coralline
patches or corals, extending from the slopes of the numerous shoals we found
on the way. On shoals having from two to three feet of water at low tide
we found the top covered with dead coral heads more or less overgrown with
Nullipores, while on the edges of the slopes began to grow Madrepores and
Millepores, with heads of Pocillipores extending into deep water. The top
of one of the largest shoals we found, fully a mile in length, was covered
with dead corals encrusted by Nullipores and overgrown with alga3 and coral-
lines, with scattered patches of thriving corals dotted over the surface and
extending over the slopes towards the bottom of the lagoon.

The approach to the lagoon edge of the south shore reef flat is very grad-
ual from the ten-fathom line, which is at a distance of from 1000 to 1500

')

* An Ecliinoneus of a pinkish color, varying to lisht chestnut, was collected on the outer reef; the
smallest specimen, measuring one fourth of an inch, was pinkish. The pedicellaria; and tentacles are of
a <lark violet. The pigmented rows of .suckers stand out prominently from the rest of the test as dark
violet lines. The covering of the glassy tubercles is only a continuation of tlic epithelial surface, similar
to that on the base of the spines, only without pigment spots. The tentacles near the apical system have
a rudimentary sucker, which is more developed on the actinal face. The genital openings are protected
by small spines. The plates of the anal system are somewhat imbricated ; those of the mouth very
much so.

MAKEMO. 105

feet from the point where the so-called reef may be said to begin, where
there is from one to three feet of water at low tide. This gentle slope is full
of great patches of Nullipores and coralline algoe separated by lanes of coral
sand and of broken shells, with here and there a coral patch of greater or
less extent. The sea face of this reef flat is lined with a belt of great masses
of boulders, probably outliers of the old ledge, standing up inside of the
breakers at this stage of the tide (nearly low tide). It was impossible to
judge of their composition, as there were none accessible on the lagoon face of
the reef flat.

The lagoon face of this wide reef flat was here and there edged with
sand bars, the beginnings of small islands and islets. Here also, as in so
many other atolls of the group, there were occasional bars of coral shingle
and smaller rolled material derived from the disintegration of the large
masses edging the sea face of the rim flat. A line of soundings run
into the lagoon showed a very gradual slope, from 8 fathoms in the
middle of a mass of shoals about 500 to lOOO feet from along the lagoon
edge of the outer reef flat, towards the deepest part of the lagoon, in about
21 fathoms, rather more than half-way across. From this point we strike
19 fathoms at a distance of six miles from the ship, and eight miles off it
was 15 fathoms, the depth we found off the opening where we were at
anchor.

We passed not less than twenty-four shoals in a distance of not more
than live miles from the lagoon edge of the flats, the slopes of all of which
were occupied by corals extending to a depth of 16 fathoms or so into
the lagoon. Bars are formed here and there. Algae were also seen growing
on the bottom, and large Nullipore patches. There were more than thirty
shoals along the line of soundings we ran across the lagoon. Here and there
a few heads of old ledge rock showed above the water line, and where deeper
the tops were seen to be discolored with masses of Nullipores and patches of
growing corals extending along the slopes.

With the aid of the water glass we were able to see that the bottom of
the lagoon was everywhere covered with patches of Nullipores and coralline
algae and of corals, mainly Madrepores, in all but the deepest parts of the
lagoon down to sixteen fathoms or so.

106 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The surface hauls made inside the lagoon proved comparatively poor:
a few Copepods, larvae of Macrurans and Bracliiurans, young fishes, a few
Appendiculariaa and Sagittae, and a small Geryonia, — a mixture of pelagic
surface life and of littoral pelagic larvae.

We examined the rocky shoals to the northward of the ship, — one about
two, the other four miles from the anchorage ; we found them both to be
fragments of the old ledge. At the first ledge there is, at a distance of from
70 to 80 feet from the flat edge of the ledge, a depth of 12 fathoms, which thus
slopes very rapidly on all sides. Fragments of the ledge have broken off
and rolled down, forming a talus ; and on the slopes thus formed corals of
all kinds have established themselves. On the second ledge quite a small
island of old ledge is left standing about five feet in height, irregular in
shape, with a diameter of ten to twelve feet. The flat part of both these
ledges is a shoal of some length, covered with fragments of the old ledge
and overgrown with Nullipores covering also masses of dead shells and frag-
ments of corals which fill the interstices of the larger masses, so that the
whole surface of the shoal presents a highly colored appearance, varying from
yellowish to pink and red, or dark violet, much as the wide reef flat of the
south shore was colored by its covering of Nullipores, corallines, and corals.

On the slopes of these ledges grow masses of corals, of Madrepores,
Pocillipores, Goniastraeas, of heads of several species of Porites, with
differently colored Astrfeans, and masses of algce and corallines growing
between the heads, and Nullipores encrusting the smaller fragments and
cementing the parts into a solid mass. On the lee side of both these
ledges, the boulders and loose material formed a regular talus on the face
of which but few corals were growing. The corals extended to about ten
fathoms, when they were in great part replaced by Nullipores and corallines,
and finally coral and coralline sand and fragments of broken corals occupied
the bottom of the lagoon from sixteen fathoms down.

In eight fathoms, about three fourths of a mile froin shore, Alveopora is
very common, growing upon old fragments of corals covered by algae and
corallines. On the greater part of the shoals, in rather shallow water, Mille-
pores grow in great abundance. In 2;} fathoms we found fragments of beach
rock and of old ledge covered by Nullipores and running inshore to connect

MAKEMO. 107

with ledges of similar material making out as points, or being isolated
boulders torn off the lagoon face and rolled into deeper water.

Two additional gaps which we examined presented no distinctive features
from others we had seen, the cut through the beach rock leaving low walls
undercut at intervals, with sand bars across the gaps forming a more or less
wide opening from the lagoon side, till it butts against a mass of beach
rock boulders at the sea face of the gap. This mass of boulders is scattered
over a length of nearly a mile in a belt fully 400 to 450 feet wide, until it
reaches the base of the shingle beach. This shingle is often driven into the
shore belt of vegetation (PI. 64), and thus becomes scattered and thrown
across the narrow land rim, and in heavy gales is rolled all the way into
the lagoon.

At one point the shingle beach was perhaps not more than three feet high ;
the slope of the wide sea face on which the masses of boulders rested ex-
tended to within five feet of the outer edge of the reef flat ; the old ledge was
exposed for a width of from 50 to 100 feet inside of the raised Nullipore
edge. The sand beaches of the lagoon side often extend into the gaps and
form a series of parallel dams across the gaps where they are open to the
lagoon side.

The face of the island of the land rim, opposite our anchorage, presents
a fine example of islands as buttresses at right angles to the trend of the
coast, for many of the gaps, not more than 50 to 100 feet apart, are only
separated by strips of low sand land from three to five feet high, ending at
the sea face, either into coral shingle beaches or into the wall of boulders
mentioned above. The reef flat is composed of old ledge, which also crops
out in the cuts below the beach rock stratum.

The recent beach rock conglomerate is made up of masses of recent coral
fragments of all sizes (PI. 65, fig. 2), from whole colonies to the merest chips,
and from similar fragments derived from the disintegration of the old ledge
rock, liuge masses of which crop out through tlie beach rock conglomerate,
so that it is often difficult to determine whether a particular outcrop of old
ledge is a boulder, or a horse, still connected with the underlying old ledge.

On going south the gaps of the land rim become less frequent. The
sand driven from the lagoon has only left low depressions between the

108

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

islets, to show where the gaps existed, and finally is overwhelming the beach
rock conglomerate, which only juts out in strips or points separated by
reaches of sand of greater or less extent.

Some of our photographs of coral shingle and coral boulders driven
inland between shrubs and trees show that they penetrate a considerable dis-
tance over the summit of the land rim (PL 64). They also show how coral
fragments, from the size of one's head to the merest chips, collect and
become cemented together to form a conglomerate or breccia merely from
tlie action of the wind and rain, and not under tlie influence of the sea,
thus gradually covering the old ledge, whatever might be its composition, if
it sliould constitute the foundation of an island.

Our examination also shows how all the low land of the rim of an atoll
is absolutely at the mercy of waves of great height, or even of a common
storm, and how the material from the outer beach, and all kinds of coral
shingle fragments, are pushed across between the shrubbery and large trees,
killing some of those nearest the shore, and how the sea may cut gullies into
the low land, either on the sea face, or through it, or down the lagoon slope.

There is a fine sink on the southern point of the entrance to Makemo,
behind the great shingle beach dam which has shut off from the sea the
extensive flat area of that end of the island.

Many blow-holes occur on the outer edge of the reef platform ; this is
cut up by numerous shallow digitations, many of which are bridged to form
the blow-holes.

Gap across the Land Rim of Makemo.

TEKOKOTA. 109

The lagoon side of the land south of the northeast passage shows the
same features as the land north of the pass. As we passed out and steamed
along the eastern face of tlie north shore, we could see that the south end of
the atoll presented the same alternating features of coral sand beach,
shingle, low rim land, and islets and islands, characteristic of the land rim
which we examined to the north of the pass.

Tekokota.

Plates 66, 201, 303.

On the southern face of Tekokota, near the northwest horn of the atoll
(PI. 66, fig. 2), where the shallow reef flat forms a wide rounded point of
light green water edging the darker blue green of the small lagoon, there
are fine examples of bars of shingle and of beach rock running trans-
versely across the reef flats, headed by a shingle beach (PI. 66, figs, 3, 4)
with a tail terminating on the lagoon side in a low sand bar or sand islet.
On an island covered by tall Fetau trees (PI. 66, fig. 4), which shelter a
regular rookery of boobies, there is a very fine outcrop of the old ledge
tapering off to the south in a line of negro-heads on the outer rim of the sea
face platform.

There is no land rim on the eastern end of the atoll (PI. 66, fig. 1). A
long island on the eastern face, four islands on the opposite face, and one on
the north side compose the whole atoll land. There is a superb line of
breakers all round the atoll following the shore line (Pi. 66, figs. 1, 2).
Judging from the color of the water in the lagoon, it must be of very
moderate depth, ])ut there is a deep hole of dark blue near the northeast
horn of the atoll, as well as a band of darker green.

Large boulders are scattered all along the rim of the reef flat, which is
quite narrow in places, the heavy swell and rollers rushing over the flat and
pouring into the lagoon over the east face.

This is also called a closed lagoon, yet water is forced into it over
seven eighths of the rim flat on the faces exposed to the trades
(Pi. 66).

110 "ALBA.TROSS" TROPICAL PACIFIC EXPEDITION.

The atoll of Tekokota is elliptical, somewhat more than a mile in great-
est diameter. On the western face off the wooded island the reef flat slopes
seaward for a considerable distance, and is well covered with corals.

Boobij:s in Rigging.

Hikueru.

Plates mi, 203.

This is a small atoll running almost east and west, irregularly elliptical,
with a comparatively deep lagoon for its size. Its greatest length is about
six miles, and thi'ee miles in width. The land rim is situated on the north
side of the atoll. The southern face is merely a reef flat over which the sea
enters into the lagoon, and is forced out again over the northern face of the
island.

Hikueru, seen at a distance from the north side, appears like a series of low
disconnected rectangular blocks with rounded edges ; in fact, that is much the
appearance of any atoll seen at from six to ten miles off, according to the
height of the cocoanuts or of the vegetation growing upon it. The islands
are separated by wide open fiats. Nautilus are said to live in the lagoon,
creeping along the bottom in the sand, and coming to the surface in calm
days.

Near the northwestern point are some large boulders of beach rock
conglomerate and of old ledge, the latter undercut and still connected with
the old ledge platform forming the outer reef flat.

MAROKAU AND RAVAHERE. Ill

The eastern part of the atoll is a wide reef flat, partly covered with beach
rock boulders and shingle on the sea face, and edged in part with low sand
bars on the lagoon side of the reef flat. All the islands of the atoll, as well
as the islets on the outer reef flat, are faced with coral sand beaches on the
lagoon side. The lagoon is from 12 to 18, and, in places, 22 fatlioins deep;
though it is said to have deep spots of 30 fathoms, the average depth is 15
fathoms.

The old ledge is, as in other atolls, generally planed off to the level of the
outer reef flat, and overlaid by recent conglomerate and beach rock, which
supplies the material to check the erosion of the old ledge, and to build
up the sand bars, islets, and islands heaped up on the rim of the atoll,
according to its position with reference to the gaps and the prevailing
winds.

Hikueru is, like Makerao, full of shoals. Corals seem to thrive remark-
ably well in this lagoon. There are great masses of them on the slopes of
the shoals and flats, and they supply a large amount of the material which
has built up the islands from the lagoon side. It is said that there are
in this lagoon, as well as in Hao, deep holes of very limited area, somewhat
like the ocean holes of the Bahamas,' but I was unable to obtain any definite
information regarding them.

On the wide flat of the southwest point, which must be 1200 to 1500
feet in width, there are long concentric lines of boulders and of shingle and
of beach rock and heads of old ledge.

Marokau and Ravahere.

Plates 70, figs. 1, S ; 201, 203; S04, fig. 5.

The Two Groups, as the islands of Marokau and Ravahere are called, are
interesting ; they probably represent the denuded summit of a ridge with a
valley of a depth of not more than 270 fathoms separating these two summit
ridges. The islands are both triangular, the northern island (Marokau)
being somewhat the larger ; the second or southern island (Ravahere) is
elongated, and is characterized by its secondary lagoon, which extends nearly

1 See A. Agassiz, Bull. M. C, Z., Vol. XXVI. p. 42.

112 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the length of the island. The two islands are somewhat more than twenty
miles in length. The greatest width of Marokau across the northern face is
about eight miles, while Ravahere is nowhere more than three to four miles
wide. The lagoons of both these islands are closed, there are no ship passages
or boat passages, but the sea has the fullest access to the lagoons over certain
parts of the reef flats.

At the northwest end of Marokau beach rock and recent conglomerate
cover the old ledge, which crops out here and there on the wide reef
fiat (PI. 70, fig. 1) of the western face, extending towards the southern
point of the island. Boulders also are scattered all along the outer reef Hat
of the western face, numerous bars of shingle extend across it, with
sand bars on the lagoon face, and with gaps of green water forming the
communication between the sea face and the interior of the lagoon. The
reef flat is at least from 700 to 1000 feet in width, as far as the southern
point (PI. 70, fig. 1). The sea face beaches of the Islands are high
shingle beaches with small boulders, principally of beach rock, scattered
along the outer edge of the reef flat (PI. 70, fig. 1). The southern part of
the lagoon is much the shallowest, the flat on the lagoon face being fringed
with a broad belt of light green water. The lagoon edge of the western side
is faced with sand bars, one of which is specially noteworthy for its length ;
it must be over a mile in length, and separated from the adjoining reef flat.
Two islets could be seen on the eastern face of the atoll which seemed to
extend well into the lagoon. In a narrow channel there are some very large
masses of beach rock and recent conglomerate on the reef flats similar to
those of other la2;oons.

At the southwest horn of Marokau there is a wide reef flat, the continua-
tion of the western reef flat (PI. 70, fig. 1), wider than any we have as yet
seen in the Paumotus, with a line of large boulders running about parallel to
the raised edge of colored Nullipores and Pocillipores. The large island at
the southern extremity of the atoll is flanked by a high shingle beach.

The two atolls of Marokau and Ravahere appear like a single atoll as
seen coming from the north, the islands of the one and of the other sepa-
rated seeminglj' by a somewhat wider gap than is usual, or by a wide pas-
sage opening into a lagoon. Passing through the strait between the atolls.

HAO. 113

we could see the southeast face of Ravahere to be one string of islands
(PI. 70, fig. 2) as far as the eye could distinguish. In addition to the
secondary lagoon parallel to the west shore the lagoon at the south end is
divided by a flat into two lagoons, a little more to the northward than is
marked on Wilkes's chart. Such a division is not uncommon in some of the
Paumotu atolls. We have found such a division by reef flats into secondary
lagoons in Anaa and Tahanea. At the north end of Ravahere a wide flat
runs from the west coast far into the lagoon, on the inner edge of which
rises an island with high shingle beaches, as on the islands on the east face of
the northern horn. The outer reef flat on the south shore is covered with
coral rubble, and on the sea face of the west flat large boulders line the
outer edge of the reef flat. Ravahere at the northern extremity is very
narrow, and only a thin line of dark blue water indicates the small extent of
deeper water in the lagoon, which is said to be very unequal in depth, and
full of deep holes.

Hao-

Plates 67, 201, 203; 205, fig. 2.

Hao was discovered by Bougainville. It is thirty miles long and about five
miles wide.' It is shaped somewhat like a boomerang ; the southern part
of the atoll turning off to the eastward at an angle from the general trend,
as is the case with Tahanea, Rangiroa, and Makemo. Two sinks are
indicated on the sketch of the entrance to Hao.^ They have probably been
formed in the same manner as those near the passes of Rangiroa, Makemo, and
the like. It is well wooded on the weather side, the islands and islets of the
lee side are generally bare, and the sea pours over into the lagoon through the
gaps between the islands. The entrance of this lagoon is on the northern side,
the tide running in and out witli such velocity as to make numerous over-
falls. The depth of the lagoon of Hao, especially at the northern extremity,
is as great as 30 fathoms in places, although the average depth is about 15
to 20 fathoms. The northern part, but specially the southern and eastern
parts of the lagoon are studded with coral knolls and coral patches, which
make navigation extremely dangerous.

' A. Chart 1111. ^ Ibid.

114 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Immediately to the westward of the entrance to Hao a ledge of beach
rock is exposed, overtopping a part of the old ledge reef fiat. Both to the
west and to tlie east of the passage there are many shallow gaps, giving free
access to tlie sea to the'interior of the lagoon. One, however, is very deep,
not more than 50 to 60 feet wide, across a narrow part of the land rim,
exposing the beach roclc and the recent conglomerate covering the old ledge,
which here and there crops out as small buttresses, about four feet in height,
at the base of the shingle beach, and runs out on the broad reef platform of
the western face. On the north side the sea face of the land rim is com-
posed of alternating reaches of coral sand and buttresses of old ledge.

The northwest horn of Hao (PI. 67, fig- 3) is formed by two islands, one
on the north face, the other on the western, separated by a wide flat nearly
planed down to the level of the sea, and cut through but still connecting the
two sides of the horn, and covered over with a mass of beach rock and old
ledge boulders, with here and there a sand l)ar.

Beyond the northwest point we came upon many cuts forming short
headlands flanked by shingle beaches and lines of beach rock or coral
boulders. The reef flat and the land rim (PI. 67, figs. 1, 2, 4) vary greatly
in aspect as we steam along the west face. In the interior of the lagoon
as seen from the west side we could distinguish a great many shoals and
ledges looming up in all directions (PI. 67).

At one point of the western face the islands run at a sharp angle across
the wide reef flat, with water gaps of considerable depth between them.
The sea end of the islands was tipped with beach rock boulders or coral
shingle, while along the sides of the islands, on the lagoon side, extended
fine coral sand.

At another point the islands were replaced by bars of coral shingle run-
ning diagonally across the reef flat, separated by shallow gaps and abutting
on the lagoon side on small sand islets and sand bars. Nowhere perhaps
have we seen better examples of the transition between a small high bare
sand bar, or one a little larger with one or two stunted bushes, passing into
a still larger one with a thriving belt of bushes, next a somewhat larger
one with a few cocoanut palms, and finally a large island such as are char-
acteristic of the atoll rim with its full quota of coral reef vegetation (PL 67).

HAO. 115

We then came upon a stretch with eleven islands,^ nearly all equidistant,
separated by shingle bars abutting on the lagoon face, upon sand bars or
sand islets, running like the islands diagonally across the reef flat. After
passing this stretch of comparatively small islands, many of the islands
on the reef flat became larger (PI. G7, fig. 4), the land rim consisting of a
series of islands of various sizes, alternating with sand bars for short dis-
tances. Here and there the ledge of beach rock and of recent conglomerate
was continuous on the sea face of the reef flat, forming a wall effectively
shutting out the sea from the interior of the lagoon (PI. 67, figs. 3, 4).

On the sea face of many of the islands on the western face of Hao the
old ledge cropped out here and there, like low buttresses, through the mass
of beach rock and recent conglomerate which covered the underlying ledge
near the base of the shingle beach, or through the coral rubble on the inner
part of the reef platform. Some of the . shingle beaches must have been
from ten to twelve feet high (PI. 67, fig. 4). The islands on the eastern
face of the atoll, as seen from the western face, were all edged by a coral
sand beach on the lagoon face.

The east face of Hao, with the exception of a stretch covered with islets
and sand bars to the south of the central part of the land rim, consists of a
few long islands. If we compare this with the condition of the west face
of Hao, we find that those reaches of the land rim which are raked by the
prevailing winds are composed of longer and more continuous islands than
the faces of the atoll against which the trades butt, where the land rim is
broken up into islets and sand bars extending across the broad reef flat.
The position of these islets is more or less unstable ; they migrate much^
like sand dunes until they become fixed by vegetation, while the larger
islands raked by the trades are more stationary, the beaches of their faces
receiving accessions from the breaking up of the material thrown up on the
flanks of the land rim, — material whicli is in its turn carried seaward or
lagoonward in a direction in general parallel to tlie trend of the land rim,
while on the exposed face the tendency of the action of the sea is to widen
the reef flat, the material being driven towards the interior of the lagoon.

1 On the chart of Hao the difference between bare sand bars and islets covered with vegetation is not
indicated.

116 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

From the southern point of the island to the eastward extends for
about five miles a wide reef flat, full of patches and bars of beach rock,
incipient shingle beaches, and piles of coi'al shingle, with sand bars and
sand islets on the lagoon face of the reef flat, with many wide rather
shallow gaps giving access to large bodies of water to the interior of the
lagoon. At the south end there is a large island marked for its superb
vegetation.

The Nullipore and Pocillipore knolls^ of the outer edge of the reef
platform were remarkably brilliant in their coloring, and with the sun
shining on the ed<j;e of the reef flat the contrast between the different shades of
blue to green and the metallic colors of the tongues of water breaking upon
these brilliantly colored coral knolls was most striking ; blue, red, green, yel-
low, orange, all contrasting to the white surf dashing across the flat ; and as
seen from the ship, with the dark blue foreground of the deeper water. Tiie
yellow belt of beach rock or conglomerate, inside the brilliantly colored
outer edge, formed a striking contrast to the high gray shingle beach or the
brilliantlv illuminated dead white or cream-colored coral sand beach running
in between the masses of the dark green belt of shrub vegetation growing
back of the top of the beach shingle and topped with rows of high cocoanut
trees, — all this combined with the light blue sky dotted with the low lines
of trade wind clouds, formed a kaleidoscope of colors very different from
that of an ordinary sea beach.

Aki-Aki.

Plates G8, 69, 201, 203.

Aki-Aki is a circular island, three quarters of a mile in diameter, formed
of elevated coralliferous limestone. It is well wooded. There is no lagoon,
a very insignificant sink occupying the western portion of the island. The
beach of Aki-Aki is highest at the south end (PI. 68, fig. 1), where there is
a shingle beach fully twelve to fifteen feet ; it is not more than from four
to five feet high at the north end, with an occasional short stretch of coral

1 These are developed to such an extent that they are sketched as islets on the edge of the reef flat
in the survey of the entrance to Hao by H. M. S. " Blossom."

AKI-AKI. 117

sand. The island slopes slightly from the south end towards the north
side, where the shingle is coarser, and coarsest at the northeast point. Ac-
cording to Mr. Townsend, the island is slightly dished towards the centre,
occupied in part by a small sink of fresh water a little way in from the
beach. The central part of this so-called lagoon is covered by low brush
(PI. 69, fig. 1), and surrounded by large trees on the outer edge close to the
beach ridge, a short distance inland.

The reef platform is from 75 to 100 feet wide, very flat, with a compara-
tively low outer edge. On the southeast side there is a continuous beach
rock ledge with a wider reef fiat platform than on the north side ; it is from
150 to 200 feet wide.

The inner part of the island is about two feet lower than tlie outer edge.
A part of it is bare or is covered with fragments of broken coral gradually
passing into a rich black soil covered with grass, and large hard-wood trees
(PI. 69) as well as Pandanus, together with bushes similar to those edging
the outer rim of the island. Part of the island is also covered with small
coral-boulders thrown into the interior while the island was building up.

Recent beach rock and conglomerate as well as parts of the old ledge crop
out in the interior, where the natives have dug water holes. A shallow sink
exists (PI. 69, fig. 2), formed undoubtedly, as in all limestone areas, by solution,
which has carried oS. more or less of the material cemented together as beach
rock. The island undoubtedly owes its shape to the throwing up of the
beaches from different directions upon the original plateau underlying the
island, as the soil of the interior is made up of vegetable matter and de-
composed coral fragments or boulders, among which can be recognized
Madrepores, large masses of Porites, Pocillipores, and AstrsBans. In the
middle of the island are found tlie largest trees and the best soil. As is
shown by the structure of this island, the existence of alternate layers of
beach rock and of recent conglomerate or of coral rubble does not by any
means indicate a talus ; it merely indicates a reef flat over which the sea
has either been building up beaches, or cutting down ledges, or adding masses
of coral sand or shingle. This may explain much of the character of the
successive layers of rock met with by boring through the upper strata at
Funafuti, said to have been due to subsidence.

118 "ALBATKOSS" TROPICAL PACIFIC EXPEDITIOX.

Nukutavake.

Plates 70, fii/s. 3, 4 ; 71, 201, 203.

Nukutavake is another interesting island from the fact that it also has no
lagoon. It is about five miles long and not more than one and a half miles
wide. As seen approached from the north, it appears highest at the north
point, where there is a high shingle beach with a wide reef flat. The
beach extends half-way towards the other extremity of the island, and is
in many places edged with beach rock ledges extending along the foot
of the coral sand or shingle beach. The island is a very narrow ridge
which has been formed by beaches thrown up on opposite sea faces thus grad-
ually building up the outer rim of the island, leaving the interior somewhat
depressed, or rather lower than the outer beaches. One of the beaches is
fully twenty feet high, and from its crown the land falls off very rapidly.

The reef flat platform is about 150 feet wide, with an occasional outcrop
of old ledge along the face of the high coral sand beach facing the village.
A section across Nukutavake from the west shows a very steep outer beach,
either shingle or sand, sloping very gradually inland, the inland slope covered
at first with coarse coral shingle, passing gradually into finer material and
then into fine soil in the central part of the island, occupied by three or four
depressions or sinks, many of them full of water, running in general parallel
to the trend of the island. We come then upon the inland slope of the beach
of the opposite side, which is very much steeper, rising rapidly to a consider-
able height and sloping abruptly to the sea face. In the depressions we
could see beach rock and recent conglomerate cropping out, and fragments
of coral and coral boulders more or less cemented together.

Where we examined the island it was about half a mile wide. The
whole of the south side of Nukutavake is faced by a line of dunes more
or less overgrown with grass or low vegetation.. Pandanus are exceedingly
numerous on this side of the island. The dunes have killed a large tract
of Pandanus, and through their slopes project dead bushes and stumps of all
sizes of Pandanus, cocoanuts and other trees. On the east side the sand
dunes are bare. The sand dunes which are characteristic of the south face
of this island I'ise in places to fully 30 feet above the top of the beach, as

NUKUTAVAKE.

119

high as the highest trees, and show well how in this island the depression
or sink, or the so-called lagoon, is produced by the enclosing of an area
within the space of coral sand or shingle beaches thrown up from opposite
sides. The highest sand dune we saw was fully 35 feet from the high -water
mark, and had greatly encroached upon the adjoining vegetation of the
outer rim of the island. Stumps of bushes and of trees could be seen pro-
truding from the sides and summit, and long stretches of trees near the
coast line were killed, the lower part of the trunk having been buried in
the sand (PL 70, fig. 4).

The old ledge rock crops out on both sides of the island, but much of the
old ledge, however, is concealed by the overlying beacli rock, which extends
across the island, together with decomposed coral boulders and coral shingle ;
this, mixed with algte and dead leaves and bushes, forms an excellent light
soil on which is found growing in the interior fine Poukas, Pandanus, and
other characteristic coral reef vegetation (PI. 71).

Following the line of the horn of the western extremity, th'ere is a well-
defined secondary lagoon parallel to the outer edge of the reef platform
(PL 70, fig. 3).

NaTIVK at AkI-Aki in CaNOK, in which HK was blown from a WlNDWAltD

Island a Couple of Hundred Miles.

120 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Finaki.

Plntes 72-75, 201, 203; 206, fig. 3; 236.

Pinaki is historically a most interesting atoll. It was discovered by
Captain Wallis in 1767. It encloses a shallow lagoon, and is about one and
a half miles in diameter ; the greatest height of the land rim is from six to
nine feet. It is surrounded by a wide reef platform which follows the out-
line of the island. There is on the southern side a narrow entrance into the
lagoon, but it is too shallow for boats to enter even in a smooth sea (PI.
206, fig. 3). The vegetation of the land rim consists principally of bananas
and cocoanuts, which have displaced the Poukas and Pandanus.

Pinaki, as seen coming from Nukutavake, appears like a high unbroken
sand beach (PI. 73). On nearer examination we found the sand beach
topped with coral shingle, and that a ledge of beach rock cropped out
occasionally at the foot of the beach, encroaching somewhat upon its face.
The beach rock covers in part the old ledge which crops out on the wide
reef flats and in the gap leading into the lagoon (Pis. 72 ; 206, fig. 3).
To the west of the entrance gap the beach consists of alternating reaches of
fine coral sand or coral shingle rising to a height of six to seven feet (PI.
72, figs. 1, 2). The land rim is well wooded, and inside of the outer belt
of bushes grow numerous Pandanus and tall Pouka trees, with here and
there groves of bananas and cocoanuts (PI. 73).

The wide reef platform is deeply indented with large gullies and
edged with Nullipore knolls (PI. 73, fig. 1). The reef flat slopes very
gradually from the base of the beach, the top of which is covered with
verdure, with a narrow belt of gray coral shingle between it and the cream-
colored coral sand beach. On the east face the beach or land rim is in great
part formed of high sand dunes, similar to those we saw at Nukutavake,
killing the Pandanus and the vegetation of that face of the lagoon by
encroaching gradually upon the land rim (Pis. 73, fig. 3 ; 206, fig. 3). On
a part of the atoll on the west side the high shingle beach abuts upon a
wide reef flat where an incipient barrier reef is formed on the outer edge of
the reef platform (PI, 72, fig. 1) by a ledge of beach rock covering in part
the old ledge.

PINAKI. 121

The gap which is the onl}- opening into the lagoon of Pinaki is about
500 yards wide, and tlie land rim at the opening is nearly 1200 feet
wide (PI. 72, figs. 2, 3). No water can come into the lagoon except during
the last part of the rising tide. The lagoon is filled with numerous islets
(Pis. 74, fig. 1 ; 75, fig. 1 ; 206, fig. 3) which rise on the lagoon edge of the
inner reef flat, which in places is fully 600 feet wide (PI. 74, fig. 1). Mr.
Alexander counted no less than 116 of these islets; they are all topped
with dead Tridacna shells, and there are great windrows of these on the
edge of the lagoon flat, close to the lagoon beach of the land rim (Pis. 75,
fig. 3 ; 206, fig. 3). The Tridacna islets are all small, ten by twelve feet
about, not more than tliree feet high, and their slopes are covered with
Madrepores. Many of the islets are connected by shallow flats. The living
Tridacnas are found in great number in the deeper parts of the lagoon towards
the northern end of the atoll, where they occur packed much as oysters in
an oyster bed. Besides the Tridacnas, the bottom of the lagoon and stretches
of the lagoon flat are covered with a species of Area, the dead shells of which
are thrown up in immense masses on the shallow parts of the lagoon and
on the inner beaches. On the west end of the island there is in the lagoon
a huge bed of these Areas. The lagoon in some places is from three to four
fathoms deep below the inlet. The water is abnormally warm, — much
above the temperature of the outer sea water. The lagoon contained
many fishes.

The old ledge crops out here and there on the sea face. To the west
of the entrance there is a good exposure of it (Pis. 72, figs. 1, 2 ; 206,
fig. 3), as well as in the middle of the entrance to the lagoon (Pis. 72,
fig. 3 ; 74, fig. 2 ; 75, fig. 2), where an outcrop forming an elongated ledge
divides the channel into two passages (PI. 75, fig. 2), while on the sides
of the passages of the channel the old ledge is covered by beach rock,
recent conglomerate, coral boulders, and shingle, — a condition of things
very similar to that which we have observed in the gaps of so many of the
Paumotu atolls (Pis. 72, fig. 1; 74, fig. 2; 75, fig. 3). The beach rock
cropped out here and there in the interior of the lagoon. The sand which
is blown into the lagoon over the land rim is cemented into fine mud when
mixed with the mass of decaying Areas and Tridacnas. The bottom of the

122 "ALBATKOSS" TROPICAL PACIFIC EXPEDITION.

lagoon consisted of coral sand, broken shells, Nullipores, corallines, and
Foraminifera.

A sand bar is forming directly across the opening of the passage on
the lajT-oon edtre of the inner flat of the atoll. The lao;oon flat is narrower
on the two sides of the passage, but widens out towards the eastern and
western beaches of the lagoon, and the widest part of the flat opposite the
entrance is separated from the opening by the deepest part of the lagoon.

This atoll is well known from a somewhat diagrammatic sketch given by
Beechey ; this figure has been reproduced in many text-books, so that it has
come to be regarded as the typical atoll. But while it undoubtedly repre-
sents an interesting phase in tlie history of atolls, its constant repro-
duction has given it a celebrity out of proportion to its importance, and
has gone far to disseminate a very erroneous impression of what an atoll
is (PL 72, figs. 1, 2).

The atoll can be taken in at a glance from the bridge of a vessel. Its
comparatively small size and regular nearly circular outline, its shallow and
narrow opening (PI. 72, figs. 1, 2), in addition to its comparatively isolated
jiosition rising from an area of great depth, all tend to emphasize the
somewhat exceptional features which characterize it. With Pinaki as a
typical atoll, not only was the great irregularity of the manj' differ-
ently shaped atolls lost sight of, but the composition of the land rim
built up of numerous islands, the existence of great stretches of submerged
reef, the great depth of many of the atolls, their existence in comparatively
shallow areas or position upon great submarine plateaus of very moderate
deptli, — all these characters were looked upon as constituting essential ex-
ceptions to " the atoll " ; " the fairie ring," as typified by Pinaki. On the
contrary, it is Pinaki which is an exceptional atoll, and the existence of
special conditions readily explains its structure.

The presence of high dunes on the south face of Nukutavake (PI. 70, fig. 4)
and on the east side of Pinaki (PI. 72, fig. 3) suggests the possibility of the
eventual filling up not only of this lagoon, but also of such islands as Aki-
Aki, Tikei, and Nukutavake. Where the central part is more or less dished,
as is Aki-Aki and Tike'i, and where, as in Nukutavake especially, the sea
face is covered with masses of coral shingle and sand, we have all the

PINAKI. 123

materials necessary for such a change. The existence of such high dunes
(35 feet) at Nukutavake and at Pinaki introduces an element which had not
been taken into account as a factor in the building up of coral islands.
Elsewhere also, as in the Marshall Islands, the changes produced by the
movement of great masses of sand are perhaps more marked and more im-
portant in shaping the outline and extent of the land rim as well as the
extent and area of the lagoon flats. The encroachment of the sand dunes
on the land rim and the killing of bushes and Pandanus and trees by sand
dunes take place at Pinaki as at Nukutavake, but not on such an extensive
scale.

We can suppose the old ledge mass of Pinaki, after being elevated to a
moderate height, to have little by little been cut down to the level of the
sea, this cutting down to have been partly mechanical and partly chemical.
The former action produced a mass of material, moving backwards and
forwards, which must have formed the earliest shingle beaches on the
periphery of the atoll or on one side or face of it, additions being made
to this mass from the death and decay and decomposition of the corals
which had found a favorable place for growth on the slopes of the old
ledge mass.

Thus we can readily imagine Pinaki to have grown ; the beaches thrown
up on the circumference finally enclosed a comparatively shallow lagoon, con-
stantly becoming shallower by accretions both from the outside and inside ;
accretions from the inside by the decay of the corals and shells, and from
the outside by the mass of coral sli ingle and boulders thrown into the lagoon
at the beginning of the building of the atoll, and also of the sand blown
in by the gradual advance and rising of the dunes.

At first there may have been more than one opening into the lagoon ;
the land rim may, as in other atolls, have consisted of small islets separated
by gaps, which with the diminution in size and depth of the lagoon were
no longer kept open by the in and out flow of water over the half-submerged
gaps. Indications of two such gaps can be seen in the stretch of low vege-
tation indicated in PI. 72, fig. 1, and in the low gap covered with coarse
shingle shown in PI. 73, fig. 2. The outer beach of the land rim in the
former has become as high as the adjacent coral sand beaches, while the

124 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

last gap is still at a considerably lower level than the high beaches on each
side of it. These became gradually closed, and finally tliere came about
the conditions existing to-day, with a single gap allowing the sea access
to the interior of the lagoon only at certain stages of the tide.

When the sand blown in, and the material derived from the death and
decay of corals and shells, has so shut off the water of the lagoon that its
access to the sea is cut off, then the last gap will be closed. We may expect
then the lagoon to become a mere brackish sink, growing shallower each
year, till nothing is left to indicate the former existence of a lagoon, once
in full communication with the sea, except the shallow dishing of the
central part of the atoll, more or less marshy, or perhaps consisting of as
solid land as any other part of the land rim. In fact, Pinaki may be regarded
as a stage antecedent to that of Aki-Aki, of Tike'i, and of Niau. It differs
from Niau, however, in not having a sink lagoon, the lagoon of Pinaki being
still connected with the sea and constituting what might be called a sound
lagoon.

At Pinaki there is a good-sized water hole, a small sink in which the
natives keep turtles, occujiying the central part of the land rim where
there is but little vegetation, where the land rim is from 400 to 500 yards
wide. In the water hole of Aki-Aki turtles are also kept by the natives.
At Nukutavake there are also sinks, eight to ten feet long, where water
collects. These sinks are the result of the banking of material around
depressions. In other islands these depressions are sometimes found in the
central part of the islands of an atoll, where water collects in moderate
quantities. Their origin is due to the same causes ; they are littoral sinks
dating back to a time when the island was probably of very much smaller
size.

The soil of the crest of the land rim of Pinaki is quite fertile, being made
up of decomposed leaves and stems and rolled fragments of coral shingle ;
while on the steep white sand slope it is quite barren, as well as on the
sand beach back of the shingle on the lagoon face. The same conditions are
found at Nukutavake and at Aki-Aki, where the humus is a little better.
This appears to be the character of the soil of all similar islands wherever
we landed in the Paumotus.

NUKUTIPIPI. 125

On the sea slope of the reef flat corals were not abundant, and on the reef
flat none were seen.

The notes for the description of the lagoon of Pinaki were made by
Messrs. Townsend and Alexander, who examined it while we steamed about
the island.

The Duke of Gloucester Islands.
Nukutipipi.

Plates 76, 77, 201, 203 : 206, fi'j. 4.

Nukutipipi Island is the easternmost of the Duke of Gloucester Islands,
a small helmet-shaped lagoon about two miles in circumference, which is
well wooded on the northern and eastern faces, with a wide bare reef on the
southwest face. Tlie vegetation consists almost entirely of Pandanus, with
a few cocoanut trees on the centre of the western face and on the northeast
face of the atoll (PI. 206, fig. 4).

Seen about three fourths of a mile distant coming up from the southeast,
the high wide coral sand beach of the larger eastern island of Nukutipipi
stands out prominently (PI. 76, fig. 2), with the few patches of beach rock
of the westernmost end of the beach and a similar line of beach rock ledge
extending into the open half-submerged reef flat which forms the southern
land rim of the atoll. The reef flat extends far into the lagoon on the
southern side ; the deeper part, indicated by its darker blue water, occupies
but a comparatively small area towards the northern part of the lagoon
(Pis. 76, fig. 1 ; 206, fig. 4). The vegetation here as well as in the greater
part of the southeastern atolls of the Paumotus is marked by the predomi-
nance of native plants, especially Pandanus, Pisonia, and Scaevola. But
few cocoanuts have been planted here as yet.

On the lagoon side the two islands of the land rim are faced with fine
coral sand beaches (PI. 77, fig. 2). On the southwest side a wide reef flat
extends far out (Pis. 76, fig. 3 ; 77'; 206, fig. 4) to form the western and
southeastern point of the atoll ; over this an enormous mass of water must
at each tide find its way into the lagoon, as the greater part of the western
reef flat is submerged, the flow of water being only broken by a narrow

126 -ALBATROSS" TROPICAL PACIFIC EXPEDITION.

line of coral shingle and by a mass of coral boulders and of beach rock
(PI. 77, figs. 1-8). The old ledge whicli forms the substratum of the reef
platform crops out occasionally, coming up through the movable material
covering it in part (PI. 77, fig. 2). On the reef flat rim also numerous bars
of shingle and of beach rock form the lagoon edge of the flat (PI. 76,
fig. 1); an islet, covered with the same vegetation as that of the two
principal islands, built up of sand derived from the interior of the lagoon,
extends across the whole width of the reef flat. Two bare sand bars have
also been tlirown up on the lagoon side of the reef flat. This islet and the
two sand bars are the flrst indications of future islands to be built up on
the land rim and to reduce gradually the great open gap of the submerged
reef flat which now occupies the southwestern face of the atoll (PL 77,
figs. 2, 3).

Nowhere were we so much struck with the beautiful coloring of the waters
of the atolls as in these southern groups, and it baffles description to give an
idea of the contrast of colors between the green line of vegetation, the
yellow or gray shingle, the cream-colored sand beach, with its wide yellowish
brown reef flat banded or dotted at low tide with dark brown masses of
^beach rock, edged with its many-colored knolls of Nullipores or Pocillipores.
We then pass through all the shades of light green water to darker green,
greenish blue, or dark blue, which a long line of white breakers separates
from the darker blue of the deep water on the sea slope. If one were
placed high enough to look into the lagoon and take in the whole at a
glance, one would see the most wonderful gradations of coloring, passing
from the dark blue of the deeper parts of the lagoon to the shallower parts
of a lighter hue, next to the greenish blue of the outer edge of the lagoon
flat, and finally to the greenish, the greenish yellow, or the lightest imaginable
emerald of the shore flats, with here and there a dark blue patch witli metallic
reflections skirting a projecting sandy point, where all the imaginable varia-
tions of green and blue seem to have blended in the brilliant sunlight re-
flected fi'om the placid, hardly rufiled water of the lagoon, or sparkle on
the broken sea and swell of the adjoining ocean. In some of the shallower
gaps, tlie water after a heavy blow sometimes becomes somewhat muddy
and slaty-colored from the amount of silt held in suspension, and the sea

NUKUTIPIPI. 127

for quite a distance is discolored and in marked contrast to the usual dark
blue color of the ocean.

There is a wide gap between the two main islands of the lagoon on the
northwestern side of the atoll (Pis. 77, fig. 2 ; 206, fig. 4). The small island
occupies a part of the northwestern face of. the atoll, while the larger island
flanks the lagoon on the north and northeast (PI. 77, figs. 2, 4). This and
the other atolls of the Duke of Gloucester Islands may indeed be called
pocket editions of characteristic Paumotu atolls. In the cut awash the beach
rock is in part overlying the old ledge, huge boulders of which are left
cropping out from the underlying foundation (PI. 77, fig. 2), and crops out
again on the inner face of the atoll. Vegetation covered in part the top
of the sea beach as well as that of the lagoon face, and ran partly in
between the shrubs and trees, showing that but little sand is as yet blown
across the beach into the lagoon.

The larger island, forming the northerly and easterly side of the atoll,
varies greatly in width, from 150 to 300 yards. At the southwest point of
the smaller island the coral shingle beach ipust be fully fifteen feet in height
in places, as a general rule at least twelve. On both islands the vegetation
comes down below the summit of the inner and outer beaches, which are
also well protected by grass extending on the lagoon face of the beach
towards the interior of the land rim. The varying width and the narrow
points of the land rim indicate probably the position of former gaps, which
have gradually closed and connected the separate sand bars, islets, and
islands once undoubtedly occupying the area now covered by the large
island.

The reef fiat is from 200 to 300 feet wide, and sand bars and incipient
islets are forming on the lagoon edge of the reef flat of the land rim. The
extent of the reef fiat extension into the lagoon is indicated by the light
green water (PI. 206, fig. 4).

If the extension of the dunes were not kept in check by vegetation, com-
paratively small lagoons like those of the Duke of Gloucester Islands, would
become filled and closed very rapidly. At present some of them are in
equilibrium, new material is added by the corals on the south face where it
is now building up sand bars and islets on the reef flat, while before the

128 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

existing stage, the building up of the larger island must have taken place in
great part from the lagoon side, judging from the comparatively small
amount of material derived from rolled and dead corals thrown up on the
northern and eastern faces of the atoll.

On the east face of the atoll we could see the blue water marking the
shape of the deep indentations of the edge of- the reef flat, where the NuUi-
pore knolls and Pocillipore patches were unusually high, many of them
ready to be torn off at the next high sea and thrown upon the reef
flat (PI. 77, figs. 1, 3). The Nullipore and Pocillipore knolls form the
outside wall of an unusually wide and deep platform lagoon, running
parallel with the western face of Nukutipipi (Pis. 76, figs. 2-4 ; 77, fig. 3),
which passes into the lagoon at the wide gaps of the reef platform (PL 76,
fig. 4).

The soundings indicate that the sea slope of this island is very steep ; it
rises -rapidly from a depth of more than 2300 fathoms at a distance of five
miles from the shore (Figs. 11, 12).

Anu-Anurunga.

Plates 78, 202, 203 ; 206, fig. 1.

Anu-Anurunga is about one and a half miles in diameter; it is slightly
elliptical, and neither in this nor in the other islands of the Gloucester group
are there any boat entrances to the lagoons ; they all come within the term
of closed atolls (PI. 206). There are, however, a number of gaps between
the islands, or wide reaches of bare half-submerged reef flats, allowing free
passage to the sea at certain stages of the tide.

The eastern land rim consists of two large islands, the one extending
from the southern point of the atoll to about the middle of the eastern face,
it is separated from the other large island by an islet and a wide gap awash
(PI. 78, fig. 1). The second island extends round the atoll to the north-
west side, and is separated from the western island by a stretch of reef
awash (PI. 78, fig. 2). The western island occupies only about a quarter of
the western face. The southern half of the western land rim is a reef

ANU-ANURUNGA. 129

awash terminating in a small islet separated by a wide gap from the west-
ern point of the southeastern island.

Coming up from the eastward, the long stretches of gray shingle beach,
dotted at the base by short reaches of beach rock ledge, formed the charac-
teristic features of the sea face of this atoll. There are but few cocoanuts
to be seen on any of the islands of Anu-Anurunga, the characteristic vege-
tation being made of the plants common to the group (PI. 78, fig. 3).

On the east face of the western island the op^n half-submerged reef flat
is very wide, while outside of the coarse shingle beaches the flat is very
narrow, with many small boulders along the base of the beach. On the
western reef fiat there are geveral extensive patches of large bouldei"s. The
deepest part of the lagoon is near the eastern face. On the western side a
wide reef fiat, the extent of which is plainly indicated by the light green
color of the water, extends northward from the western island far into the
interior of the lagoon. The gaps between the islands are shallow, yet deep
enough to allow a considerable amount of water to enter across them
into the lagoon (PI. 78, figs. 1, 2). Along the east and southwest faces
of the reef fiat extends a well-defined narrow platform barrier reef, with
remarkably high Nullipore knolls on the outer edge of the reef flat, as well
as patches of Pocillipores (PI. 78, fig. 3). The outer edge is also deeply
serrated with fan-shaped indentations.

Looking into the lagoon we can see that it is quite shallow, shallower
than that of Nukutipipi, there being no really blue water visible in any part
of the lagoon ; it all is somewhat muddy in color, or of a light green tint,
though there is a little darker water to be traced when looking into the
lagoon over the western face.

On the wide western reef flat occur also sand bars and lines of shingle, as
well as the characteristic shingle and rubble bars running at right angles
across the reef flat, abutting on the lagoon side upon incipient sand bars or
sand islets (Pis. 78, figs. 1, 2). On the lagoon side the islands are edged with
coral sand beaches, while they are in part lined with bands of ledges on the
outer sea face of the islands. Some of the smaller sand islets are prominent
landmarks on the western reef flat. There is specially a small sand islet,
set well back of the reef fiat, with two cocoanut trees to distinguish it. A

130 "ALBATEOSS" TEOPICAL PACIFIC EXPEDITION.

sandy islet on the northwest side lies also at an angle to the reef flat ; it is
protected on the sea face by a shingle ledge. Between the islands of the
northwest side are gaps over which water passes into the lagoon even at
low tide ; these islands have steeper beaches than those more to the
westward.

Anu-Anuraro.

Plates mi, 203; 206. fig. 2.

Anu-Anuraro is more angular in outline than the other islands of the
Gloucester group. Its greatest length is about two and a half miles. It is
fairly wooded on the eastern face, while its southwestern and northwestern
faces are bare, being merely a wide reef flat. There are three small wooded
islands on the atoll, one of which forms the westernmost point of Anu-
Anuraro (PI. 206, fig. 2).

The sea face of the islands of Anu-Anuraro is characterized b}' its steep
high coral shingle beaches bordered at the base at intervals by long lines of
ledge rock. There is also a great development of sand dunes on parts of
the shingle beaches, where the shingle is completely covered by the inroads
of the sand blown over them from the base of the shingle beaclies. On the
east face these sand beaches are often covered with grass and vegetation,
which reach far down towards the sea along the face of the beach.

Along the outer edge of the reef flat at the southwest horn of the atoll
NuUipore knolls take a great development. The reef flat is in places more
than three quarters of a mile wide, extending far into the lagoon, and being
half submerged in many places at all stages of the tide, allows large masses
of water to flow into the lagoon. The flat is covered by lines and bands of
boulders following in a general way the trend of the outer edge of the reef
flat as well as the beach.

The vegetation of this atoll is low, rather scanty ; the Pandanus trees, as
well as the bushes of Scaevola, are small.

On the western face of the atoll the old ledge crops out on the inner side
of the platform barrier reef channel, which is separated from the sea by a
wide reef flat, with sand bars and shingle bars and coral rubble bands

HEREHERETUE. 13 1

running more or less at riglit angles to the outer edge of the reef fiat, where
the Nullipore knolls form an almost unbroken abrupt vertical wall.

Some of the sand dunes have been driven into the lagoon, killing the
Pandanus and other vegetation, while other dunes are stationary, being
overgrown with grass and scrub vegetation ; the beach forms a grass-topped
bank which extends into the vegetation of the interior of the land rim.
Coral rubble and shingle is also blown and washed in places partly across
the islands. The base of the islands is mainly composed of beach rock
resting upon the old ledge, which crops out on the reef flats. In the
Gloucester group, where the rubble or beach rock has been washed away,
the old ledge forms the floor of the reef flats wherever we have examined
them.

Hereheretue.

Plates 79-83, 201, WS.

Hereheretue encloses a lagoon about three miles in diameter, without a
boat entrance. The western half of the land rim consists of a wide reef flat,
bare at low water, in the central part of which is jjlaced a small island with
a few cocoanut trees. On tlie southwestern face of the land rim a few sand
bars have been thrown up.

On the east face of this atoll are a great many dead trees and bushes
which have been killed by the inroad of the beach sand blown inland
(PI. 81), and along the sea face of Hereheretue, where it is not covered with
grass (PI. 80), blown sand is seen to extend under the trees and shrubs. On
the north end of the east face of the atoll there is a good exposure of strati-
fied beach rock running along the base of the high sand beach, which must
be from eighteen to twenty feet in height (PI. 81). At the northwest horn
sand and shingle bars extend across the wide gap separating two of the
islands; a high dune has also been formed there, the greater part of which
is overgrown with ves;etation.

The seven islands to the south are almost connected, the gaps between
them allowing but little water to flow across into the lagoon except at high
tide. The islands are all edged with sand beaches on the lagoon side. The

132 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

lagoon flat being quite wide (Pis. 82, fig. 1 ; 83), there is considerable sweep
for the sea in this lagoon.

An extensive ledge of beach rock and of recent conglomerate runs along
the inner face of the southwestern edge of the lagoon reef platform (PI. 82,
fig. 2). The reef flat on the sea face of the principal islands of the atoll is
narrow (Pis. 79, 80).

The beaches on the south side are formed by a series of low dunes alter-
nating with masses of coral rubble, or shingle beaches with ledges of beach
rock at the base (Pis. 80, 81). On the reef flat there are sand bars and islets
with shingle bars or coral rubble dams. These are especially well developed
on the southwest reef, where a well-marked islet is thrown up well back on
the bank of the reef flat (PI. 83, fig. 1).

We landed on the west side of the atoll of Hereheretue, on the outer edge
of a reef flat nearly three quarters of a mile wide (PL 82, fig. 3). The boat
was run up on the reef flat in one of the many indentations gouged out be-
tween the NuUipore, knolls. The reef flat consisted of old ledge, planed
down to about low-water mark, full of pot-holes of all sizes and shapes
(PI. 82, fig. 2). Between the outer edge of the flat and a sand bar perhaps
two feet high, separating the reef flat into two parts, there were numerous
pools left from two to three feet in depth, some of them quite extensive,
where many Holothurians and other Echinoderms, mollusks, and corals were
found congregated. Some of the corals, mainly Millepores, Pocillipores, and
Porites, were well-developed isolated heads of considerable size. Here and
there knolls of beach rock cropped out above the old ledge reef flat, and an
occasional horse or wall of old ledge. Close to the shore we came upon a
great undercut ledge of recent beach rock and conglomerate lying above the
old ledge flat.

Where the reef flat of the atoll is comparatively narrow there is a well-
developed platform lagoon running parallel with the base of the beach. At
the horns of the atoll this lagoon often expands into one of considerable
width (PL 79).

The island where we landed has been thrown up diagonally across the ex-
tensive reef flat of the west side of the atoll, and, like other similar islands,
is edged on the lagoon side of the flat (Pis. 82, fig. 1 ; 83) with coral sand

HEREHERETUE.

133

beaches and broken shell fragments. Here and there on the lagoon side a
beach dam of small Areas and sand was thrown up, and a few hillocks of
dead Area shells cropped out upon the lagoon side of the flat.

On the sea face of the atoll we could trace the corals down to twenty-two
fathoms. They are, however, all small masses of Millepores, Pocillipores,
Porites, and Madrepores, not to be compared in size with those growing in
the pools of the reef flat or in shallow water.

On the reef flat the surface of the old ledge and the coral fragments were
all covered with patches of many-colored Nullipores, protecting the reef flat
from further denudation and disintegration. On the outer platform slope, at
the foot of the steep and high beaches, were thrown up masses of coral frag-
ments. On the outer sea face much of the dead material is not cast upon
the beaches, but is thrown back on the outer slope ; driven back and forth, it
is ground into fine sand and shingle supplying the material for the beaches.
The reef flats encroach extensively into the lagoon, forming extensive spits
indicated by the green color of the water.

The reef flats of Hereheretue represent the condition of the flats of the
atolls of the Gloucester group. There is always more or less coral rubble
and shingle and little of the old ledge exposed, except where the outer part
of the flat is cleared of beach rock and shingle or boulders. Beach rock and
recent conglomerate take a
great development on the
inner parts of the reef flat
close to the base of the
beaches of the islands, where
it has been originally depos-
ited either upon the old ledge,
so as to conceal the greater
part of it, or between its out-
crops upon different parts of
the rim of the atoll either as
buttresses or walls or horses.

The four atolls of Hereheretue, Anu-Anurunsja, Aiui-Anuraro, and Nu-
kutipipi are most interesting. Nukutipipi is the smallest atoll of its kind we

Landing on Reek Platform, Hereheretue.

134 "ALBATKOSS" TROPICAL PACIFIC EXPEDITION.

have seen in the Pauinotus. One can take in at a glance the varying con-
ditions which exist in such an atoll, and the different processes which go to
make up a typical atoll. Anu-Anurunga resembles Nukutipipi, only it is
somewhat larger, and from that we pass to Anu-Anuraro and Hereheretue,
which represent each on a larger scale conditions which take tlieir greatest
development in such huge atolls as those of Hao, Fakarava, and Rangiroa.
On the larger islands it is somewhat difficult to trace the changes which
have taken place ; but on such atolls as Nukutipipi, which we could take in
as a whole, we readily recognized structural features which were somewhat
vague from their extensive development in the larger atolls, or from their
modification by special conditions.

Having formed our general conception of the group before reaching the
more or less isolated atolls of the eastern Paumotus, we could recognize at
once in these smaller atolls the distinctive features of the group, well con-
centrated and sharply developed from being seen on a small scale.

THE SOCIETY ISLANDS. 135

THE SOCIETY ISLANDS-

Plates 84-lO.J, ^01, 202, 20S-210.

We examined the eastern coast of Tahiti, and the western coast from
Papiete as far as Port Phaeton, at Taravoa Isthmus. We examined, in a
general way, the Leeward Society Ishxnds : Murea, Huaheine, Raiatea,
Tahaa, Bora Bora, Motu Iti, and Maupiti. There are excellent charts of the
Society Islands,^ so that it was comparatively simple to study the typical
points of the group and to gain an idea of their structure as far as it relates
to coral reefs. The different islands present only modifications of one and
the same structure, so that the more careful examination which we made
of Tahiti and of Bora' Bora undoubtedly gave us the key to the structure of
those islands we examined only in a more cursory way. We saw enough
of all of them to satisfy ourselves that there were no points of special
interest which were not well represented on the islands which we examined.

The description we have given of the modifications of the fringing and
barrier reefs of Tahiti applies to all the other islands of the Society group ;
it varies only according to the shape of the island, the manner in which the
mountain ridges have been denuded, and according to its exposure to the
prevailing winds. The Society Islands are all volcanic, edged with shore
platforms, some of great width, upon which the barrier or the fringing reefs
of the islands have grown. The structure of the reefs of the Society
Islands is very similar to that of the reefs round the volcanic islands of Fiji.
A comparison, for instance, of the charts of Kandavu, Viti Levu, Mbengha,
Nairai, and of other volcanic islands of Fiji, with those of the Society
group, will at once show the identity of their structure. Huge platforms
of submarine denudation and erosion characterize b>oth, with fringing and
barrier reefs determined by local conditions ; perhaps it is easier to follow
the changes which have taken place in the Society Islands. Such islands
as Tahaa and Bora Bora, where we anchored, as well as Maupiti, are admir-
al)le examples and epitomes of the structure and mode of formation of the
coral reefs of that group.

' A. Charts 1060, 1248, 1382, and other charts of details.

136 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Mehetia has no reef flats ; Tetiaroa and Motu Iti are composed of low
coral sand islands thrown up on a wide barrier reef flat. In Motu Iti and
Tetiaroa the volcanic peaks have disappeared, leaving nothing but a shallow
platform, upon the outer edges of which sandy coral islets have been
thrown up.

There is, however, one point in which the barrier reefs of the Society
Islands differ from those of Fiji. The barrier reefs in Fiji are generally
indicated merely by reef flats, upon which the sea breaks, and an occasional
rocky islet or negro-head ; only rarely do we find sand keys upon the barrier
reefs of the islands of Fiji. In the Society Islands, on the contrary, we
usually find the line of the barrier reefs well indicated by long lines of nar-
row islets thrown up on the reef platforms, exactly as they are in the Pau-
motus. These islands and islets are generally well wooded, and thus give a
very peculiar aspect to the barrier reef. In the case of Bora Bora, Maupiti,
and Aitutaki, we have a central volcanic peak of considerable height sur-
rounded by a wide lagoon, the sea edge of which is formed by a fringe of
wooded islets and islands forming a more than half-closed ring around the
central island, which, in Bora Bora and Maupiti, rise in slopes and nearly
vertical walls, the former to a height of nearly 2400 feet, the other to about
800 feet.

Tahiti, Huaheine, Bora Bora, Maupiti, and Motu Iti form a series of
islands in which we can follow the steps which characterize the successive
stages of denudation and of marine erosion they represent.

The Society Islands are divided into the Eastern and the Western groups,
called the ^yindward and the Leeward Islands ; Tahiti, Murea, Mehetia,
Tetiaroa and Tubuai Manu^ forming the Eastern or Windward Islands.
The Leeward group consist of Huaheine, Raiatea, Bora Bora, Maupiti, and
Motu Iti.

Huaheine, the easternmost of the Leeward group, is about twenty miles
in circumference and, like Raiatea, divided into two islands by a deep cut
similar to those of Murea, of Maupiti, and of Bora Bora, only in this case the
cut extends across the island, leaving but a narrow isthmus covered at high
water, to connect the northern and southern parts of the island. Huaheine,

1 We did not visit Tubuai M.inu.

THE SOCIETY ISLANDS. 137

although surrounded by more or less indistinct barrier reefs, is deeply in-
dented and shows perhaps as well as any of tlie other islands, the manner
in which the wide platform of erosion has little by little been formed by the
action of the sea. The wide barrier reef flats on the east, north, and
west faces of the island are separated by a comparatively shallow and nar-
row lagoon from the main island. On the northern part the wide barrier
reef flat is covered with islands more or less connected, and covered with
trees ; so that the slopes of the northern and eastern part of Huaheine
appear flanked by a wide, low, wooded platform, identical in every respect
with the narrow rim of wooded islands flanking some parts of the east face
of Tahiti and differing from them only in width and extent. We can readily
imagine that the time may come when all these islands and islets, extending
from the easternmost point of Huaheine to the northern face, will in their
turn become changed into such a narrow barrier reef as that characterizing
Tahiti. This has to a certain extent occurred on the east face of Raiatea
(PI. 210, fig. 2), where the outer reef platform is not well indicated, but is
merely outlined by a mass of patches of corals, growing at various depths ;
these crop out here and there, indicating the existence of a wide reef on
the east face, similar to that found on the west as well as on the southeast
face of Huaheine.

The peninsula of Taiarapu (Tahiti), not as yet separated from Tahiti,
represents a stage of denudation analogous to that of Tahaa a)id Raiatea,
separated by a wide and comparatively shallow passage reaching between
Tahaa and Teavarua. Similarly Huaheine Nui and Huaheine Iti are still
connected at low water by a narrow pass, a high knoll rising across Maroe
Bay in the centre of the channel which divides Huaheine into two parts.

The isthmus of Taravoa (Tahiti) is low, and the channel separating the
peninsula of Taiarapu from Tahiti is formed by Port Phaeton, which cuts
nearly across it, leaving but a narrow strip of low land uniting the
peninsula with Tahiti.

It will be noted that on all the leeward islands the reef flats of the
northern and eastern faces are much narrower than those of the lee and
southern sides, the circulation over and around the reef flats of the lee side
beinur far less active than on the weather side. On the weather faces also

138

ALHATROSS" TROPICAL PACIFIC EXPEDITION.

coral sand islands and islets have been thrown up on the outer faces of the
reef flats.

The fringing and barrier reefs which surround a large island like Tahiti,
having a diameter of over thirty miles, and summits reaching a height of
more than 7300 feet, appear narrow and unimportant when compared suc-
cessively to the barrier reefs and reef flats fringing much smaller islands,
as Murea, Raiatea, Huaheine, Bora Bora, and Maupiti, which respectively
attain heights of about 4000, 3400, 2300, 2200, and 800 feet.

It is but a step from such an island as Maupiti, where the central island
is reduced to a height of 800 feet to islands like Motu Iti and Tetiaroa,
where the central volcanic nucleus has entirely disappeared, and is repre-
sented by the flat of volcanic rocks which probably underlies the platform
upon which the coral sand islands and islets of these groups have been

thrown up. It is interesting
to note that in Maupiti the
southern and western reef
flats are covered with masses
of volcanic rocks, the outliers
of former volcanic islets and
islands once occupying the
outer rim of Maupiti.

In the Atlas of the " Voy-
age de la Coquille " we find
an excellent view of the
peaks of Bora Bora (PI. 16)
taken from the laa-oon at

o

about the place where we
anchored off Vaitape. On
Plate 17 is given a panoramic view of the islets on the reef flats of the
northern face of the island, with Raiatea in the distance. This view
is taken from the summit of Pahia which Lesson ascended ; it has been
copied by Darwin on p. 3 of the " Structure and Distribution of Coral
Reefs." On Plate IS an excellent view of Maupiti from inside the lagoon

Summits ok Hora Bora.

THE SOCIETY ISLANDS.

139

Lesson's views of the relationship existing between the outer coral reefs
and the central nucleus of volcanic islands seem to have escaped the atten-
tion of naturalists. He says,^ speaking of the central mass of Bora Bora :
"Or a ce noyeau primitif et central s'adjoint une lisiere plus ou moins
large, tres plate, pen elevee au dessus de I'eau, qui I'epose sur une base
de corail.

" Les isles basses, ou Motous, qui paraissent quelquefois a une distance
as.sez notable de I'ile principale, ont ete elevees indubitablement sur I'irra-
diation de quelques chaines du noyeau volcanique central. Jamais en effet les
bancs de coraux ne .s'etendent au large, et toujours ils sont la dependance
de rile qu'ils entourent."

From what precedes it is natural that Lesson should consider, as he does,
the passes leading into the lagoons as primordial volcanic valleys. Lesson^

Assembly [Iouse, Teavanui Village, Boua Bora.

imagines that when the submarine volcanoes do not reach the surface, corals
will grow on the submerged edge of the craters, the interior presenting an

We may compare the reefs of Tahiti with those of Mauritius and the island
of Mehetia with Bourbon, both of which, having no platform of submarine
erosion, though in an area where corals grow in great abundance, yet are
not surrounded either with fringing or barrier reefs.

1 Voyage autour du Monde sur la Corvette la Coijuille, Vol. I., par P. Lesson, Paris, 1 839.
- Loc. cit., p. 47G.

140 -'ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The vegetation of the Society Islands is already far more luxuriant
than that of the Paumotus more to the eastward. This we might expect
from the greater size of the islands, the more varied climatic conditions, and
the greater fertility of the soil. Even on the coral sand islets on the outer
edge of the barrier reef flats, the vegetation is far more varied and luxuriant
than on the similar islands and islets of the land rim of the Paumotus. Les-
son gives a list of a large number of genera which do not occur east of
Tahiti, but which are still better represented as we pass to the westward, to
Samoa, to the Tongas, the Fijis, and the Carolines.

Mehetia.

Plates 90, fig. 2 ; 95, fig. 1 ; 202.

Mehetia, the easternmost of the Society Islands (PI. 202), is an isolated
volcanic peak nearly 1600 feet in height, with a couple of rocky islets and
rocks off the southern point. On the eastern and southern faces the slopes
of the island have been abruptly cut off, and terminate in vertical cliffs
and columnar masses of basalt at the base of the slope, on the northeastern
face of the island. A few corals have been thrown up on the small beaches
of the island along the east face and near the northeast point.

On the western face considerable coral sand has been thrown up on the
western point of the island, derived from the few coral patches which are
formed on the flat, the seaward extension of the western point (PI. 95,
fig. 1).

On the summit of the island a well-marked crater exists. It is best seen
when facing the island from the north (PI. 90, fig. 2). It is interesting
to find a volcanic island like Mehetia, situated in the belt of the trades,
on which cor.als have taken no such development as they have on the
other vulcanic islands of the group. As I have stated, there are no coral
reefs around the island, only a few coral patches, and the only difference
we notice in the structure of Mehetia and of the Marquesas is the absence
of a .shore platform on which either fringing or barrier reefs can develop.

The absence of a shore platform on Mehetia and the Marquesas is prob-
ably due to the steepness of the slopes, which, when cut into, do not form

TAHITI. 141

the wide level platfonn characteristic of other Society Islands, the eroded
material probably accumulating only as a talus in deep water on the
steep declivity of the sea face. It is evident that local conditions, such
as occur on a small scale at Mehetia and on a larger scale at the Marquesas
and Galapagos, must account for the absence of coral reefs in a region
where they generally exist in great abundance, either on platforms under-
laid by volcanic rocks — as in the other Society Islands — or on platforms
eroded from elevated coralliferous limestone, as in the Paumotus and Cook
Islands.

Tahiti.

Plates S4-S9, 202, 208-210.

Tahiti, by far the largest and most important of the Society Islands, is
about thirty-three miles in length from its northwesterly point to the south-
eastern extremity. It consists of a principal land mass (PI. 202) separated
by a narrow isthmus of about one and a half miles, connecting it with the
eastern peninsula of Taiarapu (PI. 208, fig. 1). The main part of the island
is circular, slightly angular, and is flanked on the east by a line of narrow
barrier reefs which extend as far as Artemise Bank, where it becomes broken
into a series of disconnected reef patches extending as far as Point Venus
(Pis. 202 ; 208, fig. 2 ; 209). At one or two points on the east side, from
Boudeuse Pass and Faone Pass, the barrier reef becomes more or less con-
nected by secondary patches with a fringing reef, which skirts irregularly
the whole eastern coast,^ except in the reaches where the shore line is
covered by volcanic sand beaches or coral sand beaches, or a mixture of
the two. On the northwestern face from Point Venus (PI. 209) to the north-
western point of the island (PI. 208, fig. 5) (Tataa Point), beginning to the
west of Matavai Bay, the coast is flanked by a wide reef flat forming a
barrier reef separated from the shore by a narrow channel, which connects
Matavai Bay with Taunoa Pass and Papiete Pass, and with 'the harbor of
Papiete (Pis. 202, fig. 2 ; 209). To the westward a continuation of the same
lagoon comes out at Taapuna Pass (PI. 208, fig. 5).

1 A. Chart 1382.

142 -'ALBATROSS" TROPICAL PACIFIC EXPEDITIOX.

Beyond that, the barrier reef flat becomes changed into a wide fringing
reef flat, which extends almost unbroken as far as Paea^ (PL 208, fig. 4).
While the reef flat is practically a fringing reef, its outer edge is usually
somewhat higher than the adjoining slightly dished flat, so that here and
there, between the outer edge and the shore, are short stretches of
water from one quarter to half a foot in depth, the beginning of the
lagoon which will eventually be formed parallel to the shore line, as it
exists in a more or less disconnected channel to the south of Paea (PI.
208, fig. 4). From that point the reef flat is separated from the shore by
a narrow shallow lagoon opening into Maraa Pass ; the south part of the
fringing reef extending from Paea to Maraa shows traces of an incipient
lagoon chiinnel, formed by the cutting back by the tidal currents running
parallel to the shore, along the inner edge of the fringing reef ; this channel
will eventually unite the lagoon at Paea with the Maraa Pass Channel. At
the northern end the lagoon is very shallow and narrow, while to the east-
ward of Maraa as far as West Ava iti the lagoon becomes quite wide and
deep, and is navigable almost to its extremity, which is closed by a regular
fringing reef to the east of Apomaoro (PI. 208, fig. 4). This Ingoon con-
nects through two somewhat indistinct passes with the sea. At the ex-
tremity of the fringing reef to the east of Apomaoro, a small bay, Popote
Bay (PI. 208, figs. 3, 4), has been gouged out, forming an insignificant
reef harbor; from the inner edge of the adjoining fringing reef flats the tidal
currents are cutting back or carrying off in solution the rotten coral on the
flats, forming incipient lagoons which will change the fringing reef flats into
a barrier reef, separated from a narrow fringing reef by a shallow lagoon, as
we noticed it to the north of Maraa Pass. To the west of Popote (PI. 208,
fig. 3), the reef flat becomes wider, the lagoon itself is deeper, and we have
a condition of things very similar to those which exist to the east and west
of Papiete, — a series of passes separating wide reef flats bare at low tide,
flanked by a deep lagoon, with depths of twelve or fourteen fathoms, studded
with islands, islets, and reef patches, which indicate the former extension of
the mainland, from which the reef flats have been denuded. The islands of
Mapeti and Pururu in the barrier reef of the southern part of Tahiti, indicate

1 A. Chart 1382.

TAHITI. 143

the position of the former extension of spurs of the mainland, of which they
are the only outliers left (PI. 208, fig. 3).

At Taunoa the reef flat again becomes a fringing reef flat ; the entrance
to Phaeton Harbor is flanked on the two sides by gigantic reef flats (PI. 208,
fig. 1), the northern one of which is a fringing reef flat, while the southern
is a wide flat separated from the mainland by a lagoon from ten to fifteen
fathoms deep. The lagoon extends along the western and the southwestern
shores of Taiarapu Peninsula, as far as Tutataroa Pass (PI. 208, fig. 1), with
here and there a pass connecting it with the sea. Beyond Fareara Point the
extension of this reef flat, as it skirts the southeastern extremity of the pe-
ninsula, becomes a submerged flat (PI. 208, fig. 1), covered witli from two
to eleven fathoms of water. The reef flat has been eroded and forms
onlv an indistinct bar across the face of a broad lagoon, extending from
Tutataroa Pass to Tomotai Pass (PI. 208, fig. 1). The eastern and northern
face of Taiarapu Peninsula is flanked by disconnected reaches of narrow
barrier reefs separated by deep passes. From Tiitau to Papeivi Pass across
Taravoa Bay the narrow barrier reef has been greatly eroded, and only here
and there an isolated rocky islet is left. Some of the patches and stretches
between the narrow barrier reefs of the eastern side of Tahiti have also been
planed off by submarine erosion into submerged reefs (PL 208, fig. 2), similar
to those off Fareara Point.

A very striking feature of Tahiti is the number of watercourses which
flow from the centre of the island towards the shore (PI. 202, fig. 1). The
high steep slopes and bluffs which fringe the island are cut by innumerable
deep valleys penetrating almost to the centre (Pis. 86, fig. 2 ; 88, fig. 1 ;
89, fig. 1). The only locality where a gradual slope extends toward
the sea is between Paea and Punaavia (PI. 85),' where the slopes rise
gradually to the summit of Mount Taiti to a height of over 4500 feet. The
valleys radiating from the central part of the island all bring down to
the coast an immense amount of fresh water. On the eastern face numerous
waterfalls are seen, many of them falling from great heights. The amount
of water which has thus found its way into the lagoons accounts in great
part for the exceedingly rotten condition of the coral mass which forms the

1 A. Chart 1382.

144 "ALBATROSS^' TROPICAL PACIFIC EXPEDITION.

reef flats, especially near the shore. It also gives us a simple explanation
of the mode of origin of the lagoon, formed by the scouring of the tides
rimning parallel with the shore, and by the solvent action of the sea, rein-
forced by submarine erosion. This has gradually changed the wide reef
flats, forming at first fringing reefs of great breadth on the northern and
southern faces of the island, into such bays as those of Papiete and its
eastern and western extensions, and into the lagoons extending from
Teavaraa Pass to Phaeton Harbor, and on the southwest side of Taiarapu
Peninsula. The amount of silt which the numei'ous rivers of Tahiti
bring down into the lagoon of the barrier reefs is very considerable ; we
find the bottom of the lagoons covered in great part with volcanic mud
and silt, in the central part of the lagoon and in the neighborhood of the
shore, but it is mixed more or less with coral sand as we go toward the
outer face of the reef flat near the barrier reef.

On the northern and southern side of the island, as well as the western
face where the trades do not strike with any great violence, the reef flats are
broad (Pis. 202 ; 208, fig. 3). But on the eastern side, and also off the
southeastern point, where the action of the trades is incessant, the reef
fiats have been greatly eroded, leaving a wide, deep lagoon, separating the
barrier reefs from the main shore. Finally, on the northeastern side,
between Artemise Bank and Point Venus, the barrier reef has become
broken into isolated and disconnected reef patches, all pointing to the
existence of a former wide reef platform (Pis. 208, fig. 2 ; 209). The outer
edge of the platform is only indicated now by bars like those off the
southern point of the peninsula, covered with from two to four fathoms
of water and here and there passes, with from four to twelve fathoms, in-
dicating the position of former breaks in the fringing reefs, similar to those
still found south of Boudeuse Pass, and as far as the southeastern extremity
of the Taiarapu Peninsula. The barrier reefs of the east side are well
charted on the B. A. Chart 1382.

The shore platform of the east face of Tahiti consists mainly of volcanic
heads and ledges, outliers standing at a certain distance off shore (Pis. 86 ;
208, fig. 2), on which comparatively little coral grows, judging from the
nature of the sand to be found on the beaches of the main island, inside

TAHITI. 145

of the barrier reef line. On some portions of the beach this sand is for
the greater part pnrelj volcanic ; on others it is mixed with a little coral
sand, where the platform is wider and there are islets left on it. From the
amount of coral sand thrown up on the beach, it is evident that corals
flourish on these wide flats, not only on the sea face of the shore platform,
but also as extensive patches inside the barrier reef and as fringing reefs.
The volcanic ledges and rocks of the outer barrier are in part covered
by coral boulders thrown up from the sea face as well as from the ledges
between them and the shore ; on the slopes of the ledges and in the channels
the characteristic corals of the Society Islands flourish.

The meagre development of the corals on the east face may be due in
part to the great amount of detritus brought down the eastern face of the
island by the numerous rivers and streams which have furrowed the whole
island of Tahiti and cut extensive gorges penetrating to the very centre of
the island. Numerous waterfalls can be seen on the eastern slopes of
the mountains beginning the work of cutting back into the isliind. The
photographs of Plates 85, 86, 88, 89 ; 202, fig. 1, will give some idea of the
extent of the denudation and erosion which have taken place at Tahiti, not
only on the east side, but on all the faces of the island, according to their
exposure to the prevailing winds and rains.

An examination of the chart of Tahiti ' shows conclusively the effect of
fresh water streams, with the accompanying silt they bring down in the
rainy season, in influencing the growth of corals. The passes in the barrier
reef are without exception opposite or near the mouth of a river or of a
torrent (PI. 208, figs. 1-5). Aiurua River is opposite Aiurua Pass, Vaitoto
River and Vaionifa Pass, Vaitia River and Cook Anchorage, Haavini
Valley and Toharoa Pass, Mapuaura River and Faone Pass, Mataea River
and Boudeuse Pass, are all rivers opposite passes on the neighboring
barrier reefs ; all these gaps are on the weather side of the island. The
wide fringing reef flats of the lee side are along reaches of coast without
streams or small rivers ; where wide lagoons separate the barrier reef flats
from the shore, they are watered by more abundant streams, and the passes

1 A. Chart 1382.
10

146 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

throiigli the barrier reefs form the outlets of the waters which accumulate
behind the barrier reef flats.

