A R C H A E O L O G I C A L SITES AND OBSIDIAN DEPOSITS ON
T H E MOKOHINAU ISLANDS, HAURAKI G U L F
by P.R. Moore
217 Riverside Drive, Lower Hutt.
SUMMARY
Thirteen archaeological sites were recorded on the Mokohinau Islands
in addition to the nine previously reported by Spring-Rice (1980) on
Fanal Island. This includes at least one pa, terraces, midden, find spots,
as well as several areas of broken obsidian (flakes and pieces), shell, and
cooking stones related to mutton-birding activities. Parts of Burgess
Island and the Knights Group were probably cultivated.
Natural obsidian deposits on Fanal Island were exploited by muttonbirding parties, and also by the occupants of Burgess Island and the
Knights Group. The nature of the deposits, and physical characteristics
of the obsidian, are described.
Archaeological evidence suggests the Mokohinau Islands were probably occupied by a small permanent population for only a short period of
time, perhaps less than 100 years.
INTRODUCTION
The Mokohinau Islands are the most isolated of the island groups in
the Hauraki Gulf, lying 100 km N N E of Auckland and 25 km northwest
of Great Barrier Island (Fig.l). The group consists of two main islands —
Fanal (73 ha) and Burgess (52 ha) — as well as a cluster of smaller
islands and stacks adjacent to Burgess Island known as the Knights
Group. A general description of the Mokohinau islands is provided by
Wright (1980).
According to Sandager (1889, p.292) a hapu of Gt Barrier Maoris
"occupied at no very remote time the Mokohinou (sic) Islands permanently, many of them being buried in part of the boulder beach which
is still considered tapu". This obviously refers to Burgess Is (Pokohinu),
but since the erection of a lighthouse in 1883 the island has been
considerably modified and very little evidence of former Maori occupation remains.
In comparison, Fanal Island has remained largely unmodified in the
past 100 years. Nine archaeological sites were recorded by Spring-Rice
(1980), including terraces, a pit, and areas of broken obsidian (Fig. 2).
Natural obsidian deposits on the island (see Browne & Greig 1980)
provided visiting mutton-birding parties with a ready source of sharp
flakes for butchering of the juvenile grey-faced petrel, or "ooi" as they
T A N E 31, 1985-86
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Fig.l. Location map, and position of archaeological sites on Burgess Island and
the Knights Group.
were known (Sandager 1889) . Mutton-birders apparently continued to
exploit the seabird population on Fanal Is. on a regular basis up until
about 25 years ago (Wright 1980).
A n archaeological survey of the Mokohinau islands was undertaken
over a seven-day period in December 1983-January 1984 as part of a
scientific expedition organised by the Offshore Islands Research Group.
Most of the time was spent on Burgess Island and the Knights Group,
but a one-day visit was also made to Fanal.
1
A N N O T A T E D LIST OF SITES
Grid references refer to the metric (NZMS 260) sheet S07, and were
obtained from an unpublished 1:10 000 scale topoplot:
In December 1888, 3000 birds were taken off Fanal and Burgess
islands.
1
76
04
I
OSi
Fig. 2. Location of archaeological sites, mutton-birding areas and obsidian
deposits on Fanal Island. Sites recorded in May 1979 are described by Spring-Rice
(1980). Fanal Island lies 4 km SE of Burgess Island.
Site No.
1.
(0117 8592). Find spot. Two obsidian flakes (Z3735/l,2) at top of
cliff above wharf, Landing Bay, Burgess Island.
2.
(0068 8560). Midden/terraces. East side of Hokoromea, on small
point. Three obsidian flakes (Z3736), dark charcoal-rich soil,
associated with several natural terraces. Concentration of Nerita
shells c.40 m inland.
3.
(0067 8550). Find spot. Southeast end of Hokoromea, on small
island joined to main island at low tide. Single obsidian flake
(Z3737).
4.
(0050 8565). Pa. Headland forming north end of Hokoromea. Series
of terraces on higher slopes; ditch at narrowest point c. 2 m wide x 6
m long.
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5.
(9995 8550). Pa? Northwest end of Trig Island (Atihau). No
terracing or midden seen, but appears to be ditch c. 10 m long x 1.5
m wide cutting off headland.
6.
(0006 8524). M i d d e n . Near middle of Trig Island (Atihau). Minor
shell, 3 tiny obsidian flakes, rounded pebbles. One obsidian flake
collected about 40 m to the south.
7.
(0492 8194) M u t t o n - b i r d i n g area? East end of Fanal Island, at top
of cliff. Scatter of obsidian.
8.
(0480 8195) Occupation/working area. East end of Fanal Island;
large flat area on high point. High concentration of obsidian, minor
shell, on SE side of flat area, covering minimum 20 m x 10 m.
Well-rounded cobbles, minor obsidian on flat area.
9.
(0447 8213). M u t t o n - b i r d i n g area. ('Pahuhunui'). Middle of Fanal
Island, on gentle SW-slope, north side of "Eastern Valley". Scatter
of obsidian, charcoal, shell over area of at least 50 m x 20 m.
10.
(0438 8234). M u t t o n - b i r d i n g area? ('Haukawakawa'). Northern
part of Fanal Island, on ridge crest near high point (127 m). Few
shell fragments, single obsidian core.
11.
(0435 8250).Mutton-birding area ('Harakekeroa'). Northern Fanal island, on ridge crest near head of "Northern Valley". Scattered
obsidian.
12.
(0410 8234). M i d d e n . Northern Fanal Island, on ridge crest
between "Northern" and "Central" valleys. Obsidian boulders, pipi
shell, charcoal, fish bone.
13.
(0398 8234). Midden/terrace? Northern Fanal Island; prominent
flat area on spur west of site 12. Abundant obsidian, charcoal, two
Mytilus shells.
DESCRIPTION OF SITE T Y P E S
Pa
Headlands at the northern end of Hokoromea and Atihau would have
been considered favourable locations for the