On the fringing reef platform beyond the Utuofai valley and to the
north of it, there are only few corals ; the beach is made up of volcanic
sand, occasionally changed to light brown color by a little admixture of
coral sand. We then come upon a long, narrow barrier reef flat extending
quite unbroken to Boudeuse Pass ; on this flat are scattered numerous
negro-heads.

The first and second islets thrown up on the edge of the barrier reef flat
north of Boudeuse Pass are made up of coral sand and coral shingle on the
top of the beach (PI. 86, fig. 1) ; inside of the reef extend a number of
ledges which are overgrown with coral. The vegetation of these islands is
made up of the usual outer belt of shrubs and bushes with an occasional
cocoanut tree. Nansouty, the last island on the outer horn of the reef
flat, is much larger ; it is covered in part by large trees, similar to those of
the main island. Both to the north and south many coral boulders and
negro-heads are thrown up on the inner side of the barrier flat. On the
wide stretch of the coast south of Artemise Bank there are, again, but few
corals ; the beaches are composed alternately of volcanic sand and volcanic
sand mixed with coral sand, or of coral sand or coral shingle.

To the east of Point Venus there is no well-defined barrier reef on the
outer edge of the shore platforms, the slopes of the mountains are steeper,
and adjoining valleys are separated by knife-edge ridges, which broaden
out somewhat fan-shaped as they reach out towards the shore or shore
plain, as far south as Mahaena Pass and Nansouty Island.

Brander's Island is of volcanic structure (PI. 209), and the beach of the
bay east of Point Venus is made up of volcanic sand, showing that the
wide platform carrying the fringing and barrier reefs of the west side of
Tahiti has been formed by submarine erosion. Motu Tehiri and other
islands towards Taapuna Pass, enclosed in the fringing reef flat west of
Papiete, are volcanic, and the remnants of the volcanic flat platform. We
can see the planing down of the cliffs of the coast, at the base of Arue,
Haapape and of Tahara promontories, and their extension into the flat of
Matavai Bay upon which a few NuUipores and detached masses of corals

TAHITI. 147

are growing. The beaches of the bay are composed alternately of volcanic
or of coral sand derived partly from the cliffs and partly from the coral
patches.

Although the prevailing trade is from the southeast, the wind during the
fall and the beginning of winter is more from the eastward, and in the early
winter it varies between northeast and northwest ; the condition of the reef
fiats along the shores of Tahiti shows how dependent the topography of
the reefs is upon the prevalence of winds from certain directions. The
swell which comes from the northeast and east has eroded the wide barrier
reef lagoon between Mahaena Pass and Point Venus ; the northeasterly and
westerly winds have eroded the platform of Matavai Bay, and have to a
great extent directed the currents which have formed the harbor of Papiete
and the extension of its lagoon to the east and to the west.

The prevailing trades rake the east coast of the peninsula and of the
main island, and have reduced the outer edge of the reef platform to a
narrow barrier reef. On the southwest and the west faces, which are pro-
tected from the prevailing winds and from the variable winds, we have wide
barrier reef platforms still fairly extant, joined with the shore by innumer-
able coral reef patches. From the expansion of these patches the barrier
reef platform passes more into what we mny call fringing reefs or fringing
reef flats of considerable width ; the fringing reef flat off Hapaa (PI. 208,
fig. 5) being more than a mile wide, and the outer edge of the barrier reef
platform off the northwest point of Tahiti being fully one and a half miles
from shore. To the east of Papara the reef flat, both barrier and fringing,
is, in some points, nearly one and three-quarters miles wide. The reef flats
south of Port Phaeton are also marked for their great width. Off tlie north
face of Tahiti the reef flat which once existed between Artemise Bank and
Point Venus must also have been of great width, judging from the outliers
of its outer edge which are still left standing. Tidal currents of consider-
able velocity flow out through all the naiTow reef passes of the northwest,
southwest, and south coast of Tahiti. These currents are also reinforced by
the mass of water which pours down the hillside during the rainy season.
On the east coast the passes are of considerable width and much greater
depth, and there is no such concentrated flow as is noticed on the west

148 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

side. It is probable that these passes have, to a certain extent, been
formed by the action of the silt, which is brought down b}' the fresh water
flowing into the lagoon and which has killed the corals lying in their
path. The strength of the currents is also due, in great part, to the
amount of water which is forced over the sea face of the reef flats by the
incessant roll of the breakers. Even on the faces of the island where
the sea does not strike directly on the land, as on the west side, during
the prevalence of the southeast trade, there is a constant swell running in,
either from the north or south or west, which pours volumes of water over
the outer edge of the reef flat. The strength of the currents which sweep
out through the passes depends entirely upon the direction of the wind,
the prevalence of the swell, and the season of the year. The coast shelf
varies greatly in width, being indistinct, as we have stated, to the north of
Paea and comparatively narrow from Paea to Papara, where the steep
cliffs rise more than two thousand feet and slope directly to the shore ; the
shore flats widen out again to the east of Popote Bay, and form deep
indentations on the south and west coasts of Taiarapu Peninsula, The
eastern and northern coasts of the peninsula are flanked by steep blufts
rising almost vertically from the sea, to a height varying between twelve
and fifteen hundred feet, with deep vallej^s reaching- far into the interior
of the peninsula. The Isthmus of Taravao itself forms a broad, low gap
sloping towards the interior of the main island and the peninsula. From
north of the isthmus the scenery of the island is, perhaps, finer than in
any part of Tahiti (PI. 86, fig. 2). Numerous waterfalls fall from great
heights, into the deep gorges, which have been cut towards the centre
of the island ; endless furrows forming sharp spurs and ridges divide this
slope into naiTOW valleys, opening on the coast of the main island. On the
northern face of the island the slopes are moi'e gentle, and off Point Venus
one can look far into the interior of the island np the broader valleys of
that part of the coast.

The extent of the erosion and denudation of Tahiti is well shown by the
many directions from which " Le Diademe " can be seen from the sea, as off
Point Venus on the north coast, off Tuaura Valley and off the east coast, off
Artemise Bank, positions which are almost at right angles to one another.

TAHITI. 149

Mount Diademe rises to the height of nearly forty-four hundred feet, well
towards the central part of Tahiti ; it seems to cut off abruptly the ex-
tremity of Fautaua Valley (Pis. 88, fig. 1 ; 89, fig. 1).

The head waters of the Papenu rise from the great central amphitheatre
formed by the peaks of Marau, Tetufera, and Orohena ; from its southern
and eastern slopes arise the rivers and torrents of the corresponding faces of
Tahiti ; from the western faces of Marau, Diademe, Aorai, Orohena, Taiti,
Mahutaa, and Ivirairai rise the rivers which find their way to the sea on
the western and northwestern faces of Tahiti. The silt brought down by
these rivers has formed the wide flats which extend to the west of Papiete,
and form the northern coast shelf towards Faa.

A similar shelf has been formed at Tautira Point, on the north shore of the
Taiarapu Peninsula. It is a low tongue of land which extends to the north-
ward for nearly a mile from the foot of the mountain, and has been formed
by the deposits brought down by the Vaitia River (PI. 208, fig. 1). It is the
only iremnant left of the reef platform, which once existed on the north
coast of the Taiarapu Peninsula, on each side of Tautira. The great depth
of some parts of the lagoon off the eastern and northern faces of the pe-
ninsula, is undoubtedly due to original orogenic conditions. The channel to
Cook anchorage, off Tautira Point, was probably a deep valley, which directed
the river Vitia in its northerly course (PI. 208, fig. 1). Although the north-
east trades have eroded a wide platform on the east side of Tahiti, leav-
ing here and there only a narrow belt of barrier reef on the outer edge
of the reef platform, yet the growth of corals on the outer reef face is
sufficiently luxuriant to build up, from the dead material thrown up on this
reef flat, an occasional island or islet (PI. 86, fig. 1). These islets are a
characteristic feature of the reefs of the east face of Tahiti ; they resemble,
only on a more limited scale, the coral islets we observed in other islands of
the Society group, such as Bora Bora, Raiatea, and others, where the outer
edge of the reef platform is flanked by an almost continuous line of islands
and islets composed of coral sand. The islands have been thrown up on a
sub-basis of volcanic rock, and here and there an outlier of the volcanic rock
can still be traced, giving us a clue to the nature of the underlying platform,
and plainly showing that it is only the extension of spurs of the mainland

150 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

which have been eroded and washed out to sea, leaving the thin outer line
of reefs we have described.

Venus Point is, like Tautira Point, a mass of volcanic sand and mud
which has been deposited by the Tuaura River, and the jetty built up from
the opposing surf of the western and eastern sides, has gradually been built
out so as to unite with the outer edge of a former barrier reef flat (PI. 209).
A wide peninsula flanked with islands and islets has thus been n)ade, forming
a harbor to the east of the Brander Plantation, and forming on the west the
pocket of the eastern end of Matavai Bay. The islands to the east of Point
Venus are composed of volcanic sand, while the islets on the east face of
Tahiti, north of Boudeuse Pass, are mainly composed of coral sand, which
has been thrown up on the outer reef face upon a base of volcanic rocks.

On several occasions I examined the north side of the Papiete barrier reef,*
the same portion which was surveyed by the " Challenger," - for about two
miles north of the entrance towards the Taunoa entrance. We found on
the outer face of the reef slope living corals to within the range of the
breakers, up to the very crest of the rim of the reef flat ; these corals
extend, however, only to four or six fathoms, or slightly deeper occasionally,
the lower part of the slope being covered with broken fragments of dead
corals, or dead corals down to a depth of eighteen fathoms. Here and
there small patches of living corals extended below the thriving belt to nine or
ten fathoms. The principal genera were Pocillipores, Madrepores, Porites,
Pavonia, some of them brilliantly colored, but none very large ; the majority
of the specimens being small, those of larger dimensions being quite uncom-
mon. At about fifteen to sixteen fathoms the masses of dead corals were
separated by wide bare lanes of sand, with here and there larger masses,
from two to four feet, on the face of the slope.

We were also greatly struck here, as later in the Paumotus, with the
absence of Gorgonians and of other Alcyonaria. On the sea face of the edge
of the narrow and comparatively bare reef flat Pocillipores were growing
abundantly, and fragments and masses were constantly broken off from the
outer edge to form a sort of shingle on the outer reef slope, greatly to

1 Dana, Coral Reefs, p. 149.

" Challenger Narrative of Voyage, Vol. I. Part II. p. 777.

TAHITI. 151

the detriment of the growing corals. These dead fragments, as well as those
on the bare reef fiats, were covered and cemented with masses of Nullipores.

The lagoon slope of the reef flat is much less steep than the sea face (PI.
209), and on this slope are stretches of large masses and patches of living
corals, extending also on the steep slopes of the shoals or islets along the
lagoon. The larger masses are usually species of Astraeans and Porites ;
towards the inner part of the lagoon and the harbor, the bottom is covered
with fine mud, this becomes gradually composed of larger quantities of coral
sand towards the entrance and in the passages across the barrier reef.

I cannot well reconcile the condition of the outer reef of Papiete, as we
saw it, with the account given in the Narrative ^ of the " Challenger," which
describes the face of the reef as full of growing corals ; or with the state-
ment of the presence of very large blocks on the slope, and of the presence
of growing corals to a depth of thirty-five fathoms.

A great part of the reef flat is bare at low water, and exposed to the heat
of the sun during a considerable portion of the day. This evidently affects
the growing corals, and may account for the unusual number of large masses
which are washed down from the flats both on the sea face and lagoon side
of the reef. Owing to the exceptionally clear days and smooth sea on
which we examined the reef, we could see the condition of the slope of
the sea face with the naked eye down to nearly sixteen fathoms, and with
the water glass the most minute details could be traced to eighteen fathoms;
down to twenty-two we could see indistinctly that the dead corals were
replaced almost entirely by coral sand, only here and there a spur of coral
shingle extending into the sandy region. There were comparatively few
gullies and cuts along the face of the reef, the slope being unusually uni-
form and unbroken by crevasses or caverns or fissures. Nine to ten fathoms
represented the average depth to which thriving corals extended ; beyond
that they were habitually small, and grew only in limited areas between the
greater stretches of fragments of dead corals.

On the crest of the narrow barrier reef flat AlgoB and coralline Algse, as
well as the cementing Nullipores, grow in great abundance ; the last are
specially developed on the lagoon slope, covering the whole slope with a

'■ Challenger Narrative of Voyage, Vol. I. Part II p. 777.

152 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

pinkish yellow coating. Several species of Pocillipores grow on the outer
rim of the reef flat, rising to a considerable height, and forming its elevated
rim. On the lagoon slope, scattered Pocillipores and Madrepores are found,
as well as larger masses of Madrepores, Porites, and Astrasans of several
species growing in from two to six fathoms. Millepores grow abundantly
in shallower parts of the slopes, and Fungite are found on the reef flat and
slopes. Echinometr^ are abundant in the small cavities and pot-holes of
the rim and reef flats, while Echinaster, Echinothrix, Linckia, and Diadema,
as well as Heterocentrotus, are the most common Echinoderms of the outer
reef flat, spreading in the direction of the inner channel of the barrier reef.

On the deeper lagoon slopes of the barrier and of the fringing reef and
the fringing reef flats, are found the same corals and Echinoderms which
occur on the shallower flats ; the corals, however, grow more abundantly on
the deeper slopes than on the flats, while the Echinoderms are more abundant
on the flats.

Papiete Harbor and the adjoining reefs are interesting, as they have been
examined by nearly all the principal writers on coral reefs (Pis. 84 ; 85,
fig. 2; 89, fig. 2 ; 209). The outer reef was visited by Darwin ; it was sur-
veyed by the U. S. Exjiloring Expedition under Wilkes, and subsequently
re-surveyed by the "Challenger," a number of lines of soundings being run
by the "Challenger " normal to the face of the reef north of the entrance. of
Papiete to a depth of from 140 to 180 fathoms. Papiete Harbor is elliptical
in shape, about one and a fourth miles in length, three fourths of a mile in
width (PI. 209). On the northern half a number of flats and islets occupy
a great part of the harbor. The outer reef flat, which extends to the east-
ward from the entrance into Papiete Harbor, is about one eighth of a mile
in width, crowned at the sea face by a narrow ledge of coral shingle extend-
ing towards Taunoa Pass, where it expands into a club-shaped flat nearly
half a mile in width. A channel leads from the northeastern extremity
of Papiete Harbor to Taunoa Pass ; this channel is subdivided into irreg-
ular basins by spurs of the wide reef flat, running out from the fringing
reef which extends in an easterly direction from the Arsenal towards Taunoa
Village. Taunoa Pass opens into a small bay a little over half a mile
in length ; it is fringed on the east by a wide barrier reef flat, similar to that

TAHITI. 153

on the western side of Taunoa Pass. The eastern barrier reef flat extends
eastward to the western extremity of Matavai Bay, whicli is connected with
Taunoa Harbor by an irregularly shaped navigable lagoon. To the south
of this reef flat is the harbor of Papawa ; it is much like Papiete Bay. Its
central part is covered by a wide reef flat dividing a northern and a southern
channel, leading east into Matavai Bay, and west into Taunoa harbor.

Matavai Bay extends from Papawa Flarbor to Point Venus. It is remark-
able for the absence of corals along its shores. At Pipine Point, at Arue,
and Tahara Point we find a diminutive fringing reef; the remaining shores
of Matavai Bay are covered with fine volcanic sand which has been washed
down from the adjoining hills (PI. 87, fig. 2). From Ilaapape to Point Venus
a wide flat composed of volcanic .sand has covered the extension of the
volcanic rocks. The extremity of Point Venus is flanked Avitli a crescent-
shaped reef flat, nearly half a mile in its greatest width and about one mile
long ; on its outer face and in the sheltered cuts patches of corals occur.
The greater part of the corals on the reef flat have been killed by Nulli-
pores; it will, little by little, become covered with the volcanic sand which
is constantly creeping out towards the reef and will finally overwhelm it,
filling up the narrow lagoon channel which still separates it from the shore,
and connects Brander's Bay, Port Motu Au, with the eastern entrance into
the lagoon on the north side of Matavai Bay (PI. 209).

Reef patches, the remnants of a former barrier reef, extend westward
from Venus Point parallel with the shore of Matavai Bay, forming the chain
of Toa Tea Reefs, but they are merely patches of Nullipores with here and
there diminutive coral heads which have taken no part in the building up
of these reefs. The slope from the shore of Matavai Bay out into deep
water indicates a somewhat more rapid fall from the fifteen- or twenty-fathom
line (PI. 209), just as it is indicated on the outer face of the barrier reef to
the east of Papiete, with the exception that in the range between the east-
ern extremity of the barrier reef of Papawa and the western face of Point
Venus, the reef has a depth varying from ten to sixteen or seventeen, five,
four, three, two, and six fathoms, showing the existence of a former barrier
reef flat, which has been denuded by the action of the sea constantly pound-
ing upon it, and by the immense rollers which run in from the northwest

154 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

into Matavai Ba}'. Dolphin Bank (PI. 209) is the only remnant of that
ridge; but its higher points consist entirely, as I have mentioned before, of
small heads of corals covered with Nullipores. To the west of the entrance
of Papiete, the barrier reef flat is much wider than the eastern flat and
covered with negro-heads ; it extends in a westerly direction about four
miles (PI. 209). The reef flat is over half a mile in width, having only
a narrow lagoon channel widening out towards Torea Point (PI. 208, fig. 5).
There the barrier reef turns a sharp angle and runs parallel with the western
shore in a southerly direction ; it is separated by a narrow lagoon from the
fringing reef flat, which is a mass of dead corals cemented by Nullipores ;
the lagoon cuts through the barrier reef and forms the pass of Taapuna.
The reef flat to the south of the pass gradually becomes a fringing reef which
extends beyond Atiue as far as Acua. The shore beaches are composed
mainly of volcanic sand with a small admixture of coral sand.

The island of Tehiri is an outlier of one of the volcanic spurs off Torea, at
the northwest angle of Tahiti ; it is in the very centre of the fringing reef
flat which extends from Nututere Point, south of Papiete as far as Torea.
Its position, as well as that of Tataa Point, indicates the manner in which
the fringing reef flat has gradually been formed, from the erosion of the
spurs extending out from the main mass of the island towards the sea (PI.
208, fig. 5). The islands in the northeastern part of Papiete Harbor,
Motu-uta, Fareute Point, and the isolated flats and bars found in the lagoon
channel between the barrier reef flat and the fringing reef flat, as well
as other points extending out towards the sea between Papiete and Point
Venus, are the remnants of eroded volcanic spurs and ridges which once
formed the continuation of the main slope of Tahiti (Pis. 84 ; 87, fig. 2 ; 209).

We visited Point Venus to examine the level marks of Wilkes and
of Messrs. Le Clerc, Lieutenant de Vaisseau, and de Benaze, naval engineer,
relating to Dolphin Bank.' Wilkes' levels were taken on September 22, 1839,
and those of Le Clerc and de Benaze in September, 1869.- The level of
Dolphin Bank, according to Wilkes, was 7.80 ; according to the French
engineers it was 7.25; making a difference of .55 metres in thirty years.

1 We founil the stones anil tnarks as described.

2 Report published in Paris, Juue 29, 1870

TAHITI.

155

We were of course very anxious to make careful measurements, and to ascer-
tain if possible the rate of growth of corals on that bank, as it would give a
growth of sixty years. While Captain Moser was engaged in placing his
instruments in position on the monument established by Wilkes, I recon-
noitred in the steam launch the
shoal, which is about half a
mile from the shore, and sounded
across it in all directions, and
carefully examined its surface
with a water glass. I was
greatly surprised to find that
the Dolphin Bank was really not
a coral bank. Only a few di-
minutive coral heads (Porites
and Pavonia) could be found on
it; none larger than my fist.
The surface of the bank was
covered with fragments of bro-
ken coral coated with Nullipores, and no corals were growing on the slopes
as they passed into deeper water. It was very evident that unless the
conditions have been radically changed in the past sixty years, no one had
carefully examined the surface of the Dolphin Bank, as nothing was said
either by Wilkes ' or Dana or the French naval officers of the condition of
the corals on the banks. In fact, this part of the shore of Tahiti, as well
as the whole of Matavai Bay (PI. 209), is, with the exception of a small reef
flat stretch at the extremity of Point Venus, covered with volcanic sand.
A more unfortunate selection could not have been made.

A very heavy swell is always rolling over the bank, and even in moderate
weather is nearly on the point of breaking, so that it is difficult to remain
any length of time on the shallowest point of the bank, after it has been
found; Our soundings agreed with those of the charts within eighteen
inches ; as there is a considerable range of tide, it would always be difficult
to reduce them to the same plane without prolonged observations.

1 Wilkes' Narrative, U. S. Ex. Ex., Vol. II. p. 40.

Wilkes' Monument, Point Venus, Tahiti.

156 "ALBATROSS" TROPICAL PACIFIC EXPEUITION.

Narrow shore platforms cut into the volcanic rocks of the points and
headlands along the shore of Matavai Bay. The volcanic sands extend to
the east of Point Venus to Brander's Bay ; the flats formed from the dis-
integration of the land are all composed of it, as well as the islands and
islets to the east of Brander's Bay (Port Motu Au, PI 209).

It seems to have escaped Dana as well as Wilkes and Messrs. Le Clerc
and de Benaze, that Captain Beechey in 18-36 also attempted to obtain some
data regarding the rate of growth of corals on Dolphin Bank.^ He says
that " from the reports of the natives the coral bordering the volcanic islands
does not increase very fast, as we never heard of any channel being filled
up. The only direct evidence which I could obtain of this ftict was that
of the Dolphin Bank off Point Venus in Otaheite. This reef, when first
examined by Captain Wallis in 1769, had two fathoms of water upon it.
Cook sounded upon it a few years afterwards, and gave its depth fifteen
feet. In our visit to this place we found upon the shallowest part of it
thirteen feet and a half. These measurements, though at variance from
the irregularity of the surface of the reef, are sufficiently exact to warrant
the conclusion that it has undergone no material alteration during an inter-
val of fifty-six years." Beechey also noticed that the Dolphin Bank was
in a bay into which several rivers flowed, which would materially influence
its growth.

Murea.

Plates 90, fig. 1 ; 91 ; 208, fig. 6.

The island of Murea, distant from Tahiti about nine miles, is more broken
in outline than Tahiti; its sharp peaks assume most fantastic outlines (PI. 91,
fig. 1). Seen from the north, two wide valleys, separated by Tea Promon-
tory (PI. 208, fig. 6), form deep harbors extending for more than a quarter
of the depth of the island towards the interior. They open out into the
wide amphitheatre from which run the spurs and ridges which extend to
the eastern and western sides of the island (PI. 91, fig. 1). The island is
triangular in shape, each side being about nine miles in width, and is

' Beechey, loc. cit.. Vol. II. p. 190.

HUAHEINE. 157

surrounded, as Tahiti is on its eastern face, by a narrow barrier reef with
a number of passages between it and the enclosed lagoon. At the eastern
jioint, the southern point, and off the northwest point, as well as the greater
part of the north coast, the narrow barrier reef is changed into a more or less
prominent fringing reef flat, partly submerged, studded with endless out-
liers flanked with shallow patches of water, and here and there a deep
lagoon basin (PI. 90, fig. 1), the parts of which are connected on the east
face, disconnected on the north, and indistinctly marked on the west coast
(PI. 208, fig. 6). A number of small reef harbors are cut into the wide
barrier reef flat. Lakes Temae and Motuiti (Pis. 90, fig. 1; 208, fig. 6)
are evidently former lagoons which have been shut off from the sea by
the outlying barrier reef flats of the northeastern face of Murea (PI. 91,
fig. 2). Murea Island presents no features which have not been observed
in Tahiti ; as in Tahiti, there are but few islands and islets on the barrier
reef flats ; in Murea they flank its northwestern point, as do the islands
off the east face of Tahiti, and are composed of volcanic rocks, as is the
underlying reef flat.

The erosion of Murea has been even more extensive than that of Tahiti,
and nowhere do we find, except perhaps at Bora Bora, finer examples of
erosion than in the needle-like ridge and peaks, characteristic of Murea.
An examination of the chart' will indicate to what extent the mass of
Murea has been sculptured to reach its present condition. Like Tahiti,
it is well watered; numerous streams flow in all directions along the slopes
of the central mountains, and pour masses of silt into the lagoons of its
coast.

Huaheine.

Plates 92; 9i,fig.i; 202; 210, fig. 1.

Huaheine is about twenty miles in circumference, the northern part of
the island being called Huaheine Nui, and the southern part Huaheine Iti ;
they are separated by a canon extending two thirds of the way across from
the eastern face, forming Farerea Pass, and Maroe Bay. It connects with

1 A. Chart 1382.

158 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the bay on the western side to the east of Vaiorea Island (PI. 210, fig. 1).
There are a number of deep harbors extending into narrow valleys between
spurs of the main ridge, cutting deep indentations into the island (PI. 92,
fig. 1). From Fare Harbor a deep lagoon channel extends along the west
face to within about one mile of Tiva Point, the southern extremity of the
island. The lagoon is Hanked by a wide barrier reef flat. In proportion
to its size the interior navigation of Huaheine is comparatively extensive
as contrasted with Tahiti, but does not compare with that of Raiatea and
Tahaa, where a large vessel can enter the east pass of Teava Moa and sail
nearly around the east coast of Raiatea, the east coast of Tahaa, and its
northern and western faces as far south as Rautoauui Pass, or south of Teava
Moa Pass along the southern face of Raiatea, thrqugh a deep and wide
lagoon forming an almost continuous passage round the island from its
southernmost point, only a small part of the island being inaccessible by
this great inland passage.

Huaheine is charactei-ized by the great development of the islands on the
wide barrier reef flat of the eastern and northern faces. The islands are
comparatively narrow south of Farerea Pass, and are separated from the
shore of Huaheine Iti by a deep lagoon. To the north of the pass the
barrier reef islands are wider, and at the northeast and northwest points
they occupy the whole width of the barrier reef flat (PI. 94, fig. 4), being
separated from the land by a very narrow lagoon. The lagoon forms an
impounded lake off the northern face of Huaheine Nui (PI. 210, fig. 1), simi-
lar to those on the northeast face of Murea.

Huaheine might be compared in a general way with Bora Bora ; it is,
however, larger than the latter, the lagoon of the western side of the atoll is
smaller, and the reef flat of the eastern face of Bora Bora is separated from
the central island by a wider lagoon channel. The islands of the eastern
face of the barrier reef are likewise narrower, and only on the northwest
face do they compare in width with those of Huaheine Nui. The islands
on the edge of the barrier reef flat are all composed of coral sand, Vaiorea
Island and Tiva Point alone being spurs and an outlier of the volcanic
slope, which has been eroded and denuded, and upon which the barrier reef
flats have been formed.

RAIATEA AND TAHAA. 159

Motu Araara off the southern extremity of Huaheine is the only island
on the outer edge of the barrier reef which has remained to indicate the
distance to which the volcanic slopes on the southeastern face of the island
at one time extended (PI. 210, fig. 1).

Raiatea and Tahaa.

Plates 93; 9i, Jigs. 1-3 ; 96, fig. 2.; 210, fig. 2.

We followed the east coast of Raiatea from Teavarua Pass round to Pa'i'pa'i
Pass on the west coast of Tahaa. There are a number of volcanic islands on
the outer reef of Raiatea and Tahaa, indicating the extent of the submarine
platform of erosion which surrounds these islands. This platform varies in
width from three quarters of a mile to nearly two miles (PI. 210, fig. 2).
The lagoon is in many places over a mile wide, with deep indentations or
harbors, reaching into the valleys formed by the spurs running east and
west from the main ridge of Raiatea. Some of these harbors are nearly
three miles in depth, cutting well inland towards the centre of Tahaa and
Raiatea (PI. 210, fig. 2), as Hamene, Teoneroa haaoa, and Pari Bays in
Tahaa. Faaroa Bay reaches more than one third across the width of
Raiatea, and a number of indentations extend far up into the broad valleys
which stretch from its central ridge towards the east and west shores of
the southern part of Raiatea.

The northern reef flat of Tahaa is studded with numerous islands and
islets (Pis. 93, fig. 2 ; 96, fig. 2 ; 194, figs. 1-3), running at right angles to
the outer edge of the barrier reef flats (PI. 210, fig. 2), much as we have
seen the great sand islands and islets thrown up on the outer faces of the
Paumotus and of the Marshall Islands. This indicates that during the
prevalence of northeasterly and northwesterly winds on these shores a large
mass of dead material is derived from the outer edge of the northern f\ice
of the reef flat, and goes to build up the islands bordering the outer edge
of the barrier reef. The islands are from one to one and a half miles
distant from the shore, and are a very characteristic feature of the northern
extremity of Tahaa (Pis. 94, figs. 1-3 ; 96, fig. 2). Nowhere in the Society

IGO "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Islands is tliis feature so greatly developed as it is on Bora 15ora, where
more than two thirds of the outer reef flat is composed of long islands and
islets thickly wooded, forming a green belt on the barrier reef from one to
two miles distant from the base of the steep mountain slopes which rise
in the central part of the lagoon (PI. 210, fig. 3).

Kaiatea is separated from Tahaa by a passage about two and a half
miles in width (PI. 93, fig. 1), with a greatest depth of twenty-four fathoms.
The barrier reef which surrounds the islands of Tahaa and of Raiatea extends
directly across the faces of this inlet (PI. 210, fig. 2). Both on the east and
west of the passage, and in the centre (PI. 93, fig. 1), several islands and
flats indicate the position of former ridges or spurs, which once connected
Tahaa with Raiatea, and which have been eroded by the same causes which
have cut the submarine plateau extending around the islands, on the outer
edge of which the encircling barrier reef is situated.

It is only around the northern part of Tahaa that the outer edge of the
barrier reef flat is covered with islands (Pis. 93, fig. 2 ; 94, figs. 1-3 ; 96, fig.
2; 210, fig. 2). To the south of that belt, both on the east and west, the
reef is generally awash (PI. 93, fig. 1), or with gaps of from eight to ten feet
in depth, .separated by patches of coral, the color of the water indicating
their presence. In the vicinity of all the ship passes leading into the lagoon,
either on the east or the west shore, numerous islands and islets still remain
(PI. 93,- fig. 3), outliers, indicating the position of the ridges or spurs of the
volcanic slopes which have been eroded, and which once extended to the
outer edge of the reef flat (PI. 210, fig. 2), as Mahea and Toahotu Islands at
Toahotu Pass on the east side of Tahaa ; we follow these islands along the
east shore of Raiatea, as Tetaro and Taoro Islands at Te Avapiti Pass, the
islands of Tipaemau and Irirn at Iriru Pass, and similar islands at Teava
Moa Pass, at Nao Nao Pass. On the west coast they occur at Toamaro Pass,
at Tiano Pass, at Rautoaniu, and at Pa'ipa'i. Both on the east and west
coasts the islands occur only at the passes, and the reef flat is indicated by
the coral reef patches which we have mentioned.

The vegetation of the low islands fringing the lagoon is much like that
of the Paumotus (Pis. 93, figs. 2, 3; 96, fig. 2). Between the islands the
sea is pouring into the lagoon, or rushing out according to the stage of the

BORA BORA, 161

tide and direction of the wind. There is a marked contrast in the character
of the barrier reefs of the Society Islands and tliose of tlie Fiji Ishxnds.
While the barrier reefs have taken a great development off the larger islands
of Vanua Levu and Yiti Levu, we do not find at the smaller volcanic islands
in Fiji such wide barrier reef flats upon the surface of which incessant move-
ment of material takes place as in the Society Islands. There are no islands
where the barrier reefs have taken such an extraordinary development as they
have in the Society Islands. Along the northern extremity of Tahaa huge
flat pieces of reef rock or beach rock are found scattered on the barrier reef
flat. The material on this part of the reef platform apparently moves in
and out according to the supply on the flats, or according to the supply
driven out from the inner part of the lagoon. Some of the islets appear to
be wasting away, while others in close proximity are increasing in size.

South of Iriru Pass the east shore of Raiatea is flanked with
numerous volcanic islets. South of Faatemu Bay lies Haaio Island,
a volcanic islet of considerable size placed in the centre of the lagoon ; off
the west coast ])etween Punaeroa Pass and Tiano Pass numerous volcanic
islets are enclosed within the shore fringing reef or rise from the deeper
jiarts of the lagoon. South of the Tiano Pass the lagoon of the western
coast is broken up into separate basins by the extension seaward of the
fringing reef and patches in lagoons towards the barrier reef flats. The
highest point of Raiatea is about 3400 feet, while Tahaa is not more than
2000 feet high.

Bora Bora.

Plates 00, Jiff. 3; 97-103, 202; 210, jiff. 3; S35.

The most striking of the Leeward Islands of the Society Islands is

undoubtedly Bora Bora. The wide barrier reef flat wliich surrounds

the central islands is edged with islands and islets. Many of them are

of considerable size. The reef flat is widest on the south and west

coasts, its greatest width is about one and a quarter miles (PI. 210,

fig. 3) on the northwest flat. The low island of Teveiroa is covered with

a scanty vegetation, and extends across the whole width of the barrier

11

162 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

reef flat. To the north of Teveiroa, on the west coast, a number of
long narrow islands, running at I'ight angles to the outer line of the
barrier reef flat, indicate the manner in which the barrier reef flat has
little by little been covered by the material tlirown up during the preva-
lence of the westerly and northwesterly winds (Pis. 96, fig. 3 ; 97-99).
The gaps between the islands being gradually reduced by dams formed
either on the lee or the weather side (Pis. 96, fig. 8 ; 97, fig. 2 ; 99, fig.
3), exactly as we have described the formation of the land rim for many
of the atolls in the Pacific.

Teveiroa consists of a series of smaller islands which have been
united, while the islands immediately north of it are still disconnected
(PI. 210, fig. 3). On the northeast and east coasts we find long islands
with here and there a gap indicating the manner in which the land
rim of those sides of Bora Bora has been thrown up, and has little by
little formed a continuous island on the northeast face, and a continuous
island on the southern part of the east face (PI. 98, fig. 1) : the long narrow
islands are separated by a cluster of small islands which are gradually ex-
tending lagoonward over the wide barrier reef flat. Parts of the longer
islands are here and there almost separated by indistinct gaps, as is seen on
the chart (PI. 210, fig. 3). On the south face of Bora Bora and on the west
face (PI. 97, fig. 3) the wide barrier reef flat, over a mile in width, is in part
bare or awash or covered with coral patches, separated by pools or lanes of
water varying in depth from eight to ten feet. The lagoon which separates
the main island of Bora Bora from the barrier reef flat forms on the eastern
face a series of basins nearly distinct, separated by the spurs which have run
out in points from the main ridge of the island ; some of these points have
been cut, leaving here and there small islets, like Pitu u Uta and Pitu u Tni,
outliers completely surrounded by the barrier reef flat, or narrow rocky
spurs like Pan Point, Tahio and Tahihi Points. Matira Point is formed by
a series of islets and of rocks running half-way across the wide southern
barrier reef flat, showing perhaps more plainly than at any other point
in Bora Bora the former extension of the slopes of the island, to the
outer edge of the barrier reef flat (PI. 210, fig. 3).

The island of Pitu u Tai is the most distinct outlier of one of these vol-

BORA BORA. 163

canic islands, being nearly three quarters of a mile from the southern
point of Bora Bora (PI. 210, fig. 3). On the west coast of Bora Bora the
islands of Tupua, Tupua Iti, indicate the position of the former ridge,
which once extended parallel to the main ridge of the island, and through
which the entrance to the main harbor of Bora Bora has been eroded (Pis.
102; 210, fig. 3). This ridge forms the western face of the main harbor
(PI. 102, fig. 1), and also forms the eastern flank of a spur of the main lagoon
which extends around Bora Bora (Pis. 101, fig. 2 ; 102, fig. 1), but which
is interrupted between Matira Point and the .southern point of Tupua Iti by
the wide barrier reef flat which separates it from the sea. The principal
island of Bora Bora is distinguished by a remarkable double peak, Pahia
and Temanu, nearly 2400 feet above the level of the sea, two of the
most remarkable peaks of erosion found in the Society Islands (Pis. 97 ;
99, fig. 4 ; 100, 101, 103). Its southern face (PI. 103) rises vertically, and
on the northern side slopes towards the northern ridge of Bora Bora
(PI. 97), which is separated from Pahia by a deep valley (Pis. 97, fig. 2 ; 99,
fig. 4 ; 103), running across the central island from Anau to Fanui Bays.
The eastern face of the cliff is also vertical and forms the northern point
of the southern ridge of the eastern fixce of Bora Bora.

The peaks are most striking summits, as seen approaching Bora Bora
from the east (PI. 97, fig. 1). The sketch which Lesson made from the to^i
of the central peak of Bora Bora, showing the fringe of wooded islands
thrown up on the barrier reef flat surrounding it, has often been copied.

On the sea face of Bora Bora from Motu Tofari to Motu Mute the beach
slope is steep, and reaches of beach rock or coral rock crop out everywhere.
These are separated by coral sand or coral shingle beaches. Wherever we
examined the sea face of the barrier reef we found the growing coral edge
digitate and deeply scalloped and cut into diminutive boat harbors, as in so
many of the Paumotus. Both the main island Bora Bora and Tupua are
edged with a narrow fringing reef.

The vegetation of the barrier reef islands and islets is much more luxu-
riant than that of the Paumotus. A line of dark green vegetation stands
out above a white sand beach, forming a broad belt of verdure, at a distance
from the steep slopes of the central island ; it is especially striking when seen

164

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

looking over one of the islets of the barrier reef flat, or across one of the
gaps between the islets north of Teveiroa into the broad lagoon (Pis. 97,
fig. 2 ; 99, fig. 3) of the northern extremity of Bora Bora, the distant edge
of which is marked by the great curve of the narrow land rim of Motu Ome,
while to the right tower the central summits of Pahia and Temanu.

Native Hut, Bora Bou.4.

Maupiti.

Plates 10^, figs. J, ^ ,• 105, 302 ; 210, fig. ^

The island of Maupiti is not more than six miles in circumference (PI.
210, fig. 4). The highest point of the central island is about 800 feet above
the sea (Pis. 104, figs. 3, 4 ; 105). An irregularly shaped lagoon, forming a
series of intricate passages on the lagoon side of the barrier reef flat, sep-
arates Maupiti from the wide barrier reef encircling the island. The barrier
reef flat in the southern part of the island is more than two miles wide, and
through this a narrow channel flanked by two islands, one on the east and
one on the west, connects the labyrinth of the lagoon with the sea (PI. 210,
fig. 4). The central island is flanked by a wide fringing reef ; at certain
points this runs across the lagoon and becomes connected with the barrier

MOTU ITI. 165

reef flat. On the northeastern and on the northwestern extremity of the
reef flat two long, low wooded islets, with two islets in the gap separating
them, occujjy the outer edge of the reef (Pis. 104, fig. 4 ; 105, fig. 1 ; 210,
fig. 4), similar in all respects in structure to that of the islands which
characterize the east and northwest shore of Bora Bora. On the east face
of the barrier reef flat south of Tuanae Island numerous outliers of volcanic
rocks are scattered (PI. 105, fig. 2), indicating the position and structure of
the foundation upon which corals have grown. Similar outliers occur in
great number on the southern and western barrier reef flats. The main
peak of Maupiti is a remarkable perpendicular rocky bluff resembling the
ruins of a gigantic castle (Pis. 104, fig. 3; 105). Maupiti resembles in
every respect Bora Bora, though its barrier reef flat has a proportionately
greater development.

Motu Iti.

Plates lO.'f, fiys. 1, 2 ; WB.

Motu Iti ^ consists of two low islands : one of these is L-shaped and consti-
tutes the land rim of the northern part of the northwestern and eastern
faces and of a wide reef flat; the other is V-shaped, forming the land rim
of the southwestern part of the reef flat (Pis. 104, figs. 1, 2; 202). These
two islands are similar to those of Tetiaroa. They have been thrown up on
the wide triangular barrier reef flat, nearly eight miles in length and four
miles at the base. The V-shaped island forms the south flank of the lagoon,
into which there are two narrow and shallow passes. The lagoon appears
to be shallow (PI. 104, fig. 1). Of course the nature of the foundation base
of this atoll is problematical. Judging by the character of the other islands
in the vicinity, the underjying rocks of the reef flats are probably vol-
canic. They represent a stage of denudation somewhat more advanced
than that of Maupiti, as if the whole central mass of that peak had been
denuded to the level of the sea. At Motu Iti I could not see any volcanic
outliers, such as are so common at Maupiti, Bora Bora, and on the barrier
reef flats of other islands of the Leeward Society Islands.

I A. Chart lOGO.

166 "ALBATROSS" TROPICAL PACIFIC EXPEDITION,

Tetiaroa.

Plates 95, figs. 2, 3; 90, fig. 1 ; 202.

Tetiaroa consists of a number of coral sand islets thrown up on a some-
what pentagonal horseshoe-shaped reef flat, about six miles in length ; they
are, judging from the character of the reef platform of Maupiti, probably
underlaid by a platform of volcanic rocks. Beach rock crops out at the
base of the beaches of most of the islets, and between the wooded islands
crop up negro-heads of the same or of modern reef rock (PI. 95, fig. 3).
There appears to be a somewhat deeper part of the lagoon on the western
side. The southern extremity is deeply indented (PI. 96, fig. 1), with a
barrier reef along the edge of the platform, from which jut at right angles,
far into the lagoon, a couple of sandy islands separating the deeper part of
the lagoon from its shallow eastern side, clearly indicated by the light green
color of the water. On the western side of the atoll are thrown up two
islands ; the northern side is occupied by a long island separated into smaller
parts by wide and shallow cuts, while on the eastern face there are a large
island at the southeastern horn of the atoll (PI. 95, fig. 2). and two smaller
islets. The islands are all connected by negro-heads of beach rock, and long
ledges of beach rock project from the points of several of the islands. The
northeast and the southwest reef flats are well dotted with large beach rock
negro-heads.

The conditions under whichthese islands and islets have been thrown up
on the reef flats seem to be identical with those of the Paumotus, only the
nature of the substratum is undoubtedly different. The gaps between the
islands are being filled np in the same way as in the Paumotus ; the material
for tlie formation of the islands has in this case been derived from the de-
composition and disintegration of the beach rock and of the modern coral
conglomerate, formed by the fragments of the corals growing upon the reef
flats and slopes, thrown upon the volcanic substratum. In fact, Tetiaroa is
the last stage of a series in which Bora Bora stands at one end, Maupiti
coming next, then Motu Iti. and finally Tetiaroa.^ In the case of Bora Bora

1 A. Chart "G7.

TETIAEOA. 167

the mountain constituting the nucleus from which has been eroded the
submarine platform upon the outer rim of which a circle of islands has
been thrown ujd, rises to a height of over 2400 feet, while in Maupiti it
does not rise to more than 800 feet ; and in the last the central peaks have
been completely eroded, leaving only the volcanic submarine platform, on
the outer rim of which the coral sand islets and islands have been thrown
up and have enclosed a shallow lagoon.

Disintegration and erosion are quite sufficient to account for the difference
of condition of these three island groups without having recourse to special
elevation or to individual subsidence.

Motu Iti and Tetiaroa represent, in the Leeward and Windward Society
Islands, groups of coral reefs analogous to the low coral islands to tlie north-
east of Nukuhiva ; they hold to the high islands of the Society group, such
as Tahiti, Murea, Huaheine, Bora Bora, and others, much the same relation
which the low islands of the Paumotus, like the Duke of Gloucester Islands,
Pinaki, Ilikueru, Hao, Takume, and others, hold to Makatea, Niau, and
Rangiroa.

168 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

THE COOK ISLANDS.

Plates 106, fig. 1; 211; 212, ficjs. 2, 5.

In the Cook Islands, as in the Fiji group, we find islands composed of
elevated coralliferoiis limestone, like Atiu,' Mangaia, Mauki ; volcanic islands
with comparatively limited fringing reefs and barrier reefs, like Rarotonga ; "
and a series of low reefs, like the Hervey and the Palmerston Islands,^ from
which all traces of the central island have disappeared (PI. 212, fig. 3) ; and
atolls, like Aitutaki, with high volcanic peaks.

Williams,* who visited the Cook Islands, was an excellent observer, and
his account of various islands is most trustworthy. He recognized in a gen-
eral way the characteristic geological features which distinguish the islands
of the same or of different groups, and he classified the Pacific islands, first,
into high volcanic islands, secondly, into elevated limestone islands, and
finally, into low coral islands.

In Atiu and Mauki are extensive caverns, one of which is described in
detail by Williams. At Mauki extensive beds of apatite are also said to
exist. Williams speaks of Atiu as made up of elevated coral rock, a solid
compact mass of limestone. Gill also speaks of Atiu as made up of uplifted
coral perforated in every direction by caverns.

Williams describes at Mangaia a broad ridge (terrace ?), said by him to
be -300 feet, at a height of 100 feet. Gill also describes it, and figures
the terraces of Mangaia ; he speaks of the occurrence of dark volcanic rock
and I'ed clay in the interior of Mangaia.

Rurutu is said by Williams to be 150 feet in height, while the " Sailing
Directions" say the mountains attain a height of 1.300 feet. Williams
noticed the similarity of the elevated limestone to the streaked basaltic
appearance of volcanic rock. Williams also noticed that Savage Island (Nine)
■was composed of elevated coral reef, and he describes the cuts and caverns
found alonsj the shores and inlets.

'to

1 A. Chart 1264. ^ Ibid. ' Ibid. 1176.

* Missionary Enterprises, pp. 18, 23, 28, 30, 292.

AITUTAKI. ■ 169

Gill, in his " Life in Southern Seas," writes regarding Mituro that it
is about fifty feet above the level of the sea. The entire surface of the
island, on the way to the lagoon, is sharp coral rock. The lagoon in the
interior is about three miles in extent ; the water is very brackish, almost
black, with no visible outlet. Gill gives a distant view of the island.

Aitutaki-

Plates lOCfiff. 1; 211; 212, fig. 2.

The volcanic island of Aitutaki is the only one of the Cook group
which we examined; it was surveyed by Captain Rooke in 1892, and repre-
sents a condition intermediate between Maupiti and Tetiaroa. The summit
of Aitutaki is not more than 300 feet (Pis. 106, fig. 1 ; 212, fig. 2). As Atiu
is composed of elevated limestone, and Rarotonga is volcanic, I hoped we
might find Aitutaki to be in part volcanic and in part composed of elevated
coralliferous limestone ; we found it to be volcanic, an island with the
structure of Bora Bora on a smaller scale. The principal island is a little
over three miles in length and runs north and south. Its northern extrem-
ity forms the northern point of the barrier reef flat which surrounds it
(Pis. 106, fig. 1 ; 212, tig. 2). This is triangular in shape, the greater part of
the reef is awash, the eastern face being about seven miles, the southern six
miles, the western the same. On the southwestern point of the reef flat a
small sand key has been thrown up, and on the eastern face a series of low
wooded islands and islets indicate the position of the barrier reef flat; the
islands are separated by gaps similar to those we observed between the
islands on the barrier reef flats of the Society group (PI. 212, fig. 2).
Between the islands the sea has free access to the lagoon. Most of
these islands run at right angles to the general trend of the outer edge of
the barrier reef, and have undoubtedly been formed, as we could judge from
the indications of former gaps, exactly in the same way as those on the
northern coast of Tahaa, of Bora Bora, and Maupiti. With the exception of
Maina Island and the two islets near the southeast horn, there are no
islands on tlie western and southern barrier reef flats ; they are comparatively

170 "ALBATROSS" TROTICAL PACIFIC EXPEDITION.

narrow and enclose a shallow lagoon, nowhere more than four fathoms in
depth, and thickly stndded with coral knolls. There is an indistinct boat
passage leading across the barrier reef flat on the western side of the atoll
(PI. 212, fig. 2). To the west of the central part of the island of Aitutaki
the barrier reef becomes a fringing reef, the inner part of which is more or
less awash, forming an indistinct lagoon.

The principal island is also connected at its northern extremity with
one of the low islands of the belt of islands on the eastern barrier reef flat,
at the point where it becomes for a short distance a fringing reef. The
island is well wooded, with the exception of the small conical peak on the
northern side, which stands out boldly and slopes gradually to the south.

The plan of Aitutaki (PI. 212, fig. 2) resembles in many ways that of
Oeno ' in Fiji, only in the former the principal island is an elevated volcanic
island, while in the latter the principal island is low, but both are attached
to the outer barrier reef flat and extend far towards the centre of the lagoon.
In both, the lagoon is enclosed by a narrow barrier reef flat more or less
irregular in outline, somewhat triangular.

In the southeast corner of the southern barrier reef flat three or four sand
keys have been thrown up on an inner extension of the barrier reef flat. The
sand islets, like those on the outer belt of the barrier reef flat, will eventually
be covered with vegetation. On the beaches of the west face of the principal
island mainly volcanic sand is found, and very little coral sand has been
thrown up. The islands on the outer barrier reef are in every respect simi-
lar to those on the edge of the barrier reef flat of many of the Society Islands.
There are a number of volcanic negro-heads on the flats. This group is an
excellent example of a volcanic rock flat upon which corals are growing. The
formation of the underlying base can be traced, as volcanic outliers crop out
at many jjoints on the barrier reef. Aitutaki shows, perhaps as plainly as
any other volcanic island we have visited, the manner in which the lagoon and
barrier reef flats have been formed from the denudation and erosion of the
volcanic mass which once occupied the area indicated by the outer edge of
the barrier reef.

» A. Chart 1176.

NIUE. 171

NIUE.

Plates 106, figs. S, 3; 107-110; 211; 312, fig. 1 ; 313.

The island of Nine ' is about thirty miles in circumference (PI. 212,
fig. 1). It is surrounded only here and there by a steep fringing reef,
forming a narrow shelf on the western and southern sides of the island.
The cliffs on the eastern side run nearly vertically into the sea. The
highest point of the island is from 200 to 230 feet above the level of the
sea, forming a plateau that slopes gradually from the eastern side towards
the western shore. The terraces are clearly indicated near the landing-
place off Alofi, the village on the central part of the west shore (PI. 107,
fig. 1), and on the cliffs themselves, from the position of the lines of caverns
indicating the former lines of sea level on the west face (Pis. 109, 110).
In many places they disappear completely, the limestone cliffs rising verti-
cally from the sea, and cutting into the second or even the third terrace.
Deep cuts or incipient canons are formed all along the east and west shore
of Niue (Pis. 106, fig. 3 ; 108, 109), but are especially numerous on the west
shore, forming deep, narrow v.alleys or gorges, penetrating often a consid-
erable distance inland.

The outline of Niue is irregularly octagonal (PI. 212, fig. 1), its greatest
length from north to south being about thirteen miles, and its greatest
width about ten, from east to west across the southern end. As seen from
the sea approaching from the eastward, the east shore appears like a narrow
slope leading to a level top slightly sloping westward.

The two terraces above the undercut part of the cliffs consist probably
of several lines of rest ; they stand out boldly and are plainly visible two
miles off (Pis. 106, fig. 3; 107, fig. 1). The slope between them is thickly
covered with trees, and the island is well wooded (PI. 106, fig. 2). A heavy
surf pounds against the walls of the lower terrace, which at many points
has been cliauged into vertical cliffs cut back so as to include the second
and sometimes the third terrace, which is frequently gouged out into deep

1 Niue (A. Chart 1 1 76) is an isolated peak of coralliferous limestone, about 250 miles east of Vavau
in the Tonj];a Islands, rising from deep water ; soundings of nearly 2900 fathoms separate it from Aitutaki,
and of over 3000 fathoms from the northern part of the Tonga Islands.

172 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

fuiTows ; the exposed surfaces of all the terraces are honeycombed and
.pitted and covered with small spires and pinnacles (PI. 103, fig. 3). At the
southwest point the face of the pitted and honeycombed cliffs shows four
deep cuts (PI. 106, fig. 3), the first trace of the inroads made by the sea in
their steep faces, which will eventually become small, narrow canons, sep-
arating wide buttresses similar to those shown on PI. 108.

The lowest terrace forming a shelf round the base of the island at the
sea level has the appearance of an old beach rock bank (Pis. lOG, figs. 2, 3 ;
107, fig. 1). It is composed of a yellowish rock, very much decomposed.
The outer rim of the lowest terrace is remarkably high, and is built up by
Nullipores, which grow upon its face as far as the surf reaches (Pis. 106,
figs. 2, 3; 107, fig. 1). These masses of Nullipore are usually of a marked
yellow color. The lowest terrace is deeply undercut and full of blow-
holes ; its narrow platform is gouged out and then bridged over by corals
so as to leave passages through which the water is thrown up in spray by
nearly every swell (Pis. 106, fig. 3; 107, fig. 1). These blow-holes extend
nearly the whole length of the island. Where the two lowest terraces have
been undercut, the cliffs rise to a height varying from twenty to fifty feet
(Pis. 108, 109, 110). From the slope of the third terrace innumerable
little waterfalls drop from sixty to ninety feet vertically into the sea,
forming the deep ravines which are so characteristic of the west coast of
Nine. At one of the points which is deeply undercut, and cut back to the
third terrace, rise innumerable small pinnacles which cover the whole face
of the third terrace (PI. 106, fig. 3). Where this undercutting has been
going on extensively, small sand beaches are often formed at the base of the
ravines (Pis. 107, fig. 2 ; 108, 109), as, for instance, the beach at Avatele
immediately around the southwest point. A similar and smaller beach is
also found at the principal landing off Alofi, where we anchored (Pis. 107,
fig. 2 ; 108, 109). Between Avatele village and the point north of it,
are innumerable caverns and holes cut into the face of the second terrace
extending to the upper slope of the third terrace. The lowest terrace varies
in height from five to six feet. The second terrace varies in height from
thirty to fifty feet, and the slope of the base of the third terrace is about
fifty feet; the top of the third terrace appears to be from seventy-five to one

NIUE. 173

hundred feet above high-water mark. The terraces are numbered as they
appear above the undercut cliffs.

The second terrace is composed entirely of reef rock, the third terrace
consists of a mass of rubble at the bottom ; at the top a great many fossils
were found.^ The flat of the third ten-ace is quite extensive, nearly half a
mile wide in places. A good road runs on the level of this terrace around
the island. The fourth terrace is seen at intervals on the face of the island
as a hill about 200 feet above low-water mark. The ascent to the crest
behind Alofi, which was about one eighth of a mile inland, is steep to a point
of about 200 feet in height. The path then slopes steadily downward
with occasional swales for about two and a half miles. The interior of
the island is evidently lower than the outer rims, from thirty to sixty feet
perhaps than the crest immediately behind Alofi itself. The surface of
this interior sink was not honeycombed or pitted by erosion to the extent
observed in Makatea or in Ngele Levu, although there were a few deep pits
seen ; the others were nearly all small.

A very fertile, apparently shallow, reddish-colored soil, the residuum of
the disintegration of a large mass of limestone, shows, as at the Bahamas,
the amount of decomposition which has taken place. It exists everywhere
in the interior of the island. This soil supports a dense growth of ferns,
bushes, and trees; and here and there we found patches of larger forest trees,
from forty to sixty feet in height. Bananas, breadfruit, and mangos are
common. There are only a few cocoanut trees in the interior; they seem
to be limited to the second and third terraces on the sea face.

To the south of Alofi the cliffs resemble in every respect the limestone
cliffs of Kambara, and photographs of the two can hardly be distinguished
one from the other (Pis. 107, fig. 2 ; 108-110). Seen at a slight angle looking
north or south along the west shore, the heads of the deep ravines which
have been worn into the fixce of the limestone terrace by undercutting and
cutting back, appear like so many buttresses running at right angles to the
island (Pis. 107, fig. 2; 108), extending out more or less according to the
extent of disintegration by atmospheric and marine agencies to which the
limestone rock has been subjected.

1 A number of tertiary fossils were given to me by the Rev. F. E. Lawes, collected probablv back of
the third terrace, consisting of gasteropods, bivalves, and corals.

174 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Some of the diminutive canons have been cut back to a height of 180 feet,
sloping very gradually inland from the base of the first terrace. One can
readily see how the formation of these canons if extended sufficiently far
into the interior would soon enable the sea to cut up the limestone mass of
such an island as Nine into a number of columnar islands, surrounding a
sound or forming a pseudo lagoon in the interior of the limestone mass.
This incipient erosion is the first stage of disintegration of a limestone
plateau, the ultimate condition of which would be represented by such a laby-
rinth of undercut islets and islands as we find in Fulanga or at Nsrillano-ihah
or Yangasa in Fiji or at Vavau, plainly showing that the so-called lagoons
of these atolls are not lagoons, but are sounds which owe their formation to
mechanical causes very different from those which have formed a lagoon
surrounded by low coral sand islets. There is an abundant growth of coral
on the fringing reef platform, usually of Pocillipores with large blocks of
Porites, and Millepores extending on the sea face slope down to about twenty
fathoms. Lanes of sand between the coral patches begin already at ten
fathoms and often extend upward to the top of the reef platform. The edge
of the reef flat is gouged by deep indentations with from three to five or six
fathoms in depth. We anchored off Alofi, two fifths of a mile from the shore,
in twenty-four fathoms, where an extensive flat of white coral sand makes
out from the shore reef platform. From the outer edge of this, the slope
drops off rapidly. Moss figures a coast scene of Niue, showing the ele-
vated reef rock of the west coast.^

' Frederick J. Moss, Through Atolls and Islands in the Great South Sea, London, 1889, p. 46. In
Commodore Goodenough's Journal (p. 188) we also find an excellent account of the geology of Niue.

THE TU^'GA AKCHirELAGO. 175

THE TONGA ARCHIPELAGO.

Plates lll-ms, 213-219.

The Tonga Islands we found a most interesting group. The elevated
tertiary coralliferoas limestones take here their greatest development, and
are on a scale far beyond that of their development in Guam, the Lau
group of the Fijis, or the Paumotus. The first island of the Tongas we
visited, Eua, is perhaps the most interesting of the islands composed mainly
of tertiary elevated coralliferous limestone I have visited. The four
plateaus of Tongatabu, Nomuka, Haapai, and Vavau (Pis. 214-219), which
constitute the Tonga Ridge, rise abruptly from the 100-fathom line ; they are
separated by deep valleys connecting the eastern and western flanks of the
ridge. The extremity of the southern one is occupied by Tongatabu Island.
The land behind the cliffs of its southern coast rises to a height of over 270
feet, and slopes northward very gradually to form the low land which occu-
pies the northern coast of the island, where it is, except at Mount Zion and
Cook's Hill, not more than from five to twenty feet above the level of the
sea. At Cook Point and along the southern coast three terraces are in-
dicated. The northern coast is deeply indented by shallow bays, full of
islands, reef flats, and reef patches, on which corals grow in great profu-
sion. For a distance of nearly ten miles northward of Nukualofa the
plateau is nowhei'e more than fifteen fathoms deep ; it then runs as a long
tongue northward, gradually deepening into twenty to fifty fathoms to the
100-fathom line.

The Tongatabu Plateau is separated from the Nomuka Plateau by a
funnel-shaped channel with a depth passing rapidly into 300 fathoms from
the 100-fathom line. The Nomuka Plateau is rectangular (PI. 216) ; its prin-
cipal island is Nomuka. We found the island to be composed of tertiary
elevated coralliferous limestone, with a shallow sink, filled with brackish
water, occupying the southeastern part of the island. The sink is separated
from the sea by a high sand beach, about 200 yards wide.

176 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Nomuka Iki, tlic island next to Nomnka, we found to consist, at its soutli-
ei*n extremity, of stratified volcanic material, resembling somewhat the so-
called soap-stone of Fiji. I was informed that other islands in this group,
near Tonumeia, in the centre of the Nomuka Plateau, were volcanic.
Mango, as we could see it from our anchorage, appeared to be volcanic. So
that this part of the Tongas is, as has been indicated by Lister, like the Lau
group in Fiji, made up of islands in part volcanic and in part composed of
elevated coralliferous limestone or wholly volcanic and wholly limestone.
In Fiji the trend of the large volcanic islands and of the Lau group forms
an angle, in the Tonga Archipelago, the line of volcanoes and the axis of the
Tonga Plateaus are parallel. The eastern edge of the Nomuka Plateau
(which we did not visit) is edged with small low islands. We merely
steamed by the western islands of the Haapai group, but close enough to
see that Tongua, Kotu,^ and Fotuhaa, which vary in height from 120 to
200 feet, are composed of elevated limestone. The eastern flank of the
Haapai Plateau is edged with long, low islands, with extensive coral reefs
along the western reef flats of these islands.

The Haapai Plateau is triangular (Pis. 217, 218), with isolated islands
rising on the northwestern side from the deep water separating it from the
Vavau Plateau. Tt is separated from the Nomuka Plateau by a narrow chan-
nel with over 300 fathoms of water.

The northernmost plateau of the broad ridge of the Tonga Islands is the
Vavau Plateau (PL 219). This is elliptical, with a long tongue extending
on the eastern face of the ridge toward the northern point of the Haapai
Plateau, ending in isolated banks (the Disney Reef and Falcon Bank), lying
to the northward of the broad channel, with over 400 fjxthoms separating it
from the Haapai group. The Vavau group is by far the most picturesque
of the Tonga Islands. It consists of the principal island of Vavau, extend-
ing across the northern part of the Vavau Plateau. Several parts of the
island of Vavau, as at the southwestern extreihity, at the entrance to the
harbor of Neiafu, and at Neiafu, are finely ten-aced ; four terraces are in-
dicated there, and other flat-topped smaller islands show traces of two or

1 Lister considers that the raised rocks which form tlie edge of the sink of the island of Kotu must
have surrounded a lagoonj wl}en they stood at the level of the sea.

THE TONGA ARCHIPELAGO. 177

three terraces. The northern edge of Yavau Island rises to a height of
more than 500 feet, and slopes in a general way southward and inland.
The southern shore is deeply indented by bays and sounds, and flanked by
innumerable islands and islets, some of considerable height (150 to 250 feet),
they gradually become smaller and smaller toward the southward and east-
wai'd. These islands have been formed by the denudation and erosion of the
greater Vavau ; they form tongues of land and sea and sounds of all shapes
and sizes, showing the traces of the former land connections of the islands
and islets, and their disintegration to the eastward and southward by the
action of the sea. The islands and i-slets to the southward of the main island
rise from more or less extensive reef flats which stud the whole plateau, and
on which corals grow in great profusion (mainly Millepora, Porites, Pavonia,
Pocillipora, Fungia, and Astrea), and to a depth of five to six fathoms in the
sounds. In the Nomuka group they extend in the more open waters to
fourteen and sixteen fathoms.

It is evident that in the Tonga group, which is a very extensive area of
elevation, recent corals have played iio part in the formation of the masses
of land and of the plateau of the Tonga Kidge, and that here, as in the
Society, the Cook and Fiji Islands, also in areas of elevation, tliey are a
mere thin living shell or crust, growing at their characteristic depths, upon
platforms which are either volcanic or calcareous, the formation of which
has been independent of their growth.

It appears probable to Lister that the atoll-shaped islands of the southern
part of the Tonga group have grown on a bank of volcanic material laid out
in shallow water, and that there is no necessity to call on the hypothesis of
subsidence to account for their formation. The distribution of the land masses
of the Tonga Archipelago is quite different in the four plateaus. In Vavau
the main land mass occupies the northern edge of the plateau ; in Tonga-
tabu it flanks the southern edge, while in the Haapai group the narrow
eastern rim is edged by a row of broad islands, and in Nomuka the Otu
Tolu group on the east face and Nomuka Island on the northern face con-
stitute the elevated area of that plateau.

To the westward of the Tongas, from Ilonga Hapai to Fauna lai, a line of
volcanic islands extends for nearly 200 miles ; some of them have been active

12

178 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

very recently (PI. 214). Falcon Island,' thrown up in 1885, disappeared
in 1898, and Late is still active. This line of volcanoes runs at a distance
of from fifteen to twenty miles parallel with the trend of the four irregu-
larly shaped plateaus upon which rise the Tonga Islands. They are the
summits of a great ridge, over 200 miles in length, sloping very gradually
to the westward into deep water, and being somewhat steeper on the east-
ern faces of the smaller platforms from which rise the volcanic peaks of
the group.

Falcon Island has had a very varied existence. It was thrown up in
1885 to a height of about twenty feet, and in July, 1898, was destroyed by
a submarine explosion. It was first surveyed in 1889, and again in August,
1895 ; when the island was last surveyed it was about 800 by 700 yards,
nearly circular, the highest part of the island being forty feet above high-
water mark; its site is now marked by a shoal of nearly 100 yards in
extent, over which the sea is breaking with great violence." To the south
of Falcon Island are Honga Hapai and Honga Tonga ; Lister considers them
to be the fragments of an old crater. To the north of Falcon rises the
i.sland of Tofua to a height of nearly 1900 feet; it is an active volcano,
about fifteen miles to the west of the Haapai group. It has a crater
which is about 140 feet above the sea level, filled with water. Numerous
small craters form a close rim around this lake. We could easily imagine
this volcano as well as Niuafou^ to be denuded to the level of the sea,
leaving nothing but a narrow volcanic rim on which corals would grow
and form a circular atoll with a comparatively deep lagoon. Kao, the
volcano to the north of Tofua, is over 3000 feet in height and a much
sharper peak. Half-way to Late, Metis shoal rises to the surface. The
next peak to the north, Late, is an active volcano, rising to a height of
over 1700 feet. The crater is deeply indented with fissures running down
on the eastern side. Near the east coast there is a second inactive crater ;
its inner sides rise perpendicularly from a small flat ledge surrounding a
lake. Still farther to the north, about twenty-five miles from the northern

' An excellent account of Falcon Island, by Lister, will be found in the Proceedings of the Royal
Geographical Society of London, for March, 1890, p. 157. Lister visited the island in October, 1889;
he states that the height of the island was then 153| feet ; be gives three excellent views of the island.

2 A. Chart 1385. » Ibid., 1170.

THE TONGA AECHIPELAGO. 179

extremity of Vavau, rises the island of Tokii, and nearly ten miles farther
the volcanic island of Fanua lai, at the extremity of a line of volcanic
islands sejjarated from the Tonga Ridge by a channel less than 1000 fathoms.
Falcon rises from a depth of about 1000 fathoms, Tofua and Kao and Late
from less than 500 fathoms. The islands on the northern extension of the
Vavau Plateau rise from somewhat greater depth. The volcanic islands,
as far as Late, are on the edge of a bank, parallel with the Vavau Plateau,
separated from it by a channel about 900 fathoms deep.

At the Tongas the volcanic outbursts are mainly indicated by the summits
of a volcanic ridge running parallel to the greater Tonga Plateau, with the
exception of the few outbursts through the limestone area which have been
traced in the Nomuka group.

Of course, until all the islands have been carefully examined, it is imjjos-
sible to say that other points may not show volcanic outbursts, as those
observed in Nomuka.* But it is very evident that the distinction, which
was first made by Lister, of islands partly volcanic and partly of corallifer-
ous limestone, or wholly volcanic or limestone, is one of a very general
character. We find scattered over the Pacific volcanic islands in the Cook,
the Society, the Hawaiian, the Samoan, and the Fiji Island groups, or we
find coralliferous limestone islands, in the Paumotus, the Fijis, the Tongas,
and the Cook Islands. Or we find a combination of the two in the various
groups we have mentioned.

The existence of such a gigantic plateau of elevated limestone, like that
of the Tongas, which extends for nearly 200 miles in length and with an
average width of over twenty miles, indicates that the formation of these
huge masses of limestone must have taken place over extensive areas of the
sea during Tertiary times. In the case of the Tongas, the limestone was
probably deposited at a depth not much greater than 1000 fathoms, and
has been raised to form the gigantic ridge known as the Tonga or the
Friendly Islands.

Of course this thick mass of coralliferous limestone could only have been
formed during a period of subsidence ; but it was only after its elevation,

' Mango, Tanoa, Nomuka iki, Tonumeia, and Kelefesia are stated by Lister to be formed of vol-
canic tuff.

180 "AiBATROSS" TROPICAL PACIFIC EXPEDITION.

which continued until the present epoch, that denudation and erosion took
place on the gigantic scale on which they have acted upon the land of
this elevated limestone plateau and it assumed existing conditions. In the
Tonga group we find all the conditions which characterize the so-called
elevated atolls, or plateaus of limestone, or high elevated limestone island.s,
like Eua. The terraces of this, the southernmost of the Tonga Islands, and
of the Haapai and Vavau Plateaus, clearly indicate a sort of synchronism,
marking the periods of rest which have taken place during the elevation of
this gigantic ridge of limestone.

The sounding at Station 182 shows that the Aldrich deep, which cul-
minates off the Kermadec Islands in 5155 fathoms, extends much farther
north than has been indicated heretofore by the soundings. The greater
cold of the bottom also indicates the existence of a ridge separating the
Moser Deep from the eastern extension of this tongue of deep water of the
Southern Pacific. It was immediately off the entrance to Vavau, at Station
187, that sounding in 682 fathoms we brought up remarkable colored crys-
talline calcite and other crystals, some reddish in color, others gray, which
look like the weathered and w^ashed sand coming from the old coralliferous
limestone ledges. It is probable that much of this sort of bottom has been
called volcanic sand on the charts, and has given rise to the statements
that the underlying rocks of Vavau are probably volcanic in their structure.
While it is true that to the westward of Vavau true volcanic sand exists
near the line of volcanoes which stretches north and south a distance of
nearly 200 miles parallel with the Tonga Plateau, yet this volcanic sand is,
when closely examined, very different in its appearance and can readily be
distinguished from the colored calcite crystals.

Eua Island.

Plates 111-11',; l:li,fii].-l; il,i,fi(j. J, ; 213, 21 J^.

Eua Island (PI. 212, fig. 4) is at least ten and a half miles in length, and
three miles broad ; it lies southeast of Tongatabu, about ten miles distant, and
is separated from it by a comparatively shallow chainiel, with not more than
120 fathoms in the shallowest part of the channel. The soundings on the

EUA ISLAND. 181

flanks of Eua indicate that the island and the plateau from which it rises
are a part of the great Tonga Plateau. In fact, it is not separated
from Tongatiibu by as deep channels as those which divide the Nomuka,
the Haapai, or the Vavau plateaus one from the other. The soundings
to the south of Tongatd^bu, in the direction of Pylstaart^ Island, indicate a
southern extension of the Tonga Ridge, of nearly ninety miles, with irregu-
lar depths (PI. 214).

Eua was the first of the Tonga Islands we examined. It was surveyed
by Captain Aldrich in the " Egeria " in 1888. From the description given
by Dana, which was obtained at second-hand, I imagined that this island
would be simply a volcanic ridge, surrounded in places by a very narrow
fringing reef. On approaching it from the east, and striking the northern
point, we were much surprised to find it composed of elevated coralliferous
limestone, rising at points to nearly 1100 feet. The crest of the eastern
ridge, which runs parallel to the eastern coast, is not much more than three
fourths of a mile from the shore. Its highest points are towards the south,
where the successive terraces, indicating periods of inaction during the eleva-
tion of the island, are clearly seen, — terraces which run fi'om the southern
point to the northern extremity, interrupted by high vertical cliffs, the
whole extent of the eastern face (Pis. Ill, figs. 2, 3 ; 112, 113). The eastern
ridge forms the northern extremity of the island (PL 111, fig. 3); the steep
vertical cliffs extend but a short way around the western coast of Eua.

The highest point of the ridge on the western face, towards the south-
ern extremity of the island, is not more than 560 feet ; it is cut by a small
river coming out at the English Roads (PI. 212, fig. 4), and draining the
central valley of Eua, formed by the two ridges which run, the one parallel
to the east coast (PI. 114), and the other parallel to the west coast (PI. Ill,
fig. 1). On the west coast, however, the slope from the highest summit
towards the shore is quite gradual, as is also the western slope of the
eastern ridge towards the sink or drainage valley, which occupies the
central part of the island.

The .southern slope of the western ridge is .somewhat steeper than that
of the eastern ridge ; its summit forms a plateau varying from one fourth

1 A. Chart 2421.

182 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

to luilf a mile in width, giving the western ridge the appearance of being
flat-topped (PI. Ill, fig. 1), while the eastern ridge is only here and there
flat-topped (PI. 114). As we steamed around the southern point, we could
look up into the divide of the central basin between the slopes of the par-
allel ranges, and look into the drainage basin which occupies the central
part of the island (PI. 212, fig. 4).

It is quite probable that the central part of this basin was once occupied
by a lake, or a pool, or finally a morass, such as still exists immediately back
of the gap, opposite English Roads, where the river has cut a deep canon
into the western ridge, perhaps as far as the third terrace. We can readily
imagine erosion and denudation to have gone on at such a rate that the
ridge flanking the central part of the basin may have been cut down, at
some period during its elevation, so that the opening should lead from the
English Roads into this basin, and change it into a huge sound. Thus
might have been formed an interior lagoon of comparatively small size as
compared with the rest of the island, similar to that of Nomuka, having
nothing to do with elevation or subsidence, and yet resembling in every
respect what is called a raised atoll, similar to some of those we have
described.

While this was taking place, the range on the east side would probably
still be continuous, and its highest points rise to perhaps 400 or 500 feet,
while on the west the various gaps to be seen between the flat-topped
summits would have widened out into huge openings, and the western
slopes changed into a reef flat, varying in width from half a mile to one and
a half miles, the highest point of the western ridge rising perhaps to 200 or
250 feet on the western face. On the southern face a deep indentation,
which mijfht or niioht not have been connected with the central basin,
would occupy the place now taken by the more gentle slopes of the two
ridges flanking the central basin on the southern side of the island.

At the south point there are four very distinct terraces, and the fifth
and sixth, which rise to a height of 1036 feet, can be traced somewhat
indistinctly. Vertical cliffs extend north in continuation of the fourth
terrace, along the eastern face ; those rising from the shore are cut back
generally to the top of the third terrace. At the northern point the island

EUA ISLAND. 183

is a little over 640 feet in height, the highest point forming a part of the
fonrth terrace (PI. Ill, fig. 3). Along the central part of the eastern face
of Eua, the terraces are somewhat indistinct (PI. 113). A large number of
caverns are found in the third terrace near the northern point, indicating
former lines of elevation between the third and fourth terraces (Pis. Ill,
fig. 3 ; 112). An extensive sand beach has been formed near the northeast
point, by the disintegration of large blocks of limestone once a part of the
third terrace. A narrow shore platform, the first terrace consisting of
Nullipores, edges the reef platform near the north point (Pis. 111-113).
In the face of that terrace are seen caverns which are cutting out and
indicate the present sea level, just as those of the higher terraces indicate
former sea levels during the periodic elevation of Eua. Huge st.alactites
have dropped across the mouth of most of these caverns. On the west
side the terraces are somewhat indistinct (PI. Ill, fig. 1). The rounded
denuded tops of the lower terrace show in some cases very prominent
honeycombing, their surface being covered with small spires and crossed
by crevasses in all directions. Very few cocoanut trees were growing on
the island. South of the centre of the island, on the west side, there
is a deep gap in the terraces ; the slope runs uniformly to the highest
point of the island on the east side from the top to the fourth terrace.
Here and there are seen remnants of terraces five and six. Avith patches
of the characteristic red coral eaith standing out boldly in the centre
of the green slopes. Near English Roads there are extensive sand dunes
and the remnants of an old beach near the anchorage.

The south point seen from the south shows distinctly all the terraces
from the lowest to the sixth ; towards the southern end of the eastern ridge
there is a small sharp pinnacle at the top of the sixth terrace, which
may possibly be the remnant of the seventh terrace. This small pin-
nacle is a prominent object in the topography of the island, and can be
seen from many points along the shore and from the interior. On the
western crest of the main drainage valley of the island (PI. 114, fig. 2),
facing the western slope of the eastern ridge, we see that terraces four to
six have been eroded, and that there is a uniform slope leading up to the
sixth terrace and to the top of the line of hills which forms the east face

184 "ALBATROSS" TliOPICAL PACIFIC EXPEDITION.

of the island. Towards the south point the lines of terraces pass into
gentle slopes, cutting wide gaps between the summits ; only here and there
could the position of terraces four to six be determined. As far as we
could see, the third, fourth, and fifth terraces were of the same height on
the two sides of the island.

At the southern extremity of the island huge caverns have cut into the
vertical faces of the cliffs, forming here and there natural bridges. Innu-
merable pinnacles, cones, and spires stand out from the eroded surface,
leaving the slope between the third and the base of the fourth terrace covered
with red volcanic earth ; on this an entirely different type of vegetation
grows from that found on the east side of the island. We found here
bananas, pisonias, and aloes in great profusion, in marked contrast with the
hardwood vegetation of the east and west sides of the island. Lister has
described the remarkable chasm which exists at the southern e.xtremity
of Eua, formed by the falling in of the roof of adjoining caverns.
At the southern point the shore, or first terrace is somewhat higher than
in other parts of the island ; it is from eight to ten feet high. On
rounding the southern point of Eua, its little satellite, Kallau, is passed,
where four terraces are distinctly seen (PL 214). This little island is
covered with bananas and cocoanut trees, and on the northern extremity
there is a long sand beach fringed with beach rock. After passing the
southern point of Eua, there are no gaps cutting across the terraces.
The base of the second terrace is distinctly marked, pitted, and honey-
combed, and the edges of the first and second terraces are full of blow-
holes. The tradewinds, of course, are shut out from the west side of the
island by the high range of bluffs of the east coast. The terraces of the
west coast are more or less indistinct, and we generally find a gentle slope
from the top of the third terrace to a height which corresponds to that
of the fifth terrace on the east face. The Nullipore platform at the base of
the lower terraces forms huge rounded masses, a sort of wall ; on the outer
edge of the shore shelf, blow-holes exist similar to those described at the
southern and northern extremities. As we go north on the west side, sand
beaches are formed at the base of the lower terraces ; they consist mainly
of Nullipores ground up. The beaches become more extensive as we

EUA ISLAND. 185

go north, and near the outlet of the drainage valley of the island opposite
English Roads, sand beaches flank the west coast of the island (PI. Ill,
fig. 1). Immediately behind the beach, however, we generally find a small
ledge rising to a height of perhaps fifteen feet, the remnant of the lowest
terrace. This is usually eroded and honeycombed, and conceals the greater
part of the second terrace, which only reappears where the sand beach does
not exist. On the west side we can also trace, here and there, fragments
of cliffs cropping out at different heights, indicating the former existence of
various terraces (PI. Ill, fig. 1) to which they belonged. The western
slopes are thickly covered with vegetation, and seem, with the exception
of the outcrops just mentioned, to run unbroken from the beach or lowest
terrace up to the level of the fifth terrace, the terraces on the west side
having, as a rule, fallen in and crumbled so as to entirely change the
appearance of the topography. The succession of beaches and of patches
of the third and fourth terraces characterizes the topography of the west
coast of the island as compared to that of the ea^t.

From our anchorage at English Roads, we could see the slopes of reddish
volcanic earth of the west face of the cliflCs formins? the terraces on the east
side of the island, passing down towards the central part of Eua, flanked
on the west by the line of hills of its western face. Back of the village of
Ohonua, the road rises quite rapidly to a height of about 150 feet,
which is probably, the level of the fourth terrace. From there, going south
on the ridge which forms the west face of the island, we rise gradually
to a height of 310 feet, then to a height of 370 feet, and drop again to
a height of about 350 feet, at a point opposite the highest pinnacle
of the ridge on the east side of the island (PI. 114). Striking out from
this point at right angles to the ridge, we go down into a sink, which is
mei'ely a sink of denudation, showing no trace of having once been a
lagoon or a part of a lagoon (PI. 114). The valley formed between the
hills of the eastern and western sides is probably 150 feet lower at this
point than the highest point of the western ridge. It then slopes
very gradually both north and south, after rising to the south to a low
ridge, which may have been 400 feet in height, and forms the deep
valley into which we looked when rounding the southern point. The

186 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

northern line of drainage slopes gradually towards the canon north of
Ohonua village (Pis. 114, fig. 1; 212, fig. 4), and through this the water
collected in the valley comes out as a small stream. No outcrops of corallif-
erous limestone were found in the depression between the two ridges, except
on the western face of the eastern line of hills, where, at a height of about
525 feet, a small ledge was found surrounded by earth of volcanic origin.
Dr. Mayer ascended to a point a little over 600 feet on the west side of
the eastern hill range. As a rule, the soil of the western ridge is of
volcanic origin, of a light red brown or yellow color; the highest point
of the western ridge was about two and one-half miles from the village
of Ohonua. The soil of the bottom of the valley is also of volcanic origin ;
it is deep, of a dark red brown, and quite fertile. It was covei'ed with
large groves of cocoanut trees, pisonias, and a couple of species of Gar-
denia, in addition to numerous ferns and grasses ; no outcrops were found
in the lower parts of the valley. The fourth tei-race of the western
line of hills was probably 300 feet above high-water mark. We took sotne
photographs from the highest point of the western ridge to show the great
extent of the sink of the island (PI. 114), and also from other points along
the crest ; they plainly show that this is merely a valley of erosion, and that
the river at English Roads landing has cut its way through the western ridge,
and drains the valley as any other drainage valley would do. Other small
creeks run east from the slopes through the limestone country of the
western range, and disappear in the bottom of the valley at the foot of
the eastern range. At a distance of five miles from Ohonua village, the
bottom of the valley must be at least 120 feet lower than the highest point
of the western crest; it drops gradually to the level of the sea, following
the level of the creek which drains the interior valley and comes out at
English Roads. A number of fossils were found at a height of 300 feet
in the fourth terrace.

Speaking of Eua, Lister * says : " The volcanic formation comes to the
surface over a great part of this high ground (the western slope of the highest
part of the eastern ridge), and when bare of vegetation it is readily recog-

' Notes on the Geology of tlie Tonga Islands, by J. J. Lister, in Q. J. Geol. Soc, London, Vol.
47, 1891, p. 590.

EUA ISLAND. 18?

nized by its red color ; but patches of limestone occur in many places,
sometimes in large projecting mass, like that which forms the south summit,
sometimes weathered down into groups of isolated pinnacles, standing on a
volcanic basis."

The outcrop of the volcanic formation is also well seen on the western
face of the east ridge to the north of Ohonua Village.

On Plate XXIII,' Lister has given an approximate sketch map of the posi-
tion of the patches of volcanic formation of Eua." The volcanic basis
underlying the coralliferous limestones is exposed near the centre of the
eastern face, and at the shore there are dykes of intrusive rock, which
cut through the volcanic deposits but do not enter the overlying calcareous
strata.

The present topography of Eua indicates that at one time it must have
been a large flat limestone plateau, originally similar to that of Tongatabu
and Vavau, but of greater height and less extent, pushed up by volcanic
outbursts on the east coast, which was little by little disintegrated according
to the hardness of the various terraces, and finally eroded so as to form the
central valley with the comparatively smooth faces of the eastern and western
ridges. Only a few outcrops of the coralliferous limestones are seen, here and
there, in the valley, — remnants of the harder terraces, such as the
fourth terrace, a long line of which is left on the northern part of the west
slope of the central valley. On looking back on Eua on our way to Tonga-
tabu one can see, perhaps better than on the island itself, extending for a
great part of its length, the deep central valley of erosion, which has given
to Eua its characteristic topography, and certainly there is nothing less like
a lagoon than this inner valley or sink of erosion of Eua.^

1 Loc. cit., Geol. nf the Tonga Islands.

2 See Harker, Volcanic Rocks of Eiia, Geol. Map;-, June, 1891.

8 CoiiiinanikT Oldham of the H. M. S. " Egeria" has given in " Nature " of May 22, 1890, p. 85, an
interesting sketch of Kiia, corresponding in the main with Lister's account. In a note to the above Pro-
fessor Judd speaks of the limestones as made up of Foraminifera and water-worn Nullipores. As re-
gards the volcanic rocks he thinks their composition lends support to the view that all oceanic islands
are of volcanic origin.

188 •• ALliATKOSS ■' TROPICAL PACIFIC EXPEDITION.

tongatAbu.

Plates 115-118, 9A3-9A5.

The southern cluster of the Tonga group ' (PI. 214) consists of the islands
of Tongatabu (PI. 215), and its satelUtes, with the shoals extending to the
north about thirty miles from the harbor of Nukualofa, the soundings on
the northern part of the bank varying from 20 to 40 fathoms ; two inden-
tations of shallower water run into the plateau, the one from the east,
south of Dido Shoal, towards Ava Lahi Pass, and the other, west of Eua
iki, forms the main entrance into the harbor of Nukualofa.

The island of Tongatabu is about eighteen and a half miles in greatest
length. From Cook Point the southwestern shore, as well as the south-
eastern extremity, is high. Its terraced cliffs rise to about 270 feet
immediately back of Cook Point. Tongatabu is irregularly triangular in
shape. Its greatest breadth is formed by the southeastern coast, which is
about nine miles long. It tapers at the northwestern extremity to a long
curved point, Nui Aunofo Point, not more than half a mile in width, which
encloses the flats which once formed tlie northern extremity of Tongatabu,
and are now represented only by the islands and fiats of Atata, Boloa, Hakau
Tabu, Alakibeau, and Tufaka (PI. 215). From the highest point of tlie
southwest coast the shore falls very gradually towards the north, and the
whole northern part of the island is composed of a comparatively low flat,
undulating in places (PI. 116, fig. 1).

To the east of Nukualofa '" Tongatabu consists of a labyrinth of low
islands and islets (PI. 215), which occupy the whole of the straits between
Nukuleka and Holevai (PI. 115). The pass between these two points widens
out to the south and west into long fingerlike bays, extending the one
towards Bea and the other towards Mua, the land between consisting of
low swampy ground covered with mangroves ; the whole of that part of
Tongatabu forms an irregularly shaped digitate lagoon (PI. 215), which can
be navigated only by canoes (PI. 115, fig. 2).

1 A. Chart 2421. 2 Ibid., 2363.

tongatAbu. 189

To the northeast of the harbor of Nukualofa^ north of the Narrows,
immense L-shaped flats extend, on wliich are a number of low islands (PI.
115, fig. 3), such as Fafa, Monu afe, Yelitoa, Onevai, Motu Tabu, Onevao,
Fukave, Nuku, Ata, and Tau. The L-shaped flat encloses a wide bay
covered with coral patches, shoals, and islands, the principal of which is the
low island of Malinoa, and extends towards the Lahi Passage (PI. 215). Biha,
or the eastern passage, leads as far as Atata Island into a wide open bay,
flanked on the northeast by innumerable coral patches leading to Egeria
Pass, which is the principal western entrance of Tongatabu (PI. 215). To
the north of Egeria Channel is an extensive, low, triangular reef flat, which
separates it from the Lahi Pass.

To the west of Atata Island, a deep indentation of the reef flat to the
east of Niu Aunofo Point, with from seven to ten fathoms of water, is
called Maria Bay. It is cut off" from free access to the sea by large reef
patches, outliers and islands, thrown up on the western face of the plateau
of Tongatabu. The principal flats are called, the one Hakau Tabu and the
other to the northeast of Egeria Pass, Hakau Mamao (PI. 215). From that
point the Tongatabu bank gradually slopes to the northward, and dis-
appears on the edge of the broad channel which sejjarates it from the
Nomuka group. The least depth in this channel is about 270 fathoms. At
the western extremity it has a width of about four miles, and at the
eastern a breadth of nearly ten mfles (PI. 214).

As we entered the passage leading into Tongatabu, we could distin-
guish on our left patches of two terraces separated by short reaches of
coral sand beaches, the low limestone cliffs of the terraces being deeply
undercut and gouged out. Tongatabu as seen coming from the sea is
very striking. The numerous islands which once formed part of the main
land can be seen stretching to the north as far as the eye can see ; and
as we approach Tongatabu, the whole of its north shore seems cut into
myriads of little hills and sand bars, with but little vegetation. Here and
there a larger island rises among the lower ones, showing according to
its height (PI. 115, fig. 3) that it once formed part either of the first or
of the second terrace. Low vertical limestone cliffs crop out on nearly
all the islands, and these are more or less rounded according to their

190 "ALBATROSS" TKOPICAL PACIFIC EXPEDITION.

exposure to the prevailing winds ; those Avhich are more protected are
covered with a slight vegetation which has prevented their erosion and
denudation. Nukualofa, the principal harbor of Tongatabu, is merely a
channel left between the innumerable islands which must once have
formed a connected flat extending far to the north of the town, a flat
which has been changed into a very irregularly shaped lagoon, a lagoon
of erosion and denudation, covered with islands and full of manarrove
swamps (PI. 215). On landing, it is evident that a great part of the flat on
which the town is built consists mainly of teolian rocks which have been
formed by the trades blowing along the sand beaches, derived from the dis-
integration of the coral reefs and coral reef flats of Nukualofa. In the
central parts of the flats, between the islands and islets, corals grow in
great abundance, and on the slopes of the reef flat into deeper water they
are especially abundant. Numberless starfishes belonging to species found
on the Australian and Fiji reefs are seen in all directions, and the reef
flats are full of fishes which are left at low tide in large pools, where
the natives fish for them with hand nets (PI. 115, fig. 3).

Mount Zion (PI. 215), near the shore of Nukualofa, is composed of elevated
coralliferous limestone full of fossils ; it and Cook's Hill are probably out-
liers of the second or third terraces, showing that the whole of the main
island of Tongatabu has been eroded and denuded to its present level,
leaving only here and there, as we saw when entering the harbor, traces of
the greater elevation at which the land once stood. This elevation is best
seen on the south side of Tongatabu, in the rear of Cook Point, where
the terraces rise to a heiglit of more than 270 feet, as well as along the
Liku or the windward side of the island (Pis. 116, fig. 2; 117, fig. 2);
from that shore the land slopes gradually to the height of a few feet south
of Nukualofa. Near Cook Point lines of blowholes are developed on the
outer edge of the reef flat which surpass in size any of the blowholes
we have seen in the Pacific (Pis. 117, fig. 1 ; 118).

On the island of Atat^i, northwest from the village of Nukualofa, a number
of fossils have been found similar to those of Mount Zion, and they in their
tm-n are similar to those we found in Eua, and other islands in the Tonga
group. Tongatabu, as seen in the distance, is marked for its flat-topped

tongatAbu.

191

summit, and the terraces of the south point ; they are clearly visible at a
distance of ten miles. The island of Eiia iki is also flat-topped, and ter-
raced as seen from the north point of Eua.

There is no outcrop of coralliferous limestone on the great flat south of
Nukualofa. On leaving our anchorage at Nukualofa^ we passed the island
of Boloa, which rises to a height of over sixty feet, and where the undercut
ledges probably represent fragments of cliffs belonging to the second ter-
race. We also passed the island of Alakibetiu, which is somewhat lower
than Boloa ; at Atata, where the second terrace is very distinct, but deeply
undercut, the top of the island has been rounded and huge crevasses and

Native Hut near Nukualofa, Tongatabd.

cracks cut into the face of the vertical cliffs. To the north of Egeria
Channel extends a long reef flat, the outer edge of which is plainly marked
by its line of bi'eakers. A number of islets are also seen between Atata
and the outer edge of the reef flat ; this seems to be a series of huge sand
banks connecting the south spit of Atata with the eastern edge of the
reef flat to the south of Egeria Channel and to the east of Niu Aunofo
Point. Another islet south of Egeria Channel is the small narrow island
of Tufaka, with its undercut ledge like that of Atata. After passing out of

1 A. Cliart. 2363.

192 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Egeria Channel, we ran a short distance parallel to the line of breakers
which extends towards the north from Maria Bay, on the western side of
the reef.

The Nomuka Group.

Plates 119, 2U, 216.

The Nomuka group, the second bank to the north of Tongatabu, is
rectangular in outline ; its eastern and western sides being about thirty
miles in length, and its southern and northern sides somewhat longer.
The western face of Nomuka Bank is comparatively clear, the bank falling
rapidly from 30 or 40 fatlioms into more than 200 fathoms, while numerous
shoals line its eastern edge. The northern side is covered with islands,
islets, and shoals, forming a continuation of tlie islands and shoals of the
eastern face. Toward the central part of the bank several low islands
have been thrown up, and numerous patches render navigation of the
eastern side of Nomuka exceedingly dangerous, so that we did not examine
that side of the Nomuka Bank.

The island of Nomuka is composed of elevated coralliferous limestone.
Seen at a distance, it shows distinct traces of a first, a second, and a third
terrace. What is left of the third terrace rises as a low conical peak on
the summit of the second terrace. Before coming to our anchorage, we
passed Nomuka Iki, a low island on which the old ledge crops out at its
base, near high-water mark. We also passed by the island of Mu'ifuiva,
a patch of old elevated coral reef rising to a height of perhaps nine or
ten feet, topped with bushes and a few cocoanut trees (PI. 216). To the
rear of us we could see the flat-topped island of Mango Iki, and also the
island of Mango, which has a volcanic peak at the eastern extremity, its
western end being composed entirely of elevated coralliferous limestone
rocks. The highest point of the island of Nomuka is Mata Maka (166 feet
in height), and when seen from the eastern side, it looks as if a part of Koto
Maka, the next highest peak, might be a portion of the fourth terrace. In
addition to Mango, which is volcanic, 1 was informed that Fonoifua, as
well as Tanoa, are composed of volcanic rocks. Mr. Moore, who went on

THE NOMUKA GROUP. 193

shore at Nomuka Iki (PI. 216), found the soutliern peak (147 feet high)
made up of volcanic material very similar to the Fiji soapstone, but some-
what darker. An elevated ledge of old coralliferous limestone runs on. the
south side of the west end, and a high sand beach faces the northern line
of the shore. From the southeastern point sand keys extend, forming a
tlat of considerable extent.

The eastern part of the island of Nomuka is occupied by a large lagoon,
which has been separated from the sea by a high sand beach thrown up
between the southern extremities of the two limestone ransjes formintp
the western and eastern faces of the island (Pis. 119, 216). The island
must formerly have been more or less horseshoe-shaped, its faces enclosing
a sound formed by denudation and erosion and the inroads of the sea, much as
the sounds in the Bermudas and elsewhere have been formed. The lagoon
is not more than four to five feet deep, and occupies the shallow sink enclosed
between the two main I'idges of Nomuka. Yet such a lagoon it' surrounded
by a low land rim would be looked upon as an excellent specimen of
a subsidence atoll ! The slopes fiom the outer ridges toward the central
basin are slopes of denudation ; here and there are huge spurs covered with
vegetation, running out as buttresses on the flanks of the rim (PK 119,
fig. 1), a very different structure from that found in any atoll we have
examined; this can only be accounted for by the difference in the extent
of denudation and erosion, which has token place in different parts of
this basin, according to the density and more or less fi'iable nature of the
calcareous limestone of the outer ridges. The buttresses remind us of
similar buttresses in the sink of Kambara; they are in marked contrast
with the comparatively bare volcanic slopes of Nomuka Iki, and other
volcanic islets in the vicinity. A number of salt-water fishes are found in
the lagoon.

Koto Maka and the western part of Nomuka were examined by Dr.
Mayer, who found it to consist of elevated coralliferous limestone, much of
it changed to hard calcite, and containing numerous fossils near its base.
I examined, myself, the ridge to the east of the lagoon, as well .as the shores
of the lagoon itself, and found the highest point of the eastern ridge of the
lagoon to consist of calcite, and of elevated coralliferous limestone from

13

194 '^ALBATROSS" TROPICAL PACIFIC EXPEDITIOX.

base to summit. A beautiful mangrove swamp extends along the southern
part of the lagoon (PL 119, fig 1). The reef flats surrounding Nomuka are
extensive. The reef flat to the south of Nomuka Iki (PI. 216) is quite bare,
covered with Nullipores, forming a thick crust over it, with but few corals.
On the east coast Nomuka is flanked by a high coral sand beach fully fifteen
feet above low-water mark ; the coral sand is of a grayish color, mixed
with red earth near the lagoon. The soil is very fertile. There are a
few coral and sand patches near our anchorage in fifteen fathoms, and also
between the anchorage and the shore, as well as an extensive fringing
reef on the southwest face of Nomuka. The corals extending into deep
water do not seem to be numerous ; they are separated by wide lanes of
sand.

Dr. Mayer also collected fossils on the low land forming part of the slope
towards the northern extremity of Nomuka, probably a part of the second
terrace, from the first terrace, which is about nine feet high, and also
from near high-water mark. The soil of the northern slope is deep ; it
consists of decomposed coral, of a rich brown and red color, and supports
a dense growth of cocoanuts, Tahitian chestnuts, Pisonia, Paritium, bread-
fruit, limes, bananas, etc.

On the slope between Koto Maka and the shore, is a slight sink, or
basin of erosion similar to that which formed on the east face, the so-called
lagoon of Nomuka (PI. 216). The old ledge rock crops out at a point
immediately above the first terrace, where it is about nine feet high
above high-water mark. On the soutlieast face of Nomuka a huge sand
dune has formed on the weather-side, and hides the lower part of the old
ledge of elevated rock. Similar dunes can be seen on other islands in
the vicinity of Nomuka, where the tradewinds rake the coral sand beach.
The sand gradually creeping up on the slopes would eventually hide the
outcrops of the ledge, and would soon form a perfectly uniform slope of
coral sand, witli here and there an outcrop of the old ledge where it had not
been covered by the encroaching dune.

THE HAAPAI GKOUP. 195

The Haapai Group.

Plates 217, 218.

As we left our anchorage at Nomuka, we could, going north, see the
summit of Mata Maka, sloping to the shore line where limestone bluffs alter-
nate with long reaches of coral sand beaches, fringed with beach rock. To
the south rose Koto Maka, similarly flanked with low bluffs of old beach
rock alternating with coral sand beaches. Immediately above the cliff's,
the slopes were covered by thick vegetation, probably up to the height
of the third terrace ; above that the higher summits of Nomuka were
more or less bare (PI. 216). We could see in the distance, to the north-
east of Nomuka, the flat-topped Oua composed of limestone (140 feet high)
covered with scrub vegetation, as well as the more rounded summit of
Fonuaika, covered with cocoanut trees. We passed by Kito Island, a low
sand beach covered with scrub bushes (PI. 217). Tongua and Kotu re-
semble Oua, their limestone cliffs rising to a height of more than 120
feet. Off Kotu there is a sink in the reefs surrounding it, forming an
incipient atoll which has not risen to the surface from the surrounding
bank, on which is a depth of twenty to thirty fathoms. The island of
Fotuhaa is also flanked with okl elevated reef rock ; its second, third, and
fourth terraces are plainly visible when steaming past at a distance of about
three miles. The first, a low terrace, flanks the whole of the west coast ;
in the third terrace a number of caverns indicate a former sea-level, at a
height of probably thirty to forty feet above high-water mark. The cliff's of
Fotuhaa are deeply undercut to the base of the third terrace, and gouged
vertically into incipient valleys at right angles to the shore line, as we saw
them at Nuie.

The islands of elevated coralliferous limestone which dot the western
part of the southern portion of the Haapai Bank are the outliers of larger
islands ; their former extent is indicated by the extensive reef flats and
patches occupying the greater part of the area of the Haapai Plateau,
by the reef flats to the east of Oua, those surrounding Haafeva and Kotu
(PI. 217), x\lexander and Wickham reefs, and many others scattered over
the surface of the Haapai Plateau.

19(3 "ALBATltOSS" TROPICAL PACIFIC EXPEDITION.

In addition Haapai Bank is covered with small low islands, scattered over
the bank for a distance of about forty miles (Pis. 217, 218); the bank
stretches in a northeast and southwestern direction, and has a greatest
width of about twenty-three miles. On the eastern face Haapai Bank is
flanked by a continuous angular line of reefs and islands, extending from
Haano Island on the north to Lima Island on the south. Some of the i.slands
are separated by narrow passages of considerable depth ; ' they are low, and
some of them broad, and appear to consist, like the lower parts of Tongatabu,
of elevated coralliferous limestone, which has gradually been denuded to the
level of the sea, while the islands on the western part of the bank rise to a
considerable height and a-re plainly terraced.

The Haapai Bank is triangular (Pis. 217, 218), its depth varies from ten to
forty or fifty fatlioms ; it drops off rapidly from 40 fathoms to 50 and 100 and
then to the 500-fathom line on the west. A number of the islands, patches,
and flats on the western part of the bank rise from comparatively deep water,
from water fully as deep as that of any part of the channels which separate
the banks, indicating that there are a series of more or less independent
summits on that part of the Haapai group.

The larger islands flanking the eastern face of the northern part of
the Haapai Bank (Pis. 217, 218) are quite broad ; they are low. with low
cliffs of elevated coralliferous limestone edging their eastern face, or crop-
ping out on the western ; they are, according to Lister, from ten to twenty
feet, and slope very gradually towards the west. The broad and extensive
reef fiats adjoining the islands and forming their continuation on the eastern
face of the bank, have either been elevated, or have been denuded from
larger limestone lands ; they are flanked by a narrow reef platform of
about 200 yards in width, edged by a narrow line of fringing reefs which
might, from its independence of the reef flat, be called a barrier reef The
reef flat to the westward, the i-emnant of the former hind area, is represented
only by irregular patches of coral or flats covered with sand bars and sand
ridges.

The larger islands flanking the east side of Haapai Bank, Haano, Foa,
Lifuka, and Uoleva occupy the greater part of the surface of the flats which

' Over tbirty fatlioms in Ava Mata Mata Vika, and nearly twenty fathoms south of Uoleva.

VAVAU. 197

connect them ; south of Uiha the reef flats extend as a narrow belt towards
Tofanga Island, and to the south of Ava Mata Mata Vika (PI. 218) the
reef flat is merely a narrow line reaching to the southern horn of the bank,
on which there is only a single small island, Lima. Remnants of the ele-
vated limestone crojD out as outliers on the narrow reef fringe, some of them
attaining, according to the charts, a height of a few feet.

On account of the weather we did not venture into the labyrinth of
patches to the west of Lifuka, and were unable to examine the peculiar
atolls sketched on the chart of the northern part of the Haapai group.'
They differ from the greater number of the islands of Haapai and Nomuka,
which are surrounded by extensive fringing reef flats, in having an outer
somewhat raised edge forming an incipient barrier reef, resembling the
raised barrier edge of the fringing reef of the larger islands like Foa, Haano,
Lifuka, Uoleva. The transition of ni) island with its fringing reef to one
of these incipient atolls is shown by comparing such islands as Luangahu
(Pis. 217, 218),^ an islet with an extensive fringing reef, with Loftmga,
an elevated coralliferous limestone island (150 feet), or Moungaone (100
feet in height), which has in part a fringing reef, in part a barrier reef, to
such an atoll as Niniva, or Ofolanga, or Hakau Lahi, the remnants only
of islets encircled by a narrow barrier reef enclosing a space full of dry
coral patches. The earlier stages, Lofanga, Moungaone, Tongua, Kotu,
Haafeva, patches or outliers of the great Haapai land (Pis. 217, 218),
resemble the condition of the large eastern islands of Uiha, Uoleva,
Lifuka, and Haano, which in their turn recall the existing condition of
the northern parts of Tongatabu.

Vavau.

FliHcs 120-125, 219.

Approaching A'^avau from the southwest, we come npon the triangularly
shaped island, Hunga, forming the western entrance to the Vavau group
(Pis. 121, fig. 1 ; 219) . To the east two immense white patches appear on

' A. C'liart 301)y. - Ibid , 3099 and 3100.

198 "ALBATROSS" TROPICAL PACrFIC EXPEDITION.

the vertical limestone cliffs of the southwest face of Vavaii (PI. 120, fig. 2),
which has been formed by the sloughing off of large masses of limestone
rocks heaped up at the base of the cliffs. The cliffs are all deeply undercut,
and the first terrace is nearly everywhere obliterated by the mass of debris
which has fallen off from the second and sometimes from the third terrace
(PI. 124, fig. 1). To the north of Muitoulo the second, third, and fourth
terraces are plainly visible ; to the south and east, looming up over the
slopes of Fata and Kapa, rises the island of Pangai. The second, third, and
fourth terraces are very distinct along the side of Moungalafa, and form
the southern face of the bluffs on the western entrance into the harbor
(PI. 121, fig. 2). The height of Moungalafa is about 600 feet, while the
height of the tliree terraces to the south of it is probably somewhat less ;
when looking southwest, the cliffs of other islands rise vertically to a height
of more than 200 feet (PI. 120, fig. 1).

Rounding Point Fata, we pass into the main entrance to Neiafu, leaving
on the right Nua Papu, Oto, Ava, Kapa, Otungake and Pangai ; in the east
we can distinguish the line of islands on the edge of the Vavau Plateau and
an interior line flanking the western edge of the eastern part of the plateau
(PI. 120, fig. 1). All the islands to the south of Vavau, and the spurs
making out from the principal island, show the immense amount of
denudation, disintegration, and erosion which must have taken place in
this limestone land during its elevation (Pis. 120, figs. 1, 3; 122, fig. 2).
The cliffs are nearly vertical, deeply undercut, and all traces of the second
and third terraces have been obliterated. Some of the islets are almost cut
in two, deep canons having been cut into their faces (PI. 219). Oue of
the most striking of the canons of the Vavau group is the cut that separates
Kitu Island from Nua Papu (PI. 219); it is not more than twenty or twenty-
five feet wide. The vertical cliffs are full of caverns. North of the eastern
point of Pangai three terraces are plainly seen. On looking to the east
and south of Pangai we can see the numerous islands and islets com-
posed of elevated coralliferous limestone, some of which are still terraced,
scattered over the whole of that part of the Vavau Plateau (PI. 219).
To the north of Pangai rises Talau (PI. 121, fig. 3) ; one of the most
characteristic of the elevated points of Vavau; it is a cone of elevated

VAVAU. 199

coralliferoiis limestone,^ reaching a height of over 400 feet, the terraces
of which are distinct on all sides, except where it connects with the
mainland immediately to the west of Neiafu, the principal village of the
group. The terraces in the hills to the west of Teleki are also remarkably
distinct.

At Neiafu the cliffs have been disintegrated so as to leave a mass of
debris at the base. This in its turn has generally been clianged into short
reaches of coral sand beaches, but the sand beaches throughout Vavau are
few in number, and small, except in the stretch lying eastward of Neiafu
Harbor, in the long arm of the sea which starts at tlie base of Talau
and reaches the eastern face of Pangai (PI. 219). The cliffs are cut back
to the second or third terraces, and their slopes covered with large trees.
An immense amount of red earth is found on the levels of nearly all the
terraces, and constitutes one of the striking features of the main island
of Vavau to the north of Neiafu, all the way to Holonga on the north
.shore (PL 124. fig. 2).

There are no well-marked reef platforms on the sides of the deep channel
which winds its way towards Neiafu Harbor through the islands scattered over
the Vavau Plateau (Pis. 121, fig. 3 ; 122, fig. 2 ; 219) . To the south of the
village of Neiafu, the first terrace is very distinct; it is undercut and
as in this narrow arm the sea is smooth, it slopes gently into deep water
(Pis. 121, fig. 3; 219). Masses of coral, mainly Millepores, and Poritcs,
are found in large blocks down to a depth of five fathoms. At that depth
the heads become smaller, and large lanes of sand encroach between them ;
beyond that depth everything is coral sand. The cliffs of Vavau are com-
posed of elevated coralliferous limestone ; this is readily disintegr.ated, as is
shown by the multiplicity of canons, cuts, and valleys formed in these cliffs
throughout the Vavau group (Pis. 124, fig. 1 ; 125). When we reach the
southern extremity of the eastern arm of Neiafu harbor, we find a pretty
narrow gap (Pis. 123, 219), bare at low tide, separating it from Pangai Motu,
formino; the communication of this inland arm of the sea with the immense
reef Hat forming the eastern face of the Vavau group. This gap (Alianga

' Lister considers Talau an atoll similar to Kotu. It seems to me the so-called lagoon of Kotu
sliould be regarded as a sink.

200

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Passage) is a canon cut through the limestone rocks, deeply undercut on
one side, the sides of which are perhaps 200 feet high (Pis. 123, 219).

The vegetation which comes down to the water's edge on the faces of
this deep inlet of Neiafu is very luxuriant (PI. 123). In every direction
are large trees covered with vines, and the vegetation is perhaps as fine
as any we have seen in the Southern Pacific. The canons in Vavau
resemble those of Ngillangillah in Fiji, only they are on a much larger scale.
The vertical cliffs of the sound to the south of Neiafu, and all the cliffs we
have examined, are full of caverns indicating former lines of sea level. The

caverns near low-water mark are used by
the natives as boat-houses. The excellent
chart of Vavau,^ from the surveys of Cap-
tain Field, gives us the means not only
of following the changes which have
taken place in the topography of the
group, but also of tracing the manner in
which they have been brought about
(PI. 219). The bars and islands indicate
-s^ '< old connections, and are now represented
by reef flats. The cuts which have been
\. .| made across the narrow parts of the land,
like the cut at the south end of Neiafu
harbor, are due to the gradual wearing
away of the original land (PI. 219).

It is interestinof to note the similaritv of the results of denudation and
erosion of Nomuka and of Vavau. The sinks of Hunga, of Ano (PI. 219),
are similar to the sink of Nomuka. The horseshoe-shape of that island
corresponds to the ridges which enclose the sinks of the former island. A
similar denudation and erosion, together with the solution and disintegration
of the enclosed limestone, only carried on on a larger scale, gives us the
explanation of the formation of such basins as those to the south of Tofoa,
to that of Nua Papu, to the sink separating Pangai and Otungake (PI. 219),
to the bays south of Pangai, the dry sink to the north of Koloa, the

1 A Chart 3098.

Entrance to Cave, Vavau.

VAVAU. 201

impounded sink back of Tulie, the sounds on the two sides of Makave Spit,
the tongue of Vaipuua, and the extensive sink to the north of Teleki,
opposite Talau (PI. 219). We may thus account for the numberless fiords,
cuts, gaps, and inlets which characterize the southern part of Vavau
(PI. 219) ; of course, much of the material has been carried off in solution.
We have in the first place brackish lakes, like Ano, which, little by little,
have been changed into sounds like that north of Teleki (PI. 219), open-
ing more and more to the sea, until finally they become mere bights of
greater or less depth, according as solution and denudation have been
carried for a greater or less length of time.

When denudation and submarine erosion have taken place to a consider-
able extent, as on the east face of Vavau, we have a complicated series
of banks, flats, islands, bars, and islets (PI. 219). Lalalolomei Bank, and the
cluster of Hakaufussi, are remnants of land ridges and summits which have
been elevated along the eastern face of the Vavau group, and culminate in
the high land forming the island of Vavau (PI. 219), and its extension
south on the high islands of Hunga and Nua Papu. North of Euakafa
Island there is a perfect labyrinth of islands and islets, some of which are
of considerable size and height.

Vavau occupies the greater part of the northern extremity of the Vavau
Bank. We crossed over to the north end of the island of Vavau with Dr.
Hansen. Immediately behind Neiafu there is a gradual rise to the top of
the third terrace, on which the road runs as far as Feletoa, then rises again
to Holanga on the north shore, about eight miles distant. A magnificent
vegetation covers this sloping land, which rises gradually from the upper
level of the first terrace ; the whole of this is nearly denuded, a gentle and
uniform slope extends over the greater part of the first and second terraces.
The soil of this part of Vavau is vary fertile ; it consists mainly of the red
earth so characteristic of the decomposition of coralliferous limestone. On
the summit of the bluffs of the north shore (PI. 124, fig. 2), at Holanga, at
a height of 500 feet, we collected a number of fossils. Very few outcrops
of limestone are met with on the way.

A number of living corals were collected in the sound of Neiafu, Porites,
Pavonia, Madrepores, Goniastrea, Millepores, and a number of Gorgonians.

202 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

We also found living amon<^ the corals a number of specimens of Centro-
stephanus. Dr. Mayer examined Talau to the west of Neiafu Village, and
collected a number of fossils at the different points. The summit varied
in height from 380 to 425 feet. At the base of the upper cliff the height
is about 325 feet. The top of the third terrace is probably 200 feet, the
base of the second is about 100, and the summit of the second terrace,
immediately to the west of Neiafu, half-way between it and the Talau, is
perhaps 40 to 50 feet higher. The rock at the top of Talau is a hard,
reddish-colored crystalline limestone, very much altered by weathering, and
is not fossiliferous, but fossils were collected on all the other terraces.

On our way out from Vavau, we passed by the village of Teleki, where
there is an immense sink of fresh water (PI. 219), overgrown with all kinds
of lacustrine vegetation. The terraces to the west and south of Teleki are
very apparent (PI. 122, fig. 1); the top of the third terrace forms an espe-
cially well-marked line on many islands. Some of the islands on the south-
eastern part of the Vavau Plateau show indications of the second, third, and
perhaps the fourth terrace, but the line of the third terrace is the most
characteristic of all. Looking eastward between the islands of Kapa and
Pangai, we see a nutnber of small islands and islets with vertical faces
looming up in the space between tlxem and the eastern edge of the outer
reef (PI. 120, fig. 1).

As we steamed past Hunga (PI. 219), we could distinctly see the stratifi-
cation of some of the limestone strata, which suggested an ceolian origin for
those beds. This a?olian limestone probably formed only a belt, blown in
between more solid cliffs of limestone, as both to the north and to the south
the cliffs resemble, in every respect, those of other parts of the Vavau
group. At the base of the geolian cliff we could trace a coral sand beach
extending as far as a gap in the uplifted limestone to the south. The ver-
tical cliffs of Hunga are deeply undercut and full of diminutive caverns;
the island slopes in an easterly direction. To the south of Hunga, the
Lsland of Fofoa also slopes to the eastward. It is flanked on the west by
low vertical cliffs of coralliferous limestone, with here and there a low sand
beach. Still farther south, the most southwesterly of the islands of Vavau
rise in sharp weathered peaks .above low vertical cliffs, and form the last

VAVAU.

20c

barrier which separates the Vavau group from the Haapai group to the south
(PI. 219).

It would seem as if the Vavau Plateau attained its greatest elevation on
the western fiice of Vavau ; its terraces, as well as those of all the islands,
slope decidedly towards the east. On the east face of Vavau extend wide
reef flats ; on the outer edges, both the eastern and the western, exist high
islands, and islets ; sand-bars, patches, and foul ground indicate the extent
of denudation and erosion which has taken place over the former Vavau
land.

The general depth of the northern part of Vavau Bank varies from 20
to 60 fathoms, and falls off steeply into deeper water on the west side, close
to the 100-fathom line. The bank is somewhat shoaler on its eastern face.
The soundings are so irregular that it is impossible to state, except in a
general way, that the bank is sloping to the west, while the land seems
sloping to the eastward. About half-way between Vavau and the Samoan
Islands is situated Niuatobutabu, the highest point of which is 350 feet ;
it is an elevated coralliferous island, connected with the northern part of the
Tonga group by a ridge the deepest part of which is about 1100 fathoms;
the ridge slopes rapidly to the east into deep water ranging from 2500 to
over 4500 fathoms.^

1 A. Chiirt 29;i5.

Pylstaart Island.

204 "ALBATROSS" TROPICAL PACIFIC EXPEDITION'.

THE FIJI ISLANDS.

Plates 126-128 ; 220.

The Fiji Islands^ are among the most interesting groups for the study of
coral islands and reefs, owing to the great variety in the conditions under
which coral reefs occur there, their accessibility, and the admirable charts
of the group which have been published by the English Admiralty. The
dimensions of Viti Levu and of Vanua Levu, the great heio-ht of the two
main islands, and their position in the. region of the trades, are such as to
give us almost continental conditions for the formation of great barrier
reefs. The rivers which x-adiate from the central part of Viti Levu (PI. 220),
the Rewa (PI. 128, fig. 1), the Singatoke,^ the Ba (PI. 128, fig. 2), bring vast
bodies of water to the sea, and are in marked contrast to the rivers of other
Pacific islands, even of such islands as Tahiti, where the streams, although
constant, are torrents.

The coral reefs of such volcanic groups as Fiji, the Society, the Sandwich,
the Samoan, and other islands, are in marked conti'ast with the coral reefs
of such groups as the Paumotus, the EUice, Gilbert, and Marshall Islands,
where the rehandled reef rock material plays the principal part in shaping
the physiognomy of the islands.

Reaching the Lau group in Fiji from the windward side, we had a far
better opportunity of seeing the terraces of Yangasa, coming from the
northeast, than on a former visit '^ when we examined the group from the
west. We also had the advantage of greater experience in detecting
traces of terraces, which are indistinct in Fiji compared to their sharp
delineation in Nine, the Tongas, and the Paumotus. Yangasa Levu, seen
from the passage south of Na Potu, is hat-shaped, flat-topped, and when
seen from the south, three of its terraces are plainly marked. The smaller
island of Navutuiloma is also terraced, but less distinctly than Yangasa

1 l'"cir an atcount of older and recent explorations of the Fiji Islands, see J. D. Dana, Corals and
Coral Islands, 3d ed. ; Dana, (ieology of the U. S. Ex. Ex.; Seeman, Flora VitiensLs ; Agassiz, Am. Jonr.
of Science, Vol. V., p. 113 (February, 1898); J. S. Gardiner, Proc. Camb. Phil. Soc., Vol. IX.. \^^. viii.,
p. 457 (1898) ; A. Agassiz, Bull. M. C. Z., XXXIII. (1899) ; E. C. Andrews, Bull. M. C. Z., XXXVIII.
(1900); Geol. Ser. V., No. 1.

2 Bull. M. C. Z., XXXVIII. PI. 3'.

3 The Islands and Coral Reefs of Fiji, Alexander Agassiz, Bull. M. C. Z., XXXIII. (1899).

THE FIJI ISLANDS. 205

Levu. To the north the terraces of Karoni could also be seen. Passing
Fiilanu-a, we thought we could detect the traces of three terraces, with
Quoin Hill rising from the remnant of the third terrace. We passed
Marambo, where there are indications of three terraces, and Wangava,
where the top of the third terrace forms the long slightly dished top of
the island, flanked on all sides by two lower terraces.

While passing through the Fiji Islands we added a number of inter-
esting photographs of Suva and of the main island, which had not been
successfully taken during our previous visit ; among them a view of the strati-
fied soapstone beds, and a general view of the scenery of the soapstone area
back of Walu Bay. We also took a number of photographs at the mouth of
the Rewa, and a few interesting views in the interior towards the head
waters of the Rewa.

After leaving Suva we pa.ssed Nuku Muasanga on the east. Both the
northern and eastern sides were flanked with beach rock and by accumida-
tions of coral sand presenting tlie same appearance as when seen from the
west. We passed Ngele Levu and Taulalia near enough to get an excellent
view of its peculiar conical erosion. The small caiions of the group repre-
sent the immense amount of erosion and denudation which have taken place
over the old land of Ngele Levu. We steamed past this group on a
different side from that we had examined before, but found nothing differ-
ent on the north or on the east from what we had observed on our former
visit, when leaving the lagoon through the western pass, or skirting the
southern shore.

Fiji Canok, Suva.

206 "ALBATHOSS" TROPICAL PACIFIC EXPEDITI02f.

Kambara.

Plates IJG, 1J7, 2W.

On opening the south point of Kambara we eonld readily trace
three terraces ; they could also be made out indistinctly on the north
point. We visited Kambara^ in order to examine again the basin or sink
of the island. We ascended the volcanic cone rising to the south of
Tokalau Village, to a iieight of about 470 feet, and which forms the most
prominent object of Kambara. The cone has burst through the outer
rim of elevated coralliferous limestone (Pis. 126, 127) ; it rises nearly 150
feet higher than any other part of the rim of the central basin of Kambara.
It was veiy evident that this basin is a basin of erosion, and not the basin
of an elevated atoll (Pis. 126, fig. 2; 127, fig. 1). It must have formed
like other sounds we have described in Fiji, like those of Fulanga, of
Yangasa, of Ongea, of Namuka, Wangava," and many others. One of the
gaps which formerly gave access to the sea to the old sink, or formed an
outlet to the sound once occupying the centre of the island, can still be
distinguished immediately behind the village of Tokalau (PI. 127, fig. 2),
and others at one or two points on the eastern and on the southwestern
rim of the sink of Kambara. In fact, as we have shown in a former
report on the Fiji Islands,'^ I consider Naiau and Tuvutha, as well as the
i.slands we have just mentioned, to be merely elevated j^lfiteaus, or
irregular masses of coralliferous limestone, or plateaus with incipient
sounds, which have also been denuded and eroded by atmospheric agencies
to form sinks imitating to a certain extent the elevated lagoon of an atoll.
It is evident that an elevated lagoon would be far deeper than the sinks

I A. Chart 441.

'^ The top of Wangava shows a slight depression ; as seen from the top of the volcanic conu of Kam-
bara it appears like a hat, the broad brim of which is the reef platform, surrounding the island on all
sides (PI. 127), with a shallow sink formed b_v the outer edges of the rim. At first sight Wangava
appears to be an elevated atoll, vet on comparing the sinks of Kambara and Wangava with the sounds
and lagoons, the formation of which has been so carefully traced in many of the Fiji Islands, there is no
reason to consider such islands as Wangava, Kambara, Naiau, Tuvutha, as other than elevated plateaus
at different stages in the formation of sounds, the sinks of which have been denuded and eroded after
their elevation or during its process.

3 Bull. M. C. Z., XXXIII., 1899, p. 52.

KAMBAEA. 207

thus formed ; that it would have precipitous sides, leading from the outer
rim toward the deepest parts of the basin, and not the . gentle slopes
characteristic of the basins of Kambara, of Mango, and of other so-called
elevated atollis.

The gap to the south of Tokalau shows plainly that the sound
(PI. 127, fig. 2), which existed at the time when it communicated with the
sea, was eroded much in the same way as were the sounds of Fulanga, or
of Mango, or of Namuka.^ The diminutive sound formed on the southern
part of Ongea opens out into a valley which extends far inland towards the
northern extremity of the larger island of the atoll, and thus has been
formed an area of denudation in the interior of Ongea, very similar to
that of Eua, only on a much smaller scale. Similarly the topography of
Thithia, Tuvutha, of Wangava and other islands, clearly indicates that
submarine erosion, as well as solution and denudation, has been the
principal factor in shaping their topography, and that the lagoons of the
so-called elevated atolls are merely sinks, such as are common in all lime-
stone districts.^

The basin of Kambara, as seen from the top of its volcanic cone, is not
deep ; the greatest difference of level between the bottom of the sink and
the top of the volcanic hill is not more than 250 feet. The limestone rim
which forms the edge of that basin is of very varying height (Pis. 126; 127,
fig. 1) ; at some points it can hardly be more than fifty feet above the
level of the bottom. It is very evident that during its elevation there
has been connection between the sink and the sea through the lower parts
of the rim, or through some of the gaps which have been cut, probably at
a time but little antedating the present, and have given an outlet to the
drainage of that basin. The volcanic outburst has carried up on its sides
part of the limestone rim, as large masses and fragments of limestone were
picked up over the volcanic slopes. At the very top of the hill a calcareous
ridge still exists, the remnant of the edge of the limestone basin which has
been broken into by the volcanic outbiu-st. The bottom of the basin is per-
haps from 75 to 100 feet below the highest point of the calcareous rim ; it

1 Bull. M. C. Z., XXXriI.. 1K99, Pis. 20. 22.

"- Hill, R. T., Geology of Jamaica, PI. IX. fig. 2, Bull. M. C. Z., XXXIV., 1899.

208 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

has in no way the appearance of the bottom of a lagoon, — at any rate, not of
such higoons as we now find in the atolls of the Paumotns, Ellice, Gilbert,
or Marshall groups. Judging from the soundings, if one of these atolls
were to be elevated, the bottom would be almost flat, and rise very rapidly
towards the outer edge to the rim. This is not the case with the basin
forming the elevated sink of Kambara, or of any of the so-called elevated
atolls. The slopes from the outer edges to the middle of the sink appear
to be gentle slopes of denudation, and here and there are huge spurs
running out as buttresses on the flanks of the rim, — a very different
structure from that found in any atoll we have examined, and to be
accounted for only by the difference in the degree of denudation and
erosion of the coralliferous limestone in different parts of the basin (PI.
126, fig. 1). These buttre.sses are covered with thick vegetation, and are in
marked contrast with the bare slopes of the volcanic cone on the western
face of Kambara. The limestone slopes of the outer edge of the rim are
both deeply eroded, and the whole surface is covered with pinnacles, with
crevasses, with cuts, and honeycombed in every direction, showing that the
weathering of that part of the i,sland, as well as the weathering of the
limestone fragments left on the slope of the volcanic outburst, has been
going on for a long period of time. Even if this sink represented the
remnant of an old lagoon, denudation has gone on long enough to alter
its shape radically, and to give it its present topography, — a very different
one from what it would have were it the bottom of the lagoon of an atoll
raised above the level of the .sea. The top of the limestone cliffs probably
forms the third terrace. The resemblance of the volcanic cone of Kambara
to Quoin Hill at Fulanga is striking ; both these hills have undoubtedly
been prominent factors in the formation of the characteristic topographical
features of Fulanga and of Kambara. They have broken through the
original limestone area and have formed, in this way, a more or less
incomplete sound, having probably here and there access to the sea. The
sea once having gained access to the interior of the limestone area began
its work of erosion and of disintegration, a process which was further
assisted by the large rainfall, and has helped to carry off, in solution or
in suspension, the limestone composing the elevated areas. Thus was left

KAMBAEA. 209

a sink of greater or less depth, according to the length of time during
which these processes had been going on. The plateau of both Kainbara
and Fulanga runs very rapidly into deep water. The characteristic outline
of hat-shaped islands like Wangava is due to the formation of a wide reef
platform by submarine erosion and denudation.

14

210 "ALBATEOSS" TROPICAL TACIFIC EXPEDITION.

THE ELLICE ISLANDS.

Plates 129-137 ; £12, figs. OS ,- 321, m2 ; 2^, fig- 1.

The Ellice Islands^ extend in a northwesterly direction for nearly 360
miles (PI. 221). The group is composed of tlie large atolls of Funafuti (PI.
222)- and Nukufetau (PI. 212, fig. 6), and of seven smaller ones, Nukulailai,
Vaitupu, Niu, Niutao, Nanomana, Nanomea,^ and the island of Nurakita
(PI. 212, fig. 8), the southernmost of the group ; Nanomana, like Niutao
(PI. 212, fig. 7), is a flat island having no lagoon, a shallow brackish sink
occupying a part of the islands.

On our way to Funafuti we stopped at Nurakita ; we also examined
Nukufetau. I was, of course, greatly interested in my visit at Funafuti,
where a boring had been made under the direction of a committee of the
Royal Society, in charge of Professor David, of Sydney, after the first'
attempt under Professor Sollas failed. The second boring reached a depth
of 1114 feet. This is not the place to discuss the bearing of the work done
at Funafuti, as, beyond the fact of the depth reached, we have as yet no
final statement by the Committee of the interpretation put upon the
detailed examination of the core obtained, and now in the hands of Pro-
fessor Judd and his assistants.

Nurakita

Plates 129, fig. 1; 212, fig. 8; 221.

The first island of the Ellice Group we made was Nurakita; it is a
low flat island with a high beach (PI. 129, fig. 1), somewhat triangu-
lar in shape (PI. 212, fig. 8), about a mile long and one half to three
fourths of a mile wide. The high beach is topped by a wide belt of low
bushes, beyond which cocoanut trees and other forest trees stand out. The
island is surrounded by a broad reef flat forming a fringing reef.

1 A. Charts 766, 987, 29S3. - Ibid., 2983. ? Ibid., 766, 987.

NURAKITA. 211

The soutliera face of Nurakita is covered with large blocks of beach rock,
alternating with steep coral sand and coral shingle beaches. The beaches
have been driven inland, running in as long fingers between the low scrub
vegetation which borders the summit of the beach and even extending as
far as the trunks of the cocoanut trees which grow on the inner face of the
outer belt of bushes. On the southwest side we noticed a few very large
boulders of beach rock and one or two blocks resembling old coralliferous
limestone, but in general the boulders were composed of beach rock.

The approaches to the island are rather shallow ; a mile off we could
readily see bottom, and detect extensive patches of corals scattered between
stretches of coral sand at a depth of from sixteen to eighteen fathoms. A
wide flat extends around the island ; the only channels which make land-
ing possible occur between masses of beach rock on the outer edge of the
beach. A sort of secondary fringing barrier reef is found on the north
point where a small platform of shingle has been thrown up on the outer
edge of the reef flat, which must be from 150 to 200 feet distant from
the beach.

On the south point a similar lagoon has been formed on the reef flat
platform, the outer rounded rim of which is edged by masses of Pocilli-
pores and of Null! pores, from two to three feet above low-water mark.
The edge of the outer rim is deeply gouged, and forms small channels in
whicli access can be had to the reef platform at low water. Both on the
east and on the north side, the beach is steep, is at least eight to nine feet
high, covered with coarse coral shingle extending to the edge of the outer
belt of bushes. . The interior of the i.sland forms a shallow dish surrounded
by high steep beaches which have been thrown up on the outer periphery
of the island. The island has no lagoon.

We did not visit Nukulailai;' judging from the chart, it presents no
characteristics different from those of Nukufetau or Funafuti, both of
which we examined.

1 A. Chart 766.

212 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Funafuti.

Plates 129, fig. l; 130-137, 221, 222; 224-, fig. 1.

Funafuti,^ the next island of the Ellice group we visited, is about thir-
teen and a half miles in a north and south direction, with an extreme
breadth of ten miles. As seen from the sea, it looked like one of the large
Paumotu atolls (PI. 222), the land rim formed by a series of narrow islands
of different sizes flanked by a belt of low vegetation, in.side of which grow
groups of cocoanuts ; on the east face of the atoll along which we were
steaming (PI. 222), the islands and islets are .separated by gaps of variable
width. At the .southern horn of Funafuti, the reef flat is covered by huge
boulders and reaches of beach rock and coral breccia with coarse shingle
above them. The land rim of the atoll of Funafuti is even narrower than
in most of the atolls of the Paumotus (PI. 222).

The land rim of the island of Funafuti is extremely narrow, with the
exception of the slight expansion which takes place back of Fongafale at
the east point of the island (Pis. 222 ; 224, fig. 1). The photographs here
published (Pis. 129, fig. 4; 130, 131) show in succession the characteristic
features of the eastern face of the atoll of Funafuti ; first Motungie and
Motuloa Island (PI. 129, fig. 4), at the southern extremity of the atoll, next
the sea face between the islands of Telele and Funafara (PI. 130, fig. 1)
showing the wide gap with an islet in the middle. The gap separating
these two islands is covered with beach rock and shingle ; further in towards
the lagoon they are separated by a broad stretch of coral sand which fills
the greater part of the shallow lagoon of the southern horn of Funafuti
(PI. 222). The extremities of the two islands extend towards the lagoon
nearly at right angles to the outer reef flat (PI. 222), and from the centre of
the gap huge sand bars run towards the lagoon. A similar gap is next
shown between the islands of Funafara and Lua motu (PI. 130, fig. 2) ; then
comes the gap between Lua motu and Mateika (PI. 130, fig. 3).

North of the extremity of Mateika there is a break of nearly three miles
in the continuity of the encircling reef, the island of Falefatu alone

1 A. Chart 2983.

FUNAFUTI. 213

dividing the two wide ship channels on the eastern face of Funafuti, south
of Funamanu (Pis. 130, fig. 4 ; 222). From that island the encircling reef
is again continuous as far as the northern entrance to the atoll of Funafuti.
By far the greater extent of that part of the narrow eastern land rim is
occupied by the island of Funafuti (Pis. 131, fig. 1 ; 222), it forms an
inverted L, the smaller shank of which occupies the easternmost horn of
the atoll (Pis. 222; 224, fig. 1). To the south of Funafuti are Funamana,
Funangongo, and Fatato (PI. 222), all .separated by wide shallow gaps, while
to the north of Funafuti come Tengako separated from it by a dry gap
(PI. 133, fig. 2), next Amatuku (PL 131, fig. 2), and Mulitefala (PI. 131, fig. 2),
the former separated by a wide gap from Tengako. Between Mulitefala and
the islets to the east of the northern entrance to Funafuti (PI. 131, fig. 4)
there is a i-each of reef nearly three miles in length, not quite bare at low
water (PI. 222). With the exception of Tebuka the islands on the northern
and western face of the atoll are few in number and quite insignificant
(PI. 222). There are in the western face several passages (deeper gaps)
between parts of the wide encircling reef on the western side of Funafuti.
At nearly all the passages the reef flats extend a considerable distance into
the lao;oon at right angles to the reef face.

At the south point of Funafuti Island there is a gap between it and
Fatato, the island to the south of it, over which the sea is breaking with
great violence. Following the eastern face of the atoll along Funafuti
and Tengako Island, we come upon short stretches of coral sand beaches
separated by steep coarse coral .shingle beaches with cocoanuts growing to
the very edge of the .shingle (Pis. 132, fig. 2 ; 133). The belt of bushes is
narrow. Coral breccia crops out at the foot of the beach (Pis. 132, fig. 2 ;
135, fig. 2) ; this is flanked by the narrow reef platform where the coral
breccia is in place (Pi. 136, fig.l). Tlie coral breccia crops out on the outer
edge of the reef platform ; it is covered with huge knolls of Nullipores and
Pocillipores. Huge boulders of coral breccia and coral shingle in all
possible stages of disintegration (PI. 136, fig. 2) are scattered over the
reef platform.

The sea must encroach more or less on the southern part of the eastern
face of Funamanu, as we found the cocoanuts overhanging the beach, and

214 "ALBATROSS" TROPICAL PACIFIC EXPEDITIOX.

many of them on the edge of the water. Pandanus appear in Funamanu ;
the}' seem to be very common to the north on all the islands of the land
rim of Funafuti.

Skirting along the east coast of the island, after passing the eastern
point of Funafuti Island, we came upon a narrow gap (Pi. 133, fig. 2) which
separates Funafuti from Tengako, and is marked on the chart " pile of
stones " ; the gap is flanked on each side by extensive ridges of coral breccia
(Pis. 134, fig. 2; 135, fig. 1 ; 136, fig. 2). The beach of the east coast of
Funafuti is exceedingly steep and covered with large coarse coral rock
shingle (PI. 132, fig. 2), topped by the belt of low bushes so characteristic
of the coral islands of the southern Pacific. On the lagoon side of the belt
grow cocoanut trees. Pandanus and other typical atoll trees are found in
great abundance.

The reef platform is quite narrow (Pis. 132, fig. 2; 135, fig. 2; 136,
fig. 1), and the coral breccia which covers it has in a great many instances,
been worn and cut so as to form a shallow sink between the outer raised
edge of the reef platform and the base of the shhigle beach (Pis. 132, fig. 2 ;
135, fig. 2). The remnants of this breccia, which once rose to a greater
height than it does at present, occur as buttresses, running at right angles
to the base of the beach, near its foot, to a height of from two to five feet
(Pis. 135, fig. 2 ; 136, fig. 1). The base of the buttresses is separated by
ridges of coral shingle (PI. 132, fig. 2), or in some cases by coarse coral
sand. The outer edge of the reef flat rises from two to three feet above the
level of the inner part of the flat, and thus forms along the east coast of
Funafuti Island a number of extensive pools varying in depth, according
to the depth of the gaps of the outer edge through which the sea may
have access to them. As we opened out the northeast passage into the atoll
of Funafuti (PI. 131, fig. 4), we could see in the distance the sand bar and
island which flank the north side of the passage ; from its southern extremity
extends a bar of shingle more or less marked.

Turning into the northeast passage, we see in the distance the small
islands, islets and sand bars on the northern and northwestern side of the
atoll (PI. 222). Some of these islets are tufted with cocoanut trees, others
are bare, and others are thickly covered with a belt of low bushes and tall

FUNAFUTI. 215

cocoanut trees. The sea faces of these islands are flanked with lines of
breccia separated by coral shingle beaches. A long line of breakers indi-
cates the position of the outer edge of the reef platform upon which these
islands are all situated. On the lagoon side of the islands the beaches are
covered with coral and coralline sand (PI. 132, fig. 1), and only here and
there a small border of coral breccia is seen.

The small sand key of Te Afualiku (PI. 131, fig. 4) at the northeast
entrance of Funafuti atoll has a steep sand beach flanked at the base
with breccia and coral shingle ; it is topped with five low cocoanut trees.
Steaming in slowly through the northeastern entrance, we could see, on the
bottom of the passage, the masses of corals separated in the deeper part by
wide patches of sand. As we were coming in, we could see in the distance
on the west face, the islands of Fualopa and Tebuka, and the sand bars and
reef flats to the south (PI. 222). The lagoon faces of the island, as well as
the small sand key ' in the northern part of the atoll; are flanked with steep
sand beaches. Turning towards the anchorage, we steamed along ofl" the
lagoon beach of the island of Funafuti ; the lagoon beach consists of a
succession of sand beaches alternating with short buttresses of coral breccia,
extendiuff as far as the village of Fono;afale.

With our pilot as a guide, we examined the position of the second bore
hole drilled under the direction of Professor David. It is situated in a sink
west of the weather beach in the midst of a coral breccia. At that point the
outer rim of the reef platform consists of knolls of Pocillipores and of Nulli-
pores rising, to a height of from two to three feet above the general level
of the reef flat extending between it and the base of the beach (Pis. 132,
fig. 2; 135, fig. 2; 136, fig. 1). The reef flat varies from forty to 'fifty
yards in width. The outer edge is deeply gouged with passages cut by the
action of the sea, or where the sea has broken through the elevated rim
of the platform. The flat between the outer rim and the base of the beach
consists of coral breccia, planed down to the level of low-water mark or
even below it ; it is slightly dished, so as to foi-m a very shallow lagoon at
low water, flanked by an incipient barrier reef, as it were, formed by the

^ While there are many shoals and submerged patches in the lagoon of Funafuti, Te akau Tuluaga
(PI. 222) is the only dry patch in the interior of the lagoon.

216

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

constantly growing Nullipores of the outer rim. Towards the base of the
coral shingle beach, occasional buttresses of coral breccia rise to a height
of two to three feet or more, outliers showing the former height of the
elevated reef platform. The beach itself is formed of fragments of coral
breccia and of recent corals, thrown up on the steep slope of the beach to a
height of eight to ten feet above high-water mark, or left as outliers of the
disintegration of a former higher reef platform. This coral shingle forms a
dam from twenty to seventy feet in width (Pis. 132, fig. 2; 135, fig. 2), on

Position of the Bore. Funafuti.

the top of which grows the narrow belt of low vegetation which flanks the
cocoanut trees growing towai'ds the lagoon. The inner slope towards the
lagoon is much less steep than the outer slope, it is formed of similar frag-
ments of coral and of breccia, only of a less size, though occasionally huge
boulders have been thrown inland by hurricanes over the upper edge of the
shingle dam, or are outliers of the older buttresses.

The lagoon beach only rises three to four feet above high-water mark ;
it consists almost entirely of comminuted coralline foraminiferal sand with
little admixture of coral sand which has been laid down on a steep slope
towards the lagoon (PI. 132, fig. 1). The coral breccia seen on the outer

FUNAFUTI. 217

slope of the sea face seems to extend to a considerable depth, judging from
the buttresses exposed on the reef fiat. The coral breccia is made up of
rolled recent coral shingle, of pieces of coral, of shells, of sand, quite unlike
any breccia we have seen before, and partly changed into a hard ringing
limestone. Here and there I thought I could detect fragments of the old
limestone ledge ; of this I am not positive, it being very difficult in some
cases to detect the difference between the old ledge and the highly calcified
recent breccia, we were unable to find any outcrop of this old corallifer-
ous limestone at any point in Funafuti. The reef flat has been gouged
from the coral breccia exactly as has the old reef rock ledge in the
Paumotus. It supplies the materials for the building up of the island, of
the sand and of the shingle beaches, both on the lagoon and on the sea face.

On the sea face, to the south of the bore, extends a high narrow
shingle beach which shuts off a small lagoon to the west (Pis. 222 ; 224,
fig. 1). This lagoon, called Taiisale, forms an isolated pear-shaped pond in
which the tide rises and falls (PI. 137). The inner edge is lined by man-
groves (PI. 137, figs. 1, 2) ; a fine section of the coral breccia, which char-
acterizes the outer sea dam, can be seen on the western face of the
lagoon (PI. 137, fig. 3). The narrow high beach thrown up across the
eastern point of Funafuti has shut off this pond from the sea ; huge blocks
of shingle of beach rock and of coral breccia have been thrown up on the
upper part of the outer dam. According to the testimony of the natives, no
water passes over this dam ; but the dam itself must be of rather hollow
construction, and the floor of the sink must be full of cavities to allow the
existing free inflow and outflow of the sea. There is a narrow fringe of
pisonias growing on the summit of this bank.

The gap between Telele and Funafara Island ' (PI. 222) shows a stage in
the formation of such a sink as the lagoon of Taiisale (PI. 224, fig. 1), pre-
vious to the junction of the inner wings of the extremities of the islands,
and previous to the throwing up of the coral shingle dam shutting off the
bay forming the gap open to the sea. We shall have occasion to describe
the shutting off of similar bays on the sea face of some of the Gilbert and
Marshall Islands, and their change into closed ponds or sinks.

» A. Chart 2983.

218 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The Heliopora reef, described by Sollas as occupying the floor of Taiisale,^
exists under conditions very simihir to those of extensive Porites and Mille-
pora reefs, which I shall liave occasion to refer to in my description of
some of the Gilbert and Marshall Islands, more especially when giving an
account of the Millepora and Porites reefs of Taritari.

The surface rock of the land rim of Funafuti consists of innumerable
small fragments of coral and of coral breccia, more or less decomposed into
soil. On the lagoon side, on the north end of the island of Funafuti,
nothing but reaches of coral breccia, more or less disintegrated, could be
seen, with short stretches of coral sand beaches separating them. South of
the monument of Funafuti there is an extensive dry sink in the centre of
the island. This is the southern extension of the same sink which one
crosses going from the village to the bore.

Dr. Mayer examined the coral breccia, the beach rock, and the con-
glomerate existing towards the southern point of Funafuti Island, where
a line of low coral breccia cliffs and an extensive coral sand beach ter-
minates to the south against steep buttresses, and alternates with ridges of
coral breccia. He found on the lagoon side a conglomerate composed of
rounded water-worn masses of hard crystalline limestone, cemented together
with fragments of shell and of sand. This rock extends only about one
foot above high-water level, and to the eastward or inland, back of the
beach, one finds a mass of coral heads, and more or less rounded masses of a
somewhat crystalline structure. These masses and fragments of coral rock
or shingle are not cemented together, but plainly show that they are derived
from tlie disintegration of the adjoining crystalline limestone masses of coral
conglomerate, of which only a few outliers are left intact. As at other points
of Funafuti, these outliers of beach rock, of coral breccia and conglomerate
are, on the lagoon side, separated by long stretches of fine coral sand
beaches, while on the sea face of the southern part of the island, as else-
where in Funafuti, we found but little coral sand, the steep beach being
composed almost entirely of broken fragments of crystalline limestone, many
of them water-worn and rounded as on the lagoon side, but most of them
are large masses of jagged rock, evidently thrown up by unusually powerful

' Page 510, fig., Proc. R. S., February, 1897.

FUNAFUTI. 219

waves, or fragments of outliers of old buttresses or of a higher older reef
platform. These various kinds of fragments, found either on the lagoon
side or on the outer beach, form what is called the coral breccia or con-
glomerate of the seaward side (Pis. 132, fig. 2 ; 133, fig. 2 ; 134, fig. 2 ; 135,
136). There its composition can be more easily studied than on the lagoon
side, where its extension has been overwhelmed in so many places by the fine
sand thrown up on the inner beaches by the waves of the lagoon. On all
the islands with rock exposures, we came upon the hammer marks of
Messrs. Sollas and David. The low gap to the north of the village of
Fongafale is perhaps 60 to 75 feet wide ; it has been formed across
the lagoon shingle beach ; coarse coral sand is found in the middle of the
land rim, and breccia and conglomerate boulders are found on the sea face.

We examined the northern end of the island of Amatuku at a point where
the cliffs are marked on the chart as "five feet high" (PI. 133, fig. 1);
they consist of elevated conglomerate or breccia dipping towards the lagoon.
This gives us the key of the origin of the mass of material which lines the
beaches, the lagoon, the sea faces, and the summit of the land rim, all of which
has been so much disintegrated and decomposed that where no outcrop is
visible it is difficult to understand whence the mass of material which com-
poses the island, the sea faces, the sea beaches, and the land rim itself has
been derived (Pis. 134 ; 135, fig. 1 ; 136, fig. 2). The shallows and the
banks within the lagoon are merely remnants of the great stretch of coral
conglomerate or breccia which once must have covered, at a greater eleva-
tion, nearly the whole area of the atoll of Funafuti. An extraordinary
mass of coar.se broken coral shingle conglomerate and breccia forms the
northern point of Tengako (Pis. 135, fig. 1 ; 136, fig. 2) ; it is flanked by
sand bars on the lagoon side, running at right angles to the line of the
low land rim.

A section across the southern part of Funafuti does not differ from that
across the east point, back of Fongafale, and which is typical for the whole
island, only according to the width of the island, the sink between the outer
beach and the lagoon beach is more or less wide, and the dam on the lagoon
side is often a broad, white flat ridge supporting a luxuriant growth of
cocoanut trees and pisonias. The seaward ridge may be wide or narrow ;

220 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

it is composed of loose coral shingle or of beach rock or coral breccia or
conglomerate, the surface of which has been weathered and pitted and
honeycombed. In addition huge boulders are scattered upon its face, and
a mass of finer coral shingle, more or less disintegrated, has been deposited
on the inland slope between the base of tlie cocoanut trees. The sink
between the lagoon and outer ridges is evidently flooded during the rainy
season, and is left bare during the dry season. The bottom of the sink is
covered with loose blocks and small pieces of coral rock similar to those
of the sea beach, while in other places it is composed of coralliferous
mud, which has evidently been washed down from the side dams during
the rainy season.

On the eastern sea face of the island of Funafuti, we saw everywhere
evidences of an elevation varying from eighteen inches to three or four feet,
judging from the position of the buttresses of beach rock and conglomerate
which characterized that side of the island.

Elevated coral breccia or conglomerate, such as is found at Funafuti, also
occurs in many of the Paumotus, where it has been elevated simultaneously
with the old tertiary coralliferous reef rock. At other points the old reef
rock is not visible, having been overwhelmed with the mass of beach rock or
coral breccia and conglomerate which has been formed between the outliers
of the old tertiary reef rock. On the east face of Amatuku (PL 134) the
elevated conglomerate and breccia rock is well seen ; it extends as a flat
on the sea face of the island about two feet above high-water mark ; it is
pitted and honeycombed and greatly eroded. The lowest point reached by
erosion shows no trace of the old ledge, but fragments of it form a part of
the conglomerate and coral breccia rock. We have, however, been unable
to satisfy ourselves of its origin. Huge beach rock or breccia or conglomerate
slabs connect the northern part of Tengako (PI. 135, fig. 1) and the island
of Amatuku as well as the little sand islet on the lagoon side of the breccia
exposures. Making up the conglomerate and breccia, were fragments of
worn corals united together in a sort of puddingstone. The spaces between
them were filled in with smaller material like amygdules. Sometimes this
puddingstone was exceedingly hard, at others quite soft and friable, or,
again, it was calcified and rang to the hammer like fragments of the old

FUNAFUTI. 221

coralliferous limestone rocks. The northern extension of Tengako (PI. 135,
fig. 1) is a long sand spit reaching out towards Amatuku.

Some of our photographs show well the method of cutting the elevated
beach breccia and conglomerate along the east face of Funafuti into but-
tresses (Pis. 135, fig. 2 ; 136, fig. 1) and to the level of the reef platform
(PL 132, fig. 2), from the time that it was elevated, four to five or perhaps
even six feet, above low-water mark (Pis. 135, fig. 2 ; 136, fig. 1).

A similar process has gone on on the lagoon side, but at a very inferior rate,
as is shown by the character of the material derived from the disintegra-
tion on the sea face of the breccia or beach rock into very coarse shingle or
even slabs, and on the lagoon side into coral sand of varying fineness. Over
the central part of the land rim more or less fertile land has been formed
from the decomposition of the coral rock. Crossing the centre of the island
to the east of the village, we came upon a magnificent isolated mass of
beach rock conglomerate, showing plainly the extent to which denudation of
the former land rim has taken place on Funafuti, after the slight elevation
to which it had been subjected. It also showed that the position of the
outer beach must at one time have been close to that now occupied by the
present lagoon beach at the northern extremity of Funafuti Island (PI. 133,
fig. 2). At several points in Funafuti, north of the village, beyond the end
of the sand beach, the island shows traces of once having been covered by
a continuous mass of beach rock conglomerate or of its outliers, and of
boulders thrown up by the sea which filled the space between the breccia
buttresses, as at the point marked on the admiralty chart " Pile of stones."

We had no extremely low tides while at Funafuti, and therefore could
obtain only indifferent access to the outer part of the reef platform ; while
we could see that the coral breccia and conglomerate of the reef platform
were cut into spires and buttresses and knolls, and that its outer edo-e was
bordered with knolls of Nullipores and Pocillipores, yet the heavy swell
prevailing during our visit prevented us from examining in detail the outer
edge of the reef fiat or of examining the slope to the seaward on which
corals were growing.

Pava and Fualifeke, two islands to the northeast of the northern pass
(PI. 222), are connected by sand bars and by ledges of beach rock con-

222 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

glomei-ate. Tliej both stand on a comparatively wide platform, with a
narrow land rim towards the sea and towards the lagoon a wide flat, sink-
ing in a comparatively steep slope into the general level of the deepest part
of the lagoon itself.

On the western foce of the atoll, on the island of Tebukn, the beach
rock conglomerate ledge is limited to a small part of tlie northwest side,
where it is found on the very summit of the island, and there is no coarse
shingle on that side. This is pi-obably due to the fact that Tebuka is
situated to the westward of the line of action of the strong trade rollers
which beat incessantly on the eastern reef platform of the atoll of Funafuti,
and lose much of their force northward as the curve of the atoll gradually
trends to the westward.

The channels on the west .side of the atoll, like the pas.sages into the
Paumotus in similar positions, are narrow and deep, and are cut through
the wide western platform on which but few islands or islets are seen.
South of Tebuka there is only Tebuka vili vili and Fualopa, nortli of the
western horn of the atoll, and to the south a couple of small islands to
the north of the chain of i.slands forming the western face of the soutliern
horn of Funafuti atoll. Fuafatu is capped with a belt of low bushes pro-
tecting a few cocoannt trees growing on the eastern side of the island.

The flats and points on the west side of the atoll indicate the former
greater extension of the land rim which has little by little been cut down
to its present dimensions by the incessant action of the sea, of the trades,
and of the weathering due to atmospheric agencies. On the shoals which
extend between our anchorage and the shore, we found magnificent patches
of Madrepores, lai'ge heads of Porites, patches of Alcyonarians, of Millepores,
and of Pocillipores, as well as blocks of Pavonia and masses of Astreans.
The same corals we also found on other shoals in the lagoon. Great patches
of coral flourish on the slope of the lagoon, as well as on the knolls, shoals
and elevated ledges throughout the lagoon of Funafuti (PI. 222). The
corals on the slopes of the knolls flourish especially well when situated near
or opposite gaps connecting the lagoons directly with the sea. In the
lagoon calcareous Algas take a great development in eighteen to twenty
fathoms, immense masses of them extend from tliat depth towards the shore
into three or four fatlioms. ,

FUNAFUTI. 223

The bottom of the lagoon at our anchorage in Funafuti consisted of
fine coral sand and limestone mud, cementing more or less loosely the
larger fragments of corals and of shells, which form a very characteristic
plaster over the whole bottom of the lagoon wherever we had the oppor-
tunity to examine it.

During our stay at Funafuti we recorded the warmest water we observed
during any part of our trip. At noon on the first day of our. arrival, the
temperature of the water at the bottom of the lagoon, at fifteen fathoms,
Wcis 88' and of the air 92°. The next day the temperature of the water
varied between 86" and 87', and at 2 p. m. the day after, the temperature
of the water in the lagoon was 89°, while the air was 94°. The temperature
of the air on the following Sunday had increased to 104 and that of the
water remained at 89° during the day.

" In 1896 ^ Funafuti was selected by a committee of the Royal Society as
being a typical atoll in which to make deep borings, for the purpose of
throwing light upon the geological formation of atolls in general. Attempts
were accordingly made, both on the lagoon side, at about a quarter of a mile
to the southwestward of the Mis.sion House, and also on the edge of the
beach on the seaward side, at about one mile from the western end of the
island ; in both cases the borings had to be abandoned, at depths of 100 and
70 feet respectively, on account of the sand and boulders that were met
with, and the nature of the formation."

In 1897, however, the attempt was resumed by the New South Wales
government, and a depth of 1114 feet was reached (A. Chart 2983, and
Pis. 222 ; 224, fig. 1).

A bore was also driven into the bed of the lagoon from the deck of
H. M. S. " Porpoise" (Captain Sturdee) ; it reached a depth of 144 feet in the
bed rock of the lagoon, or in all 245 feet below sea level.^ It passed through
an upper layer of sand composed mainly of calcareous organisms. Broken
pieces of coral became more common in descending, and at the greatest
depth attained progre.ss was stopped by hard coral rock, at a depth but little
greater than that of the lagoon of many Pacific atolls. The core was placed
for examination in the hands of Professor J. W. Judd.

' Hydrographic Notice, No. 7, for 1897

» T. G. Bonney in " Nature," November U, 1898.

224 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Several accounts regarding the structure of Funafuti have been pub-
lished by Hedley/ Sollas,^ Gardiner,^ David,* and Bonney/ as well as a jiopu-
lar description of the atoll by Mrs. David.*^

Professor Sollas and Mr. Hedley called attention to the evidence of a
slight elevation in Funafuti from the existence of Porites and of Heliopora
at a level where they could only have been reached by high tides. It does
not seem to me as if the mangrove swamp originated in the manner
described by Hedley." I am inclined to refer its formation to the closing
of a bay which probably existed east of Fongafale, much as the gap between
Telele and Funafana at the southern point of the atoll of Funafuti is closing
(PI. 222). This mode of formation of sinks, by the closing of bays, is quite
common throughout the atolls of the Pacific, and many instances will be
found described throughout this Report.

1 agree with Gardiner that the term "hurricane beach" is not an appro-
priate one ; many of the large coral masses wliich have all the appearance
of having been thrown up by the sea are fragments of elevated reef rock
outliers ; the successive more or less concentric ridges of sand and shingle
which form the land rim are not necessarily due to individual hurricanes;
their height and width depend in great part on their distance from the
outer edge of the reef flat, and on the amount of sand and shingle availa-
ble at special points for their gradual formation and increase.

Mr. Hedley gives an excellent account of Funafuti Island and of one of
the leeward islands. He considers the lagoon to be filling up ; it certainly is
receiving material to some extent near the passes and along the lagoon
shore of the land rim ; but so large a lagoon as that of Funafuti is, as he

' General Account of the .^toll of Fun.afuti, by C. Hedley, Australi.an Museum, Sidney, Mem. III.,
1896.

2 Report to the Committee of the Royal Society Appointed to investi<;ate the Structure of a Coral
Reef by Boring, by J. W. Sollas, Proc. R S., February, 1897. .\lso in -Funafuti" : The Study of a
Coral Atoll, Natural Science, January, 1899.

' The Coral Reefs of Funafuti, Rotuma, and Fiji, by J. Stanley Gardiner, Proc. Camb. Phil. Soc ,
IX. Pt. VIII., March, 1898.

* Summary of Professor Edgeworth David's Preliminary Report on the Results of the Borings in
the Atoll of Funafuti, Proc. R. S., December, 1897.

^ Recent Coral Boriu"; Operations at Funafuti, Nature, November 3, 1898.

* Funafuti, by Mrs. Edgeworth David, London, 1899. With a note on the Results of the Borings
at Funafuti, Ellice Group, by Professor T. G. Bonney.

' Loc. cit., p. 11.

FUNAFUTI. 225

says, only very slightly affected by the agencies at work, " which must take
long to make a perceptible advance in so huge a task."

Mr. Hedley has called attention to the shallow passages which interrupt
the thread of the land rim, but not of the reef rim upon which the islets are
placed. These passages I have called "gaps," they are a feature which
occurs in all the Pacific atolls, but the gaps vary in depth from dry depres-
sions above high-water mark to flats bare at low water, to cuts through
the reef platform with variable depth, forming merely boat passages, or
to openings of somewhat greater depths passing into ship passages.

The slope of the bottom on the lagoon face of the passages is stated by
Hedley to extend into it fan-shaped. This is not universally the case, the
shape of the extension, as I have shown in other atolls, depending upon
the width of the shallow passages, their depth, the character of the bottom,
and their exposure to the prevailing winds, all of which are essential factors
in determining the resultant action.

Mr. Hedley has given a list of the plants of the Ellice group,' with inter-
esting remarks on their uses by the natives. He compares the flora of the
western atolls of the Pacific to that of the eastern islands, and finds the
number of species repeated from atoll to atoll increases as we go westward.

In the summary of his observations, Mr. Hedley states that Darwin's
theory is favored as against Murray's by the fact that the atoll is planted on
a cone, that it is girdled by a precipitous submarine cliff, and that the lagoon
is filling up ; whereas Murray demands its excavation. Similar statements
are made by Professor Sollas ; they are mere repetitions of former argu-
ments. In spite of the fact that a lagoon may be filling up at a certain
stage of its development, that does not prevent solution from being an
effective agent in carrying off material from the lagoon of an atoll. Nor is
the existence of a precipitous submarine cliff explicable only on the theory
of subsidence. There certainly are a sufficient number of such cliffs found
in areas of elevation, in no way dependent upon subsidence for their
formation.

The reports of Bonney and of David refer to the progress made in the
boring at Funafuti.

' T.oc. cit., p. 21.
15

226 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Mr. J. Stanley Gardiner has given an excellent account of the general
features of Funafuti, somewhat more in detail than Hedley. The brackish
pools of Funafuti he compares to the " Barachois " of Diego Garcia/ described
by Bourne.' They seem to me to be similar in their structure with the
"bays "and sinks so frequently met with in the Ellice, Gilbert, Marshall
and Maldive Islands, and to owe their origin to the same causes.

Gardiner noticed that some of the slabs thrown up on the slope and reef
flat were consolidated to the rock below them. He gives an excellent
description and figures^ of the outer rim of the reef flat with its fissures and
tongue-like indentations, more or less arched over by the growth of Nulli-
pores across the openings, leading to the formation of blow-holes.* Like
Sollas, he lias noticed that on the lagoon .side the beach sand is not com-
posed of coral sand, but that its principal constituents consist of fragments
of calcareous Algas and Foraminifera.

Gardiner lays great stress, and justly, on the existence of great buttresses
running at right angles to the land rim, which once formed part of a
higher land, the greater part of which has been washed away or dissolved.
Gardiner speaks of the great width of the leeward reef of Funafuti (PI. 222).
He states that with the exception of the shoals, which come nearly to the
surface and are indicated by the breaking of the sea, there are no .shoals
now forming by corals which would eventually grow to the surface. Yet
the Admiralty Chart of Funafuti.^ atoll indicates several patches rising to
a considerable height above the floor of the lagoon. Among them I may
mention that there are more than ten knolls rising to 20 fathoms from the
surrounding depth of 23 to 24 fathoms, a number to 19 flithoms, three to
18, two to 16, two to 15, one to 14, one each to 10 and 11, one to 7, four
to 4, two to 3, and four to 2^ fathoms. These patches constitute a large
percentage of the shoals which have nearly reached the surface and on
which the sea breaks.

I have already, on several occasions, called attention to the narrow bathy-

1 A. Chart 920.

2 Proc. R. S., XLIII. ]i. 440 (1888).
' Loc. cil., Funafuti, p. 4.'!3.

* Gardiner says he nevor found boulders torn off from the NuUipore rim on the reef flat. This has
not been my experience either in the Gilbert or Marshall Islands,
^ A. Chart 2983.

FUNAFUTI. 227

metrical range of corals in the interior of lagoons. Gardiner noticed that
corals grow in abundance on the slopes and summits of shallow slioals, but
were not found on the bottom of the lagoon. It is natural to suppose that
the silt from the shores of the lagoon and from the shoals should settle on
the bottom of the lagoon of Funafuti, so that corals would not grow there,
and that nothing but corallines or Nullipores would flourish in the midst of
that waste. He could find no signs that the lagoon was filling up at any
appreciable rate. He found, as I did, a hard bottom on the floor at many
points in the lagoon. Gardiner insists justly on the prominent part taken
by Nullipores and corallines in building up the thickness of a coral reef,
or its base, or in extending the rim of the reef seaward.

The difference in the width of the outer reef platform of different atolls
may be due to the gradual piling up on the sea face of successive rows of
shingle and sand beaches. Where this has taken place regularly, an original
wide sea face reef flat may gradually become reduced to a narrow belt.^
Well-marked cases of such narrow reef flats are found in the Marshall
and in the Gilbert Islands, and the land growth lagoonward from similar
causes is also well seen in islands of the same groups. That the outer rim
where coral reefs grow expands seaward, is seen on the slope of the
fringing reef off Papiete, Tahiti (PI. 209), as well as along all the sea faces
of islands where the slope is not too steep to allow the formation of a talus
made up of the dead material which has become loosened from the living
part of the coral slopes.

Professor Sollas, in an address before the British Association for the
Advancement of Science, delivered at Bristol, gave an account of Funafuti.
He does not seem to have been aware that several attempts were made
to study coral reefs by boring before the middle of the last century," by
Wilkes, Belcher, and Beechey. Professor Sollas states that an atoll like
Funafuti belongs to a family of atolls of unexceptional character, and that
the atolls of the Gilbert and Marshall Islands belong to a system all of
them excellent atolls. I would refer Professor Sollas to the Hydrographic

1 See also tlie notes of Heilley on the broadening of atoll islets, Natural Science, March, 1898,
p. 174.

2 See Bull. M. C. Z., XXXIII. p. 46 (1S99).

228

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Charts of these groups; they will show more kinds " of excellent atolls"
in these groups than he gives them credit for.

Without entering into a discussion of the permanence of the Pacific
Ocean, we need only state that the components of the great groups of
atolls in the Pacific are generally separated by deep water, and that to
bring up the bulk of the coral islands to the surface would be merely in-
creasing slightly the size of the atoll or island as it exists at present, and
would in no way present a very considerable tract of land in the very
middle of the Pacific Ocean, unless we bring up the bottom of the Pacific
with it to a height of more than 2000 fathoms. We may even be justified
if, in questions relating to the distribution of land in former ages, we are
not carried away by speculations whicli have no more stable foundation
than the ingenious sketching of continents over areas varying in depth

from 2000 to 3000 fathoms.
The statements of Professor
Sollas that the " table moun-
tain" of Chamisso which cov-
ers the summit of Funafuti, is
of a similar nature from base
to summit, and that " all this
is coral reef." is somewhat
premature ; its nature and
structure will be better under-
! stood when we can speculate
upon the data supplied by the
final examination of the core
now in the hands of Professor J. W. Judd. The results obtained thus far
from an examination of the elevated coralliferous limestones of Christmas
Island^ and of Mango' lead to very different conclusions from those expected
by Professor Sollas.

No one has, to my knowledge, called attention to the f\ict that the sound-

-?««•

^^}'^±_^'^^.

Native Hut, Funafuti.

1 A Monograph of Christmas Island, by Charles W. Andrews, Brit. ]\Iiis., 1900.
^ Notes on the Limestones and General Geology of the Fiji Islands, by E. C. Andrews, Bull.
M. C. Z., XXXVIII. No. 1, 1900.

NUKUFETAU. 229

ings taken oflf any of the coral reefs do not indicate the existence of terraces.
Surely, if there has been a general subsidence at all corresponding to the
general elevation which exists in the Paumotus, the Tongas, the Fijis, the
Ellice. Nine, the Cook and Ladrone Islands, the successive steps of which
are indicated by well-marked terraces, we should find in the so-called great
areas of subsidence traces of the subsidence, if it has, like the elevation,
taken place intermittently. Even at Funafuti, where the sections off the
atoll are more numerous and more detailed than those off any other coral
reef, no such terraces have been developed.

Nukufetau.

Plates lS9,figs. 2, 3; 2 IS, fig. 0 ; 221.

Nukufetau^ is somewhat triangular in outline (PI. 212, fig. 6), and
resembles to a certain extent Funafuti. Its main entrance is on the west
side, and there are no passages on the other faces of the atoll. Nukufetau
is about twenty-seven miles in circuit. The largest island is on the southern
point (PI. 129, fig. 2) ; the east face of the atoll is flanked by numerous islets
and sand banks, separated by gaps similar to those we have described before
(PI. 129, fig. 3).

Nukufetau, as seen from the sea, is flanked with heavy masses of beach
rock alternating with reaches of sand beaches, usually topped with black
coral shingle. The general appearance of the beach, as seen from the sea,
reminds one of that of Funafuti, but the ledges are more marked and better
characterized as buttresses, and show, as at Funafuti, traces of a slight ele-
vation. As far as we could see while steaming around the island, the
beaches, reefs, and land rim of Nukufetau did not differ in any way from
those of Funafuti. The vegetation of Nukufetau was, however, richer than
that we noticed on any of the islands of Funafuti. In addition to Pisonias
and to cocoanut trees, large hardwood trees grew in numbers in the rear
of some of the beaches.

In addition to the gaps between the islands of the land rim, the islands
were often separated by long ridges of beach rock constituting a more or

1 A. Chart 766.

230 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

less imperfect division wall between the sea face and the lagoons. The
gaps between the buttresses of beach rock gave the sea face of Nukufetau
a very characteristic aspect. Immediately behind the belt of beach rock,
small islands or islets of sand and sand bars extend at right angles to the
general line of the shore, and form walls of sand ; these may little by little
become connected, and finally close up the gap, as we have seen it take
place in the Paumotus, and thus form connecting islands closing that part
of the land rim and preventing the sea from having access to the lagoon.
Some of the reef platform sand bars extending towards the lagoon at right
angles to the outer islands are of considerable length. The reef platform
of Nukufetau is very similar to that of Funafuti, growing knolls of Nulli-
pores and Pocillipores forming its outer raised edge.

On the north end of the east face of Nukufetau are indications of
former gaps now nearly closed ; they are apparent from the aspect of the
different parts of the outer shingle beach, — it is quite white and fresh
towards the gap, while immediately behind it, or rather on its northern
side, the shingle is dark and weathered. On the chart only seven gaps
are indicated; we noticed nine. I would call attention to the remarkable
position of ten of the small islands, which follow in rapid succession, and
flank the gaps from the point marked A on the chart (PI. 212, fig. G).

On the lagoon side of Nukufetau the shore is a succession of short sand
reaches of fine coral sand, with here and there a low stretch of beach rock.
The islands of the land rim all have on their steep sea faces more or less
extensive tracts of black shingle above the beach rock ; owing to the
narrowness of the outer land rim, the shingle often extends inland far
enough to connect with the fine sand of the lagoon beaches. The depth
of the lagoon of Nukufetau is said to vary between sixteen and twenty
fathoms.

From Nukufetau we made for Niutao,' a nearly round island, about
one and a fourth miles in diameter, surrounded by a narrow fringing
reef. It has a small shallow lagoon, nothing but a brackish water sink.
The island of Niutao represents a stage in which an incipient sink has been
formed in the central part of the island. The sink of Niutao is probably

1 A. Chart 987.

NUKUFETAU. 231

merely a remnant of the open area, now nearly filled up, once existing
between the high beaches thrown up on all sides of the original reef plat-
form. Other islands, like Nurakita^ and Nanomana," are merely small coral
reef flats on the summits of which reef material has been heaped up, while
in the case of Niutao the central space has been left partially undisturbed.
Unable to land, owing to bad weather, we continued our way to Arorai.

1 A. Chart 7G6. 2 lyj.

232 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

THE GILBERT ISLANDS.

Plates 138-160, 223 ; 2%, figs. 3-6; f>26, figs. 1-3.

The Gilbert Islands (PI. 223) follow much the same trend as the Ellice
Islands. They extend from Arorai to Taritari, about three degrees of
latitude on both sides of the equator.

Three of the southern islands, Arorai, Tamana, and Nukunau are low
flat islands, and have no lagoons. Peru is a long, low flat island (PI. 226,
fig. 3), flanked by a narrow lagoon on the western side. Several of the
larger atolls of the group, Onoatoa, Tapeteuea, Maiana, Tarawa, and Taritari,
are noted for their open western faces, the western reef flats being more or
less submerged. In others, on the contrary, like Maraki and Aranuka, the
lagoons are nearly shut off from the sea, while such atolls as Apamama and
Apaiang remind us of similar atolls in the Paumotus.

The soundings we took between the various islands of the Gilbert group
indicate the absence of a connecting plateau ; they are a series of isolated
peaks and ridges, separated by deep water, rising from very considerable
depths, as will be seen by examining our lines of soundings. Stations 190-
208 (PI. 223).^ We obtained 2221 fathoms between Apamama and Maiana,
1569 south of Tarawa, 2156 between Apaiang and Maraki, and 2255 fathoms
between Maraki and Taritari. The soundings also indicate that Apaiang,
Tarawa, and Maiana are the summits of a plateau with a depth of less than
500 fathoms, i-ising from great depths north and south of it (PI. 223).

Our observations in the Gilbert and the Ellice Islands indicate that in
those districts where it is impossible or difficult to observe the structure of
the underlying platform, the coral reef question limits itself to the study
of the cutting down of the reef platform and of the land rim, of the
movements of the mass of material which rests upon the underlying
platform, whatever be its nature, the material being supplied by the
growth and decay of the corals, of the Nullipores and animals living upon
the reefs, either of the sea face or of the lagoon, and to following the endless
combinations resulting from the nature of the outer reef platform, and the

' Mem. M. C. Z., XXVI, 1902, No. 1. p. 61.

THE GILBERT ISLANDS. 233

local phenomena due to the shape of the land, the tides, and winds. In a
region where the trades blow with regularity, the rehandling and moving
of all this material is due to the action of the prevailing wind ; the extent
and character of this depend almost entirely upon the position of the land
with reference to its direction. Where the northeast trade winds strike the
islands at a sharp angle, the effect of the swell will be to follow the coast
and haul around the two sides of the atoll. Should the atoll be wide
and long, the effect of the prevailing trades will be felt, not only on the
weather, but also on the lee side, inside of the lagoon. Considerable
material will also be handled and rehandled on the lagoon side of either
face, according to the strength of the sea, the direction of the winds,
and the length and breadth of the lagoon. If, on the contrary, the
trade winds should strike an island nearly at right angles to its weather
face, then a very decided lee is formed, even in the case of comparatively
small islands. In such a case the material is moved almost entirely on the
weather side, and the effect of the sea and wind on the lagoon shores of the
outer land rim is reduced to a minimum. During the changes of the trades
exactly the opposite will take place ; but the winds then prevailing will
act only during a short time compared with that during which the long
season of the trades is effective.

To the west of the central part of the Gilbert Islands are situated
Paanopa and Nauru (PI. 234), isolated peaks of coralliferous limestone
elevated to a height of more than 200 feet. These islands are considered
as forming a part of the Gilbert group, though the most distant one,
Nauru, is about 300 miles from Nonuti. the nearest island of the Gilbert
chain. They are interesting, holding, as elevated islands, to the low
Gilbert atolls much the same relation which the elevated islands of
Makatea, of Niau, and Raugiroa atoll hold to the low eroded Paumotus.
They give us, if not the key, at any rate a strong hint as to the probable
nature of the beds formint!; the substratum of the recent reef rocks of the
atolls of the Gilbert group.

The sea face of Plea.sant Island (Nauru) (PI. 160'') is not as regular as
that of Ocean Island ; its greatest length is three and three-fourths miles,
and its width varies from two to two and three-fourths miles. The island

234

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

/:

X

.<::S^^^^^^!^5^:^2i!^

is surrounded by a wide reef flat platform from 100 to 130 yards in width,
cut away from the flanks of the elevated coralliferous limestone slopes of
the island. The topography of the island as shown from the figure i."
quite irregular; there are three main lines of hills, the higher parts of
which are about 220 feet high. Above high-water mark is a low platform (the
first terrace?), ranging in width from 30 to over 400 yards. On this most

of the natives dwell.
Near the southwest
end of Pleasant Isl-

Sectiou across Sink, S. W. to N. E. 1 . in 1

and IS a shallow la-
goon, a sink 100 by
200 yards with about
5 feet of water, en-
closed by a regular
rim ; as is seen by the
.sketch map and sec-
tion of the adjoining
figure, numerous
gaps occur between
the higher parts of
the rim. The above
data are taken fi'om
a report by Mr. F.
D. Powers to the
Pacific Islands Com-
pany limited.

This island was
visited by Kriimer,
who gave a short account of it in Globus.' T am indebted to Mr. Hiitter
for photographs of Nauru .showing the massive bluffs of elevated corallif-
erous limestone a short distance from the shore, and to him as well as to
Ml'. John Arundel for specimens of the limestone, which is identical with
that of similar elevated islands like Nine, Eua, Vavau, and others.

» Globus, Vol. LXXIV. No. 10, September, 1898.

Pleasant Island (Nai'ru).

THE GILBERT ISLANDS.

235

7=:

Sectiou East to West.

^'""^

Ocean Island (Paanopa) is also an elevated coralliferous limestone island,
rectangular in shape, about six miles in circuit ; it has the same structure
as Pleasant Island ; its highest points are from 260 to 270 feet.

Ocean Island (PI. 160") is dome-shaped, somewhat flatter from east to
west than in a section from north to south, as is shown by the section of the
accompanying figure. The slope is somewhat steeper on the weather side ;
the island is surrounded by a line of elevated coralliferous limestone cliffs,
ranging from 12 to 30 feet in height ;
from these the reef flat platform has
been cut away. The platform is
about 100 yards wide.

I am indebted to Mr. John Arundel
of the Pacific Islands Company for a
copy of the Report of Mr. Powers on
Ocean (Paanopa) and Pleasant (Nauru)
Islands.

Mr. Arundel was also kind enough
to allow me to reproduce a number
of characteristic photographs of these
islands (Pis. 160^ 160").

The sections of Paanopa and Nauru
Islands are interestinar : thev show
admirably that the sink of Nauru
and its irregular surface are due to
denudation and do not represent the
lagoon of an elevated atoll. Paanopa
has been greatly denuded and eroded
on the flanks, near the shore platform,
its dome-shaped surfiice having been but little modified by atmospheric
agencies. In both the islands deep cuts similar to those described at Niue
extend inland from the beach edge of the shore platform.

Ocean Island (Paanopa).

236 "ALBATROSS" TROPICAL TACIFIC EXPEDITION,

Arorai.

Plate 223.

Arorai Island, tlie southernmost of the Gilbert Islands, is about six miles
long, and half a mile wide, running from southeast to northwest; it is a low
island with a high beach and a small brackish lagoon in the southern part
of the island. On the southwest side the island is flanked by a steep
shingle beach, at the base of which cropped out, here and there, short
stretches of conglomerate beach rock. The high and steep white shingle
beach shows that the southwestern part of the island must, comparatively
lately, have changed its character, as the northern part of the beach is
covered with rough, highly weathered and pitted black coral rock shingle.
The northwesterly winds, during the change of the trades, blow with con-
siderable force, and this may account for the changes that have occurred in
the outline of the western part of the island. At the western spit is a
huge pile of stones, evidently built by the natives in former times, of the
origin of which the natives of the present day know nothing ; so that it is
probable that the topographical changes of the western side of Arorai have
been comparatively slight, and limited, perhaps, merely to the migration
of the shingle on the high beach southward or northward, according to the
direction of the prevailing wind. Off the central part of the island, the
reef flat is wider than at the two extremities, and parts of it are covered
with flat slabs of beach rock.

Onoatoa.

Plate 223.

Onoatoa, the next atoll of the group we visited, is about twelve miles
Ion"-; its lagoon is five miles at its greatest width. We examined the
southern part of the atoll, and steamed along a part of the land rim of tlie
eastern face; this forms a large crescent open to the west. The gaps
between the islands and islets are so shallow that at low water the
narrow land rim of the eastern face of the atoll is continuous. The west
side of the lagoon is open, and only protected in the central part by

TAPETEUEA. 237

a wide triangular reef flat giving the sea free access to the lagoon, both to
the north and south of it.

The sea face of the land rim, where we examined it, is flanked by a low
beach ; the vegetation creeps down almost to high-water mark ; little con-
glomerate beach rock is found at the base of the beach, with here and there
ridges of coral shingle, alternating with longer stretches of fine coral sand.

The absence of land rims on the western face of several of the atolls of
the Gilbert Islands is a characteristic feature of that group. At Tapeteuea
and Tarawa, as at Onoatoa, the eastern faces form a nearly continuous land
rim, Avhile the western face is only protected by a sunken reef flat, covered
with water of variable depth, enclosing very indistinctly marked ]agoon.s.
These indistinct lagoons appear to have been formed, at least in the case of
Onoatoa and Tapeteuea, from the erosion of wide fringing reef flats once
occupying the summit of the shoal areas of the atolls of Onoatoa and
Tapeteuea, on the eastern face of which the land rim has been thrown up.
The wide fringing reef flats on the lagoon side of Onoatoa may be the rem-
nant of a former more extensive flat. A similar flat has been more care-
fully examined at Taritari, where I shall describe it in detail.

Tapeteuea.

Plates 138, figs. IS ; 223 ; 226, fig. 1.

Tapeteuea is a triangular-shaped atoll,' its eastern face is nearly thirty
miles in length ; the southern face is eight miles long, with a shallow
passage into the lagoon. Its land rim is limited to a few sand bars. The
reef flat of the western face encloses an elongated triangular lagoon ;
towards the northern extremity of the atoll it passes into the wide fring-
ing reef flat flanking the western face of the northernmost island of
Tapeteuea. The greatest width of the lagoon is about six miles at the
southern face of the atoll. An indentation in the northern part of the atoll
forms an indiff'erent anchorage on the west coast (Peacock anchorage). It
is only toward the southern part of the atoll that the lagoon becomes
important. On the west face are two passages available for small craft.

1 H. O. Chart 120.

238 "ALBATROSS" TKOPICAL PACIFIC EXPEDITION.

The lagoon is said by Wilkes to be about five fathoms deep, and to have
many sand and coral shoals dry at low water.

Tapeteuea is undoubtedly the summit of a very extensive ridge, as to the
south of the charted part of the atoll an extensive reef has been reported
by the U. S. S. " Narragansett."

The northern horn of Tapeteuea^ (Pis. 223; 226, fig. 1) reminds us of
the horns of the atoll of Arhno, in the Marshall Islands, where the land rim
is flanked on both faces by a fringing reef platform widest on the lee side.
The loose material composing the eastern land rim has, as yet, reached only
an initial stage of concentration, consisting wholly of small islands, islets,
and sand bars. On the northern and southern extremities alone a part of
the land rim of the east face is continuous, and has been consolidated
into larger islands (PI. 138, fig. 3).

We came upon Tapeteuea" near the centre of the eastern face of the
atoll, where the land rim consists of numerous islands and islets, flanked
by low sand beaches (PI. 138, fig. 2) ; many of the islands seem to be
connected b}' sand bars.

On the southern side of Utiroa we saw several artificial mounds, such
as we had noticed at the extremity of Arorai. Some of them seemed to be
beacons, indicating, perhaps, a canoe passage into the lagoon. But on the
western side of the same island occurs a long line of these artificial piles,
the object of which is not so apparent, as they merely extend westward into
the narrow lagoon on the broad western fringing reef flat. As we steamed
along the east side of Tapeteuea (PI. 226, fig. 1), close to the line of
breakers, we could see that the various islands and islets to the south of
Utiroa are largely sand bars reaching out at right angles to the line of the
outer reef platform, the sea face of wliich is flanked with conglomerate
beach rock, while the lagoon end of the islands and islets is covered with
fine coral sand thrown up by the waves of the lagoon during the prevail-
ing trades. These sand bars, according to their size and age, are covered
at first by a low growth of bushes, subsequently cocoanut trees find a foot-
hold, and eventually cover the greater part of the ridges of the islands.
The gaps between the islands and islets appear to be shallow (PI. 138,

1 H. O. Chart 120. * Ibid.

TAFETEUEA. 239

fig. 2), judging from the color of the water, which is light green, like that
on the reef flat on the inside of the lagoon. The character of the east
face of Tapeteuea is well indicated on the sketch chart of the atoll made
by the United States Exploring Expedition under Wilkes ^ (PI. 226, fig. 1).

Sonth of the island of Utiroa, we came upon a low elevated vertical wall,
consisting of short reaches from ten to forty or fifty feet in length. It is
not more than three to five feet in height, is deeply undercut, and has
the appearance of being composed of the tertiai-y elevated coralliferous
limestone. Where the reef platform is wide, the vertical wall passes, little
by little, into lines of buttresses running more or less diagonally across
the face of the steep coral sand beach. On the beaches is found an
immense mass of driftwood and of logs of all kinds, mainly of Pandanus
and cocoanut trees, as well as some of the hardwood trees. This we had
not seen before ; it shows that the east face of the atoll is bathed by
a strong current coming from the eastward, bringing a mass of drift
material from islands to the eastward. Some of the gaps between the
islands illustrate well the characteristic mode of formation of the land rim
of an atoll. We could see how a short sand bar had been deposited at
right angles to the line of the outer reef flat, where fragments of beach
rock or conglomerate have formed a spur towards the inside of the lagoon,
and had gradually grown towards the interior of the lagoon, increasing
also in width, and finally almost closing up the spaces between it and the
adjoining sand bars or islands or islets, leaving, as can be seen, a more or
less shallow gap through which the lagoon has an intermittent communi-
cation with the sea.

Many of the islands of the land rim are covered with a fine growth of
Pandanus and of cocoanut trees. The last island on the northern part of
Tapeteuea shows the old ledge cropping out here and there, and extending
either as outliers, or as diagonal buttresses across the steep beaches, the
intervening spaces being covered with coarse coral shingle. The outer reef
platform off the northern point is wide ; we also find there traces and out-
liers of the low old ledge wall existing to the southward. At the northern
extremity of Tapeteuea two secondary lagoons are formed. They are due

1 H. O. Chart 120.

240 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

to the junction of sand bars, separated by a low islet, extending diagonally
over the face of the inner fringing reef flat of the lagoon ; they have
surrounded, in this way, a part of the reef flat, and separated it from
the rest of the lagoon It is easy to see how a series of chains of such
secondary lagoons may thus be formed similar to those we observed in some
of the Pauniotu Islands ; there their mode of structure is not as evident as
it is in this particular instance. The sea face coast of the northernmost
island on the eastern side of Tapeteuea consists of a long stretch of fine coral
sand, with a few buttresses of the old ledge, with here and there an isolated,
short, low coral shingle beach, flanked by wide reef flats (PI. 138, fig. 3).

Apamama.

Plates 1S8, fig. 4 ; 139, figs. 1-3 ; 223 ; 226, fig. 2.

The next island of the Gilbert group we visited was Apamama, neither
Nonuti, nor Aranuka, nor Kuria seeming from the chart to present, specially
interesting features.

Apamama is irregular in outline (PI. 226, fig. 2),* about twelve miles in
its greatest length and about seven miles in width at the northwestern
extremity. The eastern coast of the atoll is convex, forming a sharp point at
the southern extremity. The entrances to Apamama are on the northwest
and southwest faces ; the lagoon is said to be shallow, varying from two and a
half to seven fathoms in depth. We examined a part of the southern and
eastern side of the atoll.

The charts of Apamama- are not very accurate. The northwesterly
shank of the southern land rim is much longer than represented ; there
are many bays along the eastern face of Kabaiiaki, and from Tebaila to
Tabonua many gaps and cuts subdivide that part of the land rim as well
as its southern face.

From the northern horn of Apamama we skirted the eastern side of the
atoll ; this is flanked by a wide reef flat ; a shallow, reef flat lagoon is
formed between the outer edge of the reef platform and the base of the sand
beach of the land rim. Along the east shore reef platform lagoons are also

' A. Chart 731. ^ Ibid. H. O. Chart 122.

APAMAMA. 241

formed in the gaps on the sea face of tlie land rim and not on the inner
face, as we have described them for Tapeteuea. Some of the gaps, instead
of being closed on the sea face, are closed on the lagoon face (PI. 139,
fig. 2), forming at first a bay into which the waters pouring over the outer
edge of the reef flat platform have free access. Gradually as the currents
which once passed into the lagoon have been shut off, sand accumulates on
the two sides of the bay, and is forced towards the outer edge of the reef
platform. So that a part of the reef platform, once a bay, is now separated
from the adjoining district by a spur or spurs from the islands once flanking
the gap leading into the lagoon. These spurs, however, do not consist
mainly of sand, as they do on the lagoon side, but are made up generally
of coral rock shingle, and smaller fragments of coral, with comparatively
little sand, though, according to local conditions, these ledges are often
covered with fine coral sand. The bottom of the bay flanking the lagoon
is almost always a low sandy beach ; it has been formed much in the same
manner as the adjoining islets on the outer reef flat, by the throwing out of
sandy spui's on their opposite faces.

On some of the spits forming the boundary of the platform lagoons, the
reef rock platform has occasionally been elevated at least a couple of feet.
Here and there we also find outliers of the old ledge forming low vertical
walls from three to five feet in height ; they are undercut, and the spaces
between them have been filled either with beach rock, or conglomerate, or
with coarse shingle or with sand.

Pandanus trees are comparatively rare on the east coast of Apamama,
but there are a large number of Pisonias and cocoanut trees, and, in some
cases, beautiful hardwood trees. Some of the higher beaches look like
dunes covered by vegetation, and in this way long wide beaches have per-
haps been formed. We found large masses of driftwood on the eastern side
of Apamama.

Towards the southern horn, on the eastern face of the land rim of
Apamama, numerous islands and islets are found in the lagoon bays with
intricate passes between them. The islands run more or less parallel with
the outer reef flat. They indicate -the former existence of a number of
old gaps now shut out from the sea by the bars of rubble and of sand which

16

242 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

have formed in the platform lagoons. The bars of rubble on the outside
edge of the reef platform are at first covered with a little vegetation, but as
they become larger spurs or islets, and extend out into the lagoon, the coat-
ing of vegetation increases. Low sand dune reaches, overgrown with veg-
etation, unite them on the lagoon side, and form a kind of platform lagoon
on the outside edge of the reef flat differing from any we have seen before.
The secondary platform lagoons can be looked upon as owing their origin
primarily to old gaps, then to dam lagoons, then to lagoon rims filled with
islands. On the eastern face a succession of such secondary lagoons exists,
showing that the land rim must have been a series of islets like those of
Tapeteuea, running perpendicularly to the outer reef flat line. No landing
was possible on the east face of Apamama.

Near the south point on the east side, the reef platform becomes narrower
as it extends towards the south, and the low wall of old ledge which flanks
that part of the atoll is gradually changed into more or less indistinct but-
tresses ; they are situated well above high-water mark, and run diagonally
across the steep beach of that part of the land rim. Behind these ledges
sand dunes are formed which raise the beaches or the land rim to a greater
height than is usual in the Ellice Islands (PL 139, fig. 3).

At the southernmost point of Apamama the old ledge reaches well up on
the beach and has been elevated at least seven to eight feet. This is not
beach rock, but is part of the old elevated coralliferous limestone. Beach
rock or coral conglomerate is found on the outer edge of the reef flat, or at
the base of the beach. A wide coral sand beach separates the old ledge
buttresses from the beach rock, or coral conglomerate, or breccia deposited
between its outliers ; this, being softer than the old ledge rock, has in great
part been washed away. On the south side we found the same formation
as on the east face, a series of secondary platform lagoons, gaps, and small
bays ; here and there beach rock or coral conglomerate ledges are exposed,
the higher parts of which must have been elevated at least three feet above
high-water mark. One of the gaps is broad, fairly shallow, and leads
from the reef flat into the lagoon. Another bay is, perhaps, larger than
any we have seen on the east face ; it is probably older also, the dam between
it and the lagoon side being of considerable width ; the two spits flanking it

APAMAMA. 243

on the east and on the west, are formed of the same beach rock conglomerate
we noticed on the eastern face. Behind the village the dam (it can hardly
be called a dam now) has a width of nearly half a mile, and has increased to
such an extent as to form a wide land rim extending as far into the lagoon
as any part of the outer land rim. Messrs. Mayer and Moore, who landed
in this bay, reported that they saw nothing but modern beach rock or con-
glomerate on the edges of the bay, some of it slightly elevated. In tlie
centre of the land rim behind the village, an imperfectly cemented beach
rock conglomerate was noticed, and masses of coral shingle and small frag-
ments of corals well weathered, but no traces of the old ledge were seen in
this part of the island. The beach sand is fine, and the beach rock con-
glomerate or breccia is not composed of specially large fragments. The
reef flat at this point is at least 150 yards wide, and the bay about 200,
while the land belt from the lagoon to the village is about 250 yards in
width. Back of the village a number of sinks were observed from 50 to
over 100 feet in length. One of them is at least 125 feet long and 40 wide,
the depth being about 18 inches. The sinks contain more or less brackish
water. Immediately behind the sea face of the beach similar sink holes
were observed with a number of jdooIs of brackish water ; some of them are
fully eight feet deep ; they have steep slopes at an angle of even 30'. It is
very probable that these sink holes and pools represent parts of the old
secondary platform lagoon or of the old lagoon bay when it was filled with
islets and islands now connected together to form the main land rim. On
the eastern side of the bay there is a sand bar enclosing a remnant of one
of these small secondary lagoons, such as we have described from the
eastern side of the island. This secondary lagoon is about 200 feet long,
40 feet wide, and, perhaps, three feet deep. We have observed similar
sinks or troughs at Nukutavake, Fakarava, and islands in the Gilbert and
Marshall groups.

On the lagoon side of the bay the coral sand is rather coarse, while on
the bay side was found the finest sand yet seen on the sea face of these
atolls. The beaches on the sea face of the bay, and on the spits on each
side of it, have been thrown up far above the level of the land immediately
behind it. The depth of water on the reef shelf enclosing this bay is only

244 "ALBATROSS" TROPICAL PACIFIC EXPEDTTIOX.

from three to four feet at about half tide ; inside of the outer line of
breakers, for a short distance, a depth of from two to two and a half
fathoms is found, with numerous lieads of corals reaching to within one
foot or eighteen inches of the surface.

At the head of the bight in the larger bay near the village, the beach is
steep ; it consists of fine sand passing gradually into shingle at each end,
this, in its turn, giving place to beach rock or coral breccia towards the
seaward part of the shore. The sea face of the bay is composed of compar-
atively recent beach rock conglomerate, or breccia, extending to the gap on
the west side of the bay, about two thirds of the distance to the lagoon.
This rock is about two feet above high-water mark ; above it rises a beach
of shingle and small rolled pieces of coral, having the general character of
the breccia whicli constitutes the beach rock.

None of the outliers of beach rock conglomerate on the sea beach, to
the east of the bay, rise to more than two feet above high-water mark ; the
beach conglomerate is formed of fragments of modern corals and shells,
washed inland from the outlying barrier reef, and cemented with coral sand.

To the east of the bay the sea beach between the readies of beach rock
conglomerate is composed of extremely fine coral sand with scattered
patches of reddish particles ; they are similar to the red earth characteristic
of limestone districts. Immediately above the fine sand, and rising some-
times to a height of seven to nine feet above high-water mark, a mass of
coral fragments has been thrown up, evidently derived fiom the outlying
reef platform. These fragments become gradually smaller as one travels
inland, and at a distance of about 300 feet from the beach they become a
fine gray sand composed of the eroded and decomposed coral fragments
washed in from the beach. No part of the island behind the beacli was
more than four feet in height ; near the centre of the island the soil was
wet and of a putty-like consistencj' ; back of tlie village it is composed of
coral sand, cemented in some places into a soft rock ; here and tliere lie
scattered fragments of coral, more or less weather-worn. The natives have
dug holes to a depth of two to three feet, and at the bottom of these is
found the same material as that which characterizes the surface. Above
the high-water mark the lagoon beacli is steep, but slopes more gently into

MAI AN A. 245

the lagoon itself. It is composed of coarse white coral sand ; the bottom of
the lagoon is formed of the same material for a distance of 100 to 200 yards
from the shore, where some of the huts of the village are built on i:)iles.

The southern part of Apamama is thickly covered with trees, mainly
Pandanus, Pisonias, and cocoanut trees, as well as with the usual belt of
low bushes on the outer face of the land rim.

Maiana.

Platei 139, fill. 4.; HO, fig. 1 ; 223 ; ^U,fig. 6.

From Apamama we proceeded to Maiana,^ about forty miles to the north-
west ; it is a quadrilateral land rim, about nine miles long and six miles
broad (PI. 224, fig. 6). The northeastern and southeastern faces form a
continuous land rim, while the northwestern and southwestern faces consist
of a broad reef flat with only here and there an islet or sand bar to indi-
cate its position. A boat passage leads into the lagoon on the west face
at the northern extremity of the island (PI. 224, fig. 6). Near the southern
horn of Maiana a steep, wide, fine coral, sand beach extends from the belt of
vegetation towards the outer reef flat. It passes first into coral shingle,
then into beach rock conglomerate at its base, and slopes towards the outer
edge of the reef flat platform, which is edged by knolls of Pocillipores and
Nullipores. The comparatively steep slope of the reef platform differs from
that observed in other islands. On the sea face of the Pocillipore knolls
the slope is steep as it passes into deep water. Nowhere have we seen the
line of demarcation of the vegetation on the summit of the beach from the
fine sand and shingle of its slope, the beach rock conglomerate at its base,
the sloping reef platform, and the outer knoll of Nullipores, so well
defined as on the sea face of Maiana (PI. 139, fig. 4). The yellow color of
the beach rock, of the coral and beach rock shingle, is in marked contrast
with the glistening white coral sand, and in still more marked contrast with
the reddish, the orange, and the violet of the encrusting Nullipores and of
the Pocillipore knolls on the outer edge of the reef platform. The pink

1 H. O. Chart 122; A. Chart 732.

246 "ALBATROSS" TROPICAL PACIFIC EXPEDITIOX.

Pocillipores and the gayly colored Niillipores growing on the outer edge of
the reef flat platform form, perhaps, the most striking display of colors we
have as yet seen, with the yellowish brown beach rock and the light green
water of the pools covering portions of the flats, and the dark blue digitate
channels penetrating far into the reef flat slope. These small channels, cut
out of the edge of the reef flat, form convenient points for landing, and
along the shore we could see the canoes of the natives hauled up on the
beaches opposite these diminutive landing-places.

Maiana is one of the most interesting of the Gilbert atolls. It is
enclosed on the west by a wide reef flat, with only two small gaps through
which there is free communication between the lagoon and the outer
sea. Undoubtedly in former times other gaps opened into the lagoon,
but they have, little by little, been closed by the process we have
described as uniting the islands and islets of the land rim in other atolls
of the Ellice group.

As we passed the first gap on the southeastern shore, we obtained
an excellent view of the inner part of the lagoon of Maiana, and were
surprised to find in the atoll a series of inner beaches running parallel
to the outer shore, forming huge secondary lagoons, similar to those we
observed in other atolls of the Ellice group. These secondary lagoons
are formed by incipient sand bars on the broad reef flats, which extend
far into the interior of the Maiana lagoon (PI. 224, fig. 6).

We could see, at some points of the land rim, low dams (PI. 140, fig. 1),
indicating the position of the gaps which once connected the lagoon with the
sea, showing that the secondary lagoons of Maiana must have been formed
by a process similar to that now shaping the secondary lagoons on the east
and southern coast of Apamama. These secondary lagoons are certainly
not due to subsidence ; they owe their origin to mechanical agencies, such
as we have seen at work in the atolls of Tapeteuea and Apamama.

On the northeast face the beach changes its character; it is made up
almost entirely of coarse coral shingle, and even of huge boulders of coral
thrown up on the steep beach on that face of the atoll (PI. 140, fig. 1).
Here and there, however, a coral sand beach separates the reaches of
shingle beach. Outliers of the beach rock conglomerate or coral breccia

TARAWA. 247

crop out occasionally near the top of the beach, buried in part in the fine
sand, and indicating an elevation of a few feet (Pis. 139, fig. 4 ; 140, fig. 1).
The land rim is beautifully wooded (Pis. 139, fig 4; 140, fig. 1), and the
little islets thrown upon the bars and dams which form the secondary lagoons
are covered with the same trees as those which characterize the main land
rim of the atoll. Pandanus grow in great abundance on Maiana, and we
find tlie usual fringe of low shrubs on the top of the wide sand beach
(PI. 139, fig. 4); this is considerably higher than the land immediately
behind it.

Tarawa.

Plates 140, figs. ^i-Jf. ; I4I-IU; 14-5, fig. i-; 223; 22 J^ fig. 5.

The atoll of Tarawa ' is triangular in shape (PI. 224, fig. 5) ; its southern
face runs nearly east and west, and is about fifteen miles long ; the eastern
face, twenty miles in length, runs from southeast to northwest ; the western
limit of the lagoon is indicated by a rather narrow barrier reef with from two
to ten fathoms of water. The jDosition of the barrier reef is only indefinitely
indicated by patches of corals separating the lagoon from the sea (PI. 224,
fig. 5). There are several entrances into the lagoon on the west side ; many
shoals and islets are scattered over its surface.

The lagoon is said to vary in depth from five to eleven fathoms. On
the western extremity of the southern face of the atoll a large island
extends into tlie lagoon. The southern extremity of the eastern face forms
a rounded horn, while the northern extremity of the atoll forms a sharp
point, flanked on the east by a narrow reef flat, and on the west by the
extension of the western reef flat of the lagoon (PI. 224, fig. 5).

We made the south shore of Tarawa, and anchored about one eighth of a
mile off the principal islets of the south shore (Pis. 140, fig. 4; 141, fig. 1).
There is no reef platform proper on the south side of Tai'awa. The bottom
slopes very gradually seawards from the indefinite edge of the reef flat ; a
depth of 95 fathoms is olitained at a distance of about half a mile, and not
more than 200 fathoms at nearly a mile and a half from shore, a slope unlike

'- H. O. Chart 123 ; A. Chart 732.

248 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

that oif any other group of coral islands we have examined.' The beaches
of the islands on the south face of Tarawa consist of fine coral sand ; the
islands themselves are extremely narrow ; they are covered with cocoanut
trees and shrubs. The sand beaches have been formed as low dunes ; they
are somewhat higher than the islands and islets immediately to the north.
Beach rock and conglomerate ledges characterize the southern face of many
of these islands ; none rise more than a foot or two above high-water mark.
We observed, coming through one of the gaps opposite our anchorage, a
mass of discolored water, which spread fan-shape a considerable distance out
to sea. This material is derived from the immense shallow reef flats to the
rear of the gap on the southern face of Tarawa. Similar streams pouring
out the muddy water from the shallow bay to the rear of the Florida Keys
are seen at Caesar's Creek.^

At the gap opposite our anchorage, are a number of islands, more
or less parallel to the coast line, forming a secondary lagoon, similar to
those of the southern coast of Tapeteuea (Pis. 140, fig. 4 ; 141, figs. 2-4).
The eastern part of the southern face of Tarawa is flanked by a land
rim ; its western half is flanked by islets ; the western horn is formed by
a wide triangular reef flat, gradually increasing in width to about 1000
feet at low tide.

To the eastward of the gap where we anchored, or rather of the long spit
which forms the western side of the gap, a series of islets extends at right
angles to the line of breakers, separated by shallow flats, which connect the
inner lagoon with the sea (PL 141, figs. 2-4). The lagoon extremities of
some of the islands are connected, thus forming deep bays extending north-
ward from the sea face, and communicating through shallow passages with
one another on the lagoon face (PL 141, figs. 2-4). Immediately across the
lagoon extremities of these islands, a low sand bar extends, flanked with
beach rock conglomerate, more or less elevated ; this forms the beginning
of a secondary lagoon extending behind the spit of the western side of
the gap, and shows, perhaps, better than elsewhere the mechanical causes

1 Prel. Report "Albatross" Tropical Pacific Expedition, Mem. Mus. Comp. Zool., 1902, XXVL,
No. 1, p. 61, Stations 200, 201.

" Bull. M. C. Z., XXVIII., No. 2, 1896, p. 46, PI. XIV.

TARAWA. 249

which have led to the formation of these secondary lagoons (PL 141, fio;. 2).
The inner island is in reality a bar thrown up on the inner or lagoon side of
the reef flat at right angles to the outer reef flat, and a dam ' has been
formed connecting the inner and outer islands ; these bars or dams are edged
with beach rock or shingle (PI. 141, figs. 2-4). The areas thus shut oif,
finally become rectangular enclosures, entirely separated from the lagoon
(PI. 141, fig. 2), forming the peculiar secondary lagoons the structure of
which has so greatly puzzled many observers. The material for the islets
bounding the secondary lagoon is derived from the breaking up of the con-
glomerate beach rock, or breccia ledge cropping out everywhere on the
platform on which tlie land rim has been thrown up. The inner reef flat
is wide (Pis. 141, fig. 2 ; 142, 143), and extends far into the lagoon. We
were unable to ascertain how far north the flats extend.

The coral shingle found above the beach rock conglomerate consists of
fragments of the beach rock itself, more or less disintegrated. The flats
between the islands and islets are covered with fine sand, almost silt, and on
the lagoon side they are covered with masses of broken land shells. The
natives use these secondary lagoons, or parts of them, as fish ponds
(Pis. 144 ; 145, fig. 4), the islets acting as barriers, which they connect by
artificial dams to enclose limited areas of the lagoons. Immediately behind
the principal island, which has formed the dam of the secondary lagoon,
are three successive bars on the lagoon side, forming long spits parallel to
one another, and coming out as spurs from the main land rim. These,
when dammed off at their lagoon extremity, will in their turn form a third
and even a fourth line of lagoons in the same way as the secondary lagoon
we have just described has been formed.

The wide beach flat slopes most gradually to the Nullipore and Pocillipore
edge, which on this flat reef platform apparently indicates merely the low-
water line. There are no great cuts in the outer edge of the Nullipoi'e
knolls as in other atolls, except an occasional gully of three to four feet in
depth, not more than a few feet in length, flanked by knolls rising from
one to two feet above the general level. On the slope of the reef flat scat-
tered over its whole face, fine corals are growing ; the principal heads
consist of Porites, of pink Madrepores, and of Millepores ; the flat is also

250 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

covered with huge masses of Nullipores. The conglomerate beach rock is
composed entirely of fragments of modern species of corals, covered with
encrusting Nullipores. In some places the conglomerate is changed into a
hard ringing limestone, while in others the fragments of corals have merely
been agglutinated, and remain soft and crumbling.

Skirting along the east coast of Tarawa, about two miles from the
southern point, we came across a number of gaps (PI. 140, figs. 2, 3) formed
by islands and islets, separated by shallow passages, flanked on the east by a
reef platform of variable width. Through the gaps we could see the lines
of inner islands, immediately in the rear of those of the land rim, towards
which spits or dams from the outer islets were gradually reaching, forming
more or less distinct secondary lagoons. About the centre of the east face
of the atoll we came upon a large secondary lagoon, forming a huge bay,
its outer edge flanked by the reef platform on which the sea was pounding.
The width of this secondary lagoon was at least 2000 feet, and its inner
dam consisted of a series of low beach rock ledge walls, parallel with the
land rim separating the secondary lagoon from the main lagoon. Some-
what north of this point the inner or secondary row of islands on the wide
outer reef platform became even more prominent, and finally we came upon
a part of the lagoon with three and four rows of islands and islets, all more
or less parallel with the outer reef platform (PI. 140, fig. 4) ; on the lagoon
face they form prominent spits extending at right angles to the line of the
outer reef flat. The wide reef flat on which the inner rows of islands were
thrown up extends far into the lagoon. The islands and islets are flanked
on the sea face by beach rock conglomerate.

The outer and older of the islands and islets are covered with vegeta-
tion, while the inner islets are generally mere bare ledges of beach rock
conglomerate or breccia or sand spits. Somewhat farther north we came
upon another secondary lagoon where the distance from the lagoon edge of
the outer row of islands to the second row is from 1000 to 1200 feet.
Here the inner islands are as well covered with vegetation as the outer
ones ; they are occasionally connected by low sand spurs and form secondary
bays, with passages between the extremities of the island leading in one
case into the lagoon, and in the other opening out on the outer reef flat.

TARAWA. 251

The spurs usually connect the central parts of the islands, showing that
the outer islands, at any rate, have increased in size uniformly on the two
sides of the original spit.

Still farther north we find a series of three lines of islands ; the second
and the outer row are sometimes connected by a spit fully as well covered
with vegetation as the inner or the outer islands. The prolongation of the
three lines of islands is not always well marked ; they are somewhat
irregularly placed. Taken as a whole they form an enormous secondary
lagoon on the inner reef flat ; this at some points must be three fifths of
a mile in width. Farther north still, an islet of shingle and sand has been
formed directly across the gap of the two inner islets on the outer edge of
the reef flat and parallel with it.

The extent of the secondary lagoons depends wholly upon the width
of the lagoon reef flat. Where it is narrow, the secondary lagoons appear
as small bays, facing either the sea or the lagoon, according to the local
conditions which have shut off gaps, more or less wide, either from the sea
or from the lagoon. Their depth depends upon the differences of level
found upon the lagoon reef flats, upon the depth of the gaps and the shal-
lower passes, as well as the distance to which the channels or sinks extend
lagoonward across the reef flat. The lagoon faces of an atoll as large as
Tarawa are raked by seas of considerable size, so that we often find, espe-
cially on the eastern and southern faces, bars and beaches of considerable
height thrown up in the interior of the lagoon, forming the boundaries of
secondary lagoons (Pis. 143, fig. 2 ; 144 ; 145, fig. 4).

The width of the reef flats on the lagoon side of Tarawa is well seen on
PI. 143, fig. 1, and on PI. 142, fig. 2, where is exposed an extensive flat of
coral sand, of silt, and small fragments of corals and broken shells. This
flat forms a huge wide spur to the north of the inner line of islets flanking
the secondary lagoon. On PI. 148, fig. 2, is shown an extension to the east
of a high sand bar covered with vegetation, forming the northern boundary
of a long shallow sink or secondary lagoon. On PI. 143, fig. 1, we are
looking westward along the lagoon face of the land rim. Outliers of reef
rock and breccia and conglomerate crop up along the face of the lagoon ;
they have not as yet been disintegrated and ground into sand as they have

252 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

in other parts of the lagoon platform. The land rim of the east face of
Tarawa, as far as we examined it, consists of secondary lagoons such as we
have described. The secondary lagoons are not indicated on the charts of
Tarawa, of Maiana, Taritari, or the few atolls in the Paumotus where they
have been observed.

Apaiang.

Plates U5,fi<js. IS; :i23 ; ii24,fig. 2.

After skirting the eastern face of Tarawa we examined the southern
part of Apaiang,^ an atoll about sixteen miles in length, and eight miles
wide across its northern extremity (PL 224, fig. 2). Its outline is formed by
a series of large loops, the reef flats running out into well-marked points
on the northern, eastern, and western faces. The principal land rim is on
the eastern face of the atoll, while on the wide northern and western reef
flats only a few low islands are found, with the exception of the larger
island of Nuotaea, which forms the northwestern spit of the atoll (PI. 224,
fig. 2). On the southwest face two well-marked ship passages lead into the
lagoon ; numerous shoals occur in it.

The beach of the southeastern shore is flanked by beach rock ; outliers of
coarse conglomerate, separated by stretches of coarse coral sand, line the
shore above high-water mark (PI. 145, fig. 3). On the lagoon side of the
island forming the southeast point, the steep beach consists of fine coral sand.
Rounding the eastern point (PI. 145, fig. 2) of the south face of the atoll, south
of the boat passage leading into the lagoon, we found, from a depth of twenty
fathoms up to two, masses of corals covering the bottom ; they consist mainly
of Mooandrinas, Madrepores, Pocillipores, Millepores, and Alcyonarians ;
of special interest were a number of large sponges closely allied to species
found on the Australian barrier reef. As we came in through the inner
boat passage, the coral heads in the narrow part of the channel became more
and more luxuriant, especially the large blocks of Porites ; as we approached
shallow water, they spread horizontally ; as the tops neared the surface,
many of them were dead and covered with masses of white and of red Nulli-
pores, which form a cement over the whole surface of the reef flat on both

1 A. Chart 732.

MARAKI. 253

sides of tlie boat passage. These Porites reef flats are similar to the Mille-
pore and Porites flats which take such an extraordinary development in
Taritari, and are described in detail in the account of that atoll. They
show admirably how extensive areas covered with liviiit;; corals like Porites,
Millepores, or Pocillipores, are gradually changed into dead reef flats with
a surface cemented by Nullipores, and become the base upon which a land
rim of l)ars or islands or islets is gradually thrown up.

The high coarse sand beach where we landed was at least six to seven
feet above low-water mark. It is made up of small disintegrated fragments
of coral ; the same is the composition of the lagoon beach, which is
fully as steep as the sea face, but the material of this beach contained
a larger proportion of broken shells. The outer spit to the south of the
village, near the outer face of the island, is made up of a steep coarse coral
shingle beach ; it is of a gray color, weathered, pitted, and honeycombed.

On the east side of Apaiang, as far as we followed it, high coral sand
beaches, topped by scrub vegetation, alternate with low ledges of beach rock
conglomerate, forming low vertical walls slightly undercut at the base,
flanking the base of the sand beaches. The lagoon reef flat slopes but slightly,
and is covered with knolls and heads of Nullipores, Corallines, and Pocilli-
pores, colored red, pink, and yellow, giving a very variegated appearance to
the lagoon flat ; the heads are separated by large, wide patches of sand.
The outer reef flat slope, where it consists of beach rock conglomerate, is a
brilliant yellowish brown as at Tarawa.

From Apaiang we steamed to Maraki, one of the most interesting
atolls we have as yet examined.

Maraki.

Plates H6-150, 323 ; S34, firj. 3.

We steamed around the southeastern and western faces of Maraki, an
atoll triangular in shape, about five miles in length by three miles wide.
A single narrow boat passage leads into the lagoon on the western face
(PI. 146, fig. 1), with this exception, the land forms a continuous rim of
considerable height, which has been thrown up on the outer reef flat. On

254 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the east face a former gap or passage, now closed, is indicated (PI. 224, fig. 3).
This low part of the land rim is quite distinctly seen from the western face
of the land rim. The island is an interesting one ; it was considered by
Dana to be perhaps the most typical of the atolls he visited. At Maraki
nothing indicates that the island has ever been subjected to subsidence.
On the contrary, the immense amount of material tin-own up, both on the
east and on the west face, forming the land rim of this atoll, clearly shows
the manner in which the land rims of the atolls of the Ellice and Gilbert
groups have little by little been accumulated. It is only when we examine
such a small atoll as Maraki that we can take in at a glance the changes
that have taken place on the underlying platform which has supplied in part
the material for the coarse shingle beaches ; the dead and decaying corals
fringing the outer reef flat, and the material derived from the subsequent
disintegration of the beaches of conglomerate and breccia supplying the rest.
This is well seen on the west face, north of the boat passage, where huge
bouldei's of conglomerate form a shingle beach (PI. 147, fig. 2) extending
along the greater part of the northern extremity of the west face. On the
western side of the lasfoon masses of beach rock conij-lomerate are found
cropping out at the surface (PL 146, fig. 3) ; they form the underlying base
of the narrow line of islands and islets parallel to the outer land rim, a line
defining the inner margin of secondary lagoons (Pis. 149; 150, fig. 2) so
characteristic of the Gilbert and Ellice Islands, and so well developed at
Taritari and Tarawa.

Near the southeast point of Maraki^ (PI. 146, fig. 2) the reef flat slopes
gradually to the outer edge. This is marked by huge knolls of Nullipores and
of Pocillipores, forming an outer barrier to the shallow pool which extends
from the outer edge of the reef flat towards the base of the beach of the
main land rim (PI. 146, figs. 2, 3). The beach rock flanking the base of the
high and steep beach of Maraki is of a brilliant brownish yellow ; its patches
extend as large slabs "over the reef flat and partly up the slope of the high
beach, form a belt of brilliant color, in strong contrast with the white coral
sand and the light yellowish mud which covers, in places, the bottom of
the platform lagoon enclosed by the outer knolls (Pis. 147, fig. 1 ; 14S ;

1 A. Cliart 732.

MARAKI. 255

149, fig. 1; 150, fig. 1). The outer platform lagoon is full of fishes; many
of the natives were seen fishing along its edge as we passed. There has
probably been a slight elevation at Maraki corresponding to that noticed
in other atolls of tlie Ellice and Gilbert group, as some of the beach rock
conglomerate has been elevated far above the line of the highest high-water
mark (PI. 147, fig. 1).

From the southeast horn of Maraki (PI. 146, fig. 2) we turned westward,
skirting as close as practicable to the outer edge of the reef flat. As we
passed along the southern coast, we could see in the lagoon, over the belt of
low vegetation of the land rim, a secondary line of islands (Pis. 149, fig. 1 ;

150, fig. 1), running parallel with the south shore, as at Tarawa. The bril-
liant belt of color, extending from the summit of the beach to the outer
Nullipore knolls, increases in brilliancy as we proceed westward. The color
of the carpet of many-colored corals and Nullipores is reinforced by that of
long lines of green and yellow Algae, which flourish in the shallow pools left
by the tide on the flat between the base of the sand beach and the outer
edge of the reef. The knolls on the outer edge of the reef were here and
there gouged out by deep gullies connecting the pool of the platform lagoon
with the sea, but in spite of these openings there was left, even at low
water, a nearly continuous platform lagoon between the outer Nullipore edge
of the reef flat and the base of the beach (Pis. 146, figs. 2, 3 ; 148 ; 149,
fig. 1; 150, fig. 1).

A section across the south shore, as we could see it from the deck of
the vessel, showed the outer knoll of Nullipores and Pocillipores gouged at
right angles to the trend of the outer reef flat, by gullies varying in
width from ten to fifty feet. Immediately behind the knolls, the slope dips
sharply to form the bottom of the platform lagoon; it then rises uniformly
to the base of the sand beach ; the slope is covered with many-colored
rocks and fragments of beach rock and conglomerate, separated by patches
of yellow and green Algaj, and the whole more or less covered with a
coating of bright-colored Nullipores. Then comes a steeper slope of white
coral sand, flanked at the base by beach rock and beach rock conglomerate,
behind which the beach rises rapidly to a height of at least seven or eight
feet above high-water mark. The top of the steep beach was covered with

256 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the usual belt of low bushes behind which rose the larger trees, mainly
cocoanut trees. We could trace the brilliant colors of the corals growing on
the outer slope of the reef down into twenty fathoms.

Towards the western point of the southern face of the land rim, the outer
edge of the shore platform suddenly joins the beach which flanks the
western coast of Maraki (PI. 147, fig. 2). The western coast of Maraki is
flanked almost for its whole length by sand beaches and coarse shingle
beaches alternating with one another, much as we saw them in Maiana.
The absence of the shore platform on the greater part of the west side is a
most striking feature ; this may show that Maraki is a later stage than
that of some of the atolls of the Ellice and of the Gilbert groups, where
no islands exist on the reef flats of the west side, and that where few islands
or islets have been formed on the reef platform of the western face. It is
easy to see, from the case of Maraki, how these differences have been
brought about. On examining its lagoon we are able to trace the successive
steps which distinguish Maraki from atolls which have remained more or
less open on the west, like Tapeteuea,^ Tarawa (PI. 224, fig. 4), Onoatoa
(PL 22.3), or from those like Taritari (PI. 224, fig. 4), Apaiang (PI. 224,
fig. 2), Nonuti,'- with only one or two islets on the western face, until we
reach a sta2;e where the local conditions are such that the trade wind and
other prevailing winds have thrown up, on the outer faces of the atoll, a
high bank, such as exists at Maraki, which has finally closed the lagoon,
leaving only an unimportant opening leading into it.

On the west face of Maraki a large number of huge blocks of Nullipores
have been thrown up on the shore (PI. 147, fig. 2). The soundings taken
when lying off the village to the north of the boat passage show the absence
of a shore platform, and that on the west face the atoll slopes gradually
into deep water.^

As we passed the gap of the boat passage (PI. 146, fig. 1), on the west
face of Maraki, we could look into the lagoon and see indistinctly the
eastern face of the land rim, as well as the secondary lines of islands and

1 H. O. Chart 120.

2 A. Chart 731.

3 Prel. Report "Albatross" Tropical Pacific E.x., Mem. M. C. Z., XXVI., No. I, 1902, p. 62,
Station 205.

MARAKI. 257

islets and ledges parallel to the southern and to the western coast of Maraki.
The two sides of the gap of the boat passage are flanked with coarse black
coral shingle, with here and there a patch of coral sand. Huge boulders
of Nullipores (PI. 147, fig. 2), thrown up at the base of the shingle beach,
supplied the material which, on further disintegration or grinding by the
sea, formed the sand beaches stretching between the beach rock conglom-
erate and the line of NuUipore boulders.

We landed on the west coast, a little north of the monument, on a sand
beach (PL 147, fig. 1), flanked on the left with masses of Nullipore
boulders (PI. 147, fig. 2). The underlying platform has evidently been
covered with such blocks from the sea face across to the la.goon, so that it
seems as if the land rim of the western coast had been built up, by the
gradual increment due to the piling up of this coarse material upon the
underlying platform, from the lagoon to the sea face. Making a section
across the atoll at this point, we find on the west face the gradually sloping
platform which once probably extended to the inner line of islands in the
lagoon. On that slope has been formed, by the action of the huge rollers
sweeping round the northern point of the atoll and following the western
coast, the mass of shingle, composed of Nullipore boulders and of coral rock
fragments (PL 147, fig. 2), which extends inland perhaps as far as the lagoon
edge of the land rim. Next comes the reach of the sand beach, as far as
the first line of islets running parallel to the west coast along the lagoon
side of the atoll (PL 150, fig. 2). This slope may even extend a consider-
able distance into the lagoon, and on it have been thrown up a second or a
third row of islets (PL 149, fig. 2) ; they form the secondary lagoon we have
seen at different points, parallel to the southern, eastern, and western faces
of the island (Pis. 149, fig. 1 ; 150, fig. 1). From the eastern side of the
western land rim we could see that the eastern face of the lagoon rises to
about the same height as that on the west (PL 149, fig. 2). The slope of
the outer beach on the eastern sea face is very similar to that on the west,
only from the southern horn it runs into a wider outer reef platform
(PL 146, fig. 2), similar to that we followed along the southern shore
(Pis. 148; 149, fig. 1 ; 150, fig. 1), while on the greater part of the western
face this platform, as has been stated, has disappeared (PL 147, fig. 2).

17

258 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Off the west shore, from the anchorage to the landing, we found huge
patches of corals separated by wide lanes of sand. The mode of formation
of the land rim of this atoll is apparently very different from that of any
other atoll we have examined, but, as has been shown it is only the last of
the successive stages in such widely different atolls as Tapeteuea and
Taritari. Dana mentions Maraki as one of the most characteristic and
prettiest of the atolls of the Pacific ; it must be remembered that he
described its general appearance from a chart, and had no opportunity to
examine the interior of the atoll, or to trace the mode of formation of its
secondary lagoons.

Taritari.

Plates 151-160 ; '223; 224., fig. 4-

Taritari, the northernmost of the Gilbert Islands, has much the same
angular outline as other atolls of the Gilbert group, but runs east and west
(PL 224, fig. 4). It is about twelve miles in length, its western face running
northwesterly ten miles. The western part of the northern face is concave
and convex towards the eastern point of the atoll; the southern face con-
sists of two concave arcs projecting at the centre of the atoll in a sharp
point. The land rim of the southern face consists of two principal islands,
with islets and bars in the gaps between them forming indistinct secondary
lagoons (PI. 152, figs. 3, 4). The western face of the island, on which is
Butaritari, widens out to nearly three miles ; towards the east the land rim
tapers into a narrow belt less than a third of a mile in width, and ends in a
wider hook-shaped point.

The eastern island is narrow, with here and there a spit running out into
the wide reef flat, which flanks the southern face of the lagoon, as well as
the eastern and western extremities of the atoll. The lagoon of Taritari is
full of shoals, islands, islets, and coral patches, rendering navigation extremely
difficult. The western face is flanked by three larger islands, and four or
five smaller ones, indicating in a general way the position of the broad reef
flat forming the western boundary of the lagoon (PI. 154, figs. 1, 2).

South of Napuni and the adjoining islands are the broad passages which

TARITARI. 259

lead into the lagoon (PI. 224, fig. 4), flanked on the north and south with
numerous coral patches and shoals, through which a depth of from ten to
twelve fathoms can be carried to the anchorage, immediately to the north
of the village of Butaritari (PI. 151, figs. 1-3).

The northern face consists of a narrow reef flat passing gradually into
the shallow waters of the eastern part of the lagoon ; a few islands widely
separated are situated on the face of the wide eastern reef flat.

The atoll of Taritari has, off its northeastern point, a small satellite,
Little Makin Island, distant not quite two miles ; it is a coral reef flat sur-
mounted with three or four low islands (PI. 224, fig. 4).

The reef flat at the eastern extremity of Taritari is of great wadth
(PI. 224, fig. 4) ; its outer edge is well marked by huge blocks of beach rock
conglomerate and of coral shingle, with low islets running into the lagoon
at right angles to the trend of the eastern reef flat. The eastern part of
the lagoon, adjoining the wide reef flat, is evidently shallow, judging from
the light green color of the water. The existence of the islets along the
eastern edge and in the horn forming the eastern point shows that they
probably are secondary islets, and that the whole of this part of Tari-
tari will soon become an extensive flat upon which vegetation may arise.
The outer edge of the eastern horn is flanked by a steep dam of black coral
shingle forming a narrow barrier which may eventually become cut up into
islands and islets (see PI. 158). This mode of formation of a land rira on
the very edge of the reef platform, where a shingle beach may reach a
height of four to five feet, we have not noticed before. The only other case
I have observed is that above the central part of the east coast of Taritari,
where a shingle ledge islet has been thrown up directly across a gap or bay
on the very outer edge of the reef flat (PI. 157, fig. 2). In this case it is
only a diminutive islet, while in the former case an extensive arc is formed
by a steep coral shingle beach which extends for a great length on the edge
of the reef flat, and protects the lagoon from the encroachments of the sea.
The little islands and islets found on the horn (PI. 224, fig. 4) are all more
or less parallel to the outer reef dam ; they have undoubtedly been formed
as spits much as they have been described for so many other atolls of the
Gilbert and of the Ellice Islands.

260 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

Where the shingle is low the water passes at half or high tide directly
into the lagoon, while in other parts of the eastern horn of this atoll, water
can only enter the lagoon at high stages of the tide, and in some parts
where the beach is highest, it flows around the two ends of the shingle. On
the south face of Taritari the land rim is flanked by a series of steep sand
beaches, alternating with beach rock conglomerate ledges and coral shingle
beaches from four to six feet in height (PL 155, fig. 1). Large blocks of
beach rock or of conglomerate are often mixed with the shingle.

The larger forest trees characteristic of the South Pacific atolls grow
close to the highest point of the beach ; there are neither Pisonias nor the
scrub vegetation usually met with on the summit of the outer beaches
(PI. 155).

Judging from the position of the line of the breakers, the outer reef fiat
is extremely narrow. In the gap between the two principal islands of the
southern face (PI. 224, fig. 4) we found a series of islands and islets on the
inner face of the broad reef flat forming spits extending at right angles to
the outer edge of the reef platform (Pis. 152, fig. 2 ; 153 ; 156, fig. 1 ; 157),
which at this point is marked by a low, steep, coarse, coral rock shingle
beach. The islands and outer islets are flanked on their sea faces by beach
rock or conglomerate shingle, while on their lagoon face the spits are com-
posed of fine coral sand. This peculiar combination of islands and of low
outer beaches with two inner rows of islands forming a secondary lagoon
we have described in Tarawa and elsewhere (Pis. 152, fig. 2; 153; 156,
fig. 1 ; 157).

At a point near the middle of the south shore we obtained an excellent
view across the outer rim, towards the interior of the lagoon, with the
islands and islets beginning to build up secondary lagoons (Pis. 152, 153),
the outer edge of the reef flat being edged with a high dam of black coral
rock shingle (PI. 158). This dam extends fully a mile to one and a half
miles from the gap.

West of the gap on the south face, the shore of the rim of Taritari
consists of alternate sand and shingle beaches (Pis. 152, figs. 3, 4; 155,
fig. 1), or reaches of beach rock or conglomerate, and flat-topped ledges.

Here and there on the south shore of Taritari we find a still different

TARITAEI. 261

kind of secondary lagoon, formed by the bulging out of the outer edge of the
reef flat, and running parallel to a slight projection of the outer shore line
of the land rim. One of the best examples of this is south of Butaritari
on the south face of Taritari (PI. 152, figs. 3, 4).

Going west from Butaritari, towards the southwestern point, at the
extremity of the main street, we come upon a series of beach rock and
conglomerate ledges topped with steep sand beaches and enclosing shallow
lagoons. The outer rims of these are quite well defined by knolls of Nulli-
pores and Pocillipores, so that pools of from 50 to 75 yards in diameter are
formed extending from the base of the beach on the lagoon side.

West of Butaritari, on the sea face, near the southwestern point, the
outer reef flat is edged by Nullipores ; on the flat are two or three islets
running parallel with the main beach of the island (PI. 224, fig. 4). At
the west point of Butaritari we found the extension of the Nullipore edge
which has formed the extensive flat running from the southwest point
northward, and immediately behind it a steep weathered coral shingle beach
covered with vegetation. From the beach a spit covered with only scant
vegetation cuts directly across the reef flat towards the shore of the
island, and forms a secondary lagoon, isolated, or only connected very
indefinitely with the main lagoon of Taritari.

On the west side of the southwest point, near the village of Ukiaiiiiau,
we found that the southern extension of tliis wide reef flat becomes
gradually narrower as it reaches the village, and finally becomes a
part of the main shore of the island itself (PI. 154, fig. 4), widening out
again to a certain extent towards the southwest point. The Nullipore
boulders which have been thrown up on the shore (PL 154, fig. 4) consist
of large rounded masses ; tliey are mixed with round heads of Porites,
Mceandrina, and the like, and are gradually being pounded into coarse
black shingle. This, in its turn, is ground still finer, and forms the short
sand beaches alternating with beaches of Nullipore boulders. This coarse
black shingle beach resembles that of the west face of Maraki.

A part of the southern area of Taritari is similar in structure to
that of the western side of Maraki. The secondary lagoons occupying the
great expanse of the southwest point of Taritari encroach upon its outer

262 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

reef flat; this is gradually disappearing, as we traced it on the west
side of Maraki.

From the western spit of the south shore of Taritari extends a long
reach of black coral shingle forming the sea face of the southwestern
part of the atoll and the eastern side of the entrance to Taritari (PL 154,
figs. 2, 4). The extension of the sea face of the spit is formed by a series
of low islets connected by ledges and covered with scrub vegetation. The
vegetation gradually becomes more scanty, and finally disappears from the
northern islets and sand bars. On the north side of the passage a sti'etch of
disconnected islets forms a barrier parallel with the western opening into
the lagoon (Pis. 154, figs. 1, 3 ; 224, fig. 4). To the south of the passage
the great expanse of the shallow lagoon is occupied by numerous shoals
(Pis. 151, figs. 1,2; 224, fig. 4).

When about three miles from the western edge of the passage, we turned
in towards the anchorage (PI. 151, figs. 1-.3). On our way we passed islets,
shoals, flats, and bars, separated by deep lanes of blue water, the bottom
between them consisting of white mud formed from the disintegration of
the corals or Nullipores growing on the flats. The islands (PI. 154, fig. 3)
and islets to the north of the southern ship passage are better wooded than
those to the south ; they form only a very imperfect barrier to the sea,
which sweeps into the lagoon over the whole of the wide western flat
(PI. 224, fig. 4). Between the shoals most intricate passages connect the
lagoon with the sea on the western face of the atoll (PI. 224, fig. 4). A
section across the land rim to the south of Butaritari shows a secondary
platform lagoon on the sea face of the outer reef flat edged with Nullipore
and Pocillipore knolls, forming a shallow sink ; the reef flat is not more than
150 feet in width ; it rises gradually towards the base of the beach, this is
fringed with beach rock and coral conglomerate and rises to a height of
about seven feet. From the summit the slope runs gradually to the edge
of the lagoon ; a narrow sink exists immediately behind the beach near the
sea face. At the foot of the long slope, on the lagoon side, the beach ends
in a low steep coral sand beach, and the face of the slope is covered with
weathered fragments of broken coral gradually worn into the coarse sand
of the beach. The sink on the lagoon face of the slope is in places changed

TARITARI. 263

into a secondary lagoon of considerable size, showing that it has been formed
by the throwing up of the lagoon beach as a dam across a part of the low
reef flat, and enclosing it, has formed the secondary lagoon. The bottom
of the lagoon is covered with masses of Algae, and where the bottom
has been exposed as on the edges of sinks, or secondary lagoons, it is soft
and spongy.

From the shore to the west of Butaritari a wide mangrove flat extends
into the lagoon almost to the channel (PI. 151, figs. 2, 3) ; it is covered
with fine silt, composed of coralline Alga3 and extremely fine coral sand,
and scattered over it are large patches and masses of dead Porites, but in situ
(PI. 159, fig. 1). On our way to the southwestern spit we also came upon
a number of secondary Lagoons, formed by the shutting off of parts of the
flat of varying depth, either from the seaside beach shelf or from the lagoon
side, by spurs from the outer or imier lagoon edge (PL 158, fig. 1), or by
ridges and dams thrown up in succession at a time when the flat was open
to the lagoon and formed a part of its reef flat. One of these secondary
lagoons was fully a mile in width (Pis. 159, fig. 2 ; 160, fig. 1). The flats,
ridges, and dams are covered with low bushes, grass, and cocoanut trees.
Some of the secondary lagoons are hardly to be distinguished from large
sinks, surrounded as they are by vegetation (PL 160, fig. 2). Everywhere
on the land rim we found Taro sinks.

On reaching the village of UkiaiiQaii, on the west face of the island, we
came upon a steep coral shingle beach, formed by the breaking up of
beach rock conglomerate, and masses of Nullipores and Pocillipores, with
fragments of huge Tridacnas, as well as other shells (PL 151, fig. 4). The
breakers pounding upon this material have broken it up into coarse coral
shingle. The beach is steep on the lagoon side ; to the rear the ground
slopes very gradually towards the immense flat and secondary lagoons over
which we walked for a distance of about five miles, and which forms
the western extremity of the island on which is Butaritari village. Some
of the coral shingle material has become cemented, and forms a coarse
beach rock conglomerate or breccia, composed sometimes of rounded frag-
ments, and sometimes of more or less angular pieces of beach rock.

On our way to examine the eastern part of the atoll of Taritari, we

264 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

landed on the first of the islets of the lagoon ; it is entirely made up of
fine coral sand and coarse coral shingle, about three feet in height, and
perhaps 50 wide, and 100 feet long. Blocks of beach rock conglomerate
were scattered in all directions, many of them had been pounded into
more or less fine coral sand. From the edge of the beach, extending
down into the deeper water of the lagoon, were growing fine coral masses
and heads, mainly Madrepores, Pocillipores, and Porites. Very few heads
were seen at a depth of sixteen fathoms ; there the bottom consisted
entirely of wide lanes of coralline or coral sand separating the few coral
heads still left.

From this island eastward we made a number of soundings in the lagoon,
passing gradually from 17 to 11 to 3 fathoms off the lagoon reef flat extend-
ing across the gap (Keuea gap) between the principal islands of the south
face of Taritari.

At the gap north of the south horn of Taritari a row of islands runs at
right angles to the coral shingle beach ; they are covered with cocoanut trees
and low brush (Pis. 152, figs. 1, 2; 153; 156, fig. 1). The reef flats con-
necting the main islands on each side of Keuea gap are left bare long
enough to be used as a wagon road during certain stages of the tide.

On the lagoon face of the main islands of the land rim extends an immense
Millepore flat fully three quarters of a mile in width (PL 224, fig. 4), and to
the west of Keuea gap the flat juts out to a point nearly half-way across the
lagoon. The formation of this flat, covered with dead Millepores, over-
grown with Nullipores and coralline Algoe (Pis. 155, fig. 3 ; 156, fig. 2), is
readily explained by what we observed on the patch of Millepore heads
which coimects the shore of one of the islets in Keuea gap with the outer
sea ledge. On going from the sea beach of the islet north of the gap
(PI. 156, fig. 1), towards the outer edge of tlie reef flat, we come upon a
huge dam of large blocks of beach rock and of beach rock conglomerate
thrown up on the reef flat (PL 158, fig. 2), so as to form inside of it, and
between it and the eastern beach of the islet, a deep and wide secondary
lagoon (PL 158, fig. 1), in which Millepores are growing in great profusion.
The top of the heads of Millepores, as they arose and became exposed to
the air and the action of the sea, were gradually killed, and formed a pave-

TAEITARI. 265

ment of huge square or oblong or irregularly shaped masses of coral, with
flat tops, on which were growing Nullipores. Between these blocks was left
a labyrinth of passages or of narrow lanes covei^ed with fine coral sand, the
depth of which varied from two to three feet of water. At low-water mark
one could walk aci-oss, on the top of these blocks, from one to the other, and
thus reach the sea face of the dam thrown up by the sea on the outer edge
of the reef flat, and partly derived from the breaking up of elevated modern
reef rock. The secondary lagoon behind the dam (PI. 158, fig. 1) is about
200 feet in width, and extended from the northern side of Keuea gap as far
as the southeast point of the main island of Taritari (PI. 224, fig. 4) ; the
outer dam forming a barrier to what might be called a platform barrier
reef lagoon, which varied greatly in depth according to the level of the
underlying reef flat platform. On the west face of this secondary lagoon
the shore beach of the island forming the land rim (PI. 157, fig. 1) is
about eight feet in height, and slopes ver}' gradually towards the lagoon
face, where we come upon the continuation of the reef of Millepores we
have just de.scribed, which has been covered by this inner dam (PI. 155,
fig. 3). The Millepore reef flat must once have extended out from the east
face of the land rim, before the existence of the great dam now forming
the breaker to the disintegration of the existing islets of the land rim.

There must have been a time when the Millepores were abundant in the
outer secondary barrier reef lagoon, and when those on the wide lagoon reef
flat were connected with them, as they are now connected in the gaps be-
tween the islands, before a part of the Millepore flat was covered by the
material thrown up on the higher parts of this immense flat, both from
the lagoon side and from the sea face. As the Millepores cropped up at
the surface, the labyrinth of passages between the clusters became gradually
filled, as fast as the tops died and were broken off by the action of the
sea or from other causes. The Heliopora reef described by Mr. Henley and
Professor Sollas at the eastern horn of Funafuti owes its origin to similar
causes. There was a time when the different belts of the island itself held
to the lagoon the same relation which the outer breakwater now holds to
the secondary platform lagoon, formed between it and the outer breakwater;
as we walked across the island (PI. 157, fig. 1), we observed in several direc-

266

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

tions, bands of the same shingle beach and masses of conglomerate rock
which characterize the outer beach. As the inner island was not exposed
to as violent an action of the sea as is the present outer face of the reef
flat, the boulders thrown up to constitute the line of islands forming the
land rim of Taritari are much smaller than the huge blocks thrown up by
the rollers on the very edge of the outer reef. The fine coral sand beach
on the lagoon side of the land rim is formed from the dead tops of Mille-
pores, and from fragments of Nullipores, broken up and ground into fine
coral sand by the action of the waves of the lagoon itself. The secondary

Keuea Villagk, Taritari.

lagoon flanking the eastern face of the land rim is, in some places, entirely
shut off from the main lagoon by dams connecting the islets formed on
the outer edge of Taritari (Pis. 157, fig. 2 ; 158, fig. 1), while at other
points extensive gaps still exist, as between this islet and the main island,
where the village of Keuea is situated, forming a shallow reef flat upon
which numerous islets are thrown up by the waves of the lagoon, forming
spits at right angles to the great dam of the outer edge of the reef flat.
Between these islands and islets are passes connecting different parts of
the main lagoon ; elsewhere the outer dam only protects a deep bay, bare
at low water, in which numerous islands and islets exist formed by the
action of the waves of the lajj;oon.

TARITARI. 267

The dam or ledge on the outer sea face (PI. 158, fig. 2) was composed of
huge masses of coral beach rock and conglomerate piled up in endless con-
fusion, forming mounds of different heights, more or less connected (PI. 158,
fig. 1); on some of these the inner side, or sometimes the upper part of
the dam had been weathered and worn and honeycombed and broken into
sand sufficiently fine to allow vegetation to obtain a foothold. Here and
there we found little tufts of low bushes and shrubs growing on the summit
of the outer dam, as tliey once began on the summit of the inner row of
islands (PI. 157, fig. 2) ; these have gradually become connected either by
the formation of dams from the inside of tlie lagoon, or by the building
up of the main dam on the outer edge of the reef iiat ; this has changed
the gaps between the islands, which once connected the lagoon with the
outer sea, into bays opening either on the sea face or on the lagoon face
(Pis. 153; 156, fig. 1; 157).

The shores of the sand bars and spits of the islands and islets and the
inner shore lines of the gaps or of the bays were generally covered with
masses of dead shells. From the numljer of dead tests of Metalia,
Echinoneus, Laganum, and Spatangus mixed with the shells, they must
live in great numbers in the shallow and protected waters on the bay side.

The changes going on at certain points of the great outer sea dam show
that the material piled upon the outer sea face gradually becomes broken
and ground, and forms fii'st a shingle beach, and finally a fine coral sand
beach. Nowhere is there a better example than at Taritari of the process by
which additions are made to the land rim, and material is thrown up on
the flats, both on the sea face and on the lagoon face, and of the formation
of secondary lagoons, of huge bays or small gaps, by the gradual cutting off
of extensive areas of the reef flats, and their isolation under conditions
due to the prevalence of the trades, and to the general direction of the
wind, both on the lagoon side and on the sea side.

In Keuea gap the flat is covered with dead Millepores, the interstices
between them must have been rapidly filled by sand and ooze, by fragments
of dead shells, and Nullipores ; the whole became cemented, leaving only
here and there an occasional Millepore head cropping up above the general
level to indicate the character of the corals which have built up the

268 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

immense reef flat flanking the lagoon side of the southern face of Taritari.
The cementing of slab shingle on the top of the Millepore heads killed by
Nullipores shows how living and dead corals may alternate and strata be
passed through in which some coral is found in its natural attitude, while
the rest appears as if it had been transported by the sea a considerable
distance. This certainly is not the case on the extensive flats of Taritari,
where the old material, or rather the dead material, is still in place occupy-
ing the position it had when forming a part of the great living coral reef
flat of the lagoon.

On the lagoon flat to the west of the village of Butaritari (PI. 159, fig. 1),
the Porites covering the flat have been killed by a process identical to
that which has changed the great thriving Millepore reef of the eastern
part of the atoll into a shallow flat, over which are scattered small slabs
of Nullipores, and fragments of dead Millepores, the whole covered with
coral sand and ooze. On the wide Porites flat forming the extremity
of the land rim to the west of Butaritari, certain parts have been cut off
along given lines by accumulations of material derived from the dead
Porites and have enclosed limited areas constituting secondary lagoons.
Scrub vegetation, forest trees, grasses, cocoanut trees have sprung up on
the bars thus formed, and from the decay of the vegetation and the killing
of the Porites in the enclosed areas by exposure or by the growth of
Nullipores, the shallow circumscribed flats have gradually been filled, leav-
ing only indistinct areas, occupied by pools separated by belts covered with
vegetation, slightly higher than the general level of the western part of the
island west of Butaritari.

The high coral shingle beach on the western face of Butaritari, the
great shingle and boulder dam, extending north from the southern point
on the very edge of the outer reef flat, and the great sea wall running north
from the eastern point of Taritari, all clearly indicate how the wide reef
flats of these faces of the atoll have been shut off from free access to the
sea, and how an outer barrier has been formed behind which the land rim
of Taritari has slowly developed.

The first indication of the formation of an islet on the outer reef flat con-
sists of a line of coral shingle thrown up to a height of not more than four

TARITARI. 269

or five feet above high-water mark ; when this shingle has been pounded into
more or less coarse sand, vegetation begins to grow (PI. 157, fig. 2), and the
islands and islets thus formed become connected, until a large island is
formed by the union of the smaller ones (PI. 157, fig. 1). In this way the
land rim of Taritari, which on tlie south shore is composed of two larger
islands of no less than eight and six miles in length (Pis. 152, figs. 3, 4 ;
155, fig. 1), was undoubtedly formed. Here and there indistinct gaps still
exist to indicate the nature of the changes which have taken place, and are
still going on at the eastern, northern, and part of the southern faces.

Numerous shoals and coral patches exist in every part of the lagoon
we examined (PI. 224, fig. 4). On the slopes of the shoals large heads
of the different species of corals mentioned above are seen to a depth
varying from ten to sixteen fathoms ; here, as elsewhere, the number
of species which flourish in the lagoon is comparatively small. We exam-
ined no less than six of these little sand islets, on our way to Keuea.
According to the chart of Taritari^ (PI. 224, fig. 4), the lagoon to the north-
ward is full of ledges, shoals, and islets ; we passed through a number on our
way to the anchorage, and while in the atoll could see them rising against
the horizon in all directions and again when steaming along the west face
of Taritari (PI. 154, fig. 3).

Passing out of the western channel of Taritari, we had the opportunity
of noticing the structure of tlie land rim of the northwest point of the atoll ;
we could see that the islets on the outer edije of the reef flat were formins:
at right angles to its general trend (PI. 224, fig. 4), as sand spits extending
towards the lagoon, flanked on the sea face by ledges and boulders of beach
rock or coral conglomerate, while the lagoon end of the spits consisted of
fine coral sand. We observed nothing of special interest on the west face
of Taritari.

Napuni Island is a long narrow island (PI. 224, fig. 4), or rather a sand
spit with rocky ledges ; it extends north and south a distance of nearly
two miles on the sea face of the wide outer reef flat. Beach rock coral
conglomerate and boulders characterize its sea face, while shingle and coarse
sand are thrown up on the lagoon beaches.

' A. Chart 732.

270 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The northwest passage is, like the western passage, formed by a gap in
the outer reef flat, flanked on one side by a low islet running at right angles
to it, edged with beach rock and terminating in a long sand spit. On the
other side of the passage is a similar island edged with beach rock on the
sea face ; this passes gradually into a low sand spit forming a part of
the immense reef flat and system of shoals and islets which edge the
northwestern horn of the lagoon of Taritari.

The islands and islets on the west face of Taritari are very scantily
wooded. Pandanus begin to grow to the westward of the southern point,
and the summit of the beach and the lagoon side of the islands on the
outer reef flat are covered with Pisonias, with scrub vegetation, and tall
hardwood trees. Nowhere have we seen finer groves of cocoanut trees ;
they attain a colossal size, grow thickly in an unbroken mass (Pis. 152,
figs. 3, 4 ; 155, fig. 1 ; 157, fig. 1), and both here and at Maraki are per-
haps the finest cocoanut groves of the tropical Pacific.

Lagoon F'lat, Taritari.

THE MARSHALL ISLANDS 271

THE MARSHALL ISLANDS-

Plates 16 1-183, figs. 1, 3; 225; 226, figs. 4.-10.- 227, 228.

After a few days spent in coaling at Jaluit we passed about three weeks
in exploring the Marshall Islands, taking in turn the representative atolls of
the Ralick Chain to the north of Jaluit : Ailinglab Lab, Namu, Kwajalong,
and Rongelab, and then some of the atolls of the Ratack Chain, Likieb,
Wotje, and Arhno. The atolls of the Marshall group are noted for their
great size and the comparatively small area of the outer land rims, in
some of the atolls they are reduced to a few insignificant islands and islets.

In none of the atolls of the Ellice or Marshall groups, and only in a
few of the Gilbert Islands were we able to observe the character of the
underlying base forming the foundations of their land areas. In this respect
these groups are in striking contrast to the Paumotus, the Society and
Cook Islands, Nine, the Tonga, and the Fiji Islands, where the character
of the underlying foundations of the land rims is readily ascertained. In
a group like the Marshalls, we have as our guide for the character of the
base rock only that of the Caroline Islands, which is volcanic, while Nauru '
and Paanopa Islands, to the west of the Gilbert and to the southwest of the
Marshall Islands indicate a base of tertiary limestone.

The monotony of structure of the Marshall Islands^ is very striking.
They are all more or less irregular in outline, and genei'ally run from south-
east to northwest, with the exception of Ailinglab Lab, Mille, Majuro, and
Wotje, which run east and west. But the general direction of the atolls of
the two chains is practically the same. They evidently are summits of a
line of peaks or of ridges, forming on the one side the Ralick Chain, and on
the other the Ratack Chain, with spurs or parallel ridges indicating the
line of islands which run north of Wotje to Ailuk, Utirik, Bikar, and
Taongi, or the line of the small atolls of Kili, Lib, Lae, Ujae, and of

* Nauru, von Dr. Augustin Kramer. Globus, Vol. LXXIV., No. 10, September, 1898.
2 Plane von den Marshall Inseln; Hydrog. Amt d. Reichs Marine Amts, No. 113, 1890.

272 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Eniwetok, which is more or less parallel with the Ralick Chain, while
another line having the same trend is formed by Ebon and Namorik.

Parallel with the western face of Taongi, an extensive secondary
lagoon has been formed, similar to those we have described at Jaluit,
and at many atolls in the Gilbert Islands and the Panraotus.

Mille is characterized by a small satellite, elliptical in outline, about five
miles in length, and two in its greatest width ; its southwestern shore is
flanked by large islands, while the northern face of the atoll is indicated
by a comparatively bare reef flat. The depth of the lagoon varies from
two to three fathoms ; there is an opening on the northwestern face for
boats. As will be seen from an examination of the charts, in such atolls
as Mille, we find the passages, of which there are a large number, well
indicated by great sand spits and sand bars extending far into the lagoon,
as for instance the Reiher and Burrh Passages. The islands west of Luku-
nor on the south face, and the islands and islets opposite the passage in
the southern face all indicate the part which the trades have taken in
depositing these bars and islands and shoals near the openings forming
the ship channels. The atolls of Wotje, Mille, and Majuro are similar in
outline. The Eniwetok group, on the other hand, is somewhat circular.
The islands of its land rim are scattered more profusely on those parts of
the reef flat upon which the trades have the greatest influence ; its lagoon
is from eighteen to twenty-five fathoms in depth.

In all the atolls of the Marshall group the slope from the sliore on the
lagoon side is comparatively steep ; the inner reef flat however varies greatly
in width, according to its position near a gap or near a pass, or near the
central part of an island of the land rim of greater or less dimensions.

The atolls of Odia (Ailinglab), Rongelab, Wottho, Likieb, and Rongerik
are very similar, with the exception that the spits of Rongelab and Odia
turn towards the east, while that of Likieb turns towards the west. The
atolls of Aurh, Maloelab, Erikub, and Ailuk are also similar in structure ;
their western faces are open to the sea, as is the case in some of the atolls
of the Gilbert Islands, like Tarawa and Tapeteuea. Situated on banks of
irregular outline, and but imperfectly known, are the islands of Utirik and
Taka, the atoll of Bikar, which might perhaps be classed with Aurh. Mejit,

THE MARSHALL ISLANDS. 273

Jemo, Lib, Kili, and Jabwat are small islands, the summits of diminutive
ridges surrounded by reef flats similar to those of somewhat smaller islands,
like Tike'i and others in the Paumotus.

I am informed by our pilot that Lib and Mejit both have shallow,
diminutive lagoons filled with brackish water, entirely shut off from the
sea, with neither corals nor fishes, and only a few diminutive shells living
in the lagoon. Jemo has no sink, and is flat. Jabwat and Kili have
small sinks in which water collects. Jaluit, Namu, Kwajalong, Ujae, and
Wottho are more or less elongated, irregularly shaped atolls. Arhno is
the most peculiar atoll of the Marshall group, with characteristics of
some of the other atolls extravagantly exaggerated. Finally, Ebon, Nam-
orik, and Lae, three small atolls, six to seven miles in diameter, circular in
outline, approach nearer the condition of a theoretical atoll than any of the
other islands in the Marshall group. These form the principal types of
atolls of the Marshall Islands. The western faces of Namorik and Lae are
formed by a narrow reef flat ; while in Ebon the western shore slanting
slightly towards the south is occupied by islands of considerable size,
through which a long and intricate pass leads into the lagoon. The
lagoon of Ebon varies from eighteen to twenty-five fathoms in depth.
That of Namorik has recently been gradually filled up, as it is impossible
for a schooner to pass the western reef flat ; when first visited by whites,
schooners of considerable size anchored in what is now a closed lagoon
as far as navigation is concerned. In Ebon a pass from the westward
leads into the lagoon with a depth of from ten to twelve feet. The
western face of Ebon is flanked on its lagoon side with innumerable sand
spits, sand bars, and coral patches; the passes into the lagoon are com-
pletely blocked by numerous shoals which extend througli it.

Ujelang, one of the Marshall Islands, nearly 300 miles to the west of
Ujae, has the same general direction as the islands of the Ralick Chain.
It is eleven miles in length, with a greatest width of about two and
a half miles ; it is evidently the summit of a long narrow ridge to the
west of the Marsliall Islands. The depth of its lagoon is said to be
eighteen to twenty fathoms, and numerous coral patches and sand bars are
scattered through the interior.

18

274 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The land rims of all the atolls in the Marshall Islands are really
msignificant in comparison with the wide expanse of the lagoons they
enclose ; their depth as well as that of the passes is also remarkably
uniform. The conditions existing over the Marshall group are less varied
than they are in any of the other groups of atolls we have examined ;
there is not even the same diversity which exists among the atolls in the
Paumotus. The amount of moisture which falls in the Marshall Islands is
not only great, but most constant, and, owing to the varying position of
the faces of the atolls with reference to the trades, we find in consequence
the vegetation far more luxuriant than on the Paumotus, althougli the
extent of the land rim is much more limited. Dana has made an approxi-
mate estimate of the land areas of some of the atolls of the different
island groups;^ they show remarkably well the conditions which have
resulted from tlie peculiar geographical position of the Paumotus as
contrasted with the Marshalls, or the Marshalls as contrasted with the
volcanic atolls of the Carolines and of the Society Islands. It is evident
that in the case of volcanic islands, like those of the Society Islands, the
Fijis, the Carolines, Samoa, and the Cook Islands, tlie land areas are, in
consequence of the greater hardness of the volcanic rocks, far greater in
proportion to the extent of the lagoons than in such districts as Lau
in Fiji, where the atolls are either elevated coralliferous limestone islands, or
where they are partly limestone and partly volcanic ; or in the extensive
areas of the Paumotus, where they are coralliferous limestone. When we
come to groups like the Marshall, EUice, and some of the Gilbert Islands,
there is no such connection between the dimensions of the lagoon and the
land rim ; the foundation has been eroded and much of the material which
forms the land rim is consttintly shifting backward and forward during the
existence of the trades ; it is thrown up in one direction on the narrow land
rim in favorable exposures, while it is eaten away from the opposite side
during the prevalence of the westerly winds. In the Marshall Islands,
where the lagoons present such a long reach to the prevailing trades, we
often find on the lagoon face, either on the eastern or western sides of the
atoll, an amount of mechanical work performed during the season of the

•1 Dana, loc. cit., p. J 69.

THE MARSHALL ISLANDS. 275

trades, entirely out of proportion to that which takes place in smaller
atolls, although they are exposed to the same conditions, but where the
sea does not gather the strength it attains in these gigantic atolls.

It will be seen on examination of the charts of the various Marshall atolls
that the land rim is especially developed on the side exposed to the raking
of the northeast trade. It is somewhat less developed on the faces where
the trades strike the shore at a greater angle. The land rim on the
southern and western faces is usually bare of islands and islets. This is
well seen at Namu, where the bulk of the land rim is on the southern and
eastern faces, while the western and northern faces, except at the northern
horn are a belt of reef flats awash. In Odia, where the west coast faces
almost southwest, the effect of the trades in throwing up the land rim is
more apparent. It is somewhat less so on the southeastern face and
hardly appreciable on the northwestern face. Similarly we may trace the
effect of the trades on the extent of the land rim of the irregularly
shaped Menschikov atoll. Wherever the coast line faces the general trend
of the trades, the narrow land rim of the Marshall Islands is found ;
wherever, on the contrary, it runs more or less parallel to it, tlie land
rim is limited to a few insignificant islands and islets ; where the outer
face of the lagoon is protected during the greater part of the year, the
land rim is still more insignificant, or becomes a belt awash. Where any
part of the land rim is exposed to the northwest winds a few islands
and islets are thrown up on a part of the reef flat which is usually pro-
tected from the eastern trades. By carefully examining the charts we
may usually determine the causes which have brought about special condi-
tions on short stretches of the outer land rim in such irregularly shaped
lagoons as Menschikov, Namu, Arhno, and others.

The amount of water forced by the trades into the lagoons of the
Marshall Islands must be very great, the land rim being reduced to a
minimum, and a large proportion of the outer rim often covered by a
considerable depth of water either on the lee or on the weather side.
Tlie islands and islets of the land rim are, except in occasional instances,
the merest threads of land ; the lagoon is often separated from the sea by
a dam not more than six to seven feet in height, and sometimes not more

276 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

than twenty to twenty-five feet in width ; the outer reef platforms like-
wise are often very narrow, in marked contrast with the wide reef flats of
some of the Paumotu or Fiji Islands. Again the land rim is often com-
posed of a number of small islets separated by gaps of greater or less depth,
nearly as large as the islands they separate, allowing additional circulation
into and out of the lagoon. In fact, as has been noticed before, there is no
group of atolls where the land rims are reduced to such an insignificant
area as in the Marshall Islands, and where what are usually shallow gaps
become deep passes with sufficient water to allow the entrance of large
ships. In the atolls of the Marshall Islands the number of passes suitable
for navigation is in marked contrast with those of other atolls (Pis. 226,
227), especially in the Paumotu and Fiji Islands. It is not uncommon to
find passages varying from eight to twenty fathoms, or in fact as deep as
the deepest part of the lagoon itself. This would seem to indicate that
the material forming the outer rim of the Marshall Islands atolls rested
upon a submarine platform of a depth varying from eight to twenty
fathoms, and that the mass of material kept in motion and affected, accord-
ing to the local conditions, by the sea and by the winds, forms the special
feature of each atoll in the Marshall Islands.

Although the trades are the principal winds at work shaping the
land rims of the Marshall Islands, yet during three months westerly
winds prevail during the change of the monsoons. When the length and
trend of some of the lagoons is taken into consideration, we may have
acting upon the lagoon sides of the land rim, especially on the beaches
of the western islands, waves nearly as powerful as those beating on the
eastern side of the same islands daring tlie trades. Thus the movement
of loose material on the lagoon side is far more extensive on the exposed
patches and reef flats of the western slope of the eastern islands of the
land rim, than is usually the case in lagoons of a smaller size. The
reach which the sea obtains during westerly winds, or during the season
of the trades, is often from forty to sixty miles, a distance great enough
to act with considerable force on the movable material of the land rim of
these atolls.

The level at which some of the dead coral heads still in place are found,

THE MARSHALL ISLANDS. 277

as, for instance, at Gehh and Tengeli on the west. face of Menscliikov, and
the manner in which they are worn, or undercut, and form walls or isolated
tables, as it were, would seem to indicate a slight elevation perhaps of a
couple of feet, since the corals flourished on the reef flat.

The amount of sand which floats off from a lagoon and is blown to sea
is very considerable ; fresh material is constantly added from the beaches,
from the spits, and from the gaps along the land rims of such atolls as
Likieb and others in the Marshall Islands. The distance to which sand can
be carried by the trades is clearly shown by the amount of sand we
found in our nets in all the surface hauls in the Marshall Islands when
off the lee side of the atolls ; sand is floating there in considerable quanti-
ties. Off the east coast of the United States, from Cape Hatteras south,
shore sand is carried out to sea by the prevailing westerly winds to a
very considerable distance.

It is interesting to compare the charts of the great groups of atolls in
the tropical Pacific, and to note the extensive differences existing in the
outlines of the atolls. Taking the Paumotus, as a whole, the atolls are
elliptical ; the few of irregular outline have rounded corners, and a number
are circular (Pis. 201-206). In Fiji many of the Lau Islands are most
irregular in outline ; others, on the contrary, are circular or elliptical
(PI. 220).

The principal atolls of the Ellice Islands are of very different shapes
(Pis. 221, 222). In the Gilbert group we have atolls varying from trian-
gular to rectangular and elliptical or angular shape, not a single atoll
having the so-called typical outline (Pis. 223, 224, 226).

In the Marshalls a few atolls are circular,^ but the majority of the
large atolls vary even more in shape than those of the groups we have
enumerated (Pis. 225, 227, 228).

The Carolines likewise vary greatly in outline (Pis. 229-233), both the
volcanic islands as well as the low groups. In fact, by far the great majority
of the atolls of the tropical Pacific are irregular in outline, and it would be
impossible to detect from the charts their resemblance to the typical atoll.

' Kubary has given an excellent account of Ebon and a sketch of the main pass into the atoll.
Journal d. Mus. Godeffroy, Heft I. p. 33.

278

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

We made a number of soundings from south of Nurakita towards the
Marshall group ; ' these, in addition to those of the " Penguin," clearly show
that the EUice Islands are isolated peaks (PI. 221) rising from considerable
depths (from 1500 to over 2000 fathoms), and that the same is the case with
the Gilbert Islands (PI. 223) ; Maiana, Tarawa, and Apaiang however being
summits of a secondary plateau with greatest depths of 413 fathoms
(PI. 223). The thirty soundings we made between the atolls of the
Marshalls (PI. 225) ^ indicate that they also rise as independent peaks or
ridges, with steep slopes, from 2000 to 2500 fathoms. The atolls are not
connected by a great plateau or a broad ridge as would seem to be indicated
by the trend of the atolls in two parallel lines, forming the two sides of
the Marshall Islands group. The parallel chains of atolls of the Marshalls,

the Ralick, and the Ratack are really
only the summits of isolated peaks
rising but a few feet above the sea
level. The soundings between Elmore
and Namu are not as deep as between
other atolls of the group ; they indi-
cate a connecting ridge with a great-
est depth of less than 1100 fathoms
(PI. 225). Between Rongelab and
Ailinsrinae even shallower water is
indicated. The Gilbert and the Mar-
shall Islands are separated by great
depths, over 2500 fathoms. South
of Nurakita towards Fiji no depths
greater than 2000 fathoms have as yet been reported (PI. 221). The
Marshall, as well as the EUice and Gilbert Islands, seem to be somewhat
higher than the Paumotus ; but this difference is only apparent, and is due
to the difference in the height of the tides ; it is very small in the Paumotus,
while in the former groups it may be five and even seven feet.

After leaving: Arhno, our soundings indicated that we had struck the

-><>^;0!<»*ffi;.;-

Marshall Island Canoe, Wotje.

1 Mem. M. C. Z. XXVI., No. 1, Prel. Rep., p. 61, Stations 194-207, 1902.
"^ Loc. cit., Stations 208-237.

JALUIT. 279

deep basin we encountered between the Gilbert Islands and Jaluit, and
its extension in the northern Marshall Islands, a comparatively flat basin
varying between 2200 and 2G00 fathoms in depth, the spurs of which
form the channels between the atolls.

The vegetation of the atolls of the Ellice,' Gilbert, and Marshall Islands^
is more luxuriant than that of the Paumotus, probably from the greater
rainfall, though the number of species of plants characteristic of the western
atolls is not much greater. It is only in the larger western volcanic islands
— the Fiji,^ Samoan, and Caroline* group — that we note the marked
increase in the number of species of forest trees allied to those occurring
still farther west, over those on the eastern groups, like the Cook * and
Society Islands.

Jaluit.

Plates 161-166, 167, fig. 3 ; S35 ; 226, figs, i-10 ; 227, figs. 1-3; 22S, fig. 2.

The atoll of Jaluit is rectangular in shape ; the eastern and western faces,
however, run to a point towards the north ; it is abqut thirty miles in length
and seventeen miles in width (PI. 226, fig. 6). The land rim to the south of
the southeast passage forms the island of Jaluit, a long, extremely narrow
strip of land (PI. 161, fig. 1), in places but a few yards in width. It con-
sists of a high coarse shingle beach (PI. 165, fig. 1), extending from Jabor to
the southern point of Jaluit, where it forms a sharp angle, and extends north
about three miles. Across the lagoon angle of the southern horn extends a
wide triangular reef. The northeast coast from the eastern cape to the
northern point consists of a series of small islands and islets separated by
gaps and shoals with a number of deeper passages between them.

' See C. Hedley, General Account of the Atoll of Funafuti, p. 20, for an account of the flora of the
Ellice Islands.

' There is an excellent account of the plants of the Marshall Islands by Betche, Gartenzeitung
1884, p. 13.<i.

' A full account of the flora of Fiji will be found in Seemann, Flora Vitiensis. The AlgiE and
corallines of Fiji, Tonga, Samoa, have been described by A. Griuiow in Jour. d. Mus. Godeifroy, Heft
VI. p. 23. The lichens of the Tropical Pacific are enumerated by Dr. A. v. Kampelhuber in the Journal
d. Museum Godeffroy, Heft IV. p. 269.

* Ponapean Trees, Plants, Shrubs, p. 328. The Caroline Islands, by F. W. Christian.

* A list of the ferns of the Cook Islands lias been published by C. Luerssen in Jour. d. Mus.
Godeffroy, Heft I. p. 5a.

280 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Some of the islands on the east face, like Medjado, Emidj, and others,
near East Cape, are of considerable length, being over three miles, but
all are exceedingly narrow, slender threads of land, forming a land rim
flanked on the sea face by high shingle beaches, on the lagoon face by sandy
beaches and spits which project out on the lagoon flat of the atoll (PI. 162,
fig. 2). Many boat passages exist between the islands and islets, both on
the western and on the eastern faces. There are three main ship channels,
the southeastern (PI. 161, fig. 2), the northeastern (PI. 162, fig. 2), and the
southwestern passage (PI. 163, figs. 1, 2), all in the southern half of the
atoll (PI. 226, fig. 6), and deep enough to allow large ships to enter the
lagoon. Over the whole lagoon are scattered numerous flats and coral
patches. These, however, are most extensively developed on the flats of
the lagoon side in the vicinity of the ship passages which extend from two
to three miles out into the lagoon (PI. 226, fig. 6) ; the flats are formed by
the sand which blows in from the sea face of the ship passages and has
gradually extended the land rim as gigantic spits into the lagoon. In fact
the flats flanking the ship passages represent, on a large scale, the spits
found on the lagoon side of the smaller gaps between the islets and sand
bars of land rims not only in the Marshall Islands, but also in the Ellice
and Gilbert groups.

It will be noticed that at Jaluit the greatest area of land is on the
weather face of the atoll (PI. 226, fig. 6). The entrance into Jaluit Harbor
(PI. 228, fig. 2) Avas surveyed by the officers of the '" Albatross " ; their survey
shows clearly the peculiar sand flats and sand bars which have been thrown
up by the currents and by the trades on the lagoon face of the northern and
the southern side of the entrance into Jaluit. The average depth of the
lagoon is from ten to fifteen fathoms, though there are large stretches of
the lagoon where the depth varies from twenty to twenty-five fathoms.
The southwestern face of Jaluit (PI. 226, fig. 6), between Pinglapp
Island, the western horn of the atoll, and the south point is flanked
by a submerged reef flat as far as the southwest pass, and beyond by a
narrow land rim with islands and islets (PI. 163, figs, 1-3), much as
is the eastern face.

The islands are flanked by low coral shingle beaches, alternating with

JALUIT. 281

reaches of large rounded boulders of beach rock or coral conglomerate;
the summit of the steep beach is covered with low vegetation ; behind it
rise a few cocoanut trees, forming a slender line on the narrow land
rim of the atoll.

The land rim of the southeastern part of Jaluit is certainly narrower
than that of any of the many atolls which we have seen thus far. The
outer reef platform itself is also narrow, judging from the position of the
line of breakers as we saw it when steaming north along the east coast
of Jaluit from the southern point. On the eastern land rim, north of the
south point of Jaluit, there are comparatively few cocoanut trees and
Pandanus, and here and there only a few large hardwood trees, standing
out in the narrow belt of low vegetation which surmounts the summit
of the high shingle beach edging the eastern face of Jaluit (PI. 161, fig. 1).
Considerable driftwood is also seen on the beach, consisting of logs of
Pandanus, of cocoanut trees, and of different kinds of hardwood.

The coarse shingle beach of the east face becomes gradually higher as we
go north. The upper part of the beach resembles a stone wall (PI. 165, fig. 1) ;
it is steep, and consists entirely of coarse slabs of beach rock. The top of
the beach is exceedingly narrow, so much so that it looks like a dam ; it also
slopes abruptly towards the lagoon side. Steaming along the eastern coast
of the atoll, we could see over the eastern land rim and distinguish the
shoals and islands and islets, not only in the lagoon, but also across on
the western face of the atoll.

As we approach the southeast entrance into Jaluit, the reef flat of the
northern extremity of Jaluit Island becomes somewhat wider (Pis. 164;
167, fig. 2), as well as the land rim which is club-shaped (PL 228, fig. 2),
and forms the southern spit of the entrance into Jaluit. On the northern
side of the entrance, which is not more than two cable lengths wide,
stretches Eniibor, a low island (Pis. 161, fig. 4; 164, fig. 1), flanked like
the island of Jaluit with beach rock and conglomerate ledges and shingle
beaches; it is covered with a scanty growth of cocoanut trees and witli a
luxuriant growth of bushes. In the southern extension of Eniibor lies a
wide spit formed by three low islands, thrown up on tlie northern side of
the entrance to the lagoon (Pis. 161, fig. 4 ; 228, fig. 2). After passing

282 "ALBATKOSS" TROPICAL PACIFIC EXPEDITION.

into the lagoon, we turned sharply to the south, and anchored opposite
the principal village of Jaluit, near the northern extremity of the island
(PI. 228, fig. 2). The high and steep beach flanking the eastern sea face
of Jaluit Island is made up of large flat blocks of coral rock, many of
which were extremely hard, and masses or fragments of corals and coral
beach rock of all sizes, washed up on the outer slope of the island. Near
the northern extremity of Jaluit Island the outer sea face slope is steep,
while the inner slope from the summit of the outer beach to the edge of
the lagoon is very gradual ; the lagoon beach is scarcely more than one or
two feet above high-water mark. The slope which extends from the base
of the shingle beach towards the Nullipore knolls and the masses of
Pocillipores (PI. 164, fig. 2), which form the outer edge of the reef platform,
is very gradual (Pis. 164, 165). Judging from the many outliers left on
the reef flats (PI. 165, fig. 2), an extensive flat of beach rock conglomerate
must once have extended from the base of the shingle beach to the outer
edge of the reef platform, from two to three feet higher 'than its present
level. This rocky flat, however, is no longer continuous ; it has been planed
off and gouged into buttresses at right angles to the trend of the outer
shingle beacli, forming spurs which extend sometimes fifty to sixty feet
towards the outer edge of the reef platform (Pis. 164, fig. 2 ; 165). The
space between the extremity of those spurs and the outer edge of the plat-
form has been planed o& by the sea, and is covered by needles or mounds
and spires of beach rock and coral conglomerate denuded and eroded into
all kinds of fantastic shapes (PL 167, fig. 2).

The knolls on the outer edge rise from two to three and sometimes
four feet above the general level of the outer reef flat (PI. 164). They
are as usual composed of Nullipores and of masses of Pocillipores ; the
edge is indented and cut into numerous digitiform lobes. The outer
beach is about seven feet in vertical height ; the boulders and fragments
of coral and of beach rock conglomerate on the uppermost part of the
slope are generally pitted and honeycombed. On the lagoon side the
slope is more gentle ; it is covered by a mass of coral fragments thrown
over the summit of the shingle beach by the action of the sea ; this mass
gradually passes into a finer body of coarse coral sand, till we strike the

JALUIT, 283

beach rock conglomerate cropping out on the lagoon side (PI. 162, figs. 1>
3, 4), and is the extension of tlie beds of beach rock conglomerate form-
ing the spurs we have described on the sea face of the shingle beach
(Pis. 164, 165).

On the lagoon side of the beach rock conglomerate a narrow sink
has been formed between it and the numerous smaller shingle islets so
common in the lagoon of Jaluit (PI. 162, figs. 1, 3, 4), the outliers of a
former extensive coral conglomerate flat ; from the islets the slope is
gradual to the bottom of the lagoon itself. Immediately east of the
village of Jabor the island is widest, and the beach rock conglomerate
of the inner land face passes very gradually into the slope of the
lagoon (PI. 162, fig. 4), while further to the south, the belts of inner and
outer beach rock conglomerate are separated by a comparatively narrow
land rim (PI. 162, figs. 1, 3), showing that the inner and outer reef ledges
of beach rock conglomerate were once continuous, and as they were gradu-
ally elevated, have been eaten into on the one side to form the spurs on the
sea face (PI. 165), and on the other side to form the platform edging the
lagoon side of the reef flat (PI. 162, fig. 4). At some subsequent time,
the beach rock dam or coarse shingle beach was thrown up to its present
height ; the material for this dam was derived from the beach rock which
once filled the space between the spurs on the outer sea face, and whatever
material was planed off on the outer face from the top of the beach rock
platform. The beach rock conglomerate nowhere rises to more than about
two to three feet above high-water mark.

The narrow parts of the outer land rim to the south of Jabor are bare ;
the blocks of beach rock conglomerate are not sufficiently disintegrated to
allow the growth of any vegetation ; but on some of the wider parts we
found Pisonias and Pandanus. The condition of the islands on the lagoon
side to the south of Kennedy's wharf gives an excellent idea of their mode
of formation, and how they have been thrown up on the lagoon side, and on
the wide lagoon reef flats of beach rock conglomerate. Secondary lagoons
have gradually been formed from the disintegration of the beach rock con-
glomerate by the waves of the lagoon ; the land rim has been gradually
widened on the lagoon side as on the outer face, but in a less degree.

284 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The village of Jabor is on the west side on the widest part of the
island of Jaluit (PI. 228, fig. 2) ; the wider land rim forming the extremity
of the island has been formed by the washing to the westward of mate-
rial from the outer southern face of the entrance to Jaluit, and thus
little by little the fiat upon which Jabor is built has expanded. One can
see how the western shore line is gradually extending into the lagoon,
forming, near the coal wharf, a long spit made up of small shingle and
more or less coarse coral sand, gradually moving around the northwest
point of the island during the season of the trades. The beach so formed
is fully three feet higher than the island itself. Near our anchorage we
could see masses of sand blown across the narrow land rim into the lagoon
and distributed by the winds and the drift of the tides over the bottom of
the lagoon. The flat of the northern extremity of Jaluit Island is barren ;
the ground is covered with small fragments of corals and beach rock
conglomerate, more or less weathered and edged on the lagoon side, to
the south of the northern point forming the harbor, by a fine sand beach ;
this to the south of the settlement passes into the beach rock ledge of the
lagoon shore (PI. 162, fig. 4) ; the ledge has a steep face, and is eaten and
honeycombed and weathered by atmospheric agencies and by the action of
the sea fully as much, only on a small scale, as some of the most char-
acteristic of the elevated coral reef rock ledges in other parts of the
Pacific.

Immediately back of Jabor are two fresh-water lagoons, or rather brack-
ish lagoons, formed by the throwing up on the lagoon face of low beaches,
and thus isolated from the inroads, both of the waters of the lagoon and
of the sea (PI. 166, fig. 2). They rise and fall with the action of the tides,
showing how loose or porous the dam of the narrow land rim is. These
sinks ^ supply a large amount of the water used by the natives ; immediately
around the edges of some of the sinks mangroves are growing.

The reef flat to the south of the wharf is made up of beach conglomerate
gradually disintegrating and forming flats covered with larger and smaller
fragments, either of dead corals or of beach rock conglomerate (PI. 162,

■ One of the prettiest sinks that exist in the Marshall Islands is found on the island of Eniibor,
a photograph of which has been taken by Mrs. Brandeis (PI. 166, fig. 1).

JALUIT. 285

fig. 4). Large blocks of Porites and of Maaandrina, some of them fully five
feet in height, occur on the flats of the lagoon side ; they are the remnants
of the mass of beach rock conglomerate which was once elevated above the
present level of the summit of the reef rock conglomerate beach. It was
interesting to examine the rolled corals on the outer beach and to trace
the gradual disappearance of the typical characters of the different species
of corals, showing when fresh and first thrown up on the beach all their
specific characteristics, losing them as they become gradually worn by the
action of the sea, until finally the rolled masses are changed to rounded
pebbles, which have lost their coral features and look much like the
pebbles of any shingle beach. We made a large collection of the rolled
corals to show the different conditions under which the same species may
be found in close proximity, and to assist in determining the fossil corals of
some of the elevated coral reef ledges, where they must have been subjected,
before being fossilified, to the same modifying agencies as those of the
present day.

The surface of the beach rock conglomerate or breccia on the outer
sea-face platform is full of potholes of all shapes and sizes (PI. 165, fig. 2),
many of them still partially filled with the pebbles to which they owe their
origin. While the sea is rushing up and down across the face of the outer
reef flat, the pebbles are revolved rapidly in the potholes, wearing them
deeper and deeper, until finally they reach a depth where the action of the
sea becomes less or ceases. Adjoining potholes are often gradually united,
according to their shape and position on the outer reef flat, forming deep
bowl-shaped recesses, or more or less narrow troughs and intricate channels.

The large blocks found on the sea face of the reef flat (PI. 165, fig. 2)
have either been torn off from the knolls of the outer edge of the reef flat,
or else they are a part of the conglomerate beach rock or breccia ledge left,
owing to their greater hardness, after the erosion of the conglomerate on
the flat. The slope of the outer platform is quite flat (Pis. 164 ; 165, fig. 2 ;
167, fig. 2) ; a comparatively shallow sink extends between the outer knolls
and the base of the shingle beach.

Outer reef platforms as they exist in the Pacific and Indian Ocean are
only slightly developed in the West Indies.

286 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Millepores are the most abundant of the corals within the lagoons of the
Marshall Islands. In addition to Millepores, Porites, and the other larger
corals, which have already been mentioned, we collected Pavonia and
Fungia on the reef flats of Jaluit, and also a very peculiar Millepore,
different from any we had found elsewhere. The flats of the lagoon, both
on the eastern and on the western faces, are covered with Nullipores,
wherever coarse coral sand or coral shingle exists. On the lagoon face
of the land rim corals are quite abundant, as well as on the slopes
of the sand spits, to the north of the entrance to Jaluit. When the
coral heads reach the surface of the flat, they are overwhelmed by sand,
Nullipores begin to grow upon the dead materials, and little by little
they become covered, forming an inner coral reef flat similar to those
we have observed both on the inside and outside reef flats in other groups.
Following the lagoon slope, tlie corals disappear gradually towards deep
water, and at a depth of from sixteen to twenty fathoms we find only
patches of Nullipores and wide lanes of sand separating the few diminu-
tive heads still left.

The average depth of the Jaluit lagoon varies from eighteen to twenty-five
fathoms, although here and there a deeper hole occurs. Large stretches of
the lagoon are comparatively shallow, having undoubtedly been filled up
from the weather side ; we can see how a smaller lagoon might readily
have been filled from the sand and shingle blown in over the outer land
rim during the prevailing trades. This filling up of the lagoon by sand
and shingle from the outside is a prominent feature in the Marshall Islands ;
it modifies to a considerable extent the width of the flats adjoining the
land rim.

From our anchorage in nine fathoms came up a block of worn coral,
probably blown over the shingle dam into the lagoon from the outer
sea face. We found this to be a common feature on many of the islands
of the Marshall group, where the sea often breaks over the narrow outer
land rim, carrying large blocks of coral, which are deposited in lanes
along the lagoon slope of the land rim between the lines of outliers of
higher buttresses of harder breccia. This was perhaps better seen in Arhno
than in any other island of the group.

JALUIT. 287

In many of the Marshall Islands coral boulders and dead corals have been
thrown up on the low and nari'ow land or over the reef flat before the
formation of islands and islets on the inner lagoon side had taken place.
They show the continuity in the formation of the outer land rim and of
the inner islands and islets forming spits, as at the eastern point of Arhno.
Many of the ditches or sinks we have noticed are formed by the junction of
these islands and islets in lines parallel to the outer land rim. The sinks
may be circular, elliptical, or long troughs.

On our way to Imrodj Island (PI. 226, fig. 6), on the east face of Jaluit,
we came upon a mass of shells indicating either the extent to which the
lagoon has been filled up, or the extent to which patches of corals once
flourishing have gradually been overwhelmed by the sand blowing into the
lagoon. The island of Imrodj is on the east side of one of the northeastern
passes (PI. 162, fig. 2) ; it is flanked by a small sandy islet covered with
cocoanut trees ; the islet has been blown up on the reef flat during the
last seven years. Enormous breadfruit trees flourish on Imrodj and one
of the finest groves we have seen covers its central part.

A section across tlie island of Imrodj is most characteristic ; on the
lagoon side a reef flat fully 500 feet in width slopes gently from the
outer edge to our anchorage into six fathoms. On the way from our
anchorage to the shore we passed through magnificent patches of Pocil-
lipores, masses of Porites and Madrepores growing most luxuriantly from
about four fathoms to the shore which is flanked by a comparatively
steep coral sand beach. From the summit of the sand beach, which is
perhaps five or six feet high, the slope extends inland, forming a sink
about one mile in length occupying the greater part of the island. The
lagoon sand beach is covered with fragments of corals and coral heads
from the adjoining reef flat, killed by exposure to the air and overgrown
by Nullipores. Similar boulder reef flats are found in many of the
Marshall Islands.

As we go towards the sea face of the island at right angles to the lagoon
side, we come upon rolled masses of coral gradually increasing in size till
we reach the summit of the outer sea beach. There the coral rocks, the
coral and beach rock conglomei'ate boulders consist of huge masses thrown

288 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

by the breakers over the summit of the steep shingle beach, at least eight
to ten feet above high-water mark. From the base of the shingle beach
extends a wide outer reef flat consisting of beach rock conglomerate, Avith
occasional coral heads, planed down to a gradual slope from the base of
the beach to the outer edge of the reef flat.

At the northeastern extremity of the island a shingle bar has been
thrown across the outer sea flat. On this an island has been formed, and
a secondary lagoon cut of directl_y across the wide gap which separates
Irarodj from the island to the east. The formation of the island and of
the secondary lagoon on the outer reef flat, within less than seven years,
shows the extent to which modifications may take place in the arrange-
ment of the material constituting the outer land lim of the Marshall
Islands. In the course of a few years charts indicating the position of
the islands and islets of the land rim may become rapidly obsolete, as
well as the soundings on the lagoon face, where sand is blown over the
narrow land rim, or where gaps between adjoining islands have been closed,
changes which rapidly alter the general appearance of the outer land rim.
The condition of the sea face reef flat of Imrodj shows that the island
flanking it on the lagoon side is made up of material thrown up on its
inner slope, derived from the growing corals on the sea face and of the
older beach rock and coral conglomerate material once elevated a few
feet above high-water mark.

The efficiency of a wide outer reef flat in protecting from disintegration
islands forming a land rim«is well seen at the Marshall Islands. Where the
outer reef flat platform is narrow, the huge breakers and rollers strike the
beach slope at high tide (Pis. 161, fig. 1; 165, fig. 1), and either carry its
material out to sea again or break through the beach and widen the outer
reef flat at the expense of the land rim. Where there is a wide outer reef
flat platform there are at high tide sometimes five or six successive lines
of breakers on the flat (PI. 167, fig. 2), the first of which strikes the outer
sea face of the shingle or sand beach with a very moderate force ; while
over a narrow platform a single line of breakei's thunders directly upon
the beach and distributes an immense amount of loose material at each
high tide. The pools on the lagoon side of wide outer reef flats are

JALUIT. 289

gradually filling with material derived from the sea face, and islands and
islets, similar to those existing on the lagoon side of Imrodj, are eventually
formed.

A marked characteristic of the part of the sea face of Jaluit atoll near
Imrodj is the number of deep pools which separate the islands and islets,
showing that the sea must once have been driven through passes between
these islands, when they formed channels across the outer reef flat. These
channels have gradually become closed and the sea shut out from the
lagoon by the mass of material forming dams thrown across the gaps. At
Jabor, where the reef flat is of moderate width, one can see that should
hurricanes occur the whole island would be swept by the sea; even during
one of the very high tides we experienced at the time of ordinary trade-
winds, the moderate sized rollers, pounding upon the outer sea face of
Jaluit, washed over the top of the low shingle dam land rim and flooded to
a certain extent the interior of the island, filling with sea water the sinks
and pools upon which the natives depend for fresh water.

The filling up of the gaps at some of the passes is often quite rapid ;
when the sand spits on opposite sides reach out well into the deeper water
of the lagoon, and sand comes from the two sides of the gap, the building
up of the dams is rapid and the spits soon become connected.

On leaving Jaluit we steamed directly across the atoll towards the
southwestern passage. As the islands and islets of the west side came
into view we saw that they arose from a wide reef flat which, like the
flats on the flanks of other passages, extended far into the interior of
the lagoon. The lagoon face of the islands and islets was edged with
fine coral sand beaches, while on the sea face they were edged with
coral beach rock conglomerate. The islands and islets of the western
land rim are connected by flats covered with beach rock conglom-
erate. It is not astonishing that the material on the lagoon face of
the islands on the western side of the atoll showed greater mobility
than the material on the reef flat off the western face of the eastern
islands.' The sweep of the trades across the lagoon is considerable, and

' The western reef platform is wide, much wider than on the east side. This is natural, as the
conditions are exactly reversed.

19

290 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the amount of material they pile up and shape into beaches and dnnis
on the lagoon face of the western islands is quite marked as compared
with the material moved on the west face of the islands forming the
eastern land rim of the atolls.

On the western side, hardwood trees, the " iron wood trees," grow in
considerable numbers. The western passage is long, narrow, and wind-
ing (PI. 226, fig. 6) ; it extends into the lagoon from the western side
between lines of reef flats, composed mainly of Millepores and Porites,
killed as they approach the surface, much as we found the Millepores and
Porites of the Taritari lagoon flats covered by Nullipores. The reef
flats formed, in this case, a marked yellow belt on each side of the pass,
in striking contrast to the dark blue ribbon of the channel through which
we steamed. The reef flats on the lagoon side of the passage form a
large spit, cut in two by a narrow passage, and flanked on both sides
with beach rock. The southwest passage runs between the islands of Ai
and Medjerrurik. The channels we passed through, as well as the wide
bands of blue water indicating moderate depth on the reef flat in that part
of the lagoon, once formed, I have no doubt, part of the intricate passages
and channels which connected the sea with the lagoon. Land was gradu-
ally formed on the reef flat by material thrown up from the outer beach,
and the corals growing on the flat were gradually overwhelmed by sand
coming in either from the sea face or from the lagoon flats. The beaches
on the lagoon side of the land rim were formed in part of beach rock, and
in part of fine coral sand separating short stretches of beach rock con-
glomerate. A strong current was flowing in against the steady trades,
through the passage and gaps of adjoining islands, and to a certain
extent the reef flats on the two sides of the passage were swept clean
during that stage of ' the tide. On the lagoon edges of the flats the current
meeting the waves formed by the trades, the reef flats were more or less
covered with sand bars built up by the material brought on the one side
from the sea face of the land rim, and on the other from the lagoon side
by the trades blowing across the whole width of the atoll.

The full force of the trades blowing across the lagoon is felt on the
lagoon edge of the western reef platform, while the sea face of the western

JALTJIT. 291

land rim of the atoll is only disturbed by the swell of the sea during a com-
paratively short time, while northwest winds are blowing. The island to
the north of Ai is connected with it by a narrow line of light green water,
through which rises, here and there, an occasional sand bank.

The fine coral sand on the eastern face of the western land rim gradually
passes, on the beach facing the channel, into black shingle, and finally into
the beach rock conglomerate, which edges the beach on the western side of
the land rim. As we passed out, we noticed a series of spurs extending on
tlie reef flats at right angles to the outer reef line, and deflected in a direc-
tion parallel to the outer line of islets, thus forming an inner line of islands
similar to those south of the villas;e of Jabor.

The charts of most of the atolls represent usually the sand spits, which

are formed near all the passes, as at the southwest and southeast passes of

Jaluit (Pis. 226, fig. 6 ; 228, fig. 2), and are so characteristic a feature of

the passes leading into the atolls of the Marshall Islands (Pis. 226, fig. 6 ;

•227, fig. 1; 228, figs. 3, 4).

The sand spits or reef flats are extensive tracts on which Millepores and
Porites flourish. Where the corals reach the surface they are killed by
constant exposure to the air, NuUipores grow on the fragments of the dead
corals, which break off and gradually fill the interstices between the heads
and cliange the living reef flat to a bare flat covered with huge patches of
more or less coarse coral sand, with comparatively few living corals. The
existence of these sand spits formed on either side of the passages is often
indicated by the presence of a few small islands and islets running at right
angles to the general trend of the outer land rim. On the west side of the
atoll, as we steamed past it, we could see, near the centre of the western
face, the great wide flat extending far into the inner part of the lagoon
(PL 226, fig. 6), formed from the disintegration of a few larger islands still
to be seen either as islets or as low sand bars, some of them covered with
a little vegetation. The islands and islets on the wide lagoon flats and
shoals are arranged either in lines parallel to the outer land rim, or else
at right angles to its trend.

When steaming along the western face of the atoll past the northern
extremity, we could, when looking across the narrow lagoon, note the number

292 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

of islands and islets on the land rim of the northeastern face of the atoll.
We could also see across the western land rim, near the northern extremity,
the line of breakers indicating the position of shoals and islets, and low
sand bars heaped up across the gaps of that part of the atoll, or indi-
cating the position of a former land rim worn down by the action
of the trades sweeping across from the eastern face of the lagoon. North
of the centre of the western face of Jaluit is a marked secondary lagoon
(PI. 226, fig. 6) formed as have been formed the secondary lagoons of
Taritari and of Apaiang. Here, however, the secondary lagoon has been
formed by the throwing up of islands and islets and spits on the lagoon '
face of the land rim, the sea sweeping across the lagoon with sufficient
force to build up on the lagoon face of the lee side secondary lagoons
such as usually characterize the weather face of other atolls. More to the
north a similar secondary lagoon exists at Ngain, where, however, it only
forms a small bay.

The sand bars and flats encroaching upon the lagoon of the- north-
western horn of Jaluit indicate the method by which the horn of an atoll
may gradually be changed into a great sand spit by filling the space between
the land rims on the two faces of the atoll. Only a narrow gap, with a
shallow entrance into the atoll, exists at the northern end of Jaluit. From
the island of Urbett across to the west face of the atoll the lagoon is
not more than four miles in width ; the two faces of the lagoon extend
northward in a nearly parallel line, a distance of about twelve miles,
forming at the northern extremity a wide horn between the island of
Boggenadick and Bogenaga. The west face of. the atoll, with the excep-
tion of Pinglapp, which forms the western spit of the atoll, and of the
secondary central lagoons, is edged by a narrow reef flat, the greater part
of it bare at low water, with a few islands and islets thrown up on its
face (PI. 226, fig. 6).

Immediately south of the island of Boggenadick, as well as east of
Pinglapp and at the southern horn of Jaluit, extensive flats have formed on
the lagoon face of the reef, where coral patches grow in profusion or sand
bars have been thrown up, as also in the central part of the west face of
the atoll at a distance of about eight miles north of Pinglapp, where the

AILINGLAP.

293

sandy flat is at least two miles in width and is covered with nuTnerous
patches of corals and beach rock.

The strength of the waves on the two sides of the lagoon can easily be
measured by the condition of the
islands on the opposite land rims.
Judging from the mass of material
found on the reef flats of the western
face of the lagoon, it is evident that
this material must be supplied from
the wearing of the reef flat on the
inner part of the lagoon. There are
not enough corals thrown up from the
sea face of the western side of the
atoll to supply the material even for
such a narrow land rim as exists on
that side of Jaluit, yet this is the source to which many writers on coral
reefs would look for the material to form the lee land rim.

Marshall Island Canoe, .Iai.iit.

Ailinglap.

Plates 168; 171, fiy. 1 ; 225; 226, fig. 5.

Ailinglap (Odia or Elmore) is a triangular atoll (PI. 226, fig. 5). Its
eastern face is twenty-five miles in length, its western about the same,
and the northern nearly thirty miles in length. The principal islands
are on the land rim of the western face, and on the eastern face, where,
however, the land rim is much broken, there being numerous passages for
boats of considerable size through the gaps between the islands (PI. 226,
fig. 5). On the northern face are a large number of sand bars and islets
and two passages for larger vessels. The principal entrance is through
the southern passage north of the island of Enliebing (Pis. 168, fig. 1 ;
226, fig. 5). On the lagoon side of the passages we could see the same
sand bars and spits and flats which characterize the passes of Jaluit. This
lagoon is said to be from twenty to twenty-five fathoms in depth ; its

294 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

northern part is crowded with shoals, coral patches, sand bars, and sand
flats (PI. 226, fig. 5).

We skirted along the southwest shore of the atoll of Ailinglap. On the
sea face the beaches consist alternately of shingle beaches, coral sand
beaches, and ledges of beach rock coral conglomerate. There are compara-
tively few cocoanut trees on the islands, but there is a belt of vigorous scrub
vegetation and large hardwood trees close to the shingle beach (PI. 168,
figs. 1, 2, 4). The outer reef platform has a uniform slope from the base
of the beach, where the beach conglomerate crops out to the outer Nulli-
pore knolls rising on its outer edge. The beach conglomerate is usually of
a yellow color, forming a marked contrast with the black, weather-beaten,
pitted and honeycombed shingle, which rises in a steep slope immediately
behind the beach conglomerate (PI. 168). The first gap we passed showed
no secondary lagoons ; it was barred on the lagoon side by a low island with
sandy beaches, on either side of which existed a passage into the lagoon.
The shores of the islands forming the entrance to the passes were flanked,
as was the outer beach, with yellow beach rock conglomerate, and a steep
shingle or coral sand beach rising behind it (PI. 168, fig. 1). The black
shingle beaches are more continuous than the sand beaches. The west
coast of Ailinglap is deeply indented by bays (PI. 168, fig. 2), formed by
the throwing up of sand from the lagoon side on the outer reef flat, into
elongated spits, separated here and there by reaches of yellow beach rock
conglomerate and forming a kind of secondary lagoon, differing somewhat
from those we have observed in other groups (PI. 168, fig. 2).

The wide reef flats characteristic of Ailinglap slope gradually to the outer
edge; they are covered with numerous ledges and blocks of yellow beach
rock (PI. 168, figs. 2, 3). The prevailing wind blows nearly parallel with
the trend of the eastern coast. Pandanus and a belt of scrub trees form the
characteristic vegetation of the islands on the land rim of the west side of
Ailinglap ; only few cocoanut ti'ees are found on the majority of the islands
on the western face. The islands on the west coast are well wooded
and separated by narrow gaps ; they have been formed on a wide reef
flat, which, as we could see at the southwest pass, extends far into the
lagoon (PI. 226, fig. 5) ; sand bars and sandy islets separated by intricate

NAMU. 295

channels forming secondary lagoons extend on the lagoon side of the
western face of Ailinglap.

As we go farther north, the islands and islets form a narrow land i-im
(PI. 168, fig. 3), with low passes or gaps ; some of them were bare at half
tide. The wide reef flat is covered with numerous sand bars and islets
(PI. 171, fig. 1), forming on the lagoon side of the islands, and yet, in spite
of the great width of this reef fiat, the land rim did not seem to be increas-
ing in width, either on the sea face or on the lagoon face, much of the
material on the reef flats evidently being shifted backwards and forwards
according to the season of the year and the direction of the prevailing
winds. On the inner side of the lagoon, opposite its widest part, the
breakers due to the trade winds are high, their sweep is considerable, and
they must play an active part in the shaping of the land rim on the west
side of the atoll, exactly as do the northeast trades on the sea faces of the
eastern and northern part of the atoll. On the northeastern point of
Ailinglap the island forming the eastern edge of the horn is covered
with a luxuriant vegetation, and is situated on a reef flat somewhat
narrower (PI. 226, fig. 5) than that forming the western horn of the atoll
(PI. 171, fig. 1). From the northern point the islands gradually pass into
islets and finally into low sand bars; they indicate in a general way the
position of the rim of the wide outer reef of the atoll. Beach rock
conglomerate crops out on the sea face of most of the islets and islands
of the western horn, and high sand beaches characterize the lagoon side
of the land rim. The wide outer reef flat is edged by Nullipore and
Pocillipore knolls; the outer edge is deeply indented and cut, forming
numerous boat pa.ssages on the outer face of the reef. The lagoon is
said to be from twenty to twenty-five fathoms deep.

Namu.

Plates 167, fuj. 1; "29.5 ; 227, fig. 1.

Namu' is a long narrow atoll about thirty-five miles in length and a
little over four miles at its widest part. The western face of the atoll is

' Hydrog. Amt d. Keichs Mariiu'-Amts. Pliine d. Marshall Inseln. No. 113.

296 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

like the western face of Jaluit, flanked by a reef more or less exposed at
low tide, while the eastern and the southeastern faces of the atoll are
flanked by a narrow land rim, differing in no respect from those of
Jaluit or of Ailinglap.

We approached Namu on the east face so that we could look up the
weather side for a considerable distance. We skirted along a part of
the southwest shore of the atoll ; there the islands of the land rim are
covered with a remarkably fine growth of Pandanus, of Pouka, of Pisonias,
of other hardwood trees and low bushes (PI. 167, fig. 1). On the east
face we could see numerous gaps separating the islands and islets, through
many of which the sea was breaking with considerable violence. On the
southeast shore the shingle beaches are flanked with large boulders, with
only here and there a small sand beach. It happened to be high water
as we steamed by Namu, but we could see at the passes the outer shingle
beach and on the lagoon side the fine coral sand beaches; we also noticed
on the I'eef flat the sand bars and islands and islets thrown up by the sea
on the lagoon side. The sand spits and sand bars gradually become
covered with vegetation ; they often form two or three successive lines
of elongated islands and islets barring the gaps. These sand bars and
islets eventually become connected by spits with the outer islands, and
gradually form islands of greater width than those now existing on the
outer land rim

Kwaj along.

Plates 169, 170, 225; 227, fig. S.

It will be noticed from the dimensions given of some of the Marshall
Islands that with few exceptions they are among the largest atolls known ;
they equal and even surpass the largest of the atolls in the Paumotus and
Maldives.

Kwajalong, or Menschikov, the next atoll we visited, is more than seventy
miles in length.' The centre of the western coast is convex to the east.

' Menschikov and SuvacUva, one of tlie M.aldives, are the largest atolls known ; Kwajalong is no
less than seventy-five miles in length, and with the exception of one or two of the Fauuiotus none of
the atolls of the Pacific are to be compared with them in size.

KWAJALONG. 297

The northern coast juts out into a point about eighteen miles east of the
western point of the atoll ; the average width of the atoll is at least fifteen
miles. The western point forms, as do the extremities of many of the atolls
in the Marshalls, a sharp narrow spit, where two faces of the atoll meet
and run together. Similar spits exist at Namu, Mille, Ujae, and specially
at Arhno ; they are more or less marked in many of the other atolls. The
principal land rim of Menschikov atoll is on the southern part of the eastern
face of the atoll, and on the eastern face of the northern point ; the west
coast is irregularly dotted with islands and islets, following one another in
rapid succession. Numerous ship passes cut through tlie west coast, and
near these we find the same development of spits, sand bars, and reef
flats already described.

To the east of the south pass of Menschikov ' atoll extends a long
line of sand bars reaching southward to Eniibuj Island. Beach rock con-
glomerate flanks the base of the steep beaches on that island ; large blocks
of shingle and of conglomerate are thrown up on the beaches ; they consist
of fine or coarse sand.

We could see across the southern horn, on the opposite side of the lagoon,
the islands on the eastern face. The effect of the raking sea in gigantic
atolls like Menschikov, the axis of which is at least seventy-five miles long,
in accumulating sand on the lagoon side of the land rim, is well shown on
the land rim flat south of the south pass and in the break of the land rim
between Eniibuj and Kwajalong Islands. The flats are covered at low
water ; during the northeast trades the sea breaks over them.

A section of the beach on the south end of Enniilabegan Island shows
a structure characteristic of all the islands on the western land rim of
Menschikov atoll. The wide reef flat is covered with beach rock or con-
glomerate boulders ; at the base of the sea face of the beach extend outcrops
of beach rock and coral conglomerate topped with yellow rubble, masses of
beach rock conglomerate and with smaller shingle forming the summit of
the beach. The beach varies from nine to eleven feet in height ; from the
upper part of the shingle beach tongues of beach rock and conglomerate

^ Darwin has given a figure of Menschikov atoll (PI. II., fig. 3), taken from " Krusenstern's Atlas
de I'Ocean Pacifique," which has been copied by Dana. Krusenstern's figure differs greatly from that
of later surveys (PI. 227, fig. 2). On Krusenstern's chart it is called "Is. du Prince MenchicofE."

298 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

shingle extend far into the belt of hardwood trees which surmounts the
high platform of the island. We noticed here, for the first time, a pe-
culiar coloration of the water in the gaps or passages leading into the
atoll. On the sea face, but more especially on the atoll side of the gap,
in from nine to ten fathoms, the color of the water was usually of a
metallic blue, and the various colors reflected, as the depth passed into
shallower sand bottoms, represented as many hues as those on the
feathers of a peacock ; while the main channel itself, sometimes of con-
siderable depth, was of a dark blue, rendered only more intense by the
contrast of the line of white breakers rolling on the sandy reef flat.

The wide i-eef flat slopes gradually from the base of the sand or shingle
beach ; it consists of recent beach rock or coral shingle conglomerate planed
off by the action of the breakers, and is covered with shingle rubble coated
by Nullipore growths of variegated colors. Here and there on the outer
face of the land rim low sand dunes exist, or they are blown to a consider-
able height from the lagoon side, rising sometimes seven to eight feet above
the top of the highest part of the shingle beach. This method of encroach-
ment by dunes on the land rim from the lagoon side is different from any
we have seen in the Paumotu Islands, or other atolls where dunes exist.
Usually the widest beaches are on the side of the outer reef platform ; in
the case of many of the Marshall Island atolls, coral sand is piled up over
extensive flats, on sand bars and sandy islets on the lagoon side. Thus is
supplied an immense amount of material blown by the trades sweeping over
the lagoon, across to the sea face of the atoll, overwhelming, from the lagoon
side, the luxuriant vegetation covering the summit of the narrow land rim.
The knolls forming the Nullipore rim of the outer edge of the reef platform
are usually highly colored, and in some parts of Kwajalong the outer rim
has been deeply indented, forming wide boat passages leading towards the
beach slope. In other parts of the reef flat the Nullipore edge forms a wall
of considerable height, three to four feet sometimes above high-water mark,
as on Enniilabegan Island. As I have stated, the sea face of all the islands
is comparatively high, the slope towards the lagoon is gradual ; the green
vegetation of the land rim is in striking contrast with the outer black
shingle beach, and with the glistening white coral sand reaches.

KWAJALONG. 299

We went ashore on Gehh Island (PL 169, fig. 1), a small island, in reality
only a sand dune blown up from the lagoon side, overwhelming the huge
boulders and coral heads of all kinds growing on the outer reef flat. The
destruction of the corals on the outer reef flat recalls that of the Millepores
and Porites on the lagoon flats of Taritari. At Gehh, however, the heads of
corals are much larger ; many of them are dead masses thrown up on the
outer reef flat; the living corals are more isolated and consist of various
species of massive corals characteristic of the Marshall Islands, such as heads
of Millepores, Porites, Madrepores. Pavonias, and Maeandrinas. The heads
are separated by deep lanes, in which are accumulating dead corals or sand ;
the top of the heads is often covered with fragments of dying and dead
corals, killed by exposure during low tides and covered with a coating of
Nullipores. The sea breaks the tops of the dead masses, and with the sand
dunes encroaching upon them from the lagoon side we have a reef flat
formed of an entirely different character from that of any reef flat we have
yet seen.* The reef flat slopes gradually into deep water ; from the outer
edge of the platform we could trace large masses, and heads of corals of
the same species as those found on the reef flat itself, only in full activity,
growing most luxuriantly in from six to seven fathoms of water, and grad-
ually becoming more distant and smaller towards the seventeen-fathom line,
where the coral boulders have entirely disappeared, and are replaced by
fine coral sand washed down from the upper part of the reef flat.

It happened to be an unusually clear day when we examined this outer
slope, so that we were able to distinguish remarkably distinctly the corals
growing under the lee of this islet ; at some points many of the heads seemed
to extend even to a depth of twenty or twenty-two fathoms, and certainly
grew comparatively luxuriantly as far as fourteen fathoms. From seventeen
to twenty-five fathoms large blocks of Algae and Nullipores were seen. No
large masses of dead corals exist at the foot of the extensive reef flat ; its
slope is very gradual, the distance from the outer edge of the reef flat (low-
water mark) to the twenty-fathom line being about 300 yards. There is not
the sudden drop into fifty or one hundred fathoms as on many of the outer

1 A similar condition of thinpjs exists at the north end of lUeginni (PI. 169, figs. 3, 4), where the
san(] from the lagoon face has been blown over the narrow land rim and encroached upon the outer
reef platform.

300 "ALBATROSS" TEOPICAL PACIFIC EXPEDITION.

reef faces; it is onlywhen an unusually large block of coral forms the outer
edge at low-water mark that we may have a drop of four to six feet.

The base of the sand dunes is flanked by a sort of beach rock conglomer-
ate composed of fine and coarse particles, small fragments or blocks of which
had been thrown up on the sea face of the dunes.

We found at many other points on the west side of Menschikov sand
dunes overwhelming old and much-weathered coral heads near the head of
the reef flat, while on the outer part may run a ledge of higher blocks of
corals, some of which are still alive and have not been overwhelmed either
by sand or cut down by the action of the sea to the level of the reef flats,
as have the inner line of blocks. We found* a large number of Echinoderms
living in the cavities between the corals.

The mode of formation of the extensive flats we described at Taritari, on
the weather side of the atoll, is identical with that of the lagoon flats near
the openings and passes in the Marshall Islands. These flats are character-
istic of all of the atolls ; their existence has been more or less correctly
indicated and sketched out on the German charts of the group (Pis. 226,
figs. 5, 6, 9, 10 ; 227, fig. 3).

Tengeli (PI. 227, fig. 2), another island on the west face of the land
rim of Menschikov, is in a somewhat more advanced stage than Gelih,
the island we have just described. Here the mass .of sand, coming from the
inner part of the lagoon, has overwhelmed the coral heads, and it is only
here and there, on the face of the reef flat, that we see an outcrop of the
coral heads.

Between Mann and Torrutj Island a good pass exists ; on the lagoon
side of this gap a number of lines of secondary islands are formed on the
reef flat parallel to the outer island. These islands are separated by reaches
of blue water, forming two or three entrances into the lagoon from that face
of the islnnd.

From what I could ascertain of the depth of the lagoons in the Marshall
Islands, some of them are exceedingly shallow, as at Taongi (PI. 227, fig. 3)
and Namorik (PI. 226, fig. 10) ; in general they have a depth of from four-
teen to seventeen fathoms, though some of the larger lagoons reach a depth
of twenty to twenty-five fathoms.

KWAJALONG. 801

Many of tlie gaps on the west face of Menschikov are comparatively
shallow, judging from the color of the water, but occasionally a light or even
a dark blue streak indicates a deeper passage for boats or small vessels.

North of Enniigenliggelap (Pis. 169, fig. 2; 227, fig. 2), between it and
Boggen Island, stretches an extensive reef flat on which long sand spits have
been thrown out on the lagoon side of the shingle beach of those islands.
This reef flat is covered with green water, showing that the pass is compara-
tively shallow. On the lagoon flat two lines of breakers, parallel to the
outer reef, indicate the position of sand bars which are in the near future to
form a double line of islands and islets. A little north of this we came on
a still more instructive reef flat, where there is not only a second, but also a
third line of sand bars indicated by breakers on the wide reef flat. On the
very edge of the outer reef flat are two small sand islands ; the lagoon flat
extends eastward from twelve to fifteen hundred feet, then a narrow line of
blue water separates the inner edge of this flat from the second and third
line of islands and sand bars. Still further in the lagoon a fourth line of
breakers shows the piling up of sand in the shallow i)art of the lagoon.
Opposite passages and gaps the breakers usually throw up islands, islets, and
bars, wherever a considerable body of water flows across the reef flats. The
width of the reef flat of Menschikov atoll varies greatly. Sometimes it is
narrow, nothing but a shallow beach line, on the one side of which beat the
lagoon breakers, and on the other the rollers on the sea face, the land rim
forming only a narrow sand dam separating perhaps the deepest part of the
lagoon from the deep water off the sea face. Where the reef flats are wide,
they are usually cut into intricate channels and dotted with sand bars, as
near Gehh and Tengeli.

Similar lagoon reef flats are developed north of Oniimak Island, imme-
diately south of the adjoining pass. At Wotje Pass we strike one of the
finest examples of lines of secondary islands and lagoons (Pis. 170, figs. 3, 4 ;
227, fig. 2), separated by strips of deeper water than is usual on reef flats
where sand bars are readily formed. At Wotje Pass we again found high
sand dunes, blown over on the outer reef flat from the lagoon side, which
have nearly overwhelmed the beach rock on the sea face. Here sand dunes
exist not only on the two outer islands flanking the north and south side

302 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

of Wotje Pass, but also on the islands to the north of the pass ; they have
covered the shingle beach rock conglomerate edging the western face of
these islands. On the sea face of the outer land rim coarse shingle crops
out at the base of the sand dunes.

North of Eru Pa.ss we have a repetition of the same reef flats and lines of
islets. These are, however, mere narrow strips, barely apparent at high
water from the line of breakers coming from both the lagoon side and the
sea face, wliich meet from opposite directions and thus form sand bars, as
north of Illeginni Island (PI. 170, fig. 4), the sunmiits of which can be seen
cropping out here and there in the line of breakers (see also PI. 169,
figs. 3, 4). A similar condition exists at Nanuku, one of the Fiji Islands,
where the reef flat of the southern horn forms a submerged ridge, across
which the breakers of the prevailing trades roll into the lagoon side of the
island.^

At Gegibli Island, north of Eru Pass, the second and third lines of bars
and breakers must be at least three fourths of a mile from the outer land
rim. North of Lubu the reef flat disappears, and only here and there is
the presence of comparatively shallow water indicated by an occasional
breaker, or where it does not break, by a thin green line between two darker
belts of blue, indicating the position of the ridge, in from eight to ten fathoms,
in the extension of the wide reef flat of the western face of the atoll which
separates the deep lagoon from the outer sea.^ The islet of Tabik and the
chain of islands terminating with Ebadon form the narrow western point of
Menschikov. But few islets and bars exist on the narrow submerged reef
flat .which rnns from the northern to the western point and forms the
northern face of the atoll. Over this face of the atoll, as well as over
the northern part of the western face, the sea, driven by the trades, must
pour uninterruptedly.

1 Bull. M. C. Z., XXXIIL, Pis. 103, 104.

"^ According; to the German charts there is a similar well-developed, deep channel extending along
the whole western face of Taongi (PI. 227, fig. 3).

EONGELAB. 303

Rongelab.

Plates 171, figs. 2,3; 172, 173, 225; 226, fig. S.

The atoll of Rongelab (PI. 225), irregularly triangular in shape, is a little
over thirty miles in length, and about fifteen miles across at its southern
land rim. The eastern side is occupied by a narrow land rim, forming a
great bay ; there are numerous passages into the lagoon both on the eastern
and southern face. The main land rim is on the southern side and on the
eastern face ; the western reef flat is narrow, and only here and there a few
islands and islets have been thrown up during the prevalence of the
westerly winds. The island of Rongelappelap on the southeastern horn is
the principal island of the atoll ; it is exposed to the full force of the trades ;
its south shore (PI. 226, fig. 8) is flanked by a long sand beach of moderate
height ; in some places it has been blown in as dunes among the trees
and the belt of scrub vegetation (Pis. 171, fig. 2; 172, fig. 1). This is espe-
cially well marked at the eastern point of the south passage, where the sand
dunes have killed the greater part of the vegetation and have only left the
stumps of the trees rising through the sand. Along the sand dunes we
found, here and there, boulders of beach rock or coial conglomerate forming
a broken line of yellow boulders at the base of the sand beaches. The
principal islands on the east face of Rongelab are sandy islands or islets,
with few low bushes growing near the line of heavy breakers which indi-
cates the position of the outer edge of the reef flat (PI. 171, fig. 2). The
inner lagoon beaches of Rongelab (Pis. 171, fig. 3 ; 172, fig. 2) are ledges
of beach rock and coral conglomerate, alternating with coral sand beaches
and with reaches of black weathered coral shingle. The sand and shingle
is also frequently driven in between the trees from the lagoon side. The
vegetation consists mainly of Pandanus (PI. 173), and the few cocoanut
trees which have been planted by the natives.

At the pass, off" the south side of the island, a low spit runs fully two
thirds of a mile westward with two to three fathoms of water ; the peculiar
metallic color we had observed in some of the gaps of Menschikov is well
shown at the gap formed by the spit.

304 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The outer reef flat slopes gradually on the lagoon face ; we found sixteen
fathoms more than half a mile from the inner beach. No corals are found
on this gentle slope, but Algae grow in great abundance on the coralline
sand. In some places in the lagoon we found a few patches of corals,
mainly Madrepores, Porites, Pocillipores, and Millepores, but they are
comparatively few^ in number and moderately developed.

The beach rock cropping up on the lagoon face (Pis. 171, fig. 3; 172,
fig. 2) is a coarse conglomerate composed of fragments of recent corals ;
these when ground have formed the high steep beach of coarse coral sand
mixed with small fragments of broken corals. On the lagoon face of the
outer beach the slope passes rapidly to the level of the bottom of the sink
which extends nearly two thirds across the land rim of the island. At the
point where we made the section, the land rim is nearly one third of a mile
wide, and the outer shingle beach must be about twelve feet in height.
The numerous water holes and sinks are surrounded with Pandanus, Poukas,
a few Pisonias and large hardwood trees (PI. 173), and on the outer beach
is the usual belt of broad-leaved bushes and scrub vegetation (PI. 172,
fio-. 2). The beach conglomerate extends nearly half-way across the land
rim ; we then come upon masses of heads of corals until we reach the sea
beach ; its slope is covered with fragments of shingle of all sizes, varying
from moderately large heads to sand. This shingle has encroached far into
the vegetation of the land rim (PI. 172, fig. 2), and here and there we found
an isolated tree or a bush standing out from the shingle almost within reach
of the ordinary tides. The island of Rongelappelap has been built up both
from the sea and from the lagoon face ; the sand from the lagoon side and
the small shingle being blown eastward, while the disintegration of the
beach rock which once covered the outer reef platform has supplied the
material for the outer, high steep shingle beach (PI. 172, fig. 1); some of
the material of course has also been derived from the destruction of the
masses of coral heads and of Nullipores growing on the outer reef flat. Sand
dunes exist in the wide and shallow gaps to the north of Rongelappelap.

To the prevalence of the northeast trades, which in the Marshalls blow
with greater strength than the southeast trades do in the Southern Pacific,
we must look for the forces which move the great mass of material con-

EONGELAB. 305

stantly shifting in these atolls. It is interesting to note the marlied
difference there is in the method of handlino- the material in the large
lagoons, due to the reach of a very strong northeast trade or that of the
more moderate southeast wind. In fact, the action of the northeast trade
on the eastern lagoon face of the west rim of the Marshall Island atolls
is nearly as great as that of the southeast trades on the eastern face of the
Paumotus or of some of the atolls to the south of the line.

One of the most characteristic corals we found in the Marshall Islands
is a long, slender branched Madrepore which grows in smooth water in
protected parts of the lagoon. It would be an interesting study to compare
the modifications of different species of corals flourishing best in the midst
of breakers, or when found in shallow or deep water along protected shores.
The variation we have observed in some of the corals is so great that at
first glance specimens taken from different parts of the same atoll would
hardly seem to belong to the same genus.

One of the best examples of such adaptation, due perhaps to a constant
struggle against the action of the heavy breakers to which they are sub-
ject, is seen in the peculiar growth of the spines of Heterocentrotus and of
Colobocentrotus. The spines in the one case are hiassive clubs with which
the sea urchin braces itself in corners or angles of the reef flats and retains
its hold against the action of the sea; while in the other genus the immense
development of the suckers on the lower side and the reduction of the
spines to a dome-shaped pavement gives to that genus a still greater
security. It is comparatively rare to find the tests of these species thrown
up on the beach flat or on the shingle beaches. Side by side with them in
pools exposed to the full action of the sea are found immense numbers of
Holothurians; they seem to have no capacity for protecting themselves
against this very action, and yet do not appear to be affected by the
action of the breakers.

The section of the beach we examined (PI. 172, fig. 1) shows a high, steep
beach consisting of fine white coral sand of about twelve feet in heiijht,
flanked at the base by a small secondary beach of coral shingle covered
on the top by large blocks of beach rock conglomerate, thrown by the sea
towards the lagoon side.

20

306 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

The reef flat is about 100 feet wide, and covered mainly by huge blocks
of Poritesand Millepores separated by lanes of water; the tops of the masses
of coral have died and are overgrown with many colored Nullipores. The
dead coral heads of the reef flat were evidently once flourishing, but those now
alive are limited to the outer heads growing near the knolls of Nullipores
on the outer edge of the narrow reef flat we have just described. The
Nullipores are of a brilliant red, carmine or yellow color. The coral
heads have become united by the breaking off of the upper branches
and cemented with fragments of Nullipores. This reef flat is very similar
to the one we described at Gehh on the west coast of Menschikov atoll.

The lagoon side of the south face of Rongelab is exposed to the full action
of the trades sweeping aci'oss the atoll ; they have a reach of about thirty-
five miles. The strength of the trades is shown by the high breakers seen
in the gap, to the eastward of the beach where we anchored. We found
a few coral heads in the lagoon, on the way to our anchorage.

When lifting anchor we brought up a huge mass of white, dead coralline
Algte and coral mud formed from the agglomeration of fragments of dead
corals, shells, and beach rock fragments, but consisting principally of
coralline Algae and Nifllipores, forming a sticky mortar covering the
bottom of the lagoon wherever we had an opportunity to examine it. This
conglomerate is formed in an innei' sea, as it were ; it differs strikingly
from the conglomerate formed on the beaches, both on the sea face and
the lagoon face, a conglomerate made up of larger angular or worn
fragments of broken coral and of beach rock.

On the east of Rongelab are a number of sandy islets and sand points
flanked by high steep beaches, edged with beach rock and topped with
low vegetation. The island to the west of the pass resembles the main
island ; its south shore extends in a long sand spit at the west end,
and the small sand islet to the north as well as the beach are both flanked
by beach rock conglomerate.

LIXIEB. 307

Likieb.

Plates 174-177 ; 225; 228, fig. 3.
The island of Likieb has been fairly sketched by Captain Melander in
1885 ; he made a running survey from the lagoon side ; as we steamed
along the western shore of the atoll, we were able to correct, to a certain
extent, the position of the outline of the western face.

The islands and islets on the eastern face, as will be seen from the sketch
chart (PI. 228, fig. 2), are nearly all at right angles to the general trend of
the reef flat; on the western and southern faces the islands are narrow
and insignificant in size, the gaps being far apart, leaving wide areas of reef
flat awash, with only here and there a sand bar upon them. We entered
Likieb through the south pass. The lagoon is covered with numerous coral
patches scattered in every direction. On the western face are several
passes south of the island forming the northwestern horn of the atoll.
The atoll is said to be from fifteen to twenty-five fathoms in depth. The
islands of this atoll are considered as among the most fertile of the Marshall
Islands. They are subject to the trades ; but in the northern part of the
group they do not blow with the same violence as south of Ebon Island and
north as far as Jaluit and Arhno.

We arrived under the lee of Likieb much later than we expected, the
distance from Rongelab as indicated on the charts being far from correct,
as is the position of many of the islands on the charts of the Paumotu,
Ellice, Gilbert, and Marshall Islands.

Likieb is a triangular atoll (PI. 228, fig. .3), nearly thirty miles in length
and fifteen across the southern face. The northwest point of Likieb, seen
from the west side, is occupied by Mat Island, on which grow a few cocoa-
nut trees ; the rest of the island is covered with low scrub and tall hard-
wood trees. Tlie point is flanked by a steep coral sand beach, edged at
its base with beach rock conglomerate alternating with shingle reaches.
The reef flat extending from the western point is wide and slopes gradually
from the foot of the steep and high sand beach (which must be from eight
to ten feet in height) towards the outer edge of the reef platform. On
the south side of the western horn a gap between Mat and Emegua

308 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Islands runs across the base of the northwest point to the northern face
of the atoll ; on the western face a narrow submerged reef flat connects
the two islands. The outer edge of the gap is flanked with beach rock, as
are the sides of the gap between Mat and Emegua Islands. On the north
side, opposite the opening of the gap, which is shallow, an island has been
thrown up by the surf, from the lagoon side, upon the wide reef flat of
the base of the northwestern horn of Likieb.

The northwest point of Likieb has been formed by large sandy islets
thrown directly across the extremity of the reef flat forming the horn of the
atoll, the material being derived both from the lee and from the weather
side. In proportion as the islands of the land rim of the faces of the
lagoon diverge on the lee and on the weather side, a channel is formed
at the extremity of Likieb ^ separating the western island from the series
of islands and islets and sand bars which run directly across the end
of the lagoon, more or less parallel with the base of the outer island.
A wide, shallow gap is thus formed between them and the island to the
west ; on the weather side the land rim extends toward the east in a long
series of islands, islets, and sand bars ; on the lee side an island, more or
less triangular in shape, originally also made up of separate islets, is
connected with those of the weather side by shallow flats covered at high
water. The sea face of these islands is flanked with beach rock, while the
lagoon side is formed by high steep fine coral sand beaches. The second
eastern set of islands will undoubtedly, in time, become united and form
a second belt to the south of the northern one, and in time that will
again be united with the preceding belt, forming, as in the case of
Arhno, a solid spit with spurs flanking the two sides of the lagoon. This
shows very simply how the shallower parts of a lagoon are gradually
filled up by the action of the trade winds. The pass between the islands
of Mat and Emegua must be shallow, judging from the color of the belt
of light green water separating them. The pass opens out into the
shallow flat of the lagoon itself ; on the lee side it is indicated by a line
of breakers, and a slight discoloration of the water between the south
point of the second island and the island to the south of it.

1 H. O. Chart 996.

LIKIEB. 309

The island of Rongerik to the south of Emegua consists of large masses
of flat beach rock, thrown up like a shingle beach, and partly overwhelmed
by sand dunes blown over from the flats on the lagoon side. Usually the
islands of Rongelab are covered with sand at the two extremities, and it is
only in the centre that beach rock slabs and coral conglomerate crop out.
The small islands on the west face of Likieb are narrow, and have a scanty
capping of low scrub. The little island of Bokelan has a few trees on it ;
at its extremities are high sand beaches ; beach rock conglomerate crops
out only over the central part of the western face, having been over-
whelmed at the extremities of the island by the sand blown over from
the lagoon side.

The northwest face of Kapenor (PI. 174, fig. 1) is flanked by a steep
sand beach, from twelve to fourteen feet in height, capped by a rich
belt of low vegetation. An occasional boulder of beach rock conglomerate
crops out on the base of the beach at the level of about three-quarters tide.
Sand from the lagoon side has overwhelmed, to a certain extent, the reef
platform. From the west point of Kapenor extends a high black shingle
beach ; it crops out again on the flat of the lagoon side ; the beach
rock conglomerate also crops out on the reef flat. The two extremities
of the island of Kapenor and the islands and islets to the north are
covered with sand, blown over from the lagoon flats ; the central part of
Kapenor, immediately above the base of the beach, is covered in part by
shingle, in part by sand, the beach rock cropping out only irregularly. The
little islands of Rongerik, Rongelab, and Bokelan all have high sand beaches ;
sand tongues have been driven, from the beaches of the lagoon face, into
the belt of vegetation directly across the island. Scattered among the
stretches of beach rock conglomerate are masses of coral thrown up from
the reef flat. On the east side of Kapenor a bight has been formed on
the miniature horn of the northern flat of the island. This bight is
separated from the lagoon and the sea exactly as is the northwestern
horn of Likieb ; it is gradually filling by the formation of bars on the reef
flat connecting the weather and the lee sides. In this case the flat only
extends from the weather side of tlie lagoon to the lee fixce of the western
rim, but the process is the same. From Kapenor a reef flat extends to the

310 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

dee2) pass north of Maten Island ; there the lagoon sand has overwhelmed
the beach rock conglomerate, only a short stretch of shingle appearing on
the face of the central part of the beach. We could readily trace the sand
coming from the lagoon side, and gradually forcing its way over to the
sea face. The pass north of Maten has two lines of shoals blocking the
opening. Across the narrow submerged reef flat we could see many bars
extending far into the lagoon to the south of Maten Island, separated by
light green water, and here and there sand bars forming the beginning of
an islet, or reaches of beach rock conglomerate flanking the western side
of an incipient bar on the half-submerged reef flat.

Takahave, on the western face of Likieb, is densely wooded ; it is
covered with tall hardwood trees; cocoanut trees are not found on the
island. The lagoon side is flanked by a sand beach. fuUy fifteen feet in
height. The beach rock conglomerate ledge crops out on the sea face
in the centre of the island ; it has been overwhelmed by lagoon sand at the
two ends. Coming from the north one can see on the extremity of Taka-
have the lagoon sand piled up on the eastern side of the coral shingle
beach, and partly blown over its highest parts.

The south face of Likieb is convex to the north, flanked at the western
end by Lukunor, and at the eastern by Likieb Island. The western
extremity of Lukunor Island is extremely narrow ; the land, rim is a mere
thread edged by a reef platform, formed by the destruction of the large
coral heads once growing upon it, and forming the pavement upon which,
on the lagoon side, the sand bars are formed. The reef flat will gradually
be changed into a bare solid flat, covered with Nullipores, so that it will
be difficult to distinguish the separate blocks forming the gigantic pavement
of flourishing coral heads on the lee face of the land rim. The coral heads
extend on the shelving shore into deep water ; they gradually disappear at a
depth of from twelve to sixteen fathoms. At the point where we examined
it in detail we could trace the extension of the boulder reef flat both on
the sea face and on the lagoon side.

In the centre of the south face the south pass of Likieb opens between
the island of Eotile on the west (PI. 174, fig. 3) and the island of Agony on
the east (PI. 174, fig. 4), both flanked on the sea face by beach rock con-

LIKIEB. 311

glomerate ; a long sand spit extends towards the west from Agony Island.
On the lagoon side of the pass are two islands thrown up on the lagoon
reef flat, and dividing the passage into two channels. One of the islands
is a mere sand bar, and the other a low wooded islet flanked with beach
rock. In the distance loom up the islands and islets and sand bars flanked
with coral sand beaches which form the weather side of Likieb atoll.

We entered the south pass of Likieb, passing Agony Island (PI. 174,
fig. 4), flanked on the lagoon side with beach rock shingle ; the island is
covered with brush and hardwood trees. Here and there a low sand spit
reaches into the lagoon from the half-submerged reef flat on the south face.
Between Agony and Likieb Islands a number of small wooded islets occur on
the narrow reef flat to the west of Likieb (PI. 228, fig. 3). Both Likieb and
Lado are comparatively broader islands than usually form part of the land
rim in the Marshall atolls. They are both on a very wide reef flat, nearly
three miles wide at places ; the flat forms the southeastern horn of the
atoll, and has probably been formed by sand blowing into the angle of
the eastern and southern faces of the reef platform, and covering the coral
heads which probably once flourished there. The reef flat becomes gradu-
ally narrower to the westward of Lado; it is narrowest about half-way
toward the northwestern point. The lagoon side of the island of Likieb
(PI. 175, fig. 2) is formed by low coral sand beaches.

A coarse grass grows on the low beach of the lagoon side to the very
edge of the shingle flat or of the beach rock conglomerate. On the lagoon
side the shingle beaches are composed of small fragments of corals and of
beach rock conglomerate consisting almost entirely of fragments of recent
corals. The steep sea face beach of Likieb is at least fourteen feet high
(PI. 175, fig. 1). From the base of the shingle beach extends a reef
flat about 250 feet wide, planed off out of the beach rock conglomerate,
and sloping gradually towards the outer edge of Nullipore and Pocillipore
knolls rising to a height of three to four feet above low-water mark. On
the outer face the reef flat is gouged out into narrow and deep boat
passages. Masses of dead coral boulders in place form portions of the
outer reef flat (PL 175, fig. 1) ; they must have grown in the spaces
between the ledges of beach rock conglomerate which form the reef

312 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

flat. The top of the shingle beach consists of large bouldei's of dead
coral thrown up during strong gales ; the smaller fragments have been
blown over the top of the beacli, down the slope of the island towards
the lagoon side (PI. 176). The coral boulders on the lagoon face of the
beach are generally black, pitted, and honeycombed, and much worn and
weathered. On tlie lagoon side of Likieb Island a low coralline and coral
sand beach not more than three to four feet in height (PI. 175, fig. 2)
slopes gradually into ten or fifteen fathoms; on this slope Nullipores and
a few corals occur. Comparatively few corals are found on the sandy
part of the lagoon of Likieb except on the very edge of the flats and of the
coral knolls. Coi-als are found scattered over the lagoon on the flats, on
the shoals, and on their steep side. They are the usual species we have
found in other Marshall Islands, though there are a larger number of
Hydrocorallida3 than are usually found in other atolls of the group. The
bottom at ten fathoms, where we anchored, consists of fine coral sand
silt and Nullipore mud ; this extends over the lagoon wherever we
examined it.

Pools exist on the outer reef flat between the Nullipore knolls and
the base of the land rim. On the sea face the island has increased in
height from material thrown up on the top of the shingle beach. The
reef platform of beach rock conglomerate, which crops out on the lagoon
side, is only the extension of the outer sea reef platform.

Most interesting are the- so-called stranded islets of Likieb. They are
islets formed parallel to the shore on the lagoon side and have become
united by beach dams thrown up from the lagoon face as well as from
the sea face through the gaps (PI. 177). When these stranded islets have
become united, they form hummocks, as it were. That the hammocks
were once islands and islets which have become united, in the manner we
have stated, is evident from the existence of old channels, still showing the
former isolation of these islets. Mr. Jose DeBrunn tells me that on the
island of Lado similar hillocks occur.

At the gap north of Likieb Island is a wide reef flat, where the heavy
breakers have thrown up, as shingle, masses and fragments of corals
derived from the outer edge and wide sea flat which separates Likieb

LIKIEB. 313

from Lado to the north. Much of this shingle, as well as the shingle on
the outer beaches of the islands on the northern face of Likieb, is ground
into sand. Within the atoll of Likieb, as at Jaluit, sand spits extend
from near the sea face of the gaps well into the lagoon. A large amount
of sand is blown in towards the lagoon from the sea face of the numerous
islands and islets of the western land rim, and finds its way through the
gaps separating them, extending into the lagoon in gigantic spurs. These
are eventually imited from the two sides of the gap, and form a solid bar
directly across the gap on the lagoon side of the islands, leaving a flask-
like bay to indicate the position of the former gap. This bay, in its turn,
may also be closed by the gradual filling in by the sand blown in from the
sea beaches, or by the formation of a dam directly across the sea face of
the bight. Thus sinks are formed, separated by islands and islets, which,
if they had been connected with the shore of a large island, would present
the appearance of the stranded islets we have just described. To the north
of Lado this condition of the lagoon face is well seen, and one can follow
far to the north spits running out from the gaps on the lagoon side of
the reef flat.

The sand is mainly derived from the pounding up into sand of the coral
shingle on the weather side, where masses of beach rock, of coral con-
glomerate are constantly thrown up on the outer beaches, as well as of
the fragments of the dead corals thrown up on the outer reef flat from
the sea slope of the atoll. As the breakers force their way at high tide
over the reef flat into the gap, this material is little by little carried
further into the lagoon and deposited, until it forms a dam to the very
breakers which have built it. As the trades blow incessantly for nine
months of the year, we can see how, with the torrential i-ains occurring
in the Marshall Islands, this mass of material is readily decomposed into
shingle, then into sand, and finally into silt.

In the gap between Likieb and Lado we can trace the formation of
the sand flat from the consolidation of the sand spits extending far into the
lagoon ; a line of gigantic breakers indicates the position of the outer reef
flat connecting the two islands. On this wide reef flat numerous sand bars
are thrown up; they will eventually fill up the wide and shallow bay now

314 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

existing between these two islands, a bay once perhaps a wide and deep
gap connecting the sea with the lagoon. The widening of the lagoon
flats of the Marshall Islands by the transportation of the mass of material
exposed to the action of the trades differs somewhat from that due to the
action of the trades in closing the gaps between islands on the land rim
of atolls, either in the Paumotus or in the Fiji Islands.

The line of islands and islets on the east face of the atoll are well plotted
on the chart (PI. 228, fig. 3); they form a succession of islets and islands
and sand bars, separated by gaps, sending out spits across the reef flats
on 'the lagoon side. The spits gradually project across the gaps, as we
have described it, forming first tongues of sand at right angles to the
shore line, then bays open to the sea or to the lagoon, and finally sinks,
closed up by high shingle beaches on the sea face.

The rise of the tides in the Marshall Islands is from three to seven feet ;
as there are no hurricanes, the conditions under which the niASs of material
deposited on the reef flats is moved is not subject to the cyclonic conditions
which occur in Fiji, or further east in the Paumotus. In the Marshall Islands,
as at Jaluit, where the beach is not more than five feet above high-water
mark, high seas have only occasionally forced their way across the island.

The southeastern part of the lagoon, and as far as one can see, is
full of shoal patches and coral knolls. The deepest part is said to be
from twenty-five to thirty fathoms, though as a whole the average depth
of the lagoon varies from fifteen to twenty fathoms. We have not, in any
lagoon, found such a mass of floating sand as at Likieb. It was impossible
to make a haul of the tow nets anywhere without bringing up with them
a large amount of sand.

Gap across Land Kim, Likieu.

WOTJE. 315

Wotje.

Plates 178-180, figs. 1, 2; '225; 227, fig. U ; 228, fig. 1.

At the time we steamed past the western horn of the lagoon there was
hardly any sea to show the line of demarcation of the submerged .reef flat
rising between the lagoon and the deep blue water (PL 228, fig. 1). The
light green color of the shallow water on the submerged reef formed a
striking contrast with the deep blue and iridescent colors on the two sides
of Rurick Pass. We entered Wotje by the Rurick Pass and anchored
about a mile inside of the lagoon in twenty-two fathoms. We could see
in the distance Christmas Harbor, formed by the low islands and islets of
the northern face of Wotje. As far back as 1817 Wotje was surveyed by
Kotzebue. The '• Rurick " entered the atoll through Rurick Pass, near
the western extremity of the south face, explored the north face of
the lagoon from Goat Island eastward and passed out again through
Schischmarev Strait. This is one of the earliest and best charts of an
atoll. The soundings indicated (PI. 228, fig. 1) were all taken by the
" Rurick." According to the Russian chart a great part of the lagoon of
Wotje has a depth varying from twenty-five to twenty-eight fathoms.
Little notice has been taken of this atoll by writers on coral reefs, in spite
of the accurate information given by Lieutenant Schischmarev.^

Rurick Pass leads to Christmas Harbor ; no obstructions exist at that
end of the lagoon (Pi. 228, fig. 1). The gaps between the islands on
the weather side appear, judging from the color of the water, to be quite
deep. The weather side of the lagoon is in marked contrast to the lee
side, where the land rim consists of only a few isolated islands thrown
up on the narrow reef flat which forms that side of the atoll.

As we passed out of Rurick Pass on the following morning, the contrast
we had noticed the evening before in the color of the water on the two
sides of the passage was perhaps even more marked. On one side spread*
the dark blue of the lagoon, on the other the still darker blue of the deep
water off the lee side, with the bright green belt indicating, on the two

1 Otto V Kotzebue, Entdeckungs Reise, Band 2, p. 44, 1821.

316 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

sides of the passage, the position of the submerged reef, the dark blue grad-
ually passing into a lighter blue, finally into a bluish green, a yellowish or
even light green ; the edges of the passage being covered with patches of
the peculiar iridescent and metallic coloring we have mentioned before.
This band of highly colored water seen in the morning and evening sun
seems to be characteristic of the Marshall Islands ; we did not observe
it, or saw it only on a very limited scale, in any of the other atolls
we visited.

Passing out of Rurick Pass, we followed the narrow submerged reef line
of the lee face of Wotje atoll marked by its light green color, interrupted
here and there by an occasional islet or breaker. The tide at the Marshall
Islands rises from five to seven feet, so that the amount of water which is
daily poured over the reef flat into the lagoon must be enormous. In
addition this mass of water is driven by the trades, so that a very different
condition exists from that of the Paumotus, where although there is a
powerful swell, yet the tides are comparatively insignificant, the southeast
trades are more or less interrupted, and the passes are few in number and
usually narrow. The amount of water entering into the atolls of the
Paumotus bears no comparison to the rush of water entering into many
of the other atolls of the Pacific.

The first island to the eastward of Rurick Pass was well wooded, although
but a narrow thread of land. It was edged on the sea face with beach rock
conglomerate, the two extremities of the island forming sand spits, the sand
having been driven from the lagoon beach and overwhelming little by little
the beach rock conglomerate which crops out upon the reef flat (PI. 228,
fig. 1). This island is crowded with terns and forms a gigantic rookery.
To the eastward another islet is thrown up on- the half-submerged reef fiat.
To the south of these crop out occasional stretches of coral sand raised
slightly above the level of the reef flat. There is considerable swell on the
southern face of the atoll, and a long line of breakers indicates the posi-
tion of the outer half-submerged reef flat. Many of the islands and islets
near Schischmarev Pass (PI. 180, fig. 2) are only reaches of beach rock
conglomerate pounded by the breakers. At the angle of the southern face
of the atoll leading to Schischmarev Pass a large island has been formed ;

VVOTJE. 317

it is flanked-by a high black shingle beach fully fourteen feet above high-
water mark. Sand spits extend from the extremities of this island on the
wide reef flat, covered by huge coral boulders, the tops of which have died,
and have been more or less cemented, as in other coral boulder reef flats
we have described.

Sand spits and sand bars extend northward on the inner part of the
lagoon, and a number of islands, islets, and sand bars are indicated by lines
of breakers parallel with the outer line of islands. Schischmarev Pass is
near the western extremity of the deep curved bay of the south face of the
atoll (PI. 228, fig. 1). About four miles to the east of Schischmarev Pass
opens Lagediak Pass, another strait leading into Wotje. These two pa.sses
are, only on a larger scale, as we have observed in other atolls of the Marshall
Islands, blocked on the lagoon side by one or two rows of islands parallel
in a general way to the outer islands flanking the opening of the passes
(PI. 180, fig. 2). The islands and islets on the reef flat of the southern face
of Wotje are generally connected by sand bars; some of them are wooded,
covered with hardwood trees, Pandanus, and a few cocoanut trees. At
Schischmarev Pass the buter islands have been thrown up on the edge of
the wide beach rock conglomerate flat. They are separated by deep gullies
forming passes more or less clear, lanes of dark blue water separating the
outer and inner rows of islands which block the pass to the north. On
the south side of Schischmarev Pass the islands of the land rim are
partly connected by low sand bars, sometimes entirely closing the gaps
between them (PI. 228, fig. 1), though there are a number of indistinct
gaps separating the islets of the land rim. On the eastern part of the
south side of the lagoon, the islands thrown up on the reef flat are
flanked on the sea face with sand spits ; these reach out towards the
outer edge, making huge loops or shallow bays opening out to the sea.

On Wotje Island but little beach rock conglomerate is exposed on
the lagoon side, the coral sand beaches are high, and a few boulders are
scattered on the flat between it and the next islet. The islands to the
north of Wotje are similar in structure ; they show but little beach rock
conglomerate outcrop ; the lagoon face is flanked by fine coral sand beaches
(PI. 179). The gap between Wotje and the island to the north of it (Pis.

318

" ALBATROSS " TROPICAL PACIFIC EXPEDITION.

179 ; 180, fig. 1) is flanked by two sand spits. The beach on the higoon side
is about seven feet high (PI. 179, fig. 2), while on the sea side it is at least
twelve to thirteen feet. The shore of the gaps towards the lagoon are
flanked on the outer edge with beach rock conglomerate ; this is gradually
changed into fine coral sand as we reach the edge of the lagoon (PL 179j.
A line of breakers extends directly across the gap ; the light green color
of the water shows there is only a shallow passage between the lagoon
and the sea face (PI. 180).

We anchoi'ed in twelve fathoms, about three quarters of a mile off Wotje
Island. Corals grow in large patches between 6ur anchorage and the shore,
mainly blocks of Porites, patches of Pocillipores, of Millepores, and of Mad-
repores ; wide patches of AlgJB and Nullipores, separated by lanes of sand,
extend to seven or eight fathoms in depth. Along the slope of the beaches
both the corals and the Algse diminish in number with increasing depth,
to twelve or fifteen fathoms, and more rapidl}' to twenty fathoms. The
island of Wotje (PI. 227, fig. 4) is fully three quarters of a mile wide; it

is formed by a succession of
low ridges, — four where we
crossed it, — forming sinks, in
which the natives have dug
water-holes. The ridges are
covered with magnificent Pan-
danus, breadfruit, and Pouka
trees. The belt of vegetation
is much finer (PI. 178) than
on any other atoll we have
visited. Rolled beach corals are met with across the whole island ; on the
sea face the island is flanked by a wide reef flat, edged with Nullipore and
Pocillipore knolls. The reef flat is about 150 yards in width ; it slopes
gently ; large numbers of coral heads have been thrown upon its surface.
The sea beach is at least fourteen feet high, composed in part of shingle,
in part of sand. At the base of the beach extend masses of beach rock
conglomerate, made up of large blocks of coral heads, and of smaller
fragments of beach rock and corals. On the lagoon side the beach rock

Ska Fack of WDi.ik Island.

WOTJE. 319

conglomerate is finer, containing many amygdules, and made up of small
frai!;nients of corals. The largfe coral masses on the sea face of the reef
flat, the outliers of beach rock conglomerate, and the fragments of corals
thrown over the sea beach inland are honeycombed and pitted, and
much weathered.

• As we left our anchorage, we could trace on the northern extension of
the west face of the eastern land rim the successive sand spits projecting
out from the lagoon side of the land rim, and forming a series of bays
on the inner side of tlie atoll, far larger and more distinct than those we
have described as existing on the outer sea face of the south shore. Both,
however, are formed by the same agencies. On the east face the sand from
the sea beaches is blown by the trades into the lagoon between the sides
of the gaps, and the gap may be closed by the extension of the shingle
beaches on the sea face of the islands on the two sides of the gap (PI. 179,
fig. 2) ; on the south side of the lagoon the sand forming the spits extend-
ing; to the sea face on the outer reef flat comes from the lagoon .sand beach.
The sand beach or dam thrown up across the lagoon face of the bay is due
to the reach of the trades in the lagoon itself (PI. 179); but the result
is the same. In each case the gaps of the land rim are closed by sand
blown in from the outer or inner beaches of the land rim.

It is probable that the line of sinks we have described on Wotje are
evidences of gullies and gaps once separating islets on the lagoon face
of the land rim, gaps which have gradually been closed by a process
similar to that which has connected the independent islands and islets
forming the outer land rim of Wotje. If we imagine the result of the
consolidation of the double or treble row of islands blocking such a gap
as Schischmarev Pass (PL 180, fig. 2), we see that the resultant would
form a line of sinks and reaches and of gaps similar to those we observed
while crossing Wotje from the lagoon side to the sea face.

To account for the existence of islands increasing in size at both extremi-
ties, such as form the land rim of the Marshall Island atolls, we assume
that the base upon which the loose material of which they are built is
moved must be either stationary or have been elevated. There is not
sufficient new material supplied from the growth of corals to build up

320 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

such a land rim while the atoll is subsiding. The evidence we have
shows a certain amount of elevation, indicated by the position of out-
liers and outcrops of the underlying base or fundament upon which the
loose material has accumulated. If the land had been subsiding, this
material must in the end have been washed off from its surface and
deposited either on one side or the other of the face of the atoll.

According to the chart, many shoals and flats exist or are forming
in the lagoon of Wotje, especially in the northern part along the whole
length of the land rim (PI. 228, fig. 1). Where we steamed past shoals
and flats their position was marked by long lines of breakers, separated
by greenish bands of shallow water, indicating the intervening sandy flats.
The amount of sand continually in motion on these flats is considerable,
and shows how fast the coarser materials, the boulders and the blocks
thrown up on the beaches, are pounded and ground into sand. In an
enormous lagoon like Wotje (thirty miles by fifteen), the northern side
of the lee face is, of course, subject to the influence of the northeast
trades. The very outlines of the islands of the land rim on the weather
side of the atoll indicate how regular the action of the trades must have
been in throwing up this mass of material upon that face of the atoll.
As seen from the south, across the lagoon, the islands appear like rec-
tangular blocks of nearly uniform size, with rounded corners, separated
by gaps. The islands are all edged on the lagoon side with glistening
white coral sand beaches. They are from five to six feet high. As we
steamed out of Schischmarev Pass, we observed on the second island to the
west a huge boulder, a mass of Porites, thrown high up on the reef plat-
form, similar to those found on the reef flat of the sea face. Several hauls
made by the Kramer machine to limited depths outside of the atoll brought
less pelagic material than in the lagoon. This may be due to the great
disturbance of the surface outside of the latr:oon, where the trades drive
the pelagic material to a considerable depth, while in the lagoon the
pelagic material lives in comparatively smooth water ; a large proportion
of the surface of the atoll is sheltered at all times during the prevalence
of the northeast trades, or in calm weather, or during the short time that
westerly winds prevail.

ARHNO. 321

Arhno. •

Plates 180, figs. 3, 4; 181; 182, figs. 1,2; 335; 3S8,fig.4.

Arhno, the last atoll we visited in the Marshall Islands, is rectangu-
lar in outline (PI. 228, fig. 4), the southeastern and northwestern faces being
about seven miles in length, the southwestern about thirteen, and the north-
eastern about ten. From the northern extremity of the northeastern face
of the atoll extends a long spit, about six miles in length, and off the north-
eastern point of the atoll a similar spit, fully ten miles long ; the northeast
face of the atoll is a gigantic arc, running in a northeasterly and northerly
direction, forming, as it were, two handles to the rectangular lagoon of
Arhno (PI. 228, fig. 4). The charts of Arhno ai'e somewhat misleading;
it was not until we had steamed around the northern point of the
island, and obtained a general idea of its topography as seen from the
sea, that we understood its peculiar shape.

We examined the northeastern, the northwestern, and eastern face of the
atoll, as well as part of the southwestern coast. The depth of the lagoon
varies from ten to twenty-five fathoms; a large number of shoals and patches
are scattered over it. The slope from the land rim towards the bottom of the
lagoon Is quite steep ; at our anchorage in Arhno we found a very rapid drop
from the shore to fifteen or seventeen fathoms, the remainder of the lagoon
being comparatively flat, as in the Paumotus.

We entered Arhno through Dodo Pass (PI. 228, fig. 4), and anchored
off the east face, immediately at the base of one of the long spits which
give it its peculiar outline (PI. 181, fig. 3). We could look up the narrow
lagoon between the two sides of the northeastern spit formed by a western
line of islands and on the east by Terranova (PI. 228, fig. 4). The
western part of the horn of the lagoon is separated from its northeastern
extension by an elbow of Terranova Island running directly across the reef
flat from one side of the spit to the other. A similar formation occurs at
the north point of Likieb. At Arhno, however, the spit is much longer;
the eastern extremity is flanked on one side by the northern extension of
Terranova, and on the other by an open reef flat enclosing an auxiliary
lagoon, with an opening about an eighth of a mile in width, suitable for

21

322

"A.LBATKOSS" TROPICAL PACIFIC EXPEDITION.

the navigation of small boats. The eastern extension of Terranova is
partly flanked on the lagoon side by a high sand beach, and a heavy
shingle beach on the sea face rising from a narrow reef flat. On the
lagoon side of the land rim a large part of the shore is divided into a
series of bays, separated by points and spits of beach rock conglomerate
and rolled coral boulders which have been thrown over the island, or
rather thrown over the reef flat forming the eastern spit, before the

island was built up to
uJM^ ; its present height. The

greatest width of the
secondary lagoon is one
and a quarter miles, and
its length about three
miles. The islands and
islets on the western
face of the northeast
horn of the lagoon (PI.
181, figs. 3, 4) are flanked
by coarse shingle beaches
on the sea face, and by sand beaches on the lagoon side. They are
well wooded and, as a general rule, have been built up at right angles
to the trend of the horn of the lagoon. The gaps between the com-
ponent islands and islets have, little by little, been closed from the outside
or the inside, according to the prevalence of the trades. The formation
of the secondary lagoon of the northeastern spit is easily explained by
the accumulation of loose material thrown up on the reef flat, derived
either from the eastern or the western face of the horn bounded by the
line of islands on the west and Terranova on the east of the lagoon.
This has separated the horn of tlie lagoon from the principal lagoon
exactly as the secondary lagoon of the northeast point has been separated
from the northeast horn of the main lagoon.

The northeast horn of the lagoon is undoubtedly gradually filling up ;
a number of coral patches, sand bars, and spits will little by little encroach
upon the lagoon, the depth of wliich is at present very considerable,

BoiiLDKR Cusps, ]j.4goon Face ok Noiitueast Spit.
Arhxij.

ARHNO. 323

and change parts of it next to the land rim into a reef flat, continually
becoming broader.

The bay of the northeastern extension of the lagoon is more than a
mile wide. The islands on its northern face (PI. 181, figs. 3, 4; 228, fig. 4)
are separated from the islands to the east of Dodo Pass by a long stretch
of reef nearly awash at low water; on its outer edge a line of heavy
breakers is pounding and constantly throwing material across the flat
into the inner part of the lagoon.

The sea face of Terranova, the principal island on the eastern side of the
atoll, is nearly fourteen feet high ; it consists of coral boulders derived from
the outer narrow reef platform thrown up to form a steep beach. The summit
of the beach is fully fifty feet in width ; large masses of coral have been
rolled inland across the whole width of the island to form the spits in the
northeastern lagoon. It is evident from the position of the masses of coral
boulders tliat the island forming the eastern face of the northeast branch
of the lagoon has been built up by material derived from the outer eastern
face, as has been formed the high steep bank of the east shore of Terranova.
The spits on the western face of Terranova, once lines of boulders extend-
ing across a wide reef flat, have been excluded from the sea by an outer
dam; this has obliterated all traces of the gaps existing between the
islands once forming the east face of Arhno. The lines of rocky ledges on
the lagoon side remain to indicate the gaps, closed by the formation of a
shingle dam as the nucleus of the land rim of the east face of Arhno. The
eastern face of the northeastern extension of the lagoon is occupied by
Terranova, a narrow and slightly hook-shaped island. The lagoon beach is
composed of fine, slightly reddish coral sand, with here and there a stretch
of beach rock made up of a conglomerate of broken corals cemented with
fine coral sand. Near the southern extremity of the island on the lagoon
side is a spit composed of broken angular masses of dead coral. This mass
is underlaid by beach rock, and at this point the lagoon beach is from six
to eight feet above low-water mark. About fifty feet inland, back of the
lagoon beach, the lowest land of the island is found ; that is, there exists
immediately behind the lagoon beach a long trough-like depre!s.sion running
parallel with the lagoon beach nearly half the length of the island. There

324 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

are no sinks or ponds in this depressed region. The bottom is sandy and
covered with scattered broken or beach-worn corals washed in from the sea
face of the island.

The island is not more than 200 yards in width ; back of the eastern
face of the trough the land rises gradually to the summit of the sea beach.
This is flanked by a reef flat varying from 100 to 300 feet ; upon it
are scattered loose heads of corals of large size ; many of them have
been driven together on the beach, forming a continuous wall of about
ten to fourteen feet in height. This wall of beach-worn coral is underlaid
by beach rock conglomerate and the whole island is covered with masses
and fragments of coral washed in from the reef on the sea face. At a
distance of about two thirds the length of the island towards the southern
extremity we could trace these masses of corals thrown completely across
the island, where they have formed the coral boulder spits of the inner
face of the lagoon, underlaid by the beach rock conglomerate, as I have
described them on the sea face of the beach.

The soil of Arhno is fairly productive. Its larger islands are covered
with grass, fine groves of cocoanut trees, with magnificent breadfruit,
Pandanus, and Pisonias, and the usual belt of low vegetation growing
upon the summit of the beach.

The long island of Ine occupies the southern part of the atoll ; it does
not differ from that which flanks the eastern face. There are said to be
several boat passages on the southwest face of the lagoon (PI. 228, fig. 4).

We steamed out of the atoll through Dodo Pass, and skirted the eastern
face of Arhno on our way round the northern point of the atoll. On the
northern point a Y-shaped land rim is thrown up on a wide flat (PI. 228,
fig. 4) ; at its southern base the islands have united in a single crescent-
shaped island, extending from one side of the spit to the other. The shanks
are formed by lines of islands on the opposite faces of the northern point ;
they are separated by wide gaps and enclose a secondary lagoon in the
centre of the northern reef flat. Where the larger island cuts directly
across the secondary lagoon of the northern point a shallow wide bay
forms a closed area ; its western face is formed by the islands thrown up
on that face of the wide flat of the northern point. The northern extension

ARHNO. 325

of the islands forms the sweep of the eastern and western face of the horn
of the northwest point (PI. 182, figs. 1, 2). To the south of the first
transverse island a second row of islands cuts across the southern part of
the wide reef flat of the northwest point, flanked in its turn by islands
and islets with a steep sea face and high shingle or sand beaches. They
form the western land rim ; this passes gradually into a more or less
indistinct reef, the position of which is barely indicated by the color of
the water. On the north face is a continuous line of islands covered with
luxuriant vegetation, with steep shingle beaches extending east from the
base of the northwest point (PI. 180, fig. 3), flanked at the base with
high shingle and beach rock, extending as far as Dodo Pass (PI. 180,
fig. 4), and from Dodo Pass to the base of the northeast point.

At the base of the northern spit the land rim extends on one side
towards the southeast, north of Dodo Pass, and on the other towards the
westernmost point of the atoll. On the broad reef flat of the western
face, which is bare at its northern extremity, are a number of islands and
islets near its western point ; this is occupied by an island of somewhat
greater size. Skirting along the western coast we could see the lagoon
side of the many islands and islets extending northward from Dodo Pass
to the base of the northern spit (PI. 180, fig. 4).

When off the eastern face of the northwest point of Arhno, we were
able to examine the secondary lagoon formed on that spit (PI. 182) ; it
differs but little from the secondary lagoons of the spits or exten.sions
of many of the atolls in the Marshall Islands. In the case of Arhno,
the northern extremity of the flat of the spit is exposed to the action of
the sea from all directions ; the secondary lagoon is open to the north
(PI. 228, fig. 4), the northern reef flat being too deep to allow material
to accumulate, either on its weather or on its lee face. The reef flat of
the northern point, south of the secondary lagoon, is more than a mile
wide. Two rows of islands and islets flank the eastern and western face ;
from the extremities of the islands extend lines and bars of sand and
shingle at I'ight angles to the general line of the land rim, with here
and there gaps opening on the extensive inner reef flat. We could see
from the east side the sand beaches on the lagoon face of the islands

326 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

of the west »ide, with their sand spits and bars, forming the southern
edge of the secondary lagoon of the northern point (PI. 182, fig. 2).
The secondary lagoon must be of considerable depth, judging by the
dark blue color of the water. The northern extension of the two sides
of the secondary lagoon is indicated by a mere thread of breakers and
of discolored water, showing the extension of the reef flat as it passes
into the deeper bank off the northern point of Arhno (PI. 228, fig. 4).

The islands of the west face extend about five miles south of the base of
the secondary lagoon of the northern spit; they are on the very edge
of the wide reef fiat. On the lagoon side of the flat exists here and
there a huge sand bar connected with the outer shingle beach forming the
west face of the land rim. The islands and islets are separated by wide
gaps, edged by shingle beaches, the sand spits running towards the lagoon
forming wide, exceedingly shallow bays. We skirted for a considerable
distance along the west face of the narrow outer I'eef flat of the islands.
The position of the wide reef flat which forms the northern j^art of
the western side of the atoll is indicated hy the reach of greenish or
light green water extending eastward into the lagoon.

Along the northeast face of Arhno, from the northwest point to Dodo
Pass, bars run at an angle across the wide reef flat, with a number of
islands and islets and spits, connected at half-tide by beach rock con-
glomerate and shingle. The outer reef flat is comparatively narrow, but
on the west side the lagoon flat is wide, and there are from two to
three lines of islands and sand bars and sandy islets on the lagoon reef
flat immediately north of Dodo Pass (PI. 180, fig. 4).

The islands are flanked on the lagoon side by beach rock conglomerate
surmounted with coral shingle on the outer face of the reef platform, and
with fine coral sand on the inner side of the reef flat. These islands and
islets become gradually connected, forming a series of irregular parallelo-
grams enclosing shallow basins; these finally become filled up, forming a
wide island extending more or less diagonally across the reef flat. When
this process has taken place on the flat of a point, as, for instance, the
northwest point of Likieb, the point will gradually be filled up, and thus
a secondary lagoon be formed. Should this take place on the northeastern

ARHNO. 327

point of Arhno, for instance, the secondary lagoon will be formed by a
land rim on one side, leaving the face exposed to the action of the sea
more or less open. The islets in the vicinity of Dodo Pass are interesting
(Pis. 180, figs. 1, 2 ; 181, fig. 1) ; the inner line of islets, banks, and flats
and spits gives us an excellent example of the manner in which a wide
reef flat becomes gradually covered with islands and islets, and finally may
become changed into a wide land rim by the movement of the material
carried backwards and forwards by the breakers, material which has been
supplied from the disintegration of the outer beach rock conglomerate,
from the corals thrown up on the sea face, or from the corals growing on
the slopes of the interior of the lagoon. The coarse shingle of the beaches
consists of rolled fragments of corals near the summit and at the base of
boulders which are scattered over the reef flat of the atoll ; this is fully
three quarters of a mile wide at low water at some parts of the land rim.
On the two sides of Dodo Pass the breakers sweep across the gaps between
the islands and islets (PI. 180, fig. 4) exposed to the action of the prevailing
wind, throwing a large amount of material into the gaps. Many of the
islands on the sea face between the northwest point and Dodo Pass are
covered by dunes blown westward over the rolled corals and coral heads
of the lagoon flat. Immediately east of Dodo Pass a large wooded island
has been formed on the inner side of the reef flat. The islands to the east
of Dodo are larger than those immediately to the west, and are separated
by wide gaps generally bare at three-quarter tide (PI. 228, fig. 4). On the
lagoon face of the islands are numerous bars of shingle or of sand at
right angles to them, running far into the flats ; these, little by little,
become covered with sand and vegetation. Dodo Pass is flanked on the
western face by a series of flats, shoals, islands, and bars ; on the northern
side they extend nearly three miles into the lagoon parallel to the north-
eastern and eastern coast. The ridge which forms the northern point
extends a considerable distance northward as a bank, with from three and
a half to six fathoms of water for a distance of over two miles north of
the reef flat. It is probable that the northern and northeastern points of
Arhno are spurs of the main ridge or summit upon which, after its
denudation, the atoll of Arhno has been built up. To the eastward of

328 " ALBATROSS " TROPICAL PACIFIC EXPEDITION.

Dodo Pass the reef flat was, as on the north, covered with a number of
islands and islets, extending to Tagelib Pass and beyond to East Pass
(PI. 228, fig. 4). From Tagelib the reef flat is bare, the sea breaking
heavily upon it; it remains bare as far as the base of the small lagoon
which extends like a huge horn in a northeasterly direction from the
northeast corner of Arhno.

On the west side of Arhno, near the t^outh point, we encountered high
shingle dams, forming exceedingly narrow land rims, the outer sea face
and the lagoon being separated by a mass of rubble thrown up on the sea
face and washed, in part, towards the interior of the lagoon.

A striking feature of Arhno is that the sea face of the islands on the
land rim of the northeastern part of the atoll is flanked by heavy shingle
(PL 181, fig.' 1), similar to that which has been thrown upon the eastern
face of the atoll.

In many places the high shingle beaches form isolated dams of con-
siderable length ; as, for instance, the immense dams of rubble on the sea
face of the secondary lagoons of Taritari, where the rubble has been thrown
to a height of at least nine feet. With the decomposition of this rubble
and broken fragments into sand, islands covered with vegetation have
been built on the line of the dam. At the northeast point of Arhno,
spits of rubble, similar to the sand spits so common in the gaps of the
atolls of the Marshall Islands, have been thrown out from the lagoon
face of the immense dam forming its eastern land rim.

The small islets of the Marshall group which are not atolls or possess
no sinks, or where only slight depressions exist, must have been thrown
up on isolated peaks or ridges, as have secondary lagoons on extensions
of the faces of spits of such atolls as Likieb, Arhno, and Rongelab. That
is, beaches are thrown up on a shoal to a height of from twelve to fourteen
feet enclosing a circular sink, or an elliptical depression, or a longitudinal
trough, the existence of which has nothing to do with either elevation or
subsidence ; it is merely an open space left between a series of encircling
beaches. The sink is gradually filled witli material thrown over the
beaches from all directions. Thus a low island is formed with a slight
depression or with a shallow lagoon, the land rim of which may become

NAMORIK. 329

covered with vegetation, and seem to be an atoll raised from the depth
of the sea, or the remnant of a peak which has gradually sunk, according
to the theory of subsidence. Yet a large number of such atolls have been
formed merely by the transporting of dead material from the outer face
of the shoal, and its deposition on the inner parts of the flat.

Namorik.

Plates 2^5; 226, fig. 10.

During our passage from Jaluit to Namorik, we were unable to do any
work on account of the heavy trades, so gave up all idea of stopping at
that atoll and kept on to Kusaie. Namorik is open to the west, nearly
circular, and about six miles in diameter. Namorik atoll, from the descrip-
tion given by Hernnsheim, is undoubtedly gradually filling up. Pn the
western face is an enormous reef flat flanking a diminutive lagoon (PI. 226,
fig. 10), with passages only for small boats, though forty years ago, accord-
ing to sketches I have seen, schooners of considerable size entered the
lagoon and crossed the reef flat. This does not necessarily mean that to
the growth of corals is due this difference in the depth over the flats. The
material which has covered them is probably material blown in over the
reef flat from the sea face. The main reef flat is, according to some
sketches, covered with many large coral boulders, one of which is said to be
of the size of a native house. The depth over the reef flat has, on that
side, been diminished by the disintegration of the beach rock conglomerate,
and of the boulders mentioned above.

330 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

THE CAROLINE ISLANDS.

Plates 18-2, Jigs. 3, 4; 183-193, 235, 229-232; 233, fiys. 1-3.

*

We visited among the Carolines the islands and atolls of Kusaie, Pingelap,
Ponapi, Andema, Losap, Nama, the Royalist group, Truk, and Namonuito,
obtaining thus an excellent survey of the high volcanic islands of the group
from our examination of Kusaie, Ponapi, and of Truk, while the others
represent the structure of the low atolls ; some of them have probably a
volcanic basis, and others a tertiary limestone foundation, but neither were
observed at any of the low islands we visited.

Of the eastern Carolines, Kusaie and Ponapi are volcanic islands, and
of the western, Yap and the Pelew group are also volcanic. The reefs of
the Pelew group have been well described by Professor Semper.^

The barrier reefs of the volcanic islands of the Carolines are similar in
character to those of the Society Islands, though some features, such as the
great width of the platforms of submarine erosion of Truk, Ponapi, and of
Kusaie, and the development of a border of mangrove islands at the base
of the volcanic islands, are not found in the Society Islands.

The Truk Archipelago is perhaps the most interesting of the island
groups of the Carolines ; it is the only group of volcanic islands surrounded
by an encircling reef I have thus far seen in the Pacific which at first
glance seems to lend any support to the theory of the formation by sub-
sidence of such island groups as Truk. I can well imagine that an investi-
gator, seeing for the first time coral reefs in this group, would describe the
islands as the summits, nearly denuded, of a great island that had grad-
ually sunk. But a closer examination readily shows, I think, that Truk is
not an exception to the general rule thus far obtaining in all the island
groups of the Pacific we visited during this trip ; that we must look to
submarine erosion and to a multitude of local mechanical causes for our
explanation of the formation of atolls, of barrier and encircling reefs, and

' Die Naturlichen Existenzbedingungen d. Thiere, v. Karl Semper, Leipzig, 1880, I!<). TI., p. 39.

THE CAROLINE ISLANDS. 331

tliat subsidence has played no part in bringing about existing conditions
in the atolls of the South and Central Pacific. This group was not visited
by either Darwin or Dana.

Nowhere have we seen better than at Truk how important is the part
played by a submarine platform in the growth of coral reefs. The encir-
cling reef protects the many islands of the group against a too rapid
erosion, so that they are edged by narrow fringing reefs, and nowhere
do we find the wide platform so essential to the formation of barrier reefs.
The effect of the northeast trades blowing so constantly in one direction
for the greater part of the year is of course very great ; the disintegration
and erosion of islands within its influence is incessant, and their action
undoubtedly one of the essential factors in shaping the land rims of the
different atolls, not only according to their local position, but also accord-
ing to the geographical position of the groups. Thus far I do not think
any observer has given sufficient weight to the importance of the action of
the trades in modifying the islands within the limits of the trades; nor has
it been noticed that the coral reef areas are, with few exceptions, situated
within the limits of the trades, both north and south of the equator.

We did not visit a number of the eastern and central Carolines, but,
judging from the Admiralty Charts, they present no features of special
interest. The small land rims of some of the low atolls are very striking ;
for instance, at the Mortlock Islands,' the land rim of Sotoan, its principal
atoll, nearly twenty miles in length and six in width, is indicated only by
a few islands and islets ; the greater part of the atoll is marked merely
by a reef flat with extensive coral patches on its western and northern
face. Lukunor, another atoll of the Mortlock Islands, has been surveyed
by Captain Lutke. It is slightly pyriform in outline ; its lagoon has a
depth varying from twenty to thirty fathoms, with an average depth of
about twenty. The land rim of the southern and of the southern part
of the east face of the atoll consists of a large number of islands and
islets; the narrow northern and western reef flats are awash.

The Hall Islands resemble the Mortlock group, as do the Lamotrek and
the Uluthi Islands, all of which have been surveyed by Captain Liitke.

1 A. Chart 772.

332 " ALBATEOSS " TROPICAL PACIFIC EXPEDITION.

There are also among the Carolines a number of isolated islands and islets ;
they appear, from the Russian surveys, similar to some of the above-named
islands or to such islands as Pingelap.

Wolea Island 'has also been surveyed by Captain Liitke. It consists
of two open arcs of flats on which low islands have been thrown up, the
lagoons in the two arcs varying in depth — the eastern from five to
twenty fathoms, and the western to twenty-five. The eastern lagoon
is entered by a passage of about three quarters of a mile in width,
while the western lagoon is partly closed by two indistinct patches ;
the ridge separating the lagoon from the sea rises to a depth of four or
five fathoms.

We may note that the islands of the western part of the Carolines run
from southwest to northeast, having the same general trend as the southern
group of the Ladrones. The line of elevation of the central and eastern
Carolines from Kusaie to Truk runs in a general way from south of east in
a westerly or slightly northwesterly direction ; a number of parallel lines of
elevation pass through the low atolls of the eastern and central part of the
central Carolines.

The soundings made by the "Albatross" from Jaluit to Namonuito^
indicate that there is no great plateau from which the Carolines rise, but
that the various groups are, as is the case with the neighboring groups
of the Marshalls and Gilberts, isolated peaks with steep slopes rising from
a depth of over 2000 fathoms. The line we ran from the northern end of
Namonuito to Guam developed the eastern extension of a deep trough
running south of the Ladrones. The existence of this trough had been
indicated by a sounding of 4475 fathoms made by the "Challenger"^ to
the southwest of Guam. We obtained, about 100 miles southeast of Guam,
a depth of 4813 fathoms, a depth surpassed only, if I am not in error, by
three soundings made by the " Penguin " in the deep trough extending
from Tonga to the Kermadecs,^ and by two still deeper made by the

1 A. Chart 772.

2 Mem. M. C. Z., Vol. XXVI., No. 1, 1902, Prelim. Report, p. 63. Stations 238-244.

3 A. Chart 2930, Oceanic Soundings, Sheet 3. Named "Challenger Deep" in the Summary of
Results, Chart Ic, of the Voyage of the " Challenger."

* Ibid.

KUSAIE. 333

U. S. S. " Nero " ' to the eastward of Guam, probably in continuation of
the same " Deep " called the " Caroline Deep '' by Professor Supan.^

Kusaie-

Plates 18^, fig. 3 ; '184.-187, ns, 229.

The easternmost island of the Carolines, Kusaie, is about seven and three-
quarters miles long from north to south, and nearly nine miles from east to
west. It is a volcanic island ; the central part, Mount Crozer, rises to over
2100 feet in height; the northern summit. Mount Buache, rises to nearly
2000 feet (PI. 229).

Kusaie is the first of a series of islands differing from any we had seen
since leaving the volcanic regions of the Society, Cook, and Fiji Islands.
High peaks with needles of all possible shapes show the extent of erosion
and denudation which has taken place in the volcanic summits of the Caro-
lines (Pis. 184, fig. 2; 185, fig. 2). Kusaie, as seen coming from the ea.st, at
a distance of from three to four miles, steaming towards Chabrol Harbor,
shows perhaps as well as any other island of the group the extent to which
its volcanic rocks have been subjected to erosion and denudation. It is cut
into a number of deep valleys centering towards the middle of the i.sland,
with here and tliere a marked point or pinnacle of harder material left to
indicate the former height of the range.

Between the northern and central part of the island runs a deep
valley connecting Chabrol Harbor on the east to Coquille Harbor on the
west (PI. 229). Kusaie is somewhat irregular in outline; a deep indenta-
tion on the east side forms Chabrol Harbor, flanked on the north by Lele
Island. The southern shore forms a deep bight; in the centre of which
is the reef harbor Port Lottin. Coquille Harbor is a similar reef harbor
on the west side.

The principal ridge of the island runs east to west from Point Duperrey

' The deep soundings of the " Nero " have been marked " Nero Deep " on II. O. Chart .529, pub-
lished .June, 1900, but it does not give the deep sounding of the "Challenger" to the westward
(44 75 fathoms), whieh was the first indication of the probable existence of a deep trough south of Guam.
The deepest sounding made by the " Nero " attained the enormous depth of 5269 fathoms.

2 Petermann's Mitteil., 1899, Vol. 45, VIII., p. 180.

334

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

to Cape Vauvilliers (PI. 229), with a series of peaks varying between
1500 and 2100 feet, and deep valleys running south and north from the
ridge. A spur extends from the eastern end of this ridge towards the south
to Cape Tupinier, from which valleys run east, west, and south. Kusaie is
flanked by an extensive reef platform forming either a fringing reef or
a barrier reef with deep reef harbors, like Coquille, Chabrol, and Lottin
(PI. 229). Chabrol Harbor is a deep valley between two chains of volcanic
rocks; on its sea face a platform has been worn away to the north of
the entrance to the harbor, forming a comparatively narrow reef flat
covered with low vegetation, with a similar reef flat off the east face of
the chain forming the southern point of the entrance to Chabrol Harbor.
Owing to the heavy sea running across the entrance, we did not enter the
harbor; turning south we skirted the outer reef platform; it increases in

width towards the south and is cov-
ered with low islands and islets.

The greater part of the base of the
shore slope of Kusaie is fringed by
a belt of mangrove islands ; between
Port Lottin and Cape Tupinier it
forms a most intricate system of lanes
and bars (Pis. 184, fig. 2 ; 185, fig. 3 ;
186, 229). Between these points
there is an outer line of mangrove
islands and islets (Pis. 184; 185, figs.
1, 2), with a passage of considerable
width and depth (PI. 186), connecting
with the eastern part of Port Lottin
and the barrier reef of the lagoon, which extends from Port Lottin to about
one and one-half miles south of Point Duperrey (PI. 229), affording thus,
with the passage in the lagoon to the west of Port Lottin, an almost con-
tinuous boat track around Kusaie with the exception of the short stretches
where the reef flat becomes a fringing reef. Between Port Lottin and
Cape Vauvilliers the lagoon is broader and wider than on the east or north
face The mangrove belt on the outer edge of the reef flat is formed by a

^

JtHSlO&T

Port Lottin and Adjoining Mangrove
Islands.

KUSAIE. 335

series of small islands at right angles with the outer beach. This mangrove
belt is a most characteristic feature of the barrier reef of.Kusaie. The man-
groves grow upon a labyrinth of low islands (PI. 229), formed of material
washed down from the hills immediately behind the shore line ; this mate-
rial is mixed with coral rock material thrown up by the waves on tlie outer
broad reef flat which we were skirting. The beaches of the outer mangrove
islands are composed either of coral shingle or shingle composed in part of
beach rock conglomerate and in part of volcanic rock.

As we approached Cape Tupinier, the southern point of the east face of
Kusaie, we could see the rounded bluffs forming the termination of the spurs
extending towards the southern reef flat of the island, with deep valleys
running towards the interior separating them. From the base of the
spurs beach rock and volcanic boulders extended over the reef flat in huge
spits (PI. 229) ; on these grow the mangroves which form so characteristic
a fringe to that part of Kusaie (Pis. 184, figs. 1, 2 ; 185, figs. 1, 2). They
recall the belts of vegetation we have observed in some of the Society
Islands, especially at Bora Bora, where the vegetation, instead of con-
sisting of mangroves, was principally made up of cocoanuts and the usual
reef bushes. At Kusaie the vegetation at the base of the volcanic slopes
consists of magnificent forest trees (PI. 186) ; they also extend over the
mangrove islands and islets and give to the belt a different aspect from
that which characterizes the belt of vegetation on the outer reef flat of
the Society and Fiji Islands. ^

A similar belt of mangroves skirts the greater part of the northwestern
coast ; from Cape Halgan, the northern point of the island, it extends both
west and south, and thus forms a nearly continuous belt around Kusaie,
interrupted only at some point where the barrier reef flat is rather narrow,
or where the barrier reef becomes a fringing reef (PI. 229). The greatest
width of the reef flat is about a mile ; a number of basins are formed by
projections of the spurs from the volcanic slopes to the outer edge of the
reef flat, especially between Port Lottin and Cape Vauvilliers (PI. 229).
The islands of Lele and Yenas are the remnants of the spur which once
ran from Mount Buache to Point D'Urville (PI. 229).

It is evident, from the position of the volcanic rock outliers and from

336 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

the composition of the shingle of the outer barrier reef Hat at points where
the barrier reef is narrow and impinges upon the volcanic slope, that the
barrier reef flat has been formed by submarine erosion, that on its surface
have grown the reefs which supply the material for the sand and for the
sand beaches on the lagoon face of the reef and of the islands, while here
and there in the basins of the lagoon and in the channels a few coral
patches rise. Even on the outer sea face of the reef flat, the shingle is
partly mixed with volcanic rock showing that the outliers and outcrops of
the lava masses are only covered by a thin sheet of limestone. South
of Chabrol Harbor the beach rock conglomerate contains a number of
volcanic pebbles.

The greater part of the corals on the flats themselves have been
killed by the volcanic silt washed down the deep valleys of Kusaie, and
by the vegetable matter derived from the decay of the mangroves ; this
when held in suspension in sea water kills the corals in the immediate
vicinity on the mangrove belt.^

We entered the little reef harbor of Lottin through a passage which
reminds one of the lagoon openings of the barrier reefs of some of the
Society Islands (PI. 229). At the head of the harbor, the reef flats
become almost fringing reefs ; they are narrower than on the south
side of Kusaie, where the platform off the base of the gentle southern
slope of Kusaie is far wider than that of any barrier reef we have
visited thus far (PI. 229). The entrance to Lottin Harbor is on the
south side of Kusaie ; it is flanked on one side by two low islands, thrown
up on the outer reef flat, on the other by a ledge of coral boulders on the
spit forming the eastern entrance to Port Lottin (PI. 182, fig. 3). The
outer edge of the reef flat of the southern coast, from Cape Tupinier to
Port Lottin, consists of a series of reaches of beach rock and of large
coral boulders. Numerous deep passages, similar to the one leading into
Chabrol Harbor, cut through the outer edge of the reef platform, and
form a series of tortuous channels leading into the great expanse of the
shallow lagoon which separates the outer reef flat from the shore belt

' Corals are killed by overflows from the swamps of the Everglades aloug the southern e.xtremity
of the coast of Florida.

KUSAIE. 33

00/

of mangroves (PI. 229). At the southern extremity of Kusaie, near
Cape Tupinier, large angular boulders of coral reef conglomerate were
thrown up on the spits, supplying the material for the coral shingle
beach which characterizes the sea face of the belt of mangrove islands
separating the inner lagoon from the outer lagoon. The flats and islands
of the inner lagoon have been formed by the accumulation of volcanic
sand, washed down from the adjoining slopes, and forming patches upon
which the mangroves have taken root. The patches are often separated
by deep lanes of water, in which corals may grow ; where corals have
been overwhelmed by the volcanic sand they form disconnected patches.
Thus has been built up the inland labyrinth of mangrove islands which
reaches from Port Lottin not only lound the south shore of Kusaie, but
also on the eastern, as well as the western and northwestern faces of
the island (PI. 229).

The reef flat to the eastward of our anchorage is covered with large
patches of beach rock conglomerate ; on their slopes corals were grow-
ing in profusion^ and mangroves had, here and there, taken possession
of islands or islets disconnected, as yet, from the labyrinth of islands
forming the inner belt of the reef flat. We examined the channel leading
among the inner belt of mangrove islets, on the east side of the harbor.
The channel runs at least five miles parallel to the shore line, is from
three to six feet deep, meandering in all possible directions, and sending
off branches at right angles, forming an anastomosing belt of channels
as far as Cape Tupinier. There are an endless number of water lanes,
with ample depth for their canoes, which the natives use in passing
from one part of the island to the other, inside the barrier reef. The
mangrove trees take here an enormous size, many of them being between
forty and fifty feet in height, and their branches, together with those of
the Fetaus, the Poukas, the passion flower trees, and other hardwood
trees, form an immense arch which sometimes covers the channels so
completely as to make a tunnel through which the canoes or boats may
pass (PI. 186). The main channel of the lagoon runs along the base of
the volcanic slopes of Kusaie ; it is separated from them by numerous

small mangrove islets, covered with volcanic mud, which finds its way

22

338 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

between the roots of the trees growing upon the islets. Between this
inner channel and the outer face of the mangrove belt innumerable islands
and islets are forming, reaching as far as the outer beach. As we come
upon the southeast corner of the island, where the outer reef flat
approaches, and even encroaches upon the mangrove belts, the roar of
the surf can be distinctly heard. From Cape Tupinier these intricate
channels open out into more or less wide bays, separated from the sea
only by the high dam of beach rock conglomerate, or of coral rock
thrown up as a long shingle beach, and extending north as far as Chabrol
Harbor (PI. 229). From Cape Tupinier the lagoon channel extends nearly
to Point Duperrey. The outer belt of mangroves is quite narrow, while
the inner belt is far less important than off the southern coast. The
western shore of Chabrol Hai'bor is again edged by mangrove islands.

The island to the west of the channel leading into Port Lottin consists
of coral rock and shingle thrown up at least six feet above high-water mark.
A similar process took place upon the whole of the volcanic reef flat; as it
was cut away, the masses of limestone which form the various patches upon
which corals are now growing were thrown upon it from the then existing
sea face (PI. 187). Here and there volcnnic rocks jut out, and piles of
volcanic stones are to be seen cropping out in all directions. This shows
that below the patches of corals volcanic rocks exist, the outliers of which
indicate the process of planing off the great reef flat which has taken place
on the eastern, southern, and western faces of Kusaie (PI. 229).

The islands off the entrance of Chabrol, and off other parts of the coast
of Kusaie, show how the barrier reef platform has been formed by denu-
dation and submarine erosion of the longer slopes and bluffs. From the
former have been cut the wider reef platform, as on the south coast, and
from the latter the narrow reef flats where there is barely room, some-
times, for a canoe to pass between the volcanic slopes and the coral
shingle dam forming the bari'ier reef. Where the barrier reef platform
is reduced to a minimiun, owing to the steepness of the slope of the
island, we pass at once from the narrow reef shelf to the volcanic rocks,
as on the eastern slope ; -where the pitch of the volcanic rocks is less steep,
a wider and extensive reef flat has been eroded. On this shelf, however,

KUSAIE. 339

the outliers and outcrops of volcanic rock still indicate the mode of origin
of the wide reef platform.

On the outer sea fa<ie, especially on the eastern face, a number of
cocoanut trees and hardwood logs have been thrown up on the shingle
beaches. To the east of Port Lottin a small fre.sh-water river flows
through the volcanic shingle, so that a considerable amount of volcanic
silt has been carried out by the river to the outer edge of the inner
harbor. The corals flanking the harbor are partly killed by this volcanic
silt. We found heads of Porites, of Maeandrina, of Pocillipores, of Mad-
repores, and of Millepores growing luxuriantly on all the flats and shoals
and ledges of the lagoon to the west of Port Lottin. In the lagoon to
the west of Port Lottin an outcrop of volcanic rock occurs in the very
midst of the mangrove islands. On the western side of Kusaie the
reef flat gradually becomes narrower, until at Point Vauvilliers the outer
edge of the reef flat is only separated from the western slope of Kusaie
by a narrow lagoon.

The lagoon channel to the south of Chabrol Harbor is undoubtedly kept
clear by the streams running down the slopes of the eastern coast.

As we steamed out of Port Lottin and followed the outer belt of land
rim towards Point Vauvilliers, we foiuid the outer beach to consist of
volcanic .sand mixed with fine coralline .sand. At our anchorage, in
twenty-one fathoms, volcanic sand or silt composed the greater part of
the material we brought up, although at a comparatively small distance
on both sides of us were extensive reef flats on which corals were growing.
On examining the wide lagoon to the east of the anchorage, we found,
as we approached the shore, the bottom to consist of fine volcanic silt,
brought down by the rains from the hill slopes, and carried to the very
edge of the reef flat. The patches of corals and coral heads were as
frequently killed by volcanic sand as by coral sand, formed by the dis-
integration of the coral heads overwhelmed by the sand coming from
the outer sea face. About three quarters of a mile from Port Lottin is
the western lagoon ; its outer sea beach is formed of heavy shingle and
of coral boulders thrown up to a height of seven to nine feet. On the
top of the shingle beach an extensive belt of mangroves was growing,

340 "ALIJATROSS" TROPICAL PACIFIC EXPEDITION.

in continuation of the line of mangrove islands edging the reef flat
to the west of Port Lottin. The outer rim of mangrove islands extends
continuously from Point Lesson to Point Vauvilliers, where volcanic heads
crop out. On the northern extension of the reef flat coral boulders
form a gigantic spit, shutting off the inner lagoon from the wide reef
flat to the north (PI. 229). On this wide reef flat flanking the north-
west face of Kusaie (PI. 229) the islands of Hesi, Berard, and Gabert
rise to a slightly greater height than the numberless outcrops of volcanic
rocks which dotted, in all directions, the western barrier reef flat of
Kusaie from Point Vauvilliers to Coquille Harbor. As far as we could
see, the inner belt of mangroves which characterized the southwestern and
southern part of the west coast extends in a northerly direction, to join
the labyrinth of mangrove islands coming from the east, to the north
of Coquille Harbor.

Pingelap.

Plates 183, figs. 2-4 ; S25 ; 237, fig. 5.

Pingelap,^ the next group we visited, is an irregularly rectangular atoll,
with sides of about two and one-half miles in length (PI. 227, fig. 5).

Pingelap is undoubtedly an atoll built upon a volcanic platform, the
lagoon of which is enclosed on the east by Pingelap Island, and on the
northern horn by Tugulu and Takai Islands, two low islands well covered
with cocoanut trees. On the sea face the islands are flanked by heavy
shingle beaches (PI. 183, figs. 2-4); on the southernmost part of Pingelap
the lagoon face is flanked by a steep coral sand beach ; this gradually
passes into the wide reef flat which connects all the islands (PI. 227,
fig. 5). The reef flat encloses a shallow lagoon ; in the gap between
tlie two larger islands a shingle beach separates the lagoon from the
outer sea face. The western reef flat itself is even at low tide covered
with sufficient water to be navigable for canoes and small boats. It is
covered with large boulders and masses of smaller coral blocks. The
deepest part of the lagoon, said to be fifteen fathoms, seems to be in

' A. Chart 772.

PINGELAP. 341

the northeastern part, towards the gap which separates Pingelap from
Tugulu Island. The islands, as far as we could see, were formed by
high beaches thrown up on the two faces, forming a central sink, run-
ning parallel with the shore lines. High breakers are seen directly across
the eastern gap, as the sea during the season of the trades runs high on
the windward side. No island in the Carolines has probably so large a
population in proportion to the extent of land as this atoll. No less than
1000 inhabitants are said to live on the southern island (Pingelap), and
certainly, as we approached it, the number of natives crowding the
be.ach, with the many canoes drawn up near high-water mark (PI. 183,
fig. 4), would indicate a large population, depending for its food on the
products of the sea, and on the supply of cocoanuts growing upon the
islands. The intercourse of the natives of Pingelap with the outside
world is most limited ; when we passed the natives had not seen a ship
manned by whites for more than eight months.

We did not observe the base underlying the loose material of this
atoll ; judging from the structure of the adjoining islands, this base
probably consists of volcanic rocks. The low atolls in the Carolines
hold to the volcanic islands of the group the same relation which the
atoll of Tetiaroa holds to the volcanic islands in the Society gi'oup,
although in the region adjoining both the Carolines and the Society
Islands atolls exist which are undoubtedly built upon platforms of a
limestone origin, and some of the Carolines are composed of elevated
coralliferous limestones.

The atoll of MokiP resembles Pingelap in every respect. Namoluk
and Ifalik have the same general features. Feys or Tromelin Island,
according to the description in the " Sailing Directions " and the Admiralty
Chart,^ is an elevated coralliferous limestone plateau of about two and
one-half miles in circumference, steep to and rising to a heiglit of thirty
feet. This and the Oraluk or Bordelaise group are the only elevated
coral reefs of the group ; the latter is about half-way between Ponapi
and Truk. We did not visit Oraluk; the "Sailing Directions" state
that on the northwestern extremity of the group an elevated coral reef

' A. Chart 772. - Ibid.

342 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

rock island is found (San Augustin) which rises to a height of 107 feet;
on the southeastern end of the atoll a small limestone island. Baxo
Trista, is fifty feet high.

The Seniavina Islands.

We next visited the Seniavina Islands ; they consist of the high volcanic
island Ponapi and the low atolls Pakin and Anderaa ; the last are separated
from Ponapi by deep water. Ponapi rises to a height of nearly 2900 feet,
while the atolls of Andema and Pakin have been thrown up on a volcanic
platform, dennded to about the level of the sea, or upon a summit elevated
to the depth at which corals grow.

Ponapi.

Plates 188-190, figs. 1-3 ; 2^5,

The island of Ponapi is about twelve miles long north and south and
perhaps thirteen miles from east to west. It is surrounded by a wide
reef flat ; at some points this is nearly three and one-half miles in width
(PI. 230). Within the barrier reef surrounding the main island a number
of smaller volcanic islands are formed, satellites as it were of the principal
island; on the outer edge of the reef flat a number of low coral sand
islands have been thrown up.

Ponapi is distinguished from Kusaie by the number of the volcanic
islands enclosed within the barrier reef; their position shows even better
than at Kusaie how a wide and broad reef flat has been eroded from
the central mass and has left as outliers such islands as Jekoits, Parum,
Langa, Mantapeti, Tababac, Tacahu, Mutokaloj, Tauche, Mutok, Tulatik,
Tahuak, and other islands, all in the extension of spurs from the main
ridge (Pis. 188; 189, figs. 1-3; 190, figs. 1, 2); in some cases they are
on the very outer edge of the barrier reef (PI. 230).

The base of the volcanic slopes of Ponapi is, like Kusaie, fringed

PONAPI. 343

with a shore belt of mangrove islands and islets, but it does not attain
the great width of the mangrove belt on the southeastern coast of Kusaie,
as will be seen by a comparison of the charts (Pis. 229 ; 230). The outer
edge of the barrier reef flat surrounding Ponapi carries but few insignifi-
cant islands and islets, covered with an exceedingly scanty vegetation
(Pis. 188; 189, figs. 1-3), in striking contrast to the vegetation which
thrives on the islands thrown up on the outer barrier reef of Kusaie.

Near the eastern and western side of Kiti Harbor one can see how
the volcanic sand brought down from the hill slopes is gradually filling
the great barrier reef lagoon flat, and how mangrove islets extend out
towards the barrier reef and may finally bring about a condition of
things very similar to that existing on the south shore of Kusaie, both
to the west and to the east of Lottin Harbor. The reef harbors are
more numerous in Ponapi than in Kusaie (compare PI. 230 to 229),
but they are small and can hardly shelter vessels of any size. During
the prevalence of the trades it is somewhat dangerous to enter such
narrow harbors as that of Metalanim (PI. 188, fig. 2), or of Jamestown
(Jekoits), mere openings in the reef less than one fourth of a mile in
width. A heavy swell breaks across the openings leading into inner
channels generally obstructed by bars and shoals and flats, the position
of which it is diflicult to ascertain except under favorable conditions
of tide and light.

We made Ponapi ' at a ]ioint a little to the south of Metalanim Harbor,
with Narpoli Island rising to the north on the wide reef flat flanking
the southern entrance of that harbor. The sugar loaf Mount Takain,
on the northern side of Metalanim, is one of the best examples of the
extent of the erosion to which the volcanic rocks of Ponapi have been
subjected.^ The island of Narpoli is volcanic, as well as other islands
on the wide reef flat to the south of the entrance of Metalanim Harbor.
The sea face of some of these islands is covered with fine coral sand
beaches and few coral boulders. The islands and islets near Metalanim
are well wooded. On the wide reef flat to the north of the entrance

> H. O. Chart 425 ; A. Chart 981.

- Basalt V. Jer lusel Ponapi, A Wiehiiian, Jour. d. Mus. Godeffroy, Heft VIII., p. 123.

344 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

to Metiilanim only a single island occurs (PI. 188, fig. 1). To the
south of Metalanini, north of Port Lod, an immense tongue of mangrove
islands runs out to the very edge of the outer barrier reef flat (PI. 188,
fig. 3). We happened to pass this point at moderately high tide, when
the barrier reef flat, edged by the brealiers, formed an immense shallow
bay, indicated by the green water, though a strip or tongue of some-
what deeper, water runs from the reef flat towards Metalanim Harbor.
As we approached Port Lod the tongue of mangrove islands gradually
recedes from the edge of the barrier reef flat, and approaches the foot
of the slope of the island (PI. 188, fig. 4). To the east of Point Nantiaiti
extends a shore belt of mangrove islands, similar to that south of Metala-
nim and similar to the mangrove shore belt so characteristic of Kusaie.
Immediately below Point Nantiaiti are two small volcanic cones (Likintakai
Island) ; they show how far the outliers of the ridges and spurs of Ponapi
may reach into the main barrier reef flat. This outlier also indicates
the amount of denudation which has taken place from the southeast
point of Ponapi in a westerly direction, and formed the immense barrier
reef platforms so characteristic of Ponapi and of Kusaie. On the outer
edge of this reef platform, to the south of Mutok Island, but few low
islands exist (PI. 190, fig. 1); they are either patches of volcanic rock,
disintegrated and covered by low vegetation, or negro-heads ; these may
be fragments of a volcanic mass, or a patch of coral rocks thrown up
on the outer edge of the barrier reef lagoon. To the west and east of
Mutok Island the shore of Ponapi is flanked by a narrow fringe of
mangrove islets running round the base of the slopes of the ridges
and spurs (Pis. 189, fig. 4; 230).

Immediately to the east of Mutok Island a deep indentation (Port
Mutok) is formed in the outer edge of the barrier reef, opening into a
deep channel running across the reef flat, and leading into a bay
immediately behind Mutok Island. On the southern barrier reef flats,
between Mutok and Kiti Harbor, numerous bars of beach rock have
been thrown up, separated by bands of greenish or bluish water, accord-
ing to its depth ; the bands of deeper water probably indicate the southern
extension of the valleys on this face of Ponapi. The spurs and ridges

PONAPI. 345

separating them have gradually been eroded, and nothing is left to
indicate that they formerly extended almost to the very outer edge of
the barrier reef flat. West of Mutok Harbor along the southern face
of the barrier reef fiat of Ponapi are a number of deep gaps cutting
into the outer edge of the barrier reef flat, forming either reef harbors
or entrances into the barrier reef lagoon. The gaps are connected by
pools and a labyrinth of lanes formed around the coral shoals which
occupy so great a part of the barrier reef lagoon flat of the southern
face of Ponapi. The reef harbors of Ponapi, as well as those of Kusaie,
are deep and narrow ; they are usually in the extension of the numerous
water courses which run down the slopes of these islands in all directions,
as at Kiti, Metalanim, Port Lod and Jamestown (Jekoits).

Cocoanut trees grow on the sandy islands of the outer edge of the
barrier reef (Pis. 189, figs. 1, 2; 190, fig. 3); the outer islands when
flanked by shingle are usually bare. It is only when we strike the
base of the main volcanic slopes of Ponapi that we come upon the
magnificent vegetation already characteristic of the Marshalls to the east,
and especially developed in the Carolines and as we go westward.

We followed the south shore of Ponapi as far as Kiti Harbor, where
we anchored much in the same position taken bj' the " Coquille," nearly
seventy years ago. Near Kiti Harbor the mangrove islets extend out
much farther from the coast than they are marked on the chart. The
chart is very definite as regards the position and extent of the islands
existing at the mouth of Kiti Harbor. Their present dimensions indicate
a considerable change, as natives informed us that the outer islands have
been greatly modified within the last seven years (PL 190, fig. 3); they
certainly do not agree with the view given by Captain Duperrey in
the Atlas of the Voyage of the " Coquille."

A section across Ponapi beginning at the outer reef of Kiti Harbor
shows that on the edge of the barrier reef numerous coral boulders
have been thrown up; mangroves grow here and there (PI. 189, fig. 3),
especially on the small sand bars or sand islets of the outer reef The
outer slope of the reef is quite abrupt ; the sea face is covered witli
gigantic masses of Porites, Millepores, Ma^andrina, Goniastrea, Madrepores,

346 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Alcyonarians, and Actinarians, growing in great profusion upon it. The
coral belt of tlie outer slope is in marked contrast with the corals of the
shallower water dividing the lanes and pools of the lagoon flat, where
the coral belt is comparatively shallow, although the species are the
same as those which grow on the outer face.' The lagoon flat between
the outer edge of the barrier reef and the edge of the mangrove belt
is, as has been described, covered with pools and lanes of more or less
deep water, alternating and separating the patches of corals which have
grown up from the bottom of the lagoon, the greater part of which
have been killed by silt. On the edge of the outer mangrove belt
(PI. 189, fig. 4), which is probably not more than 100 to 150 yards
wide, a few small coral masses are thrown up, and the whole slope
facing the lagoon is covered with deep, dark blue, finely ground mud.
In the inner Kiti Harbor a volcanic ridge runs down close to the shore.
It is very narrow and flanked with a band of mangroves.

Looking up the west coast from our anchorage in the outer Kiti Harbor,
the great extent and width of the barrier reef flat to the west is very
striking (PI. 190, fig. 2) ; near the entrance to Kiti Harbor a series of
low islands and islets and sand bars encloses a pool of about one and
one-half to two miles wide. The islets on the west side of the entrance
of Kiti Harbor are well wooded ; the islands on the eastern side have,
according to the statement of the pilot, been washed away, and nothing
remains to indicate their former extent except a few isolated coral rock
boulders on the edge of the outer reef flat. The water of the lagoon
on tlie south and west shore of Ponapi is exceedingly muddy from the
silt brought down by the rivers emptying into Kiti Harbor and dis-
charged through the long belt of mangrove islands. Something anal-
ogous occurs along the Florida keys, when the water dammed up in
the Everglades is forced between them in times of floods. Only at
Ponapi the land is high, the slopes are broad, and the silt is scattered
more uniformly, and not concentrated at a few channels, as is the case
along the Florida reefs.

• Ueber die Korallen d. Insel Ponapi, v. Dr. F. Briiggeman, Jour. d. Mus. Godeffroy, Heft XIV.,
p. 201.

PONAPI. 347

The n.avigation of the lagoon, which varies greatly in width, is somewhat
intricate, though it is said by the pilots that the Missionary Steamer " Morn-
ing Herald " can navigate from the west side of Kiti Harbor as far as Port
Metalanim. To tlie west of the outer Kiti Harbor the flats and pools form
an intricate network of channels, with from three to ten fathoms of water,
which can be navigated from the mast-head of small schooners without diffi-
culty. At any rate, canoes find but little trouble in circumnavigating the
island by running out -from one reef harbor into the adjoining one, where
the lagoon channels are too narrow for them to pass. Kiti Harbor cannot
be entered from the lagoon to the west. From the outer entrance to Kiti
a tortuous passage leads into the inner harbor (PI. 230).

To the east of the outer Kiti anchorage a similar condition exists.^
As far as we could see endless patches of coral separate lanes, or leave
deep pools between them ; the corals on some of
the patches grow with great luxuriance. At other
places nearer the shore, towards the edge of the
mangrove islets, they become overwhelmed with
volcanic sand, and are gradually dying, forming
shoals and bars upon which mangroves begin to
grow and finally become a part of the existing
belt of mangrove islands off the shore. The for-
mation of these coral patches and their ultimate
connection with the belt of mangrove islets indi-
cates the gradual mode of formation of the belt of
mangrove islands along the south and west coast

of Ponapi from the shoals of the barrier reef flat itself These coral patches
have grown up wherever the conditions were favorable, and increased in
size, laterally and vertically ; when they reach the surface they are either
killed by exposure to the sun or are overwhelmed by volcanic silt. The
dead corals are then in their turn cemented by Nullipores ; living corals
flourish only down to a comparatively moderate depth ; as the silt settles in

1 See tlie view of the great reef flat east of the anchorage in Kiti Harbor, given in the Atlas
of the " Voyage de la Coquille," Plates 49 and 60, giving a general view of Ponapi, as seen from the
same anchorage.

348 "ALBATROSS" TEOPICAL PACIFIC EXPEDITION.

deeper water, corals no longer find propitious conditions for growth, and
even on the lee side of the patches corals are killed by the silt. Corals
growing on the slope of the patches extend generally down to fifteen or
eighteen fathoms.

The corals on the flats have all disappeared at a depth of twenty fathoms,
where nothing but silt and a mud bottom are found. According to the prox-
imit}^ of the coral patches to the belt of mangroves, the depth to which
they reach varies from ten to fifteen or twenty fathoms. We found
growing among the corals Alcyonarians, sponges, and large Actinians.
The corals were mainly huge heads of Millepores, Madrepores, Goniastreas,
Porites, Pavonias, and also Fungia. Nowhere in the Pacific have we
found more magnificent corals than in the Carolines, reminding us of
those which flourish on the Great Barrier Reef of Australia, where the
sponges, Alcyonarian and Actinarian masses play such an important part
in the physiognomy of the coral reefs. A few M^andrinas also occur, the
first we have seen for a long time; between the heads grow large masses
of Sabella. The coloring of the corals is also much more brilliant than
that of the coral reefs to the eastward. The corals I have mentioned
form huge masses of pink, purple, yellow, and brown ; they alternate with
green sponges, with the many variegated, banded, and striped Alcyona-
rians, and with the large masses of purple Actinians which grow to an
enormous size among the coral heads over the more exposed parts of
the flats. A coating of Nullipores has gradually spread over the dead
corals. It is mainly on the slopes of openings and channels leading into
the barrier reef lagoon that corals are most flourishing, sheltered as they
are to a certain extent from the encroaching silt. The Porites heads grow-
ing near the inner edge of the mangrove flats are the first to be killed.
Near the outer edge of the reef flat the tops of the coral patches are
killed by the loose material thrown in by the action of the sea, and this
loose material is in its turn cemented by a coating of Nullipores. As we
approach the inner mangrove belt of the muddy reef flat, the bottom
becomes covered by volcanic silt, the water becomes dirtier and dirtier,
the corals have all been killed, excepting those which live on the upper
slopes of knolls or are attached to the sides of large heads.

PONAPI. 349

According to the tradition of the natives, the prevaiHng winds affect
the position of the islands on the outer edge of the barrier reef. They
seem to be eaten away on the east side, and during the hist eighty or
one hundred years to have been building up on the western face.

The amount of water which comes down the slopes of Ponapi during
the rainy season is enormous ; the extent of denudation and disintegra-
tion it effects is considerable, as can be seen from the formation of the
deep trough-like river valleys of that face of Ponapi. The channel of the
river which empties into Kiti Harbor is filled with bars of pebbles and
of gravel. The volcanic rock of which Kusaie and Ponapi are composed
is readily disintegrated and decomposed into a fertile soil, or washed
away as silt and deposited immediately off shore and in the deeper parts
of the eastern and western barrier reef lagoon flanking the island of Ponapi.

The fauna of Ponapi is quite different from that of the islands more
to the east. Fruit bats are found here, as well as paroquets, pigeons,
babblers, flycatchers, swifts, king-fishers, three species of lizards, and two
of bats. The vegetation is also different from that of the low coral
islands of the Marshall, Gilbert, and EUice groups, although the vegetation
of the former is already in striking contrast to that of such islands as
the Pautnotus, where the rainy season is not so continuous as it is further
to the westward. The vegetation of the Carolines, as far east as at Kusaie,
is almost continental, resembling somewhat that of the Malayan district
to the west. The variety of forest trees found on the slopes of Ponapi is
veiy striking ; they run down to the inner channel in the mangrove belt,
along the shore of Ponapi. It is interesting to compare the list of the
magnificent forest trees occurring on the Carolines, as given by Christian,^
with the list of the scanty vegetation characteristic of the Paumotus found
in Dana's " Coral Islands," "" or the more recent list of the similar flora of
Caroline Lsland given by Professor Trelease in his Report on the Botany
of the American " Eclipse " Expedition to Caroline Island.^

1 The Caroline Islands, by F. W. Christian. 1899, p. 328.

2 Corals and Cor.al Islands, 3d ed., 1890, p. 326.

8 Mem. National Acad. Science, 1884, Vol. II., p. 88.

350 "ALBATROSS" TEOPICAL PACIFIC EXPEDrno:N\

Andema Islands.

riates IS J, Jig. J, ; J.SJ, fiy. 1 ; 225, 230.

Andema' atoll is irregularly triangular in shape, with sides of about
seven miles in length. It is about eight miles to the west of Ponapi
(PI. 230). The islands composing the atoll of Andema are all low
(PI. 182, fig. 4), flanked by coarse shingle beaches, with but few coral
blocks on the outer edge of the narrow reef flat. A ship passage
from sixteen to twenty fathoms deep opens into Andema lagoon. The
gap between the island of Kahalape and Pachiai has been formed by
the same process as have the gaps of the Marshall Islands. Coming from
the southeast, we see that the northern island on the east face (PI. 183,
fig. 1). and those on the southern face of the atoll, are lianked by low
shingle' beaches ; the land rim is limited to the southeastern and eastern
faces. On the northern and western sides the reef flat is bare, with a
few narrow ledges, and comparatively few heads of coral are exposed at
high water (PI. 230).

The islands of the land rim of Andema, like those of Pingelap, have
been thrown up on an underlying base, probably a volcanic summit
planed down, as were probably a number of the other low atolls of
the Carolines. On Panemur, the westernmost island of the group (PI.
230), large coral boulders form the outer edge of the reef flat, with
here and there a few fragments of volcanic rocks, showing that the
land rim of Andema must at one time have consisted, in part, of vol-
canic rocks. It is difficult to explain the formation of such islands as
Andema and Pingelap and similar low atolls in the Carolines as due to
subsidence. We can trace in Pingelap, Truk, Kusaie, and in Ponapi
four succes,sive stages of disintegration, due to denudation and erosion,
of which Ponapi is the highest, Kusaie the next, and Truk still lower,
until we reach such submarine platforms as those of Andema and of
Pingelap. If we ascribe their formation to subsidence, we must admit

1 II. O. Chart 425.

LOSAP. — NAMA. 351

that it has taken place over an extensive area extending from the
Pelews to the Poniotus, the greater part of the tropical Pacific,' where we
find depths varying from 2000 to 2500 fathoms separating the islands
and atolls of the Caroline, Ellice, Gilbert, Marshall, and Paumotu Islands.
Such an explanation involves, in addition, the sinking not only of these
islands from a comparatively great height, but also the uniform subsidence
of the entire belt of deep water indicated by the soundings. Some of
these depths reach over 3000 fathoms.

Pakin ' is about fifteen miles to the westward of Ponapi. It is somewhat
crescent-shaped, about five miles long ; the reef flat is less than a mile in
width. At Pakin the islands of the land rim are scattered irregularly on
the northeastern and eastern reef flat ; they enclose a very indistinct
lagoon on the western face.

'n^

Losap.

Plates 232; 233, fij. 3.

We passed Losap ^ at a distance of about five mile.s. According to
the " Sailing Directions," the atoll has a lagoon of a depth of about
sixteen fathoms, with a number of passages leading into it. It consists
of a series of low islands, covered with tall trees, rising to a height of
from sixty to eighty feet. There is a small secondary lagoon at the
northeast end of the atoll.

Nama.

Plate

The island of Nama (D'Urville) consists of a low flat-topped island
covered with tall trees ; it has no lagoon. It is somewhat higher than
the low atolls of the Carolines and may be a summit of elevated
coralliferous limestone.

1 A. A^assiz, Mem. M. C. Z., Vol. XXVI., No. I, 1902. List of Stations, p. 29.

2 A. Chart 981. 3 a. Chart 772.

352 "ALBATEOSS" TROPICAL PACIFIC EXPEDITION.

The Royalist Islands.

Plates 190, fig. J^; 231, 232.

The Royalist Islands^ are an elongated atoll, a satellite of Truk
(PI. 231), of an irregularly rectangular shape, about eleven miles in
lentrth and five across the southern face. The northern extremitv is
not more than a mile and a half from the !-outhern point of the barrier
reef of Truk, and separated from it by a deep channel. Two passages
lead into the lagoon, one at the southern, the other at the northern
extremity. The northern passage is flanked on the east by Givry Island.
Hacq Island is in the central part of the eastern barrier reef flat, South
Island (PI. 190, fig. 4) is at the southernmost point of the atoll, to the
west of the southern passage. The south side of Fanek Island, on the
north side of the southern passage, is composed of a long line of yellow
coral boulders and covered wirth low vegetation, the beach rock extending
on the outer end of the reef flat, with here and there a larger coral boulder
thrown up by the sea. In the Royalist Islands the vegetation everywhere
reaches close to the coral boulders scattered on the wide reef flat. A
narrow belt of deep water extends along the western face of the northern
land rim of the atoll.^ The wide reef flat forming the southern part of
the lagoon is full of patches, reaches, and bands of shallow water, with
here and there a cluster of large coral blocks, especially near the northern
and western extremities. The reef flat is from two thirds to three fourths
of a mile in width. Far beyond the northern horn of the Royalist lagoon
we could see to the north the high peaks of Truk, and to the west the
high islands in the western part of its lagoon. On reaching the north-
ern end of Royalist atoll, we found the western edge of the reef flat
flanked with an extraordinary line of huge coral boulders, honeycombed
and undercut, forming ledges of the most fantastic outline, extending to
the extremity of the western horn of the atoll.

1 H. O. Chart 425.
» A. Chart 982.

TEUK. 353

Truk.

Plates 191-193, 231, 232.

Truk ^ is the largest atoll in the Carolines. The circumference of the
lagoon enclosed by the outer barrier reef is not less than 125 miles (PI. 231).
In our approach to Truk we followed much the track of the " Astrolabe and
Zelee," though we entered the lagoon of Truk through Aualap Pass, east of
Faleu, and steamed towards the northwest between Eiol and Udot Islands,
after being abreast Tsis Island. We could follow, as we passed, the in-
tricate passages formed between the spurs of the islands and the coral
reef flats which reach out from their sides. We anchored off the island
of Uola, the largest island in the eastern part of the atoll.

As one enters the lagoon from the south, the appearance of this atoll
is most striking ; when once in the central part of the lagoon, after losing
sight of the barrier reef flat, facing the eastern cluster of islands (PI. 191,
figs. 3, 4), with the western cluster to the rear (PI. 193, figs. 1, 2), the
numerous peaks, rising, as it were, directly out of the sea (Pis. 191,
figs. 3, 4 ; 193, figs. 1-3), appear like summits of islands gradually sinking.
Had this atoll been among the first visited by us, it would have been
n.atural to explain its present condition as one due to subsidence. Yet
whenever the line of the barrier reef with its belt of islands and islets
thrown up on the outer reef flat again became well defined, the atoll at
once found its place among other similar but smaller atolls, the structure
of which we have explained by the mechanical action of the trades, of
atmospheric agencies, and of submarine erosion.

The reef flats forming the great encircling barrier reef of Truk
are generally wide (PI. 231) ; they are broadest on the northern and
northeastern faces, gradually becoming narrower towards the southern
part of the eastern face, and quite nari-ow in parts of the southern
face. On the northern and eastern faces the barrier reef flat is covered
with a large number of low islands (PI. 191, figs. 1, 2) ; between the
disconnected portions of the encircling reef flat a number of deep passages

1 A. Chart 982.
23

354 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

exist by which the lagoon can be entered, not only on tlie north side,
but also on the east, as well as the southeast side (PI. 231), the principal
passes being on the north face to the west of Pis Island (PI. 193, fig. 4)
and on the east coast opposite Gregoire Island (PI. 193, fig. 3). On the
southeast face are also numerous passages, as well as along the southern
face of the lagoon, where the barrier reef flat is narrow, with only here
and there a low island thrown up on the face. Between the disconnected
reef patches on the southern face there are no less than seventeen passes,
all of considei'able depth. The western point of the reef flat forming the
western extremity of the atoll is broad ; on it are four low islands (PI.
231). The greater part of the lagoon varies from fifteen to twenty-five
fathoms in depth ; a few soundings indicate depths of thirty-five to thirty-
six fathoms. The northwestern part of the lagoon is nowhere more
than thirty fathoms, the deepest part being towards the southern face
of the atoll.

The i.slands on the outer margin of the immense atoll of Truk .are
very irregular in size ; they have been washed up on the outer barrier
reef flat, both from the sea and from the lagoon face. Numerous sand
keys, more or less covered with vegetation, have also been thrown up
on the barrier reef flats (PI. 231). Truk is helmet-shaped and not less
than thirty-five miles in diameter; as we approached the atoll, we could
see gradually rising from the central parts of the lagoon the moun-
tains of Umol, of Toloas, of Ruk, and of other islands, the character of
their slopes clearly indicating their volcanic origin (Pis. 191, figs. 3, 4;
193, figs. 1, 2). The islands were flanked at the base by sand and coral
shingle beaches, derived from the fringing reefs which encircle them (Pl.-
231). The fringing reefs have grown upon the disintegrated spits of the
islands and their shores, and have formed extensive reef flats. The outer
barrier reef rim of the atoll differs in no wise from the rim of en-
circling reefs such as we found in the Society and Fiji Islands, where
the central land mass of the lagoon, or the land mass of the rim, was
made up of volcanic rocks.

Enclosed by the encircling barrier reef are a number of high volcanic
islands, at a distance of froui two to fifteen miles from it ; twelve of

TRUK. 355

these rise to a considerable height. Uola is over 1300 feet, Toloas
rises to 1200, Kuk to nearly 1000, Umol to over 800, Udot to about
1000, and the large island of Tol has several peaks, the highest of
which is more than 1200 feet (PI. 231). In addition to the large vol-
canic islands, a number of smaller islands are scattered through the
atoll, such as Eiol, Periadik, Tarik, Ulalu, Fala, and others, rising from
twenty to 300 feet above the level of the sea. The names given to the
islands in the lagoon of Truk and on the Royalist atoll — such as Quo\',
Gaimard, Brongniart, Gaudichaud, Bouquet, Givry, Hacq, Lauvergne, Ber-
trand — are many of them names associated with the " Astrolabe and Zelee "
expedition in the early part of the past century ; a survey of Truk was
made in 1838, by Dumont D'Urville, who spent considerable time in
this atoll.

Uola, the largest island on the eastern half of the lagoon, is triangular,
a little over four miles in length and about three and one-half miles wide
on its western face. The principal ridge of the island extends parallel to
the southeastern face (PI. 192, fig. 2) ; it is separated by a deep valley, cut
down almost to the level of the sea, from Mount Ton Azan, the summit of
which forms the northern extremity of the island (PI. 191, fig. 3). Uola
is surrounded by a fringing reef, as are all the other volcanic islands in
the group we have examined ; here and there the disconnected fringing
reef flats are separated by short stretches of coral sand beaches. The
smaller islets in the eastern half of the lagoon from Eo north are simi-
larly edged with a fringing reef (PI. 231).

A steep beach of fine yellow coral sand extends on the west coast of
Uola from the village to the northern extremity of the island. About
100 feet back of the water line the beach reaches its greatest height ;
it is covered in many places with loose masses of broken coral of small
size, mainly Madrepores and Porites. A beach of the same character
extends along the greater part of the west face of the island towards
the southern point. Back of tliis, fine coral sand mingled with volcanic
particles, washed down from the adjoining slopes, extends to the foot
of the mountain slopes. This platform of coral and volcanic sand is
somewhat lower near the foot of the mountain slope than it is near the

356 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

shore, so that inland one finds stagnant pools of water, in which a
dense growth of mangroves flourishes (PI. 192, fig. 1). A sluggish stream
of brackisli water winds through the flat between Mount Ton Azan and
the main range. This stream appears on the western side of the island,
about one and one-half miles north of Mission Station. It has numerous
small tributaries and is from three to three and one-half feet deep and
about twelve feet wide; its channel is scoured by the tide, as well as
by the fresh water flowing from the hills. The edge of this stream
is covered with black volcanic mud containing coral fragments and coral
sand ; a dense wall of mang'rove bushes follows its course. Neither beach
rock nor coral reef rock was found in place or on any part of the shore
flat to the south of the village ; but here and there one finds small loose
blocks of eroded coral. These extend inland to the foot of the mountain
slope ; they are nowhere more than five feet above high-water mark.
Several small islands of beach rock conglomerate lie off the beach line
of the western coast of Uola ; they are raised only about eight inches
above high-water mark and support a fine growth of mangroves (PI. 192,
fig. 1). They are probably covered by high spring tides; there is little
evidence to show that they are elevated reef rock.

Ruk, the next island in size in the eastern half of the lagoon, is
four miles in length, with a greatest width of about one and one-fourth
miles (PI. 193, fig. 1).

Toloas Island is irregularly circular, about two miles in diameter (PI. 193,
fig. 1), with a long spur extending off the eastern coast nearly a mile, and
parallel to it a low volcanic ridge, forming the island of Erin ; Toloas and
Ei-in ai'e included within the same fringing reef flat.

To the south of Toloas rise a couple of low volcanic islands. To the
southeast of Ruk lies Umol (PI. 193, fig. 1); it is irregularly triangular in
shape, a little over two miles long, with an extensive spit running south
similar to that of Toloas. At the base of the spit the low island of
Atokin has been thrown up ; it indicates the position of a former ridge
like that of Kutua Point on Toloas. Between these four larger islands
and the barrier reef flat, distant from five to eight miles, extends a line
of low volcanic islets : Herit, Fanamu, Onna, Onnaram, Fananan, and

TRUK. 357

Fanan (PL 231). These islands are I'emnants of a volcanic ridge once
probably extending in the centre of the eastern part of the lagoon, more or
less parallel to the outer barrier reef flat ; they are separated by depths
! varying from seventeen to twenty-four fathoms. To the eastward of
iRuk are four other volcanic islands, each about a mile in length. Tsis
'Island runs in a northwestern direction, while Eiol, Periadik, and Tarik
'(PI. 191, fig. 1) run in an easterly direction nearly parallel with the
I principal range of Uola. To the west of the central line which divides
the lagoon of Truk into two almost equal parts is another group of
islands; the largest, Tol (PI. 193, fig. 2), is nearly seven miles in length,
running from southeast to northwest. A deep bight extends almost
one third the length of the island on the northeastern side, bounded
by a low peninsula rising not over 300 feet ; it is connected by a nar-
row isthmus to the principal island. To the east of Tol is the ti'iangu-
lar island of Fala-beguets, about one and one-half miles in length ; to
the north of Fala-beguets, the islands of Ulalu and Kuli ; they are about
three fourths of a mile long and run east and west. In an easterly
direction from Tol, near the central part of the atoll, lies the island of
Udot (PI. 193, fig. 2) ; it is Y-shaped, with one ridge running north and
south, and the other running in a southeasterly direction. To the west-
ward of Tol are two volcanic islands, Pata and Polle, the former about
one and three-fourths miles in length, and the latter nearly two and
one-half miles lono;.

In the northern half of the atoll, about half-way between Udot and
the island of Pis, are two islands, the largest of which is Brongniart
Island, a low sand island, over a mile in length, thrown up on an ex-
tensive reef flat (PI. 231). Several of the islands and islets near the
eastern and southern faces of the atoll are low sand islets thrown up on
some of the numerous coral reef shoals scattered over the southern half
of the lagoon of Truk. The southern part of the lagoon has been fairly
well surveyed and a number of lines of soundings extend across to the
northern part of the atoll. The islands thrown up on the outer barrier
reef flat on the eastern and northern coast are all noted for the high
shingle beaches facing the sea, and the steep fine coral sand beaches

358 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

on the lagoon side. Nearly all the islands of the outer reef flat are
well covered with cocoanut trees and with the usual belt of low bushes
characteristic of the outer barrier reef flat islands.

The summits of Truk vary from 100 to 1200 feet in height. The
outline of some of the islands clearly shows the extent of denudation to
which they have been subjected. Patches of beach rock conglomerate
flank some of the islands ; small narrow belts of mangroves also line the
shores, as in Kusaie and Ponapi, only on a very small scale. We see
in this atoll, perhaps better than in any other we have visited, that its
present configuration is mainly due to orogenic conditions ; the great depths
of parts of the lagoon represent valleys formed at the time of upheaval
of the original mass of Truk, the spurs separating them having been
planed off to form the great platform of Truk.

We must look upon the deep parts of some lagoons as due to the sub-
marine erosion and denudation of the outer slopes of the spurs of the
original land masses. Volcanic slopes often extend far across the barrier
reef platforms ; when denuded and eroded they become islands and islets
and bars, shaved down to the level of the sea and covered with coral
sand, or with large coral boulders thrown up between them on the outer
barrier reef flat. Here and there an islet may be the remnant or the
outlier of one of the volcanic spurs, once extending close to the outer
edge of the reef.

The points of the islands we passed on the way to Uola are covered
with short reaches of coral. At the northern extremity of Tsis Island
a long line of volcanic boulders extends far out into the lagoon, and is
the remnant of a spur of the central ridge of the island.

Between the islands the lagoon is full of patches, some of which are
volcanic ledges broken into all kinds of fantastic shapes, while others are
coral reef flats which have grown up on the volcanic ledges after they have
been eroded to below the level of the sea. A long line of such ledges ex-
tends between Periadik towards the northern point of Ruk.

The shore of Uola is edged by a fringing reef belt, varying in width from
500 to 800 feet, extending out in a gradual slope into the lagoon to a depth
of from five to six fathoms. Where coral heads growing to the surface have

TRUK. . 359

been partly killed and covered with Nullipores the belt forms the extension
of the shore line. In somewhat deeper water, the corals form huge clumps
separated by lanes of sand ; the corals do not reach a greater depth than
five to eight fathoms, when they disappear, having gradually become sepa-
rated by wider and wider lanes of coralline sand as they extend into deeper
water. In depths of less than seven to eight fathoms, huge patches of
black coralline Algaj, alternating with large masses of Millepores and
Madrepores, are found scattered over the bottom of the fringing reef belt.
Large pieces of coral rock have been thrown up on the beach ; they are
derived from adjoining elevated masses of undercut coral beach rock ;
this would indicate near the landing of Uola an elevation of some three
to four feet. The fringing reef impinges on a steep sand beach about five
feet in height, and in some parts has formed a flat of at least 1000 feet in
width, over which large coral boulders are scattered. This flat has been
formed on the top of the extension of the adjoining volcanic slope or flat,
and abuts against the volcanic sides of the hill. The honeycombed and
weathered coral masses, occurring as outliers on the volcanic slopes, indicate
the height to which this flat must once have been elevated.

When volcanic outbursts have thrown up limestone masses, the action of
solution, disintegration, denudation, and erosion upon such rocks is very
rapid ; sea-water also carries off in solution and suspension a large amount
of material, leaving fewer spits and outliers than is the case when volcanic
rocks are subject to the same agencies.

On this limestone plateau cocoanut trees are growing in great profusion.
On the volcanic hillsides the vegetation consists of breadfruit trees, sago
and ivory nut palms and Pouka trees (PI. 192, fig. 2). Tlie shore of Uola
is flanked by a narrow fringe of mangroves, growing close to the sand
beaches, or of mangrove islets formed mainly of volcanic sand mixed with
coral sand (PI. 192, fig. 1). Off Uola the water of the lagoon is exceed-
ingly muddy ; a mass of volcanic silt being carried out as far as our
anchorage, fully half a mile from shore.

On the south side of Uola the same conditions exist ; points of sand make
out from the fringing reef, and masses of corals are thrown up on the beach ;
reaches or patches of. black as well as green coralline AlgiB occur on the

360 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

fringing reef, while scattered over the extensive shallow flat were growmg
masses of Pocillipores, three or four species of Madrepores, and huge masses
of Porites elevated from three to four feet, killed in the centre, but still liv-
ing at the base. These formed huge agglomerations extending into deeper
water, where are found many massive species of Madrepores, with Mycedium,
Allopora, Pavonia, and masses of sponges, Gorgonians, and Alcyonarians.

To the south of Uola rises Tolomen, a conical peak on Toloas, nearly
1200 feet in height, and still further south the cone of Umol, about 850 feet
in height. From the anchorage we could trace on the volcanic flats extend-
ing towards Tol numerous coral ledges, the remnants of the spurs which
once extended from the base of the many islands of Truk towards the
interior of the lagoon. We could also see the islands occupying the south-
west corner of Truk, the highest point of which (at Tol) reaches a height
of about 1200 feet.

We left Truk by the northern passage. Steaming by the northern end of
Uola, we looked across the valley which separates the southern ridge from
Mount Ton Azan on the northern extremity of the island (PI. 231). The
neck connecting the two parts of Uola is a low reef flat, the remnant of
the elevated reef flat which once surrounded the greater part of this island.
To the north of Uola lies Gregoire Island ; to the westward, well on the
way to the north passage, lies Brongniart Island. Still further to the
north and east, on the outer edge of the barrier reef rim of Truk, we see
Gaudichaud, Quoy, Guinard, and a number of low well-wooded islands on
the flats to the east of Pis Island. The islands on the barrier reef flats
are connected by sand banks and sand bars, or by ridges and stretches of
beach rock conglomerate. Some of the barrier reef flats of the eastern and
northern part of the atoll have a width of nearly three miles. The outer
low islands are covered with magnificent vegetation.

On the northwest face of the rim of the atoll there are only two islands.
On the northern face, running east to west, Pis Island, flanked by sand bars
and sand spits, occupies the whole length of the flat thrown up between two
passages leading out of the lagoon ; the principal passage is to the west of
Pis (PI. 193, fig. 4). Another smaller pass exists to the eastward of the
smaller islets on the northeast face of the reef, but it is so tortuous that it

TRUK. 361

cannot be used by vessels of any size. Pis Island is flanked on the sea face
by a high coarse shingle beach, while on the lagoon side it is edged with a
magnificent beach of fine coral sand of considerable height, on which the
natives draw up their canoes. The islands on the northern face have been
thrown up by the combined action of the trades, the sea and swell from
the lagoon side. The spits at the extremity of the islands on the north
face of the atoll of Truk are generally covered with masses of boulders ;
deep water separates some of the smaller islands on the inner side of the
barrier reef flats of the lagoon, showing that this part of the lagoon was
at one time a reef flat similar to that to the west and to the east, merely
flanking the inner coral patches which have now become more or less
connected with the outer land liin, forming as it were small secondary
lagoons similar to those we have described elsewhere.

The island of Pis is covered with magnificent vegetation and is one of
the most thickly populated of the islands in the Carolines ; the natives
living there have but little contact with the settlements at Uola and the
southern part of Truk.

On the larger volcanic islands the vegetation reminds one more of the
vegetation of the eastern continental islands; it is even more luxuriant
than that of Kusaie or of Ponapi. Judging from the little that is known of
the larger forest trees, it is evident that the flora has felt the influence
of its greater proximity to that of the East. We are constantly reminded of
the similarity between the floi'a of the Malay Archipelago and the flora
of the Carolines, a similarity gradually becoming less marked as we go
east to Ponapi, to Kusaie, and to the Marshall Islands. This relationship
appears still more striking when we take a more southerly course and pass
east through Fiji, Samoa, and the Cook Archipelago to the Society Islands,
where it is difficult to recognize that part of the flora which owes its origin
to a mis^ration from the west to the east.

On examining a chart of the Carolines, we notice that the central part of
the Carolines occupies an area where denudation and erosion have been far
more active than it has been at the eastern and at the western extremities
of the group. On the east the islands of Ponapi and of Kusaie rise to the
height of nearly 3000 feet, and on the west such islands as Yap and the

362

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Pelew Islands rise to 2000 feet, a greater height than that of the islands
of the Truk lagoon. Within a radius of one hundred and fifty miles of
Truk are a number of low islands and atolls eroded to the very level of
the sea, such as Namonuito, the Hall, the Mortlock Islands (PI. 232), and
the numerous islands and islets lying between Namonuito and Wolea,
none of which rise far above the level of the sea. Of course there is
no proof that the base of the low atolls to the east and to the west of
Truk is composed of volcanic rocks ; it is only by analogy that we can

Native Canoes, Mokn, Truk, Carolines.

venture to say that some of the low islands of the Carolines are underlaid
by a volcanic base.

On the other hand, the existence of islands composed of elevated coral-
liferous limestone, such as Nama, of San Augustin in the Oraluk group,*
said to be 110 feet high, of Feys (PI. 233, fig. 2), as well as the presence
of elevated reefs of tertiary age in the southern Pelew Islands," makes it
probable that some of the low coral atolls of the Carolines may rest upon a
foundation of tertiary limestones, as is the case in the Paumotus, the Fiji
and Tonga groups, and other isolated islands in the Pacific.

1 A. Chart 982.

2 Semper, C, Die Palan Tnspin, pp. 17, 155, 277, 2S5 ; Zeits. f. Wiss. Zool., 18(18, XTTI., p. 555:
Die Naturliohen Existenzliedingiinnen d. Thiere, 1880, II., p. 39. A. Wichraan, Zur Geolog. Ivenntniss
•\. P.ilau Inseln, Jour. d. Mus Godeffrov, Heft VIII., p. 123.

NAMONUITO. 363

Judging from the structure of Kusaie, of Ponapi, of Truk, of Yap, and of
the Pelevvs, we may infer that some of the low islands represent only a
state of greater denudation and submarine erosion than the groups I have
just mentioned. Truk is perhaps the best evidence we have that such
extensive denudation has taken place, for it requires but little imagination
to picture its islands reduced to the level of the sea, when Truk would be
an atoll similar in all respects to the larger low atolls like Namonuito, the
Mortlocks, and others, differing from them only in having numerous coral
flats upon which low islands like Gregoire, Brongniart, and many others in
the atoll have been thrown up. These low islands in their turn might
eventually be changed into mere coral shoals should the denudation go
on a step farther. We noticed that in Truk, as in the low atolls of tlie
Carolines, the principal land rim thrown up on the outer barrier reef is
found on the northern and the eastern faces, where the barrier reef flats
are exposed to the full action of the trades or of the sea during the change
of the trades and the prevalence of northerly winds.

Namonuito.

Plates m^ ; 233, fig. 1.

The only one of the large low atolls of the Carolines we examined is the
Namonuito group. It is a triangularly shaped flat (PI. 233, fig. 1), its apex
towards the north, at a distance of about twenty-five miles from the south-
ern face of the reef, which is nearly forty-five miles in length. The lagoon
has been fairly surveyed in 1828,^ by the Russian ship '' Seniavina," which
crossed and recrossed the lagoon in several directions. The charts do not
indicate any features of interest other than those we observed.

The southeastern point of Namonuito projects out as a sharp reef flat
covered by shallow water, enclosing a secondary lagoon very similar to those
on the northern and the northeastern points of Arhno, but there are no
islands on the sides of the secondary lagoon.

On the extremity of the eastern spit rises the island of Pisaras, on which
a few cocoanut trees grow; it is flanked by coarse shingle, and a shingle

1 A. Chart 772.

364 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

beach partly covered by coral sand. Owing to the depth over the barrier
reef flat ridge, no breakers were visible on the reef to the north of Uneyeute
Island until we came close to Unalik. Here, about the centre of the
northeast face, are a number of islands and islets on the edge of an
ill-defined plateau, with here and there shoal spots where corals have
been washed up. They are separated from the island of Onoupe, lying
to the north of them, by a pass with deep water ; a continuation of the
reef flat can be traced farther north, trending in a northwesterly direction.

The shore of Onoupe is flanked by a shingle beach ; high cocoanut trees
grow on the island ; two islets are situated on the barrier reef flat, near
the northern point of the lagoon. At many points on the east and south
faces the presence of the reef flat is merely indicated by the difference in
color of the water covering the flat, and the occasional reef patches which
rise to the surface. The western horn of the atoll is occupied by the low
island of Ulul. The lagoon varies in depth from twenty to twenty-five
fathoms. Namonuito, Oraluk, and similar atolls represent the extremes of
the minimum development of a land rim, a mere thread of a narrow reef flat
encircling the lagoon, with only an occasional islet to indicate its presence.^

The atolls of the Mackenzie group are very similar in structure to
that of Namonuito, although the .shape of the atolls is somewhat different.
The same is the case with the Hall Islands, with West Faiu, Lamotrek,
Olimarao, Faraulep, Kama, and Ifalik ; wliile Feys (PI. 233, fig. 2),
Pikelot, and East Faiu are the oidy islands of the Carolines known cover-
ing nearly the whole reef flat upon which they have been thrown up,
that is, they are diminutive summits similar to the small islets in the
Marshall Islands, in the eastern part of the Pauraotus, and other groups in
the tropical Pacific.

1 If the sketch of Oraluk on A. Chart 982 is correct the barrier reef flat of the atoll is by far
narrower than that of any atoll known to me. Some of the narrow barrier reefs of Tahiti may be
compared to Oraluk,

THE LADRONES. 365

THE LADRONES.

Plates m-199; ^82; 233,fign. 4., 5.

The Ladrones form a line of volcanic islands, many of which are active ;
they extend north from Guam as far as the Farallon de Pajaros ; there
are no less than twelve active volcanoes in a distance of less than 300
miles. The southern groups of the Ladrones are islands partly volcanic
and partly composed of elevated coralliferous limestone. In Guam a
volcanic massif forms the southern half of the island ; in the northern
part Mount Santa Eosa, a volcanic outburst, rises at least 200 feet above
the general level of the limestone plateau of Guam. At Rota Island we
could only trace the existence of a small volcanic outburst, on the north-
western shore of the island.

The islands of the next cluster to the north, Saipan, Tinian, and Aguijan,
are partly volcanic and partly limestone ; we did not visit them, but their
probable geological structure is indicated by the sketches given on the
Hydrographic Charts.^

The line of the Lndrones beginning at Santa Rosa reef forms a gigantic
flat arc ; the southern portion rims from the southwest to the northeast,
the central portion runs nearly due north, and the northern group extends
in a somewhat northwesterly direction. Between the Ladrones and Japan
a line of volcanic islands extends somewhat to the west of the line of the
Ladrones ; its principal groups are the Volcano, the Bonin Islands, Lot's
Wife, Aoga-sima, and the volcanic islands and islets which run south of
Oosima. These form a line of active volcanoes running for more than 20'
of latitude, from the southern part of the Ladrones to the south coast of
Japan. The line of soundings of the " Nero " ^ indicates the remarkably
uneven character of the bottom along that line of volcanic islands.

The irregularity of the bottom along that line is in marked contrast to
the line of soundings at right angles to it, extending from Guam to Midway
Island ; the latter indicates a fairly uniform level bottom of an average

1 H. O. Chart 1748. 2 h. O. Chart 529.

366 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

depth of about 2700 fathoms. Across the south of Guam extend "CaroHne
and Nero Deeps " ; they are probably the eastern extension of " Challenger
Deep." This deep valley, with a greatest depth of 5269 fathoms, sepa-
rates the Ladrones from the Carolines.

Guam.

Plates 194-198 ; 232; 233, fig. 4.

The island of Guam is rectangular, al)Out twenty-two miles in length ;
its greatest width across the southern part is eight miles, and in the
northern six miles, narrowing near the central part of the island at the
latitude of Tumun Bay to about three miles in width (PI. 233, fig. 4).
South of the central part of the western shore, between Agaiia and Agate
Bay, extends the peninsula of Orote ; it runs out four miles in a north-
westerly direction, and forms the southern side of the harbor of San Luis
d'Apra ; the north side is protected by Cabras Island, about two miles in
length ; its western extension has been denuded and eroded into a wide
barrier reef flat, Luminan Reef and Calalan Bank extending as far as
Spanish Rock, the western extremity of the northern strip enclosing the
Bay of San Luis d'Apra (PI. 195, fig. 1). This bay has been eroded out
of the elevated coralliferous limestone of which the northern part of
the island of Guam consists.

From Port Pago north (PI. 233, fig. 4), on the east coast, are most
distinct coralliferous limestone terraces, marking the position of the former
sea level, and indicating the periods of rest during the elevation of
Guam ; where they are not well defined their position is still indicated
by the lines of caverns which crop out in the vertical faces, and give an
indication of the position of former lines of sea level. The mode of
formation of the vertical cliffs of the eastern side of the island, by the
gradual sloughing off of the lower parts of the vertical faces and encroach-
ing upon successive terraces, is well seen north of Anao Point ; the parts
thus falling oflf remain as outliers of the older terraces on the narrow
shore platform. The vertical cliffs of the northern part of Guam vary in

GUAM. 367

height from 300 to 500 feet (PI. 194, figs. 1, 2). The lowei- part of their
faces is riddled with crevasses and cracks, and at a higher level, probably
on the face of the fourth or fifth terrace, numerous caverns crop out.

We struck the east coast of Guam near Point Hanoum ; the vertical
cliffs of the east face consist of elevated coralliferous limestone, risinc at
the northern extremity of the island to more than 300 feet (PI. 194, fig. 1).
They flank the eastern shore of the island from Point Ritidian, the north-
ernmost point of the island, as far as Port Pago ; there the vertical cliff's
become indistinct patches and isolated cliffs resting upon the volcanic massif
of the southern half of the island. Magnificent terraces can be traced in
all directions, indicating the periods of rest dming the elevation of Guam
(PI. 194, figs. 1, 2). The vertical cliffs representing the lower terraces are
deeply pitted, honeycombed, furrowed, and distorted.

On the east coast, north of Point Anao, some of the coralliferous
limestones are stratified, dipping towards the sea ; others, nearer the
northern extremity, show evidence of great
disturbance, probably caused at the time of
their elevation, when Sta Rosa Peak burst
through the coralliferous limestones in the
interior of the northern part of the island
(PL 198, fig. 3). They resemble in every
way those of similar limestone islands, such
as Makatea, Nine, Eua, Vavau, and others
in Fiji, with which we had become famil-
iar in our explorations. Outside of Viti Twisted strata, East Face of
'- ^ Guam, South of Patay Point.

Levu and Vanua Levu, Guam is the largest

island we visited, composed in part of volcanic rocks and of elevated

coralliferous limestone.

At the northern extremity of Guam are five distinct terraces ; the first
and second are somewhat lower than the third and fourth ; the mass of
vegetation growing on the slopes sloughed off from the limestone bluffs,
has, at many points, obliterated all traces of the terraces. Taragay Bay,
at the northern extremity of Guam, is an immense sandy flat, flanked by
a comparatively broad reef platform (PI. 233, fig. 4), full of horse-heads

368 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

and of negro-heads; it extends between Point Tagua, past Point Ritidian,
as far as Falcona anchorage on the west coast. From that point the
vertical cHffs edge the coast until we reach the reef flats of Tumun and
Agaiia Bays (PI. 194, fig. 2), which extend as far as Cabras Island. To
the south of Orote Peninsula a narrow reef flat juts out from the west
coast at various promontories in the extension of spurs of the volcanic
slopes (Pis. 198, figs. 1, 2; 233, fig. 4). At Merizo Bay a broad reef flat
forms the southwestern extremity of Guam. Two low islands. Cocoa
and Bali, have been thrown up on the southwestern extremity of this
wide reef flat; it extends to the eastward as far as Point Ajayan, and
is lost as we reach Port Ynarajan. Beyond that point, as far as Port
Pago, the coast is edged by a narrow reef flat. The northern part of
the east coast of Guam, between Port Pago and Point Patay, consists of
steep vertical cliffs, varying in height from 150 to over 500 feet. At
Point Hanoum a narrow reef flat again skirts the eastern shore as far
as Point Anao.

As we looked back on the northeast point after turning to the west,
we could see indistinct traces of the terraces which once ran round it;
from constant erosion and disintegration, the lines of terraces have been
changed into a long irregular slope, with here and there a rounded step
indicating the position of a former terrace.

The general level character of the northern part of the island to the
south of Point Ritidian is very apparent as seen from the sea. The sur-
face slopes slightly to the west towards the central part of the island.
The northern face is flanked by a coral sand beach ; irregular patches of
corals extend from Point Tagua round the west side. The sloughing
off of the sea face of the terraces has obliterated their lines of demarca-
tion. Their number is indicated by the position of the rows of caverns
seen on the cliff faces. At the northwest point the fifth terrace stands
out boldly. The steep slope at the base of the point is probably the
remnant of the third and second terraces, while the first terrace slopes
more gradually to the sea. Looking south from Point Ritidian we could
see the succession of headlands formed by the line of vertical limestone
cliffs separating the shallow bays or indentations between the headland

GUAM. 369

knolls (PI. 194, figs. 1, 3). The low vertical cliffs on the western shore,
rising here and there directly from the sea, are not more than fifty to
sixty feet high and are probably remnants of the first and part of the
.second terrace, while the higher vertical clitfs immediately behind, which
gradually become lower and lower as we go south, are parts of the
second, third, and fourth terraces. From the latter the land extends nearly
horizontally towards the interior of the i.sland (PI. 194, figs. 1-3).

From the northwest point looking south, we could see at a distance
of about twenty miles the volcanic ridge on the southwest .side of the
island ; its peculiar outlines are in marked contrast with tho.se of the lime-
stone bluffs and points we followed from Point Hanoum (Pis. 195, figs. 2, 3 ;
197). The west coast presents no striking differences fiom the east coast
until we come upon Punta de los Amantcs, where the caverns plainly
indicate the existence of four terraces in the face of the vertical cliffs. To
the south of the point an extensive coral sand beach stretches along the
base of the cliffs; to the south of Point Fafai a number of broad valleys
open out on the west face ; they extend inland and have been formed from
the disintegration of remnants of limestone, such as still flank, in places,
the lower portions of the volcanic mass which has burst through the
coralliferous limestone once occupying the .southern part of the island
(Pis. 194, fig. 3; 195, figs. 1-3; 197, fig. 1; 198, fig.s. 1, 2).

As we steamed south, parallel with the west coast, the high vertical cliffs
become gradually lower, until at Punta de los Amantes we find the lowest
of the vertical cliffs which, to the north, form a series of promontories at
right angles to the west coast, separated by deep bights (PI. 194, fig. 2).
The east as well as the west coast presents a deeply scalloped appear-
ance, due to the gradual inroads made by the sea in the vertical cliffs
(PI. 233, fig. 4). The bays forming the small reef ports on the southern
part of the east coast of the island, like Port Pago and Ports Ynarajan
and Tarafofo, as well as the larger indentations like Tumun and Agaiia
on the west coast, and a number of smaller bights, indicate the character of
the submarine erosion which has taken place on those shores during
the prevalence of the trades or of westerly and northwesterly winds
(PI. 233, fig. 4). The extent of the disintegration of the faces of the

24

370 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

terraces is well seen north of Point Hanouin, where a huge boulder-
like mass resting on the lower terrace is all that is left of the terrace
immediately above it.

The harbor of San Luis d'Apra is protected on the north by Cabras
Island and the adjoining reef on the west, an outlier of the limestone
mass which has been broken through by the volcanic outburst (Pis. 195,
figs. 1, 2 ; 233, fig. 4). On the south of the harbor lies Orote Peninsula
(Pis. 195, fig. 3 ; 233, fig. 4), a broad low spit of elevated coralliferous lime-
stone ; the western face of its northern base is eaten away and forms the
shallow reef flat on the western face of the harbor (PI. 195, fig. 2). From
the anchorage in San Luis d'Apra we could distinctly trace the position and
extent of the remaining limestone masses (Pis. 195, fig. 2 ; 197, fig. 1). The
base of the long spit forming Orote Point (PI. 195, fig. 2) extends to the
eastern part of the harbor; its structure is indicated by the characteristic
vegetation of a limestone area ; it is in marked contrast to the bare volcanic
slopes immediately in tlie rear.

Cabras Island (PI. 195, fig. 1) consists of old elevated coralliferous
limestone, deeply pitted and honeycombed ; the limestone mass is full of
crevices, pot-holes, and funnels, covered with stalactites (PI. 196) ; numerous
fossils are found in it, mainly corals. Traces of a recent elevation of from
three and one-half to four feet are seen in the undercutting of the small
buttresses of coralliferous limestone jutting out into the beach. This line
of elevation follows the shore of Cabras ; it is very recent, as is plainly
shown by the well-preserved calcified barnacles found on the under side
of the shelf where they had been protected from the rain. Cabras Island
(PI. 197, fig. 1) does not rise more than eight to ten feet above high-water
mark ; the shore is undercut and the island furrowed by numerous gullies ;
it is full of caverns, crevices, and pits.

In the distance, and running across the eastern flanlv of the harbor, rises
the highest point of the volcanic massif of the southern part of Guam
(Pis. 195, figs. 2, 3; 197, fig. 1; 198, fig. 2). To the north of Cabras
Island rise a number of elevated coralliferous islands ; they are outliers
of a point similar to Orote Peninsula, on a smaller scale, projecting from
the base of the western face of the volcanic mass of Guam (PI. 233, fig. 4).

GUAM. 371

Here and there we could distinguish on the western slope of the volcanic
mass the remnant of an ancient elevated coralliferous limestone bluff
standing like a wall to indicate the height at which the coralliferous
limestone had once existed and the amount of erosion and denudation to
which that extremity of the island had been subjected (PI. 194, fig. 3).

Some of the patches of red earth scattered over the volcanic slopes
(PI. 197, fig. 2) are probably similar to the red earth so characteristic of
many atolls in the Paumotus and of other limestone islands ; it represents the
existence of former huge masses of limestone, the iron having accumulated
in sufficient quantities to perceptibly color the slopes on which it has been
deposited. Of course, in addition to the iron deposit derived from the
limestone, the greater part of the red earth of Guam owes its origin to the
disintegration of reddish volcanic ash which has been changed into silt and
swept down the slopes of the hills.

The harbor of San Luis d'Apra has been formed as an angular sound
gradually encroaching into the banks and spits which gave it its original
outline. Parts of these banks form the intricate passages between the
flats covering the eastern extremity of the harbor and the anchorage (PI.
233, fig. 4). To the north, towards the town of Agaiia, a long narrow
reef flat stretches at the base of the volcanic slope (PI. 194, fig. 3). This
reef flat is covered by the remnants of elevated coralliferous limestone
masses ; its eastern outliers are still found on the western volcanic slopes
of Guam.

The southern part of Guam consists of a volcanic massif which has burst
through the coralliferous limestone (Pis. 195, fig. 2 ; 197, fig. 1 ; 198, fig. 2) ;
at Mount Tinkio it has risen to a lieight of over 1000 feet. This is the
highest point of the volcanic ridge ; it has burst through the limestone near
Agaria and extends parallel to the west coast from Agana to the southern
point of Guam, running at a distance varying from a mile to two miles from
the shore (PI. 233, fig. 4). This ridge slopes rapidly to the west, but towards
the east the volcanic slopes pass gradually to the southern part of the east
coast of the island (PI. 233, fig. 4). Outside of the volcanic slopes run a
few limestone outliers, such as Cabras Island (PI. 197, fig. 2), the Orote
Peninsula (PI. 195, fig. 3), Point Facpi (PI. 198, fig. 1), and a line of

372 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

islands and islets south of Orote Peninsula, parallel to the west coast
(PI. 198, figs. 1, 2). This volcanic massif has burst through the mass of
coralliferous limestone which once covered the whole of Guam, so that its
southern part is really volcanic, with the exception of a few limestone
outliers (PI. 198, figs. 1, 2), while its northern extremity is composed of
elevated coralliferous limestone.

Considerable denudation has taken place on the volcanic slopes of Guam,
as is shown on the west coast from the presence of huge isolated masses of
limestone and coralliferous rock elevated and left as outliers of the cliffs
once forming the second or third terraces. The extent of this denudation
is also seen in the interior of Guam, from the existence of the manifold
peaks, ridges, and pinnacles, forming a chain parallel to the outer line of
cliffs on the east side for about one third of the northern end of the
island.

From our first position on the east coast, we could see the gradual change
taking place in the topography towards the south, as the terraces of elevated
coralliferous limestone gradually died out towards the southern extremity
of Guam (PI. 233). On the western and southern sides of the mass of
volcanic rocks which has burst through the southern part of Guam the
former limestone masses wliich once covered the sides of the volcanic
outburst have in great measure disappeared (PI. 197, fig. 1), owing to the
extensive disintegration which has taken place over the whole southern
part of the island of Guam. The slopes of the volcanic hills consist of u
soft material, are much eroded, and are rapidly washing away ; the valleys
form diminutive caiions with remarkably steep sides.

To the south of San Luis d'Apra the slopes of the main ridge have been
greatly denuded and eroded. They are covered with patches of volcanic
red earth and with nodules of the same material. Towards the south the
shore reef has been elevated, although until we reach Facpi there has been
no volcanic outburst close to the coast.

The peninsula of Orote is, like Cabras, composed of elevated coral-
liferous limestone. It contains well-preserved fossils ; they show no signs of
metamorphism, as do tho.se collected in the vicinity of Mount Makaiia, east
of Agaiia. The fossils, however, are highly calcified, and their hardness and

GUAM. 373

the crystallization of the rocks would seem to indicate that they were of
considerable age.

Near the town of Agate, on the west coast, the outcrop of coral rocks
becomes more or less covered with volcanic soil washed down from the
mountains immediately to the east. About half a mile to the south of
Agate is a remnant of a spur (PI. 233, fig. 4), similar to that of Orote and
of Cabras ; it has all the characteristics of the elevated coralliferous lime-
stone of Orote. To the south of San Luis d'Apra the outl\'ing islands
and islets of the west coast, as far as Point Facpi, consist of elevated coral-
liferous limestone rock much nndercut and eroded (PI. 233). The Peladgi
Islands, Alutung and Anaya, are about fifteen feet in height and deeply
nndercut. The small island off Point Facpi is at least thirty feet high and
is exceedingly jagged and honeycombed (PI. 198, fig. 1). The coast in
the region of Facpi and immediately to the north is quite abrupt; the vol-
canic rocks form a bluff at least seventy-five feet in height (PI. 198, fig. 1).
A number of volcanic negro-heads lie at the foot of the bluff, extending
fully fifty yards out into the sea, while at a distance of 100 to 120 yards
lie the high coral islands just mentioned with a few coral negro-heads
at their base.

Immediately to the north of Point Facpi is an elevated coral reef about
two and one-half feet above high-water mark. The corals here are recent
and appear to be in place ; while they are hard and to a certain extent
calcified, they differ materially in structure and appearance from the
elevated crystalline coralliferous limestone masses of the i.slets to the
north and of Orote Point, as well as from the coral boulders derived
from the outlying islands.

Looking south from Point Facpi we could see that the islands of
that part of the west coast are also composed of elevated coralliferous
limestone and are about the same height as Alutung and Anaya. The
shore line is volcanic for a considerable distance to the south of Point
Facpi ; we then strike again the elevated coralliferous limestone with its
characteristic high bluffs.

Apurguan Point form's the northern promontory of the harbor of Agana.
Immediately to the east of Agana we could see outliers of elevated coral-

374 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

liferous limestone. The character of its magnificent vegetation shows
its extent and position, and is in marked contrast to the bare and barren
volcanic slopes covered with reddish earth (PI. 197, fig. 2).

At the base of the volcanic slope forming the eastern side of San
Luis d'Apra Harbor is a wide limestone flat varying greatly in width,
from a few feet to at least 1000 ; it has been formed by the washing
down of hill slope material, which has become mixed with the disin-
tegrating coralliferons rock. Upon this flat, and its northern and south-
ern extension, cocoanut trees grow in great profusion.

The road leading to Agana runs north from the landing. It skirts the
west shore, crossing successive spurs of elevated limestone rock. At a
distance of about two miles we strike the first volcanic ridge ; it extends
towards the beach, the road passing round the foot of the volcanic bluff.
This ridge is composed of greatly decomposed gray volcanic rock con-
taining much hornblende. We next come upon a spur of hard ringing
limestone full of corals and of other fossils and of red earth. This and
other spurs of coralliferons limestone are all that is left of the former
mass of limestone elevated by a volcanic outburst (PI. 194, fig. 3). The
slopes of the volcanic hills to the east of the road are covered with red
volcanic earth and decomposed volcanic tufa.

As we go north the limestone spurs increase in height and gradually pass
into the limestone mesa of the northern part of Guam (PI. 194, figs. 2, 3).
From the hill east of Agana (PI. 197, fig. 2) we could see Sta Ro.sa Peak,
a volcanic mass rising from 150 to 200 feet above the general level of the
limestone (PI. 198, fig. 3). The surface of the northern part of the island,
while generally level (PI. 198, fig. 3), is crossed with crevices and full of
pot-holes and sinks and funnel-shaped cavities, the whole pitted and
honeycombed and covered with spires and pinnacles — much as we have
found the surface of islands composed of old coralliferons limestone in
other parts of the Pacific. Northward the island gradually rises to a
height of 350 to 500 feet.

South of Agaiia, at the junction of the volcanic outburst with the
elevated coralliferons limestone (PI. 194, fig. 3), we can trace the suc-
cessive terraces existing between the shore of Gapan Island and the

GUAM. 375

highest point of Mount Makana, about 600 feet above the town. Some
of the terraces are clearly indicated on the island of Cabras as well
as at the extremity of Point Orote (Pis. 195, fig. 3 ; 196), and on the
western face of the peninsula, where they gradually disappear, owing to
denudation.

Mount Makana is about 600 feet in height; its summit consists of
various kinds of volcanic rocks; it has protruded through the coral-
liferous limestones, a spur of which extends to fully 400 feet along the
side of the mountain towards Agaria.
Near the sea coast, and to within a
few hundred yards of the point of
protrusion of the volcanic material,
the elevated coralliferous limestone
is of moderate hardness, containing
many well-preserved fossils. Near ' ' -^^*-^

the point of iunction between the "^"^ctio.n- uf V.,lcanic Outburst and Lime-
stone, West Coast of Guam.
volcanic mass and coralliferous lime-
stone, however, it suddenly becomes highly crystallized, very hard, and the
fossils disappear. The coralliferous strata are much tilted at this point,
plainly showing that the volcanic mass has burst through the coralliferous
limestone. From the anchorage we could trace this bed of limestone broken
into cliffs and lifted into masses with precipitous sides by the volcanic
outburst, the limestone belt being clearly indicated by its characteristic
vegetation.

Volcanic agencies have been at work at Guam in very recent times.
Unata was destroyed by an earthquake in 1849 ; this is not remarkable, as
Guam is at the extremity of a long line of active volcanoes extending south
from Japan ; it may be that the volcanic outbursts which have pushed
through the limestones, or have elevated parts of the islands of the
Ladrones, are of comparatively recent date.^

We can imagine a large island like Guam, partly composed of coral-
liferous limestones, to be gradually eroded to the level of the sea. by a

* The marine barracks and other buildings at Agafia were destroyed by earthquakes on the 25th of
September last.

376 " ALBATROSS " TROPICAL PACIFIC EXPEDITION.

process identical with tliat Ibnuing sucli atolls as Fulanga, Vanua Mbalavu,
or Mbengha, in Fiji. The result would be a gigantic atoll, shaped somewhat
like Wotje in the Marshall Islands; it would pass through a series of stages,
each one of which is represented in some atoll at Fiji. A huge sink may
first have formed in the northern extremity of Guam ; the bays edging the
coast may have been extended inland until they reached the sink. The
sea would then rapidly open a sound or a series of sounds in the interior
of Guam; these sounds might be separated by ridges or lines of islands, and
while these changes were going on, the outer edge would gradually be re-
duced to a low limestone belt enclosing the sounds or cut into a series of
islands, with a huge volcanic nucleus at the southern extremity. Finally,
a gigantic atoll would be made by these successive changes, but one in the
formation of which subsidence played no part.

Nativk Hut, Guam.

Rota.

Plates 199; 232; 233, fig. 5.

To the northeast of Guam lies the i.sland of Rota (PI. 2-32); it is about
twelve miles in length, and has a greatest width of perhaps five miles ; it
rises to about 800 feet, and runs nearlv east to west. I was not surprised

KOTA. 377

after examining the charts of the Lach'ones to find that Rota, as well as
Guam, consisted of elevated coralliferous limestone. The western extremity
of Rota is formed by a long rectangular peninsula ; its terraces are most
distinctly marked and five periods of elevation are clearly to be distin-
guislied (PI. 199, fig. 2). The western peninsula is connected by a narrow
neck with the main island (PI. 233, fig. 5), a huge ma.ss of coralliferous
limestone sloping equally in all directions, but most distinctly terraced
(PI. 199). In So.sanjaya Bay and off the northwestern shore of Rota the
island is flanked by a narrow reef flat (Pi. 233, fig. 5). The outliers and
horse-heads on the Avestern shore (PI. 233, fig. 5) indicate the amount of
erosion to which this island has been subjected.

On Rota the terraces markiuij the successive elevations of the .southern
Ladrones are adtnirabl}' preserved. At a distance of three miles off shore
five terraces could be distinguished. The summit of the island is almost
level (Pis. 199, fig. 2; 233, fig. 5). Coming from the south we could see
no indication of any volcanic outbursts. The spit forming the southwestern
extremity of Rota, separating Sosanlagh and Sosanjaya Bays, also shows
remarkably well-defined terraces (PI. 199, figs. 1, 2). There are four of
these on the southernmost spit, and, when facing the main island, at least
seven terraces are pin inly indicated. The face of the southern spit is riddled
with caves (PI. 199. fig. 2). The lower terrace is deeply undercut, showing
traces of two stages of elevation, one not more than three or four feet,
identical in height with the low terrace de.scribed at Cabras Island. Look-
ing across the low land separatmg the southern promontory of Rota from
the main island, we could see numerous caverns in the vertical face of the
cliffs of the main mass of Rota. As we steamed north we observed that
the slope of the northwestern point, as well as the character of the vege-
tation, indicated a volcanic outburst at that exti'emity of the island (Pis. 199,
fig. 1 ; 233, fig. 5).

It is probable that others of the southern islands of the Ladrones we did
not examine are, like Rota and Guam, elevated coralliferous masses forming
the summit of an extensive limestone plateau thi'ougli which more recent
volcanic rocks have burst at different points. After volcanic outbursts the
elevated coralliferous limestone beds have often been denuded and eroded

378 "ALBATROSS" TROPICAL PACIFIC EXPEDITION.

to the line of the slope of the volcanic mass, and have disappeared. The
sketch of the island of Saipan and others to the south, as shown on the
Hydrographic Charts/ would indicate the existence of a number of terraced
islands. On leaving Rota we entered the field of the " Challenger's "
soundings, and, stopping all work, shaped our course for Yokohama.

I H. O. Chart 1748.

LIST OF THE STATIONS

OCCUPIED BY THE U. S. P. C. S. "ALBATROSS," DURING HER
CRUISE IN THE TROPICAL PACIFIC,

August, 1899-March, 1900.

SAN FRANCISCO, CALIFORNIA, TO NUKUHIVA, MARQUESAS ISLANDS.

1

1

Date.

1899.

Position.

Temper-
atures.

as.

Nature

of
Bottom.

Remarks,

Latitude
North.

Longitude
West.

Sur-
face

Bot-
tom.

o /

o /

o

o

1

2

3

4

5
6

7

8
9

10
11

Aug. 26
Aug. 27

Aug. 28
Aug. 29

Aug. 30

Aug. 31

Sept. 1

Sept. 2
(( ((

Sept. 3

31 10
28 23

26 18
24 45

22 42

20 26

18 19

17 13
16 52
16 38
14 38

125 00

126 57

128 54

130 16

131 54

133 28

134 57

136 09
136 12
136 14
136 44

63

66

68
69

70

75

76

78
76
78
79

34.6

1955

2368

Red clay. Light
brown ooze.

Lost thermometer and detacher ; 320
miles from Point Conee|)tion.

150 miles from Guadalupe Island, 500
miles from Point Conception. Large
haul of manganese nodules, sharks'
teeth, and cetacean bones.

34.6
34.6

2628
2740
2810

2881

2766
3oo:i

Light brown ooze,

same as at St. 2.

Red clay.
Light brown ooze,

same as at St. 2.

Red clay.
Dark brown mud

ooze. Red clay.

Red clay. Dark brown
ooze. Very sticky.

Too rough to trawl ; distant from
Guadalupe Island 800 jniles, from
Point Conception 960 miles.

Distant from Guadalupe Island 9G0
miles, from Sebastian Visoaino 1060
miles.

3088
2646

Red clay.

Deepest part of Moser Basin.
Passing out of deepest part of Moser
Basin.

12
13

14

15
16
17

Sept. 4
Sept. 5

Sept. 7

Sept. 8
Sept. 9
Sept. 10

12 07
9 57

6 41
4 35

♦

2 38
0 50

137 18

137 47

137 00

136 54

137 22
137 54

81

82

82

79
79

79

35.2

2883
2690

2776

2583
2440
2463

Red clay, radiol.

Red clay. Light
brown ooze, coarse
mineral particles.
Radiolariau ooze.

Gray ooze glob.

Large balls of manganese nodules, ce-
tacean bones, sharks' teeth.

Foram. no radiola-

riaus. Not sticky.
Fine gray ooze. Ra-

diolarians.
Light yellow gray

glob. ooze.
Light yellow gray

glob. ooze.

To Hawaiian Islands 1500 miles, to

Marquesas 660 miles.
Sea too heavy to sound after this till

Sept, 13.

380

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

13

19

20
21
22
23

Sept. 13

Sept. 14

Position.

Latitude Loncritude Siir-
South. West. face.

23

13
28
31
33

Temper-
atures.

138 .59

139 09

139 10
139 12
139 26
139 36

Bot-
tom.

33

3.3.1

35.5

2-175

2287

2267
2183
1939
1802

Nature

of
Bottom .

Light gray yellow
ooze. Globig. ooze.
Radiolai'ian.

Coarse glob. ooze.

Glob, ooze with vol-
canic particles.

Glob. ooze. Many
voloanie particles.

Glob. ooze. Fine vol-
canic particles.

Gray ooze. Glob, anil
Radiol, anil coarse
volcanic particles.

Remarks.

Abont 175 miles to Marquesas.
Stations 1-18 ret'erreil to H. O. Chart

No. 527, corrected to April, 1S97.
Stations 19 to 29 relVrrcd to H. O.

Chart No. 1797, edition of Mav,

1899.

Globigcrinae si ill retaining their color.
Developing the Marqnesas Plateau.

MARQUESAS ISLANDS TO TAHITL SOCIETY ISLANDS, VU NORTHWESTERN

PAUMOTUS.

Stations in Vicinity or the M.\uquesas Islands.

^ /

o /

O

O

2i

Sept. M

8 41

139 46

80

• •

1040

23

It a

8 4S

139 48

SO

38

830

2,-)

"

S 52

139 52

80

1173

27

Sept. 15

9 01

140 04

79

. .

687

23

Sept. 17

9 03

140 13

80

• •

1284

Coarse glob. ooze.

Volcanic particles.
Globig. and volcanic

mud and fragments
Glob. ooze. Ptero

pods and volcanic

particles.
Glob. ooze. Volcanic

particles.
Rocky. Volcanic

fragments.

15^ miles N. 43° W., same as below.

13 miles N. 73° W. of Haunauu Point.

Ua Huka Island.
17 miles west of Mt. Uranupe, Nuku-

hiva Island (Tai-o-hae).

6 miles S. 20° E. of Anna Maria Bay.

.\bout IS miles S. 13° W. of Chicka-
koff Point.

Stations from the Marqiesas to Rangiroa.

a

1

o /

O

o

29

Sept. 17

9

16

140 25

SO

34.9

1932

30

Sept. 18

10

29

111 52

81

35

2456

31

Sept. 19

12

20

144 15

80

35

2700

32

Sept. 20

13

37

145 42

SO

35

2451

33

(C ((

14

10

146 10

81

35.1

2527

34

te c(

14

26

146 25

81

. .

120S

33

Sept. 21

14

42

147 OS

SO

1462

Light yellow gray
glob. ooze. Coarse
volcanic particles.

Lightgrayglol). Few
Radiol. Volcanic
particles.

Red clay.

Red clay withForain.

Red clay.

Very light col. glob,
ooze.
Fine coral sand glob.

25 miles from Cape Chickakoff, Nuku-
hiva, 20 miles from Ua pu Island.

Stations 30, 31 referred to H. 0. Chart
No. S24', Oct. IS88.

Deepest part of Channel separating the
Marqnesas from the I^inmotiis.

Stations 32-35 referred to H. O. Chart
No. 77, corrected to 1899.

22 miles N. 28° E. of entrance to Aliii.

About 2^ miles northwest of entrance

to Ahii.
Position according to H. 0. Chart

No. 77.

LIST OF STATIONS.

38]

s
i

1

Date.
1899.

Position.

Temper-
atures.

II

Nature

of
Bottom.

Remarks.

Latitude
South.

Longitude Sur-
We^t, jface.

Bot-
tom.

Rangikoa to Tikahau and to JIatahiva.

36

Sept. 21

o /

14 45

o /

147 38

SO

o

706

Volcanic rock frag-
ments.

Stations 32-35 referred to H. 0. Chart
No. 77, corrected to 1S99.

Distant 16 miles northeast of Avatoru
Pass, Kangiroa, according to II. 0.
Chart No. 77. Stations 36 to 60
referred to H. 0. Chart No. 85, cor-
rected to 1S91.

37

Sept. ii

80

■

112

Coral sand.

1 mile from Beacon at the entrance to

Avatoru Pass.
Stations 37 to 42. Running a line

N., normal in continuation of Avatoru

Pass.

38

SO

504

Broken shells and
sea-urchins. Ptero-
|mk1s. Glub. Rad.
Mineral particles.

If miles from Beacon, entrance to
Avatoru Pass.

39

" "

80

615

Fine coral sand, glol).
ooze. Bmkeiisiiells

Same line, 1 mile farther nortli.

40

■, „

• • •

80

G61

Mineral particles.
Coral sand. Glob
Pteropods. A few
Radiolarians.

Same line, 1 mile farther north.

41

tt t.

. . .

....

SI

684

Coral sand. Glob, and
volcanic )iarticles.

2 miles farther north, same line.

42

81

819

Coral sand. Glob.
Volcanic particles.

2i- miles farther north. Same line.

.Vbout 8 miles north, off Avatoru en-
trance. St. 35 was about 25 miles at
right angles to Rangiroa, and showed
a "depth of 1162 fathoms, the edge of
plateau being between it and St. 36.

43

" '■

1.0 13

M7 53

82

3^

Coarse coral sand.

About 1 miic from Reef oS south
shore Rangiroa.

44

(( ((

82

391

Coarse coral sand.

1 nnle from south shore, Rangiroa.

45

" "

82

524

Coarse coral sand,
broken shells. Pte-

1 mile from last station. Normal to
coast.

4()

" "

SO

450

ropods, glob. ooze.
Pteropod ooze, coral
sand, small manga-
nese nodule.s, round
grains of coral sand.

2 miles from last station.

Positions of St. 43 to 60 approxi-
mate, referred to H. 0. Chart No.
85, as corrected by " Albatross."

47

■ * ■ *

82

764

Coral sand, volcanic
or manganese parti-
cles. Glob.

3 miles from last station.

4S

80

897

Glob. Foram. Ptero-
pods. Manganese
or lava particles.

5 miles from last station, 11 ni. S. 15°
W. of Station 44.

49

tt ((

15 25

148 OS

80

1123

Coral sand, manga-
nese (?) particles.
Cilobigerinae.

50

Sept. 25

15 25.5

148 24.4

80

80

1486

488

GInh oo7e ATaiicn-

51

15 02

148 24

nese particles (?).
Coarse coral sand

1 mile from shore of Tikahau, going

Glob.

towards Matahiva.

382

"ALBATROSS" TEOPICAL PACIFIC EXPEDITION.

1

Hate.
1899.

Position.

Temper-
atures.

.21

Latitude
South.

Longitude
West.

Sur-
face.

Bot-
tom.

o /

o /

o

o

52

Sept. 25

15 01.4

148 25

so

670

53

.. ..

81

• •

782

54

.. ..

81

. .

850

55

.. „

. . .

81

844

56

"

14 66

148 44

81

711

57

« «

80

486

58

(( ((

80

624

59

(( ((

....

80

860

60

"

80

1257

Nature

of
Bottom.

Coarse coral sand,
broken shells and
glob.

Pieropod ooze. Glob.
Manganese parti-
cles (?).

Pteropod ooze, few
lobig.

Globig. ooze, small
manganese nodules.

Pteropod ooze, fine
coral sand. Globig.
ooze. Small man-
ganese nodules.

Coarse coral sand.
Volcanic (?) parti-
cles. Manganese (?)

Coarse coral sand.

Glob. ooze. Coral
sand. Volcanic (r)
particles.

Coarse coral sand.
Globigerinae. Vol-
canic (?) particles.

Remarks.

1 mile from last position.

This sounding is deeper than one off
Rangiroa at same distance from shore.

2 miles from last position.

last position. Same
last position. Same
position. Same

3 miles from

normal.
5 miles from

normal.
8 miles from last

normal.
Changed course to go round the north

side of the Island of Matahiva.
3 miles from last station, going north.

2^ miles off west shore of Matahiva.
4 miles off southwest shore of Ma-
tahiva.

Off south shore of Matahiva, about 7J
miles farther offshore than St. 59.

Mahhiva to Makatea and to Papiete, Tahiti Island.

61

Sept. 25

O /

15 16

o /

148 46

O

79

0

1762

62

Sept. 26

15 33

148 45

80

2267

63

t( a

15 42

148 44

SO

2247

64

<■ ..

15 51

148 15

80

581

65

« .<

15 57.3

148 18.8

80

1363

66

It a

16 10

148 26

80

2238

67

Sept. 27

16 32

148 40

SO

2363

68

a (t

16 57

148 58

79

2224

69
70

C< ((

17 14
17 21

149 10
149 15

80
80

1930
1585

71

u .<

17 25.3

149 26

81

775

72

Sept. 27

17 26.5

149 32.4

79

867

Lightgray glob. ooze.

Glob, ooze and mud

(volcanic?), allied

to red clay.
Globigerinae and

mud allied to red

clay.
Coarse coral sand.

I Coarse coral sand.
Small manganese
nodules.

Volcanic mud. Man
ganese nodules
Globigerinae.
Volcanic mud. Glo-
bigerinae.

• Coarse volcanic mud.
Globigerinae.

I Fine volcanic mud,

yellow brown.

Coarse volcanic mud.

Manganese(?) nodule.

■ Fine volcanic sand.

Coral sand. Globig-

St. 61 to 180 referred to H. O Chart
No. 77, corrected to 1899.
Ou way to Makatea.

About li% miles off the bluff on west
side of central part of JIakatea.

5 miles south of Makatea.

This is the first of a line of soundings
from Makatea to Tahiti. St. 65 to 72.

20 miles from last station.
10 miles from last station.

4^ miles N. 32° E. from Point Venus.
6 miles from last station.
4 miles N. 54° W. from Point Venus.
6 miles from last station.

LIST OF STATIONS.

383

THROUGH THE PAUMOTU ARCHIPELAGO.

Tahiti to Makatea via Tetiaroa.

£1

a

s

Date.
1899.

Position.

Temper-
atures.

If

Nature

•3

Latitude

Longitude

Sur

Bot-

S.-H

£

South.

West.

face

tom,

&S.

0 1

O 1

o

o

73

Oct. 5

17 27

149 32

79

• •

867

Fine volcanic saud
Pteropods.

3.8 miles N. 55° \\. IVoni Point Venus.

74

l( (t

17 28 4

149 34

79

1 8 miles N. 82° W fl-mn Pnint Vpniis

Drit'ted,whiletrawhiis,fromSt.73to74.

75

IC It

16 57

147 29

SO

1592

Volcanic mud niixec
with globigeriuac.

Tetiaroa distant 6 miles.

Makatea to Apatakt via Niau.

76

Oct. 6

o /

15 ofi.2

O /

147 40

o

so

o

35

2209

Light brown volcanic
mud and glob. ooze.

St. 76 to SI. Line from Makatea to
Niau.

77

Oct. 7

16 03

147 11

79

36'

1322

Glob. ooze. Volcanic
particles.

n

it ti

10 08

140 42

79

39

6(J9

Glob. ooze.

About 10 miles off Niau.

79

16 10

146 23

79

• •

252

Coral sand and glo-
bigerinae.

.\bout f nide off shore, Niau.

80

t( a

16 11.5

146 25

80

491

Pteropod ooze. Glo-
bigerinae.

1.75 miles off shore, southwest of vil-
lage, Niau.

81

a ((

15 54.5

146 20

SO

* *

677

Coral sand. Glob,
ooze.

14 miles from Niau, bearing S. 3° E.
About 10 miles from Kaukura N.
14° W.

82

(( ((

15 42

146 20

80

* *

675

Pteropod ooze.

In triangle Apataki, distant N. 6 miles;
Kaukura, S. 60° W., distant 9 miles;
Toao, N. 81°, distant about 12 miles.

83

a Li

15 31.

146 26

SO

333

\ mile S. 45° W. from Pakaka en-
trance to Apataki.

84

Oct. 8

15 35.8

146 27.5

79

39.4

613

Coral sand. Glob.
Broken shells. Pter-
opods.

Off Apataki Entrance, about 2 miles
S. 50° W.

85

it ti

15 34.3

146 28

so

520

Coral sand.

About 1 mile S. 55° W. of Pakaka
Entrance.

Apataki to TikeI

86

Oct. 8

O /

15 18.3

146 23

o

80

O

38.8

654

Coarse coral sand.

First of a line to Tikei. About 1 mile
from northwest corner of Apataki.

87

Cf ((

15 15

146 07

80

1364

Glob. ooze. Pew
volcanic particles.

About 7 miles N. 45° E. off northeast
point of Apataki.

«8

Oct. 9

14 57

144 34

80

■

360

Coarse coral sand.
Pteropod shells.

J- mile off west shore of Tikei where
landed.

Ngaruk P

ass, Faka

rava, to Takume via Anaa and Tahanea.

89

Oct. 14

o /

16 03.5

O /

145 43

o

80

0

599

Coarse coral sand.

About 1 mile N. 28° W. of north en-
trance to Fakarava. First of line of
soundings in continuation of Ngarue
Pass.

384

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Date.

90
91

92
93

94
95
96
97

9S

99
100
101

102

103
104

105
106

107
108

109
110
111
112

Oct. 11

Position.

Temper-
atures.

Latitude
South.

Oct. 15

(t ((

Oct. 16

Oct. 17

16 02

16 38
16 44
16 51

16 57

17 09
17 14.5
17 17

17 21

17 22
17 20
17 16

17 10

17 03
16 55

16 53
16 55

16 24
16 20

16 13

16 03

15 53

15 54

Longitude
West.

Sur-
face.

145 43.5

145 31
145 35

145 42

145 49

146 00
145 49
145 45.5

145 41

145 37
145 31
145 27

145 19

145 08.5
145 03

145 00
144 56

143 59 80

35.7

36.10
39.7

143 55

143 48
143 32.5
143 26
143 06

Bot-
tom.

39

36

36
35.1

38.6

666

602

839

1300

1531

1079

527

Nature

of
Bottom.

Bemarlu.

Coarse coral saud. About 3 miles farther north thau last

Pteropods. station. 3J miles N. 35° W. from

Ngarue Pass.

About 2 miles due S.W. from south-
west Point of Fakarava.
I- mile farther than Station 91.

Coarse coral sand.

Pteropod ooze.
Coral coat«d with

manganese.
Glob. ooze.

Fine volcanic mud
and globigerinae.
Glob. ooze.

Coral frgts. covered
with manganese.

804 Globig. ooze and
many very small
manganese nodules

642 Pteropod ooze. Man
gauese nodules on
coral saud.

568 Manganese nodules
Coarse coral saud.
Coral sand.

36.3

35

35.4

225

1110

1679

1733
966

654
269

467
856

987
1084
1805
1568

10 miles farther than 92. Line to
Anaa at first 40 miles to S.W., then
30 miles to north side of Anaa.

10 miles from Station 93.

Changed course towards Anaa at this
station.

Pteropod ooze. Fine
eoval sand. Man
ganese nodules.

Light yellowish bromi

globig. ooze.
White glob. ooze.
White glob, ooze

Few manganese

nod. grains.
Very small manganese

noilules. Coral sand.
Coarse coral sand.

White coral sand.

Pteropod ooze. Fine
coral sand. Light
yellow gray glob.
Few volcanic par-
ticles (?).

Pteropod ooze. Glob.
Volcauic (larticlesP).

Light yellow gray
glob. ooze.

Light yellow gray
glob. ooze.

Glob. ooze. Light
yellow. Manganese.

6 miles from Station 96.

Off Anaa, 6 miles from Station 97.

About 1]% miles off northwest face of
Anaa.

About J mile to edge of reef off vil-
lage at entrance to lagoon of Anaa.

About 5 miles N. 50° E. off Anaa En-
trance. This is first of a line of
soundiugs across to Tahanea. St.
101 to 106.

15 miles from Station 102.

About 10 miles from Station 103, 4
miles W.S.W. from southwest point of
Tahanea.

About 2 miles W. of southwest point
of Tahanea.

About -J mile off south shore of Taha-
nea and about 3 miles S. 45° W. of
southwest point of Tahanea.

1 mUe N.W. of northwest Pass of
Makemo on angular line to Ilaroia.

4 miles N. of northwest end of Ma-
kemo.

10 miles north of Station 108.

15 miles north of Station 109.

At next station on line to Karoia
changed direction at Station 111.
20 miles from St. 111.

LIST OF STATIONS.

385

£1

a

3

Datt

1898

■

Position.

Temper-
atures.

'it

1
1

Latitude
South.

Longitude
West.

Sur-
face.

Bot-
tom.

0 /

o /

o

o

113

Oct.

17

15 55

142 39

80

1503

m

"

"

15 56

143 29

80

35.7

1385

115

li

"

15 56.3

142 29

81

40.2

508

116

Oct.

IS

15 53

142 14

79

38.7

572

117

**

"

15 5i

142 16

79

38

563

Nature

of
Bottom.

Glob. ooze. Light
yellow. Manganese.

Glob. ooze. Few man-
ganese particles.

Coarse coral sand.
Pteropod ooze.

Coarse coral sand.

Coral sand inorusted
with manganese.

Remarks,

20 miles from St. 112.

This is about 5 miles from centre ol'
west coast of Raroia.

About ^ mile from the shore at north-
west point of Raroia.

About li miles oB' southwest point of
Takume.

Halfway between Takume and Raroia.

Takume to Makemo via Raroia and Tae.nga.

O t

O /

0

O

118

Oct. 18

16 12

143 31

80

38.2

630

119

(( li

16 14

142 50

80

35.5

1516

120

. .,

16 21

143 14

80

36.5

928

121

Oct. 19

16 25

143 33

79

36.1

1108

Coarse coral sand.
Pteropod ooze and
manganese particles

Glob. ooze. Manga-
nese particles.

Glob, and pteropod
ooze.

Glob, ooze, a few
pteropods, and man-
ganese particles.

About 1 mile off southwest point of
Raroia.

Half way between Raroia and Taenga.

About 3 miles S. 67° W., off south-
west face of Taenga.
About half way to Taenga.

Makemo to Hikueru via Tekokota.

o /

o /

O

O

122

Oct.

20

16 29

143 41

79

39.7

540

123

Oct.

25

16 35

143 31

80

39

603

124

^'

"

16 42

143 10

79

• •

1321

125

Oet.

26

16 51

142 57

79

36

1135

126

•'

"

17 07

142 49

79

35.9

1235

127

«

"

17 2U

142 35

79

. .

617

128

"

"

17 28

142 38

80

36.6

1009

129

Oct.

27

17 35

142 42

80

43.8

348

130

it

*'

17 35

143 44

80

37.8

798

Coral sand. Ptero-
pod ooze.

Coarse coral sand.

Glob. ooze. Manga-
nese.

Glob. ooze.

Glob, manganese.

Coral sand.

Pteropods and glob,
ooze.

Coral sand and bro-
ken shells.

Coral sand. Ptero-
pod ooze.

About 1 mile off north shore of Ma-
kemo.

About 1 mile off entrance to Makemo.

11 miles E. by S. off east point of
Makemo, on line to Tekokota.

Half way between Nihiru and Marutea.

About 1 mile west from Tekokota.
Half way to Hikueru from Tekokota.

6 miles north of centre of Hikueru

atoll.
|- of a mile W. of northwest point of

Hikueru.
1^ mile "west of last station.

normal.

Same

HiKUEKu TO Hao via Marokau and Ravahebe.

O f

o /

O

o

131

Oct. 28

17 47

142 29

79

35.7

1372

132

,<

IS 00

142 29

77

35.6

1620

133

(( ((

18 05

142 33

78

35.5

742!

134

tl tl

18 06

143 24

79

37.6

807

Glob. ooze.

Glob. ooze.
742' Pteropod ooze.

"^ine coral sand and
manganese nodules.

25

Half way between Hikueru and Maro-
kau.

8 miles west of Marokau.

About 2 miles offnorth end of Marokau.

3 miles off northwest point of Maro-
kau.

386

"ALBATKOSS" TROPICAL PACIFIC EXPEDITION.

135

136
137
138
139

Date.

Oct. 28

t( if

Oct. 29

Position.

Tiatitude
South.

18 08
18 07
18 05
18 08

Longitude
West.

141 49

141 26

141 03

141 04

Temper-
atures.

Sur-
foce.

Bot-
tom.

48.1
35.2

42
37.6

278

2187

1713

425

S12

Nature

of
Bottom.

Fine coral sand.
Manganese nod-
ules. Globigerinae,

Fiae volcanic mud.
Globigerinae.

Globigerinae and few
manganese particles

Coarse coral sand.

Coral sand.

Remarks.

Half way between heads of pass be-
tween Marokau and Ravahere.

About 20 miles from last station.

About 20 miles from last station.

Depth indicates rise or spur.
Abinit A- mile oiT northwest point of

Hao.
2 miles W. of northwest face of Hao.

Hao to Aki-Aki.

140

Oct.

29

0 /

18 27

140 21

0

77

o

35.1

2042

141

Oct.

30

18 29

139 53

78

35

1490

142

"

"

18 30

139 30

78

35.1

2103

143

"

"

18 34

139 19

78

35.6

1364

144

'*

'*

18 30

139 15

• •

• •

377

Light brown volcanic
mud with globiger-
inae.

Globigerinae. Large
species. Few maU'
ganese particles.

Fine light brown vol
cauio mud, witli
globigerinae.

Manganese particles
Globigerinae.

Coarse coral sand,
broken shells.

20 miles from Hao. Stations 140-144,
hue Hao to Aki-Aki.

Ridge 25 miles from last station.
20 miles from last station.

5 miles from Aki-Aki. 10 nides from
last station.
1 mile off southwest eud of Aki-Aki.

Aki-Aki to Pinaki via Nukutavake.

145

Oct. 30

0 /

IS 3G

139 14

78

o

35

1725

146

Oct. 31

IS 56

139 05

78

35.1

2343

147

vi i(

19 17

138 54

78

35

1688

148
149

19 16
19 23.5

139 49

138 46

78
78

38.9
37

636

860

Coarse coral sand. 5 miles south of Aki-Aki. Stations
145-148, line Aki-Aki to Nukuta-
vake.
Red clay. Few glo- 20 miles from last station.

bigerinae.
Manganese nodules. 6 miles W. of north end of Nukuta-

Globigerinae. vake.

Coral sand. 1 mile off north point of Nukutavake.

Nothing in cup. 3.5 miles northwest of Pinaki, between

Hard bottom. it and Nukutavake.

Pinaki to Nukutipipi.

0 /

o /

o

o

150

Oct. 31

19 27.5

138 44

79

41

486

151

Ct tl

19 27

138 47

79

35

1907

152

(> ((

19 35

139 13

78

35.1

2335

153

Nov. 1

19 45.5

139 54

77

35.4

1494

Coarse coral sand.
Pteropod ooze.

Glob. ooze. Volcanic
mud.

Red clay. Few glo-
bigerinae.

Globigerinae, small
nodules and ]iarti-
cles of manganese.

1 mile west of Pinaki. St. 150 to 158,
line Pinaki to Nukutipipi.
5 miles W. S.'W. from Pinaki.

25 miles from last station.

40 miles from last station. This
ridge may be a spur of Ahunui, or
au independent ridge.

LIST OF STATIONS.

SS7

154
155

156

157
158

Date.
1899.

Nov. 1

Nov. 2

Position.

Latitude
South.

19 5.2

20 07
20 31
20 46.5
20 43

Longitude
West.

140 16

141 00

142 00

142 51

143 0.5

Temper-
atures.

bur-
face.

Bot-
tom.

35
35

33

35

39

Nature

of
Bottom.

2284
2391

2467

2315

649

Red clay.

Manganese particles.
Red clay.

Red clay. No or-
ganic remains.

Red clay and num-
ber of globigerinae.

Coral sand. Broken
shells. Pteropods.

20 miles from last station.
40 mdes from last station.

60 miles from last station.

About 5 miles southeast from Nuku-
tipipi.
About 1 mUe southeast of Nukutipipi.

NuKUTipiPi TO Hereheeetue vi.\ Anu-Anukunga and Anu-Anuraro.

0 /

0 /

O

o

159

Nov. 2

20 42

143 03

77

• •

736

160

ft tt

20 40

143 09

78

35.5

1609

161

« ..

20 37

143 15

78

39

574

162

« *i

20 37

143 IS

78

38.5

659

16:;

u u

20 34

143 23

78

35.2

1890

161

.. ..

20 29

143 29

78

40.7

438

165

IC ((

20 27

143 32

77

42.5

406

166

It (I

20 15

144 00

77

34.8

2265

167

Nov. 3

20 02

144 28

78

34.9

2524

168

<c ..

19 54

144 48

77

35

1719

169

" "

19 54

144 53

78

39.5

594

Coral sand, ptero-
pods, broken shells,
manganese particles

Coral sand. Few
globigeriuae. Man-
ganese particles.

Pteropod ooze.
Coarse coral sand
and maugauese par-
ticles.

Coral sand, ptero-
pods, and broken
shells.

Light gray glob,
ooze. Small and
large globigerinae.

Coral sand.

Cora! sand. Ptero-
pods. Small man-
ganese nodules.
Red clay. Globig-
erinae. Manganese-
Very soft red clay.
Few globigerinae.

Globigeriua ooze.

Coarse coral sand.

1 mile W.N.W. on course of Nuku-
tipipi to Anu-Auurunga.

Half way to Anu-Anurunga. Sound-
ing indicates a low ridge connecting
the islands of the Gloucester group.

1 mile off east side of Auu-Auuruuga.

One mile northwest of .\nu-Anurunga,
on line to Aiiu-Anuraro.

Half way to Ann-Ann raro from Anu-
Auurunga.

f of mile from shore off southeast side

of Anu-Anuraro.
^ mile northwest of Anu-Anuraro.

St. 165 to 168, line Auu-Auuraro to

Hereheretue.
26 miles from last station.

3 miles from last station. Continue to
find manganese particles and small
nodules at nearly every sounding.

6 miles from last station. East of
Hereheretue.

1 mile otf the east coast of Hereheretue.

Hereheretue to Tahiti via Mehetia.

■^ /

■J r

O

o

170

Nov. 3

19 54

144 59

78

62.1

189

171

.. ,.

19 50

145 03

78

35.3

1688

172

.<

19 22

145 47

77

35

2322

Coral saud. Manga-
nese particles.

Light gray glob,
ooze. Manganese
particles.

Red clay with glo-
bigerinae.

j'j mile from edge of reef on west side
of Hereheretue. St. 170 to 176, line
Hereheretue to Melietia.

5.3 miles northwest of Hereheretue.

50 miles from last station.

388

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

173

174

175
176

178
179

Date.

1899.

Nov. 4

Nov.

Position.

Latitude Longitude
South. West.

18

18 28

18 03
17 54

17 51

17 46
17 35

146 32

117 11

147 48

148 00

148 03

148 23
148 48

Temper-
atures.

Sur- Bot-
face. torn.

78

34.8

35

34.8
38.1

69

34.9
35

0&.

2440
2037

2120
832

142

2111
1755

Nature

of
Bottom.

Red clay. Large
haul of trawl of
mauganese nodules.

Two spherical manga-
nese nodules, about
15 mm. in diameter
jammed cup open.

Coarse volcanic mud.

Volcanic mud and
coral sand.

Volcanic rock and
coral sand.

Volcanic sand.

Volcanic sand.

Remarks.

50 miles from last, lialf way to Mehetia
from Hereheretue.

14 miles southeast of Mehetia.

1^ miles oif southeast face of Mehetia.

J mile off north shore of Mehetia.
St. 177-179 Mehetia to Tahiti.
23 miles from Jlehetia.
30 miles from Tahiti.

SOCIETY ISLANDS TO TONGATABU, TONGA ARCHIPELAGO, VIA LEEWARD
SOCIETY ISLANDS, THE COOK GROUP, AND NIUE ISLAND.

Fbom Tahiti to Leeward Society Islands.

180

Nov. 15

17 30

149 41

79

36.7

981

Volcanic sand. Pter
opod ooze.

About halfway to Murea from Papiete.
5 miles from the northeast point of
Murea.

From Aitutaki to Niue.

181

Nov. 22

18 54

O /

162 31

79

34.7

2498

182
183

Nov. 23
Nov. 24

18 59

19 04

164 47
167 41

82
SO

33.4
33.9

2S82
2472

No sample.

Red clay.
Red clay.

Glob.
Radiol.

Sts. ISl-184 referred to 11. O. Chart
No. S25», corrected to April, 1890.

From Niue to El'a (Tonga).

184
185

ISfi

Nov. 20
Nov. 27

20 15

21 18

21 18

172 00

173 31

173 51

SO

34

34.15

3141
4173

4540

Red clay. Radiol.
Light brown volcanic
mud. Radiol.

Light brown volcanic
mud. Radiol.

Near 4702 fms. hole, siliceous sponges
in trawl. Deepest haul of trawl yet
made. Lost tliermo.

VAVAU TO FIJI.

0 /

o f

o

o

187

Dee.

4

IS 47

174 15

79

082

188

Dec.

6

18 43

175 28

79

36.2

1381

Pteropods and very
peculiar coral sand,
resembles volcanic
sand, with white
crystals of calcite,
gray brown.

Volcanic mud, glob.

Between Vavau and Late.
Sts. 185 to ISS referred to B. A. Chart
No. 2421, corrected to August, 1899.

Beyond Late to westward.

LIST OF STATIONS.

389

1

3

Zi

Date.
1899-1900.

Position.

Temper-
atures.

■Si"

Nature
of

Remarks.

■c

Latitude

Longitude

Sur-

Bot-

ai

^

South.

West.

face.

tom.

S£

In Fiji Archipelago.

189

Dec. 7

o /

18 50

0 1

178 28

o

79

0

42.9

453

Fine coi-al sand. Pter-
0 lod ooze. Few
s, ob.

About in centre of passage between
Yaugasa-Mothe. Soutberuextensiou
of eastern Fiji plateau.

190

it (I

18 54

178 35

79

47

324

Coral sand. Colored
in part by manga-
nese.

Between Namuka and Yangasa.
Sts. 189-193 referred to B. A. Cliart
No. 2691, corrected to Dec, 1897-

191

18 56

178 43

79

39.3

600

Pteropod ooze. Frag-
ments of pumice.
Fine coral saud,
glob.

6 miles S. 23° W. from west end of
Namuka. Between Namuka and
Marambo.

192

IS 56

178 50

79

42.4

450

Coral sand. Ptero-
pods. Manganese,
glob.

2.7 miles N. 19° W. from Marambo.
In centre of triangle Marambo,
Kambara, Wangava, about 5 miles
distant.

193

Dec. 9

18 56.5

179 16

80

37

990

Very fine light yellow
brown eortd ooze.

About 15 miles west of Kauibara, on
way to Totoya.

FIJI THROUGH ELLICE AND GILBERT ISLANDS TO JALUIT, MARSHALL

ARCHIPELAGO.

194

Dec. 21

o /

12 43

O /

179 50

Longitude
East.

o

85

35.6

1445

Ligbt yellow brown
glob. ooze.

H.O. Chart No. 825', cor. April,I895.

195

Dec. 22

1900.

10 47

179 30

245

Coral sand, rocky.

Tanner machine. \ mile south, off
Nurakita. B. A. Chart No. 1830,
corr. March, 1S98.

196

Jan. 1

0 18

LatitiKle
North.

173 54

170

Hard bottom.

f mUe south of village off south side of
Apamama. Sts. 196-207 H. 0. Chart
No. 119, corr. May, 1S99.

197

Jan. 2

0 30

173 35

83

35

2221

Ligbt yellowgrayglob
ooze. Strnck glo-
bigerinae of Equat.
Current (obtained
before in Paumot us)

On way Apamauia-Maiaua, About 16
miles from northwest end of Apa-
mama.

198

0 46

173 09

84

35.6

1365

Yellow gray glob,
ooze. Very coarse
large species.

About 9 miles southeast of Maiaua.

199

1 12

173 05

84

43.5

413

Same coarse large
glob, ooze as before.

Halfway to Tarawa from Maiana. Un-
known summit.

MO

tC <t

1 20

173 03

* •

95

Broken sliells. Coral
saud.

About \ mile from centre of south
shore of Tarawa. Tanner sounding
machine.

«01

(C Ci

1 20

173 04

900

About 1 mile E. of last station off south

shore of Tarawa. Tanner sounding

machine.

202

Jan. 3

1 17

173 09

84

35.3

1569

Coarse large globig-
erinae. Same as
before.

About 5 miles S. 12° E. of southeast
point of Tarawa. Shoal said to ex-
tend there. Evidently no plateau;
may be a ridge, connecting the islands
Maiaua, Tarawa, and Apaiaug.

390

ALBATROSS" TROPICAL PACIFIC EXPEDITION.

1

a

3

Date.

Position.

Temper- i
atures. [

Nature

^

1900.

' S a

of

TtAmnrlrfl

"3

XI §

Bottom.

Al^JlHH t^O'

.52

Latitude

Longitude

Sur-

Bot- 1 0.5

£

North.

East.

&ce.

torn.

&&

203

Jan. 4

0 /

1 40.5

o /

172 59.5

o

0

170

\nmit 9 nnil^s froTii iniifhfnst nnint of

ilUVJIll £1 Uljll. 3 IIVJIII 3UU.I LlCcta L UUlllt Ul

Apaiang, between Apaiang and north

point of Tarawa. Tanner sounding

machine.

201

Jau. 4

1 52

173 15

84

34.9

2156

Light gray glob,
ooze. Small spe-
cies.

15 miles from Apaiang, on way to
southeast point of Maraki, about
half way.

205

it (£

2 04

173 10

80

*

431

Coral sand and glo-
bigeriuae.

About \ mile off shore off west coast
of Maraki, N.'W.-by-W. from mouu-
meut.

20G

Jan. 5

2 27

173 09

SO

34.8

2255

Glob. ooze.

About 26 miles N.W.-by-N. of Maraki.

207

2 49

173 01

83

35.3

1461

Glob. ooze. Large
species.

About 10 miles southeast from centre
of south shore of Taritari.

FitoM Taritari to Jaluit.

20S

Jan. 7

3 57

172 00

O

S3

0

34.7

2480

Light yellow glob,
ooze, coarse and
fine.

About 60 miles northwest from Tari-
tari. St. 208-239 B. A. Chart No.
983, April, 1891.

209

Jan. 8

4 25

171 13

83

34.7

2505

Lightgray glob, ooze,
medium size.

About 130 miles northwest from Tari-
tari, about half way to Jaluit.

210

it (4

4 54

170 21

S3

34.7

2444

Light gray glob. ooze,
coarse and njedium
size.

About 60 miles southeast from Jaluit.

211

Jan. 9

5 20

IfiO 43

83

34.8

2411

Light yellow drab
glob. ooze.

About 30 miles from Jaluit.

212

(( (1

5 44

169 45

82

35

1937

Light gray glob,
ooze.

.\.bout 5 miles S. \ W. from the south
point of Jaluit.

THRC

UGH THE MARSHALL ARCHIPELAGO.

213

Jan. 14

O /

6 34

169 13

O

83

O

35

2613

Glob. ooze.

About 30 miles northwest from Jaluit.

214
215

Jan. 15

7 00
7 08

169 01

108 56

82
82

35
35.9

2137

1283

Coarse globigerinae.

Coarse globigerinae.

About 9 miles S. 30° E. of southeast

point of Ailinglab Lab.

216

7 29

168 32

82

36.5

1068

Coral sand.

0 miles northwest of west point Ai-
huglab Lab.

217

it n

7 37

168 27

82

37

906

Coarse globigerinae.

Hah' way to Namu.

218

it ti

7 45

168 21

83

39.7

031

Coarse coral sand.

About 2 mUcs south of south point of
Namu.

219

Jan. l.T

8 02

107 43

82

35

2179

Glob. mud.

About 12 mileswest of centre of Namu.

220

Jan. 1()

S 38

167 37

82

35

1897

Glob. mud.

About 12 miles southwest of west
point of Kwajalong Island.

221

Jan. IS

11 09

106 40

80

43.4

400

Coral sand.

\ mile south of Southeast pass of
Rongelab.

222

i( ((.

11 07.5

166 46

80

39

827

Coral sand.

1^ miles south of Southeast pass of
Rongelab.

223

It li

10 40

167 15

80

35

2409

Glob, and light brown
volcanic mud. Red
day (?)• .

About 35 miles southeast from South-
east pass of Rongelab.

224

Jau. 19

10 30

107 42

80

35

2586

Globigerinae and
lightbrownvolcanie
mud. Red clay (r)

About 35 miles from last station,
towards Likieb.

LIST OF STATIONS.

391

i

a

55

Date.

Position.

Latitude
North.

Longitude

East.

o /

o /

225

Jan,

19

10 15

168 06

226

Jan.

20

9 55

168 56

227
228
229

Jan.

21

9 48
9 47
9 4U

169 14
169 14
169 32

230
231

Jan.

23

9 19
9 17

170 10
170 11

232

it

■'

8 50

170 26

233
23i

Jan.

21

7 54
7 21

170 56

171 35

235

Jan.

2S

6 57

171 34

236
237

«

29

6 34
6 11

170 59
170 25

Temper-
atures.

Sur- Bnt-
face. torn.

34.9
34.9

81 42.6
81 36.9
81

41.7
36.1

34.9

36.5
36

36

34.9
34.7

2609

2231

468
934

1583

482
1187

2221

1009
1326

1253

2482
2486

Nature

of
Bottoui,

Globigcriuae and
liglit brown volcanic
mud. Red clay (?)

Glob. mud.

Coarse coral sand.
Coarse coral sand.
Globigerinae. Very

fine species.
Coral sand.
Coarse coral sand

Trace of manganese.
\s\\. and gray glob

ooze.

Coarse globigerinae.
Coarse globigerinae.

Cream colored coarse

globigerinae.
Globigerinae.
Fine glob. mud.

Remarks.

About 35 miles from last station, on
way to Likieb.

About 8 miles W. S.W. of Kapenor
Island. West of north point of Li-
kieb.

^ mile south of South pass of Likieb.

lA mile south of South pass of Likieb.

About half way Likieb to Wolje.

1 mile south of Schischmarev Pass.

2 miles south of last station.

About 40 miles south of last station,
half way bctweeu south end of Erikub
and Maloelab.

About 7 miles N. 50° W. from north-
west point of Arhno.

About 6 miles southwest of south point
of Arhno.

About 40 miles from last station.

About 40 miles from last station.

The same deep water we found on
coming nortli from the Gilberts, and
also all through the Marshalls and
between the islands both of the Raliek
and Ratack chain.

MARSHALL ISLANDS THROUGH THE CAROLINES TO GUAM, LADRONES ISLANDS,

AND TO YOKOHAMA, JAPAN.

238

'-' /

o /

O O

Feb.

5

5 48

169 01

82

35

2424

Glob. mud. Coarse
diat. cvsts.

30 miles west of Jaluit.

Through the C.\rolines.

239

Feb.

9

o /

^

/

S2

O

43.5

371

240

Feb.

13

6 49

156

36

82

34.9

2475

241

(C

"

6 51

154

39

81

35

2533

242
243

Feb.
Feb.

14

15

6 55
6 47

152
152

40
11

82
82

41.5
35

526
2162

244

Feb.

17

8 06

151

08

81

35

2205

Volcanic and coral

sand.
Glob, and light brown

volcanic mud.
Glob. nmd. Light

brown fine volcanic

mud.
Coarse coral sand.
Light gray glob.

mud and few vol- About 17

canic particles.
Glob. mud.

\ mile south of Port Lottin, Kusaie.

\ way Ponapi and Truk. Sis. 240-

244 H. O. Chart No. 1754, 1898.
I way Ponapi — Truk.

About \ mile south of Nama.

miles southeast of South
Island, Royahst Islands.
About lialf way between Truk and
Namouuito.

392

"ALBATROSS" TROPICAL PACIFIC EXPEDITION.

Date.
VMO.

Position.

Temper-
atures.

si

Latitude

North.

Longitude
East.

Sur-
face.

Bot-
tom.

Nature

of
Bottom.

Remark B.

Namonuito to Guam.

245

246

Feb.
Feb.

18
19

o /

9 31
10 34

149 36

148 25

O

81
81

O

35
35

2735
2993

247

Feb.

20

11 35

147 15

SO

35

3213

248

(t

"

12 51

145 40

81

35.8

4813

249

Feb.

21

13 OS

145 25

SO

35

2337

Red clay.

Red clay and small
particles of manga-
nese nodules.

Manganese nodules.
Pumice. Red clay.

Manganese. Pumice.
Volcanic particles,
disks of diatoms(?).

Fine volcanic sand.

50 miles northwest from Magur islet.

100 miles further towards Guam. Sts.
245-249 H. O. Chart No. 529, corr.
June, 1896.

100 miles furtlier, same course, towards
Guam.

Our deepest sounding. 100 miles fur-
ther, same course, towards Guam.
Thermometer could not have regis-
tered correctly.

About 25 miles further, same course,
distant 45 rn. from north end of Guam.

INDEX.

Adam and Eve Point, 1

Agana, 374

Agate, 373

Agate on sea wall of Rangiroa, 10

Agony Island, 310

Ahanga Passage, 199

Ai, 290

Ailinglap, 293

Bays of, 294

Entrance into, 293

Northeastern ])oint of, 295

Shape of, 293

Slope of outer platform of, 294

Southwest shore of, 294

Trades at, 294

Vegetation of, 294

Wide rc'cf flats of, 294
Aitutaki, 169

Barrier reef flats of, 169

Denudation and erosion of, 170

Islands of barrier reef at, 170

Sand keys at, 1 70

Shape of, 169
Aiurua Pass, 145
AiuiTia River, 145
Aki-Aki, 116

Beach rock at, 117

Boulders at, 1 1 7

Coralliferous limestone at, 116

Dimension of, 116

Vegetation of, 117

Width of reef flat at, 117
Alakibeau, 188
Aldrich Deep, 180, 332
Alexander Reef, 195
Alofi, 171
Alutung, 373
Alveopora, 106
Amatuku, 213
Anaa, 84

Buttresses of old ledge at, 85

Depth of lagoon of, 84

Lagoon fiat of, 85

Lagoon of, filled by islets at, 85

Outcrops of old ledge at, 84, 85

Anaa — Can tinned

Reflection from lagoon flat at, 85

Size of, 84
Anaho Bay, 4
Anau Bay. 163
Anaya, 373
Andema Islands, 350

Compared to volcanic islands, 350

Disintegration of, 350

Land rim of, 350

Subsidence at, 350

Underlying base of, 350

Volcanic outliers at, 350
Andrews, C. W., 228
Andrews, E. C, 228
Anu-Anuraro, 130

Dimension of, 130

High coral sliingle beach at, 130

Nullipore knolls at, 130

Old ledge at, 130

Sand dunes at, 131

Vegetation of, 130
Anu-Anurunga, 128

Depth of lagoon of, 129

Dimensions of, 128

Gajjs of land rim of, 129

Submerged reef flat of, 129
Aogasima, 365
Aorai, 149
Apaiang, 252

Boat ])assage into, 252

Color of Nullipores at, 253

Dimensions of, 252

Nullipore cement at, 252

Pontes fiats at, 253

Range of corals in, 252

Southeast face of, 252
Apamama, 240

Bays of, 240

Coral shingle at, 241

Coral soil at, 244

Deptli on reef shelf of, 243

Elevated limestones at, 242

Elevation of , 24 1

Gaps at, 240

394

INDEX.

Apamama — Continued

Height of beaches at, 244
Mayer, Dr., on, 243
Moore, Dr., on, 243
Old gaps at, 241
Outliers of beach rock at, 244
Outliue of, 240
Passes iuto, 240
Platform lagoous at, 240
Reef platforms of, 242
Sand dunes at, 242
Secondary lagoon at, 243
Vegetation of, 241
Apataki, 68

Corals at, 69, 70
Islands of laud rim at, 69
Lagoon of, 70
Land rim of, 68
NuUipore knolls at, 69
Old ledge at, 69
Old ledge boulders at, 71
Platform lagoon at, 69
Shape of, 68
Shore jdatform of, 69
Apurguan Point, 373
Arhno, 321

Beach rock couglomerate of, 326
Boulder cusps at, 322
Charts of, 321
Dodo Pass at, 321
East face of, 325
Filling up of horns of, 322
High siiingle beaches at, 328
Horns of lagoon of, 322
Islets on north face of, 327
Northeast spit of, 326
North face of, 325
North sjjit of, 325
Secondary lagoon of, 322
Vegetation of, 324
West side of, 328
Arorai, 236

Artemise Bank, 141, 144
Arue, 146
Arundel, John, 234
" Astrolabe and Zelee " Ex., 355
Ata, 189
Atata, 188, 190
Atiu, 168

Elevated limestone of, 1G9
Gill on, 168
Williams on, 168
Atokin, 356
Aualap Pass, 353
Australian Reefs, 190
Ava, 198

Ava Labi Pass, 188

Ava Mata Mata Vika, 197

Avatele, 172

Bali Island, 368
Baxo Trista, 342

Elevated limestone of, 342
Height of, 342
Beecbey, Capt., 7

On absence of lagoons, 8
On bottom of lagoons, 9
On coral islands, 8
On Henderson Island, 8
On Paumotus, 7
On Piuaki, 9

On plants of Paumotus, 7
On sinks at Hat, 8
Survey of Gambier, 7
Belcher, Capt., boring at Hao, 10
Bellingshausen, 94
Berard, 340
Bertrand Island, 355
Betche, 279
Bogenaga, 292
Boggen Island, 301
Boggenadick, 292
Bokelan, 309
Boloa, 188
Bonnefin, E., 54
Bonney, T. G., 224
Bora Bora, 161

Assembly house at, 139
Barrier reef flat of, 162
Double peaks of, 163
Fringe of islands of, 163
Islets on flats at, 162
Lesson on peaks of, 138, 163
Native hut at, 164
Vegetation of reef at, 1 63
West coast of, 163
Bordelaise Group, 341
Boudeuse Pass, 141, 145
Bougainville, 113
Bouquet Island, 355
Bourbon, corals at, 6
Brandeis, Mrs., 284
Brander Island, 34, 146

Channel off, 40
Brander's Bay, 153
Plantation, 150
Brougniart Island, 355
Briiggeman, F., 346

On corals of Ponapi, .'i46
Burrh Passage, 272
Butaritari, 258

INDEX.

395

Cabras Island, 370
Calalan Bank, 366
Cape Halgan, 335
Cape Martin, 1
Cape Tupinier, 334
Cape Vauvilliers, 334
Caroline Deep, 333
Caroline Islands, 330

Admiralty Charts of, 331

Central area of denudation uf, 361

Eastern, 330

Low islands of, 361

Semper on, 330

Soundings at, 332

Submarine platform of, 331

Trend of the, 332

Western, 330
CKabrol Harbor, 333
Challenger Deep, 332
Chiekakoff Point, 1
Christian, F. W., 279, 349

Vegetation of tlie Carolines, 349
Christmas Harbor, 315
Christmas Island, 228
Cocoa Island. 368
Colobocentrotus, 80
Comptroller Bay, 1
Cook Anchorage, 145, 149
Cook Islands, 168, 279

Gill on the, 168

Vegetation of, 279

Williams on the, 168
Cook Point, 175, 188
Cook's Hill, 190
Coquille Harbor, 333

Dana, James D.,

On absence of corals at Marquesas, 5

On absence of fossils in lagoon basins, 63

On area of Marshall Islands, 274

On Dolphin Bank, 156

On Fiji Islands, 204

On lagoons shut off from sea, 23

On Makatea, 18, 63

On sinks at Manihi, 79

On tertiary limestones of Ilouden, 50

On tertiary limestones of Manihi, 50

( )n vegetation of Paumotus, 32, 349

Darwin,

On absence of corals at Galapagos, 5
On absence of corals at Marquesas, 5
On the Gambier Islands, 7
On Kwajalong, 297

David, Mrs. T. E , 224

David, Prof. T. E., 210, 224

Dido Shoal, 188

Dodo Pass, 321

Dolphin Bank, 154

Beuchey, Capt., on, 156

Cook, Capt., on, 156

Dana ou, 155

Leclerc and Be'naze on, 154

Moser on, 155

NuUipores on, 155

Wallis on, 156

Wilkes on, 154
Duke of Gloucester Islands, 125
D'Urville, Dumont, 355

East Faiu, 364

Ebadon, 302

Ebon, 273

Echinoneus, 104

Egeria Pass, 189

Eiol, 353, 355

Ellice Islands, 210
Atolls of, 210

Emegua, 309

Emidj, 280

English Roads, 186

Eniwetok Group, 272

Enniilabegan Island, 297

Eo Island, 355

Eotile Island, 310

Eru Pass, 302

Eua, 180

Caverns at, 1 84
Central basin of, 1 82
Central valley of, 185
Channel north of, 180
Drainage valley of, 186
Eastern range of, 182
Eastern ridge of, 181
Elevated limestone at, 181
Fossils at, 186
Gaps in terraces at, 183
Honeycombed rocks at, 185
Mayer, Dr., on, 186
Xullipore platform, 184
NuUipore terrace at, 183
Shore platform of, 183
Sixth terrace at, 183
South point of, 182
Southern .slope of, 181
Surveyed by Capt, Aldrich, 181
Terraces of, 181, 182
Topography of, 187
Vegetation of, 184, 186
Volcanic earth at, 184
Volcanic outcrop at, 187
West face of, 185
Western ridge of. 181

396

INDEX.

Eua iki, 191
Euakafa Island, 201

Faaroa Bay, 159
Faatemu Bay, 161
Pafa, 189
Fakarava, 76

Depth of Ngaruc Pass at, 77

Ecliiuouiius at, 80

Lagoou sand beach at, 79

Lee side of lagoon of, 80

Modern beach rock at, 78

North pass at, 76

Nullipore knolls at, 78

Old ledge covered by beach rock, 80

Old ledge outcrops at, 77, 78

riatform lagoou at, 80

Rotoava anchorage at, 77

Sea breaks in lagoou of, 77

Secondary lagoon at, 77

Shore platform of, 78

Sinks at, 79

Trend of land rim at, 76

Width of western reef fiat, 76
Fala, 355
Falcon Island, 178

Lister on, 178
Falefatu, 212
Faleu, 353
Fanek Island, 352
Fanua lai, 179
Fanui Bay, 163
Faone Pass, 141, 145
Farallon de Pajaros, 365
Faraulep, 364
Fare Harbor, 158
Farerea Pass, 157
Fareute Point, 154
Fata, 198
Fatato, 213
Fautaua Valley, 149
Feletoa, 201
Feys, 341,362, 364
Fiji, 204

Charts of, 204

Coral reefs of, 204

Erosion of, 205

Exidoratious of, 204

Lau grou]), 204

Reefs of, 190

Rivers of, 204

Soapstone at, 205

Terraces of, 204

Vegetation of, 279
Fitzroy, Capt., 74
Foa, 196

Fofoa, 202

Fongafale, 219

Fonuaika, 195

Fotuhaa, 195

Fualifeke, 221

Fualopa, 215

Fukave, 189

Funafara, 212

Funafuti, 212

Alovonariaus at, 222
Beach rock slabs at, 220
Bottom of passes into, 225
Boulders on flats of, 2! 2
Buttresses at, 214, 226
Charts of, 226

Conglomerate outliers at, 221
Corals at, 222

Crystalline limestone at, 218
David, Prof., on, 215
Deuudation at, 221
Depth of bore at, 223
Dimensions of, 212
Easteru face of, 212, 220
Elevated breccia at, 220
Expansion of reef, 227
Filling of lagoon of, 224
First bore at, 223
Former land rim of, 222
Gaps at, 225

Gardiner, J. S., on, 224, 226
Hedley, C, on, 224
Height of, 219
Heliopora reef at, 218
Mayer, Dr., on, 218
Nullipore boulders at, 226
Old ledge at, 217
Pools at, 214
Position of bore at, 216
Range of corals at, 227
Reef flat platform of, 221
Royal Society borings at. 223
Second bore at, 215
Secondary lagoon at, 217
Section across, 219
Shoals and banks at, 219, 226
SoUas, J. W., on, 224
Southern horn of, 21 2
Sturdee, Capt., on, 223
Submarine cliffs off, 225
Temperatures at, 223
■ Vegetation of, 214, 225
Western face of, 222

Funamanu, 213

Funangongo, 213

Funuarua Island, 46

INDEX.

39^

Gabert, 340
Gaimard Island, 355
Galapagos, absence of corals at, 4
Gardiner, J. S., on Fiji, 204, 224

On Funafuti, 224, 226
Gaudichaud Island, 355
Gegibu Island, 302
Gehh Island, 299

Corals killed at, 299

Sand dune at, 299

Slope of reef fiat at, 299
Gilbert Islands, 232

Northeast trades at, 233

Soundings iu, 232

Underlying platform of, 232
Gregoire Island, 354
Griinow, 279
Guam, 366

Caverns of cliffs at, 368

Denudation of, 372

Dimensions of, 366

Disintegration of, 369

East coast of, 366

Elevated coralliferous limestone of, 372

Elevated coral reef at, 373

Erosion of, 368, 375

Fossils of, 372

Junction of volcanic outburst and elevated lime-
stone, 374

Limestone outliers at, 373

Mesa of northern part of, 369

Northwest point of, 369

No subsidence at, 376

Ked earth at, 371 •

Ridges and pinnacles of, 372

Road to Agafia in, 374

Sloughing of sea face of, 368

Southern part of, 371

Southern volcanic massif of, 370

Terraces of, 366, 367

Twisted strata at, 367

Vegetation of, 373

Vertical limestone cliffs of, 366

Volcanic agencies in recent times at, 375

Volcanic bluffs at, 373

Volcanic earth at, 371

Volcanic negro-heads at, 373

Volcanic rocks of, 367

Volcanic slopes of, 372

Volcanic soil of, 373

West coast of, 369

Haafeva, 137
Haaio Island, 161
Haano Island, 196

Haapai Bank, 196

Depth of, 196

Islands of, 196
Haapai Group, 195

Elevated islands of, 195
Haapai Plateau, 175, 195
Haapape Promontory, 146
Haavini Valley, 145
Hacq Island, 352, 355
Hakahe, 3
Hakaufussi, 201
Hakau Lahi, 197
Hakau Mamao, 189
Hakau Tabu, 188
Hall Islands, 331
Hamene Bay, 159
Hanaiapa, 4
Hansen, Dr., 201
Hao, 113

Buttresses at, 115

Color of reef flat at, 116

Coral shingle bars at, 1 14

Depth of lagoon of, 113

East face of, 1 1 5

Gaps at, 114

Islauds on reef flat, 114

NuUipore knolls at, 116

Old ledge at, 115
Hat-shaped Islands, 209
Hatutu, 1
Hedley, C, 224

On Funafuti, 224

Vegetation of Ellice group, 279
Henderson Island, 8
Hereheretue, 131

Dimension of, 131

Echinoderms at, 132

Island across lanil rim at, 132

Lauding at, 132

Nullipore knolls at, 132

Old ledge flat at, 132, 133

Platform lagoon at, 132

Range of corals at, 133

Reef flats at, 133

Vegetation killed by sand at, 131
Hernnsheim, 329
Hesi, 340

Heterocentrotus, 80
Hikueru, 110

Deep holes at, 111

Depth of lagoon, 1 1 1

Nautilus at, 110

Old ledge at. 111

Shoals in, 1 1 1

Trend of, 110
Hiva Oa, 4

398

INDEX.

Holanga, 201

Fossils at, 201
Holevai, 188
Honga Hapai, 178
Honga Tonga, 178
Huaheine, 157

Compared to Bora Bora, 158

Dimensions of, 157

Islands on barrier reef of, 158
Huaheine Iti, 157
Huaheine Nui, 157
Hunga, 197

yEoIiaii limestone of, 202

Limestone strata of, 202

Vertical cliffs of, 202

Ifalik, 341, 364
Illeginni, 302
Imrodj, 287

Bench, height of, at, 287

Boulder reef fiats of, 287

Breadfruit trees at, 287

Section across, 287

Shingle bar of, 288
Ine, 324
Iriru Pass, 161

Jaluit, 279

Beach rock conglomerate at, 283
Buttresses at, 282
Conglomerate beach at, 282
Continuity of laud rim of, 286
Corals of lagoon of, 286
Currents in lagoon of, 290
Depth of lagoon of, 280, 286
Dimension of, 279
Driftwood at, 281
Filling of gaps at, 289
Filling of lagoon of, 286
Flat outer platform at, 285
Flats of lagoon face of, 292
Fresh-water lagoons at, 284
Gentle slope reef platform at, 282
Lagoon face of islands of, 289
Lagoon shore extension at, 284
Land rim swept by sea at, 289
Large blocks of corals at, 285
Long islands of rim of, 280
Millepore flats of, 291
Narrow laud rim of, 279
Northeast face of lagoon of, 292
Northern horn of, 292
Nnllipore knolls at, 282
Pools ou lagoon face of, 288
Poritcs flats of, 291
Porous laud rim of, 284

Jaluit — Continued

Potholes at, 285

Kange of corals at, 286

Rolled coral blocks at, 285

Sand bars encroaching on lagoon of, 292

Sand blown into lagoon of, 280

Sand spits of, 291

Sinks at, 283

Secondary lagoons at, 283, 292

Ship channels at, 280

Shoals in lagoon of, 280

Slab beaches at, 281

Slope of lagoon face of, 282

Southeast passage into, 281

Southern horn of, 279

Southwest passage of, 289

Steep sea face of, 282

Sweep of trades across lagoon of, 289

Vegetation of, 281

Western passage of. 290

Wide outer reef flats of, 288
Johnson, Lieut.,

Boring on Aratika, 10
Judd, J. W., 223, 228

Kahalape, 350
Kallau, 184
Kama, 364
Kambara, 206

Bottom of basin of, 207

Buttresses at, 208

Central basin of, 206, 207

Gaps at, 206

Height of, 206

Slope of denudation of, 208

Terraces at, 208

Tokalau Gap at, 207

Volcanic cone of, 206

Volcauic outburst at, 206, 207
Kapa, 198, 202
Kapenor, 309
Karoni, 205
Kauehi, 74

Dana on huge boulders at, 75

Effect of prevailing winds at, 74

Entrance to, 75

Low gaps at, 75

Old ledge boulders at, 74

Sand bars at, 74

Secondary lagoon at, 75

Weather land rim of, 74
Kaukura,

Outliers of old reef rock at, 38
Keuea Gap, 264
Kiti Harbor, 343
Kito, 195

INDEX.

309

Kitu Island, 198
Koto Maka, 193
Kotu, 195
Kotzebue on Tikei, 71

Ou Wotje, 315
Kramer, Dr. A., 234
Krusenstern, Capt., 297
Kuli Island, 357
Kusaie, 333

Belt of mangrove islands of, 334, 337

Coral patches at, 337

Corals killed by silt ,it, 336

Driftwood on, 339

Erosion and denudation of, 333. 338

Frinjjing reefs at, 336

Ileislit of, 333

Lagoon basins at, 335

Lagoon passages at, 334

Main lagoon cbannel of, 337

Main ridge of, 333

Outcrops of volcanic rocks of, 338

Outline of, .333

Passes through reef platform of, 336

Subniarine erosion at, 338

Vegetation of, 335

Volcanic boulders at, 335

Volcanic rock outliers at, 335

Volcanic sand beach at, 339

AVater lanes at. .337

Wide bays of. 338

Wide reef flat platform of, 338
Kutua Point, 356
Kwaj along, 296

Chart of, by Krusenstein, 297

Dunes .at, 298, 300

Gaps on west face of, 301

Great size of, 296

High sea face of, 298

Lagoon reef flats wide at, 302

Nulliporc knolls of, 298

Sand bars in lagoon of, 301

Secondary isl.ands at. 301

Section of beach of, 297

Southern horn of, 297

South Pass of, 297

Trades at, 302

Western point i>f, 297

Lado, 311

Jose Delirunn on, 312
Ladrones, The, 365

Caroline Deep off, SC.r,

Challenger Dec]) off, 3(16

Coralliferous limestone isl.ands of, 365

Deepest sounding off, 366

Ladrones, The — Cnntinucd

Irregular soundings along, 365

Nero Deep off, 366

Soundings of " Nero " in, 365

Southern islands of, 377

Volcanic islamls of, 365
Lagediak Pass 317
Lahi Passage, 189
Lalalolomei Bank, 201
Lamotrek, 331
Langa, 342
Late, 178
Lau Group, 204
Lauvergne Island, 355
Lele Island, 335
Lifuka, 196
Likieb, 307

Bays at, 313

Coral patclies in lagoon of, 307

Corals on lagoon flats of, 312

Dead corals in s/(« at, 3 1 1

East face of, 307

Floating sand at, 314

Gap at, 313

Grass on, 311

Ilydrocorallida; at, 312

Incorrect position of, 307

Islands on east face of, 314

Lagoon sand overwhelming outer platform of,
309

M.aten Pass at, 310

Melander, Capt., survey of, 307

North point of, 308

Sand spits of, 313

Sinks at, 313

South Pa.ssof,-3U

Stranded islets of, 312

Width of island of, 311
Likintakai Island, 344
Lima Island, 196
Lister, 179

On Eua, 186

On Haapai Bank, 196

On Kelefesia. 179

( In Mango, 1 79

On Noniuka il:i. 179

On Tanoa, 179

On Tonnmeia, 179

On volcanic and limestone islands, 179
Little Makin Island, 259
Lofanga, 197
Losap, 351
Lot's Wife, 365
Lua motu, 212
Lubu, 302
Luerssen, 279

400

IKDEX.

Lukunor, 310
Luminan Reef, 3G6
Liitke, Capt., 331, 332

Mackenzie Group, 364
Madagascar,

Corals at, (i
Mahaena Pass, 147
Mahea Island, 160
Maiana, 245

Boat passage at, 245

Color of beach rock at, 245

Coliiring of Xiilli|)orcs at, 246

Coral shin^'le at, 246

Dimensions of, 245

Secondary lagoons of, 246

Slope of platform of, 245

Vegetation at, 245, 247
Maina Island, 169
'Makatea, 56

Absence of reef platform at, 62

An elevated limestone island, 56

Areas of drainage of, 64

Bottom of sink, 62

Buttresses of old ledge at, 60

Caverns at, 61

Central sink of. 5?, 60

Crevasses in sink of, 61

Dall on fossils of, 59

Dana's visit to, 56

Eastern face of, 56

Erosion at, 62

Fossils of, 1 8, 5!)

Incrusting Nnlliporcs at, 59

Landing places at, 59

Lines of caverns of, 58

Lines of undercntting, 59

Norlliei']! point of, 58

Outline of, 56

Palh across, 60

Sea slope of, 59

Slope of southern face of, 56

Southern face of, 56

Terraces of, 56, 57

Vertical cliffs of, 57

West face of, 58
Makemo, 99

Accession to reef by corallines a(, 100

Beach rock conglomerate at, 107

Blow holes at, 108

Bottom of lagoon of, 104

Conglomerate ledge at, 10.3

Corals in pass of. 102

Corals on shoals of lagoon at, 1 06

Echinoderms on reef flat of, lo;!

Gaps of laud rim of, 100, 107, 108

Makemo — Continued

Islands as buttresses at, 107

Land rim of, 102

Masses of boulders at, 105

Northeast face of, 101

Old ledge outcrops at, 101, 102, 106

Pass into, 102

Pudding-stone at, 103

Kange of corals at, 100, 104, 105

Sand driven from lagoon at, 1 07

Shingle beach of, 101

Shingle driven into vegetation of, 108

Shoals in lagoon of, 105

Sink of 108

Slope of lagoon at, 104

Surface hauls at, 106
Mangaia, 168

Terraces at, 1 68

Williams on, 168
Mango, 102, 228
Mango Iki, 192
Mann, 300
Mantapeti, 342
Mapuaura River, 145
Maraa Pass, 142
Maraki, 253

Absence of shore platform at, 256

Beach rock of. 254

Blocks of Nnllipores at, 256

Bottom of lagoon at, 254

Closing of land rim of, 256

Color of Nullipores at, 255

Dana on, 254-

Elevation of, 255

Increase of laud rim of, 257

Monument on. 257

Nullipore knolls at, 254

Secondary lagoons of, 254

Secondarv line of islands at, 256

Section acro.ss, 255

Size of, 253

Slope of. 254, 257

Underlying platform of, 254

West face of, 256
Marambo, 205
Marau, 149
Maria Bay, 189
Maroe Bay, 157
Marokau, 111

Dimension of, 1 12

Sea face of, 112

Wide reef Hat at, 112
Marquesas Archipelago, 1

Absence of reefs from, 3

Native hut at, 6

Soundings at, 5

INDEX.

401

Marshall Islands, 271

Areas of, 274

Atolls with small lagoons in, 27.3

Canoe of, 293

Deep basin south of, 279

Depths of lagoons of, 273, 300

Elevation at, 277

Extent of lagoons of, 274

Great nioisture at, 274

Insignificant hind rims of, 274

Monotonous structure of, 271

Movement of loose material in, 27C

Passes into atolls of, 276

Ralick Chain at, 271

Ratack Chain at, 271

Heacli of trades at, 274

Rise of tides in, 314

Shape of atolls of, 272, 277

Slope of lagoons of, 272

Small islets of, 328

Small islets of rim iu, 276

Soundings in, 27B

Trades at, 275

Trend of atolls of, 271

Underlying base of, 271

Vegetation of, 279

Water driven into lagoons by trades, 275

Weather side laud rim of, 275
Mataea River, 145
Matahiva, 54

Bonnefiu on lagoon of, 54

Filling of lagoon of, 55

Gaps of, closing of, 54

Ridges of old ledge at, 54

Vegetation of, 55
Mata Maka, 192
Matavai Bay, 146, 153, 155
Mateika, 212
Maten Island, 310
Matira Point, 162
Mauki, 168

Apatite beds at, 168
Maupiti, 138, 164

Bluffs of, 105

Central island of, 164

Dimension of, 1G4

Height of, 164

Shape of, 1C4
Mauritius,

Corals at. 6
Mayer, Dr.,

On Eua, 186

On Nomuka, 193

On Talau, 202
Medjado, 280
Medjerrurik, 290

Mehetia, 140

Absence of shore platform at. 140

Corals at, 4, 140, 141

Crater of, 140
Melander, Capt., 307
Merizo Bay, 368
Metalanim, 344
Metis Shoal, 178
Mituro, 169

Gill on, 169
Mohican Island, 34

Old ledge of, 40
Mokil Island, 341
Monu afe, 189
Moore, 70

On Nomuka Iki, 192
Mortlock Islands, 331
Moser Deep, 180
Motuloa, 212
Motungie, 212
Motu Araara, 159
Motu Iti, 165

l.-laiids of, IG5

Lake, 157

Underlying rocks of, 165
Motu Mute, 163
Motu Tabu, 189
Motu Teheri, 146
Motu Tofari, 163
Motu-uta, 154
Moungalafa, 198
Moungaone, 197
Mount Buache, 333
Mount Crozer, 333
Mount Diademe, 148
Mount Makana, 372
Mount Santa Rosa, 365, 374
Mount Tinkio, 371
Mount Ton Azan, 360
Mount Zion, 190
Mua, 188
Muifuiva, 192
Muitoulo, 198
Murea, 156

Erosion of, 157

Outlines of, 156
Murray, Sir John, 225
Mutok Island, 344
Mutokaloj, 342

Naiau, 206
Nama, 351

Coralliferniis limestone at, 351, 362
Namoluk, 341

26

402

INDEX.

iNamonuito, 363

Eastern spit of. .3f).f

Low atoll of, 363

Kus-siaii .survey of, 363

Wo.^toni lioni of, 364
Namorik, 329
Namu, 235

Vegetation of, L>96
Nao Nao Pass, 160
Na Potu, 204
Napuni Island, 258, 269
Narpoli Island, 343
Nauru, 233
Navutuiloma, 204
Neiafu, 176

Cliff.sat, 199

Corals at, 20 r

Entrance to, 198

Kange of corals at, 199

Keef platforms of, 199

Third terrace at. 202

Vegetation at, 200
Nero Deep, 333
Ngarue Pass, 76
Ngele Levu, 205
Niau, 64

Bcacli of sea face of, 65

Corals on reef flat at, 65

])en.*ity of water in lagoon of, 66

Diminutive marine shells at, 67

Lagoon of closed, 65

Lagoon or sink of, 67

Lagoon sluit off from sea, 23

Nidlipores .at, 65

Old ledge .at, 66

Poeillipores at, 65

Range of corals at. 65

Sand encroadiing on old ledge at, 66

Shape of, 6+

Slope of land rim of, 65

South shore of, 67

Submarine erosion at, 67

Terraces of, 65

Widtli of reef flat of, 66

Wooded land rim of, 64
Niniva, 197
Niuafou, 178
Niuatobutabu, 203

Connection with Tonga, 203
Niue, 171

Blow holes at, 172

Canons at, 1 74

Cliffs of, 171

Erosion at, 174

Moss on, 174

Nullipore m,a.sses at, 172

Nine — Continued

Soil of, 173

Terraces, height of, at, 171

Terr.aces of, 171, 172, 173

Williams on, 168
Niutao, 230
Nomuka, 192

Buttresses at, 193

Coralliferous limestone of, 192

Depth of lagoon .it, 193

Fertile .soil of, 194

Fishes in lagoon of, 193

Height of beaches at, 194

Highest point of, 192

Island of, 192

Lagoon of, 193

Mangrove swiimp of, 194

Mayer on, 193

Old ledge outcrop at, 192

Sand dune at, 194

Slopes of denudation at, 193

Vegetation of, 1 94
Nomuka Group, 192

Bank of, 192
Nomuka Iki, 176, 192
Nomuka Plateau, 175
Nua Papu, 198
Nui Aunotb Point, 188
Nui Nui, 33, 44
Nuku, 189
Nukualofa, 190
Nukufetau, 229

Black shingle at, 230

Dei)th of lagoon of, 230

Dimension of, 229

Gaps .at, 230

Islands on rim of, 230

Lagoon sand beach at, 230

Vegetation of, 229
Nukuhlva, 1
Nukuleka, 188
Nuku Mbasanga, 205
Nukutavake, 118

Sand dunes .at, 1 18

Native canoe at, 119

No lagoon at, 1 18

Old ledge at, 119

Secondary lagoon at, 119

Section across, 118
Nukutipipi, 125

Color of wiiter at, 125

Dimension of, 127

Extension of dunes at, 127

Formation of i.slands at, 126

Lagoon of, filling, 127

Nullipore knolls of, 128

inde;x.

403

Nukutipipi — Continued

Platform lagoon at, 128

Steep sea face slope of, 128

Vegetation of. 125
Nurakita, 210

Approaches to, 211

Dimensions of, 210

Seconilarv fringing reef of. 21 1

Sink of, 211

Soundings off, 278

Ofolanga, 197
Ohonua, 185
Olimarao, 364
Onevai, 189
Onevao, 189
Onoatoa, 236

Absence of western rim of. 237
Onoupe Island, 364
Oniimak Island, 301
Oosima, 365
Orahik, 364

Klevatcri limestone at, 342

Narrowest land rim of, 3G4
Orohena, 149
Orote Penin.sula, 370
Oto, 198
Otungake, 198
Oua, 195
Outline of,

Carolines, 277

Ellice Islands. 277

Fiji, 277

Gilbert Islands, 277

M.irsliall Islands, 277

Paumotu Islands, 277

Paanopa, 233
Pachiai, 350
Paea, 142
Pahia, 163
Paipai Pass, 159
Pakaka Entrance, 68

Bottom of, 69
Pakin, 351
Panemur, 350
Pangai, 198
Paoi, 45

Papara reef flats, 147
Papawa Harbor, 153
Papenu River, 14')
Papiete, 150, 1E2

Algae at, l.'il

Barrier reef at, 150. 151

" Challenger " ,at, 150

Papiete — Cmitivucd
Corallines at, 151
Corals at, 151

Echinoderms a1, 152

Lagoon .slope at, 152
l?ange of corals at, 151

Slope of reef Hat at. 151
Pari Bay, 159
Paumotu Archipelago, 7

Absence of Alcvouarians in, 29

Area of elevation of, 29

Atolls rising from moderate depths in, 28

Birds of, 31

Canoe and native of, 119

Character of corals of, 29

Crnstacea of, 31

Deepe.st sounding in, 28

De])tli of lagoons of, 23

Development of Nnllijjores at, 30

Dished isliinds of. 24

Echinoderms of, 30

Elevated coralliferous limestone islands of, 20

Elevation of western islands of, 18

Klat-topped i.slands of, 24

Formation of land rim of, 21

French Hydrographic Charts of, II

Islands of accretion in, 17

L.agoons shut off from sea in, 23

Land rims of, 15, 21

Lines of upheaval of, 27

P.aucity of marine animals in, 31

Pearl oysters, age of, at, 30

Pearl oysters, reproduction of, in, 30

Reef flat pudding-stone in, 21

Secondary lagoons of, 22

Shells in mud of lagoons of, 63

Shoals, ledges, and islands in lagoons of, 22

Small atolls of, 19, 23

Small size of Tridacnas of, 30

Surface hauls in, 31

Surveys of, 1 2

Transportation of cocoannts in, 32

Trend of islands of, 27

Vegetation of, 7, 31

Western islands of. 18

Western plateau of. 1 9

Wind follows trend of islands in, 22
Paumotu Plateau, 25

Soundings on, 25
Pau Point, 162
Pava, 221

Peacock Anchorage, 237
Periadik, 355

Permanence of Pacific Ocean, 228
Phaeton Harbor, 144, 147
Pikelot, 364

404

INDEX.

Pinaki, 120

Alexander on, 121

Area beds at, 121

Bottom of lagoun :it, 1 22

Coral shingle at, 120

Depth of lagoon of, 121

Islets in lagoon of, 121

f)l<l ga])s at, 120,123

Sand bars at, 122

Sand beaeh at, 120, 123

Sand blown in at, 124

Sand dunes of, 120, 122

Townsend on, 125

Tridacna at, 121

Vegetation of, 23, 120

Water hole at, 124

Width of reef platform of, 120
Pingelap, 340

Population of, 341

Shallow lagoon of, 340

Voloanio ])latform of, 341
Pinglapp, 292
Pis Island, 357
Pisaras Island, 363
Piti u Tai Island, 162
Piti u Uta Island, 162
Point Ajayan, 368
Point D'Urville, 335
Point Facpi, 371
Point Fafai, 369
Point Fata, 198
Point Hanoum, 367
Point Lesson, 340
Point Nantiaiti, 344
Point Patay, 368
Point Ritidian, 367
Ponapi, 342

Alcvonariaus of, 346, 348

Bands of deep water at, 344

liars of pebbles in Kiti Kivcr at, 349

Bottom of lagoon of, 346

Briiggeman on corals of, 346

Changes of reef flat islands of, 345

Channel across reef flat of, 344

"Coquille," The, at, 347

Corals killed by exposure at, 348

Dimensions of, 342

Effect of trades at, 349

Forest trees at, 349

Mangrove islands, belt of, 343

Masses of corals at, 345

Muddy water of lagoon of, 346

Navigation of lagoou in, 347

Nnllipore coating on corals at, 348

Outliers of spurs of volcanic ridges at, 344

Kauge of cor.als at, 348_

Ponapi — Continued

Keef harbors of, 343

Section across, 345

Sonth shore of, 345

Tongue of mangrove islands at, 344

Vegetation of, 346

Volcanic islands in barrier reef at, 342

\'olcanic rocks of, 349

\'olcanic silt on bottom of lagoon at, 348

Water coming down slojies of, 349

Wiclunan on, 343
Popote Bay, 142
Port Lod, 344
Port Lottin, 333
Port Motu Au, 153
Port Pago, 368
Port Tarafofo, 369
Port Ynarajan, 368
Powers, F. D., 234
Punaavia, 143
Punaeroa Pass, 161
Punta de los Amantes, 369

Quiros, 7
Quoin Hill, 205
Quoy Island, 355

Raiatea, 159

Barrier reef of, 160

Channel separating Tahaa from, 160

Height of, 161

Vegetation of, 160
Ralick Chain, 271
Rangiroa, 32

Appearance of, seen from sea, 35

Avatorn Pass, 34

Bare sand bars of, 48

Beach concealing old ledge wall of, 46

Bottom of lagoon of, 45

Buttresses of old ledge of, 48

Coral shingle of, 38

Corals on reef plateau of, 37

Corrected sketch of, 48

Currents in, 34

Current tlirougli gaps of great wall at, 51

Dana on great wall of, 46, 51

Denudation of, 16

Deposits covering old ledge of, 40

Destruction of islands in lagoon of, 44

Disintegration of great wall of, 51

Erosion of. 36

Exposure of old ledge in gaps at, 43

Formation of cuts in land rim of, 42

FormatH)n of land rim of, 35

Formation of sand bars at, 49

Formation of sinks of, 42

INDEX.

405

Rangiroa — Continued

Gaps iu laiul rim of, 41

Great wall cut into fragments at, 4"

Great wall of elevated limestone at, 46

Height of beach of, 39

Lagoon beach of, 38

Lagoon of, bottom of, 36

Lagoon sink of, 39

Lagoon slope of, 46

Lee laud of, 37, 49

Narrow laud rim of, 45

Northern laud rim of, 33

NuUipores on outer platform of, 47

Kauge of corals iu lagoon of, 41

Sea face of, 43

Sea face of the great wall at, 47

Section across, 37, 38

Shore platform of, 40

Size of, 14, 35

Soundings in lagoon of, 36, 45

Spur of old ledge dam of, 52

Tiputa entrance at, 33

Vegetation of, 33, 36, 39

Water flowing over reef flats of, 14
Raroia, 94

Bays at, 96

Boulders of beach rock at, 96

East face of, 95

Eutrance to, 97

Gaps at, 95

Large boulders at, 95

Length of, 94

Low ga])S at, 95

NuUipore knolls at, 96

Ohl ledge at, 95

Pocillipore knolls at, 96

Sand beaches at, 95

Shingle beaclies at, 95

West side of, 97

Width of shore platform of, 96
Rarotonga, 169
Ratack Chain, 271
Rautoanui Pass, 158
Ravaliere, 111

Large boulders at, 1 \'l

Secondary lagoou of, 1 1 1

Width of, 112
Raveskoi Islands, 90
Reiher Passage, 272
Resolution Bay, 2
Rewa River, 205
Rodriguez,

Corals at, 6
Rongelab, 303

Adaptiition of Echinoderms at. 305

Beach rock at, 304

Rongelab — Continued

Bottom of lagoon uf, 306

Corals iu lagoon, 304

East face of, 303

Lagoon side of, 306

Land rim of, 303

Northeast trades at, 304

Sand dunes of, 303

Section of beach at, 305

Sinks at, 304

South pass into, 303

Variation of corals at, 305
Rongelappelab, 303
Rongerik, 309
Rota, 376

Caves at, 377

Elevated coralliferous limestone of, 377

Northwestern puiut of, 377

Southern spit of, 377

Terraces of, 377

Volcanic outburst at, 377

Western peninsula of, 377
Royalist Islands, 352

A satellite of Truk, 352

Line of boulders at, 352

Northern passage of, 352

Vegetation of, 352
Royal Society, 210, 224

Committee on boriug iu a coral reef, 210, 224
Ruk, 354, 356
Rurick Pass, 315
Rurutu, 168

Williams on, 168

Saipan, 378

San Augustin, 342

Elevated limestone of, 342

Height of, 342
San Luis d'Apra, 370
Savage Island, 163

Williams on, 168
Schischmarev, Lieut., 315
Schischmarev Pass, 316
Seeman, 204, 279

Flora Viticusis, 204
Semper, C, 362

On geology of I'elew Islauds, 362
Seniavina Islands, 342
Seychelles,

Corals at, 6
Sinks and Sounds of,

A no, 200

Ihingii, 200

Kidoa, 200

Makave Spit, 201

406

INDEX.

Sinks and Sounds of — Cnnlimied

Nua l'ai)U, 200

I'angai anil ()t\iiij:ake, 200

Teleki, 201

'I'ofoa, 200

Tulie, 201

Vaipnua, 201
Society Islands, 135

Hairier reefs at, 13fi, 137

Deniiilation at, 135, 137

Eastern, 13ft

Fringing reefs at, 138

Heights of, 138

Islets ou barrier reef at, 136

Lesson on vegetation of, 3.5

Modifications of, 135

Shore platforms at, 135

Submarine ileniniation, 135

Vegetation nf, 140

Western, 136

Wooded islets at, 136
Sollas, Prof. J. W., 210, 224

Unexceptional atolls, 227
SosanjayaBay, 377
Sosanlagh Bay, 377
Soundings,

Across Hangiro:i lagoon, 45

Aki-Aki to Nukutavake. 27

Among Kllice Islands, 278

Among the Ladrones, 365

At Fakarava, 81

At Makemo, 104, 105

At Nine, 171

Between islands in lagoon of Fakarava, 82

Between the (iilbert Islands, 232

Between tlie Jlarslnill Islands, 278

By " Nero," 333, 365

Deepest, 333, 366

ICast of Tonga, 1 80

From Nanionuito to .lalnit, 332

Guam to Japan, 365

Guam to Midway Island, 3G5

Hao to Aki-Aki, 27

Ilikueru to Mamkan, 27

In lagoon of Taritari, 264

M.akatea to Tahiti, 26

Matahiva to Makatea. 2fi

Niau to Apataki, 26

Nukntipipi to Melu-tia, 27

Off .Vvatorn Pass. 25

Off Niirakita, 278

I'inaki to Nukutipi])i, 27

Rangiroa to Tikaluui, 26

South of Tonga, 181

Ti kalian to M.ataliiva. 26
Submarine terraces, 229

Taapuna Pass, 14C
Tababac, 342
Tabik, 302
Tabonua, 240
Tacahu, 342
Taenga, 98

Large bouMers at, 98

Low land rim of, 98

.Sand bars, west face of, 98

Shape of, 98
Taeroere, 47
Tagua Point, 368
Tahaa, 159

Beack rock at, 161

Height of, 161

Keef flat at, 1 59
Tahanea, 85

Boulders on reef flat of, 86

Depth of secondary lagoon of, 86

Digitate channels of, 86

Formation of islands of laml rim of, 89

Formation of spits .at, 89

Islets of reef flat of, 87

Lagoon sand bars of, 88

Length of, 85

Low land rim at, 87

Northern point of, 88

North face of, ^8

Sand bciiches at, 87

Sand buttresses at, 89

Secondary lagoon of, 86, 88

Shingle beaches at, 87

Spreading of cocoannt trees at, 87

Water driven over land rim at, 87
Tahara Promontory, 146
Tahihi Point, 162
Tahio Point, 162
Tahiti, 141

Alisence of Alcyonariaiis at, 150

Artemise Bank at, 141

Barrier reef flat at, 142

Barrier reef lagoon at, 142

Barrier reefs of, 141

Corals of east face of, 145

Dimensions of, 141

Eastern coast shelf of, 149

Erosion and denudation at, 148

Islets on barrier reef of, 146

Mapeti Lsland at, 142

Matavai Bay at. 1 4 1

Origin of lagoons at, 144

Point Venns at, 141

Pnrurn Island .at, 142

Botten coral on fl.ats at, 143

Shore platforms of, 1 44

Silt of streams at, 145

INDEX.

407

Tahiti — Continued

Southeast trades at, 147
Tauuoa reef Hat at, 143
Tidal currents at, 147
Watercourses at, 143
Waterfalls at, 145
Tahuak, 342

Taiarapu Peninsula, 137, 144, 149
Taiisale, 217
Tai oa Bay, 2
Tai-o-hae Bay, 2
Taiti, 149
Takahave, 310
Takai Island, 340
Takume, 91

Colored NuUipore knolls of, 92
Depth of lagoon of, 93
Gaps of laud rim of, 92
Islands of east face of, 93
Islands on lee land rim of, 91
Lagoon flats wide at, 92
Lagoon of, not closed, 91
Large boulders at, 92
Length of, 91

Outcrops of old ledge at, 92
Recent conglomerate at, 92
Sand beaches at, 92
Secondary lagoon at, 94
Shingle beaches at, 92
Surf wash into lagoon, 91
Trend of, 91
Wide reef flat at, 92
Young cocoanuts at, 93
Talau, 198

Fossils at, 202
Height of, 202
Lister on, 199
Mayer on, 202
Terraces of, 202
Upper cliffs of, 202
Tanoa, 192
Taongi, 272, 302

Secondary lagoon of, 272
Taoro Island, 160
Tapeteuea, 237

Artiticial mounds at, 238
Dimension of, 237
Driftwood at, 239
Gaps at, 238

Islands of land rim of, 238
Nortliern horn of, 238
Old ledge at, 240 .
Secondary lagoons at, 239
S. S. " Narragansett " survey of, 238
Vegetation of, 239
Taragay Bay, 367

Taravoa Isthmus, 137, 148
Tarawa, 247

Cuts in outer edge of, 249
Depth of lagoon of, 247
Dimensions of. 247
Discolored water at, 248
Dunes at, 248
East coast of, 250
Fish ponds at, 249
Islands on platform of, 248
Lagoon f.ace of, 251
Lines of islands in lagoon of, 251
Position of barrier reef at, 247
Secondary lagoon at, 248
Slope of atoll of, 247
Slope of flats, 249
South side of, 247
Wide lagoon reef flats of, 250
Width of secondary lagoon of, 250
Vegetation of, 250
Tarik, 355
Taritari, 258

Angular outline of, 258

Broad passages into, 258

Connecting passages of lagoon to sea at, 262

Corals in lagoon of, 264

Coral shingle at, 268

Dam of huge blocks at, 264, 267

Echinoderms in lagoon of, 267
F^orest trees at, 260

Gap of south face of, 260

Islets in lagoon of, 264

Keuea village at, 266

Lagoon flat at, 270

Land rim of, 258

Laud rim on edge of pl.itform of, 259

Low outer beaches at, 260

Mangrove flat .it, 263

Millepore flat of, 264

Narrow reef flat of, 260

Northern face of, 259

Nullipiire boulders .at. 261

Passes connecting lagoon of, 266

Pavement of coral blocks, 265

Pl.atform lagoon at, 262

Porites flat of, 268

Secondary lagoon at, 261

Sho.als and patches in lagoon of, 269

Sink at. 262

Soundings in lagoon of, 264

Tridacnas at, 263

Vegetation of, 270

Western channel of, 269

Western spit of, 262

West face of, 263

Wide reef flats at, 261

408

INDEX.

Taritari — Cnnliniird

Wi.lth i>f cjist face of, 259
Tataa Point, 141
Tau, 189
Tauche, 342
Taulalia, 205
Taunoa, 143
Taunoa Pass, 152
Tautira Point, 149
Te Afualiku, 215
Te akau Tuluaga, 215
Te Avapiti Pass, 160
Tea Promontory, 156
Teava Moa, 158
Teava Moa Pass, 158
Teavarua Pass, 144, 159
Tebuka, 213
Tehiri Island, 154
Tekokota, 109

Depth of lagoon of, 109

Rookery at, 109
Teleki, 199
Telele, 212
Temae Lake, 157
Temanu, 163
Tengako, 213
Tengeli, 300

Teoneroa haaoa Bay, 159
Tepoto, 90
Terranova, 321

Lagoon lieach of, 323

Sea face of, 323
Tetaro Island, 160
Tetiaroa, 166

Disintegration and erosion at, 167

Formation of, 166

Negro-heads at, 166

Underlying stratum of, 166

Sand islets of, 1 66
Teveiroa Island, 162
Thithia, 207
Tihere Entrance, 71
Tikahau, 52

Entrance to, 52

Dimension of, 53

Dunes at, 53

Filling of lagoon of, 55

Land belt of, 53

Old ledge of, .53

Outline of, 53
Tikei, 71

Uridges over digitating channels at, 73

Central pool of, 73

Central sink of, 71, 72

Conglomerate beaches at, 72

Tikei — Continued

Depth of channels of reef platform at, 73

Digitate channels at, 73

High sea face beach at, 72

Old ledge outcrops at, 71

Potholes at, 73

Sinks covered by Algic at, 72

Wide reef fiat platform at, 72
Tiva Point, 158
Toahotu Island, 160
Toa Tea Reefs, 153
Tofanga, 197
Tofua, 178
Toharoa Pass, 145
Toku, 179
Tol, 357

Toloas, 354, 355, 356, 360
Tolomen Peak, 360
Tomotai Pass, 143
Tonga Archipelago, 175

Corals of, 177

Elevated plateau of, 179

Lister on, 177

Terraces of the, 180

Volcanic islands of, 177

Volcanic outbursts at, 1 79

Volcanic sand off, 180
Tongatabu, 188

Blow holes at, 190

Egeria Channel at, 191

Flats of, 1 88

Fossils at, 1 90

Lagoon, of, 188

Limestone outcrops at, 191

Native hut at, 191

■Nukualofa, 188, 190

Slope of, 190

Star-fishes of, 190
Tongatabu Plateau, 175

Trend of, 176
Tongua, 195, 197
Tonumeia, 176
Torea Point, 154
Torrutj Pass, 300
Trelease, Prof., 349

Bot.any of Caroline Island, 349
Tromelin Island, 341
Truk Archipelago, 330, 353

" Astrolabe and Zcle'e " at, 353

Coral boulders in, 361

Coralline Alga> in, 359

Corals on flats of, 360

Deep passages into, 353

Depth of lagoon of, 354

Eastern pass into, 360

INDEX.

409

Truk Archipelago — Conliimed

Elevatiou of, 359

Fringing reef lielts of, 358

Great encircling reef of, 353

Height of islands uf, 355

Islanils on outer margin of, 354

Largest Caroline atoll, 353

Mangroves in, 356

Mount Ton Azan at, 355

Muddy water in, 359

Native canoes of, 302

Northern jiass of, 360

Northwest face of, 360

Original land masses of, 358

Range of corals in. 359

Shoals and patches in lagoou of, 358

Submarine erosion of, 358

Summits of, 358

Vegetation of, 359,361 •

Volcanic islands .of, 354

Volcanic islets of, 356

Volcanic mud in, 356
Tsis Island, 353, 357
Tuanae Island, 165
Tuanake, 90
Tuaura Valley, 148
Tufaka, 188, 191
Tugulu Island, 341
Tulatik, 342
Tupua Island, 163
Tupua Iti, 163
Tutataroa Pass, 143
Tuvutha, 206
Two Groups, 111

Ua Huka, 3
Ua pu, 3

Udot, 353, 355, 357
Uiha, 197
Ujelang, 273
Ulalu, 355
Ulul Island, 364
Uluthi Islands, 331
Umol, 354, 356
Unalik Island, 364
Uneyeute, 364
Uola Island, 355

Beaches of, 355

Corals at, 355

Height of, 355
Uoleva, 196
Utiroa, 238
Utuofai Valley, 146

Vaeio Bay, 3

Vaionifa Pass, 146
Vaiorea Island, 158
Vaitia River, 145
Vaitoto River, 145
Vavau, 197

Canons at, 200

Capt. Field on, 200

Caves at, 200

Chart of, 200

Denudation of, 198, 200, 201

Deptli of bank of, 203

Fertile soil of, 201

Fossils at, 202

Height of, 201

High land of, 201

Slope of plateau of, 203

Terraces of, 198

Vegetation of, 201

Vertical cliffs of, 198
Vavau Plateau, 175

Denudation and erosion of, 177
Velitoa, 189
Venus, Point, 144, 146, 150, 153

Barrier reef at, 144

Leclerc and Benazc on, 154

Marks of Wilkes at, 154, 155

Volcanic sand beach at, 146

Walu Bay, 205
Wangava, 205, 206
West Ava iti, 142
West Faiu, 364
West Indian Group,

Absence of platforms in, 6
Wichman, A., 362

On geology of Pelew Islands, 362

On Pouapi basalt, 343
Wickham Reef, 195
Wilkes, Capt., 9

On coral reefs, 9

On elevated limestones, 10

On Kauehi, 74

On Makatea, 10

On method of surveying atolls, 10

On Paumiitus, 11

On sea wall of Rangiroa, 10

Sketch of Matabiva. 10, 55

Sketch of Hangirua. 13

Sketch of Tikabau. 13

Sounding in Raraka, 9

Soundings off Clermont-tonuerre, 9
Wolea Island, 332
Wotje, 315

Ciilor of water in, 315

Corals in lagoon of, 318

410

INDEX.

Wotje — Continued

Extension of wtst face of, 319
Increase in size of, 319
Islands of laud rim of, 319
Lagoon sand spits in, 316, 319
Lee face of, 316, 318
Lieut. Scliisclimarev on, 315
iMovement of sand at, 320
Kookery at, 316
Slioals in lagoon of, 320
Sinks of, 319

Wotje — Continued.
South face of, 317
Surface and deep hauls in, 320
Survey by Kotzebue, 315
Vegetation of, 318
Wooded island of, 316

Wotje Island, 317

Wotje Pass, 301

Yangasa Levu, 204
Yenas Island, 335

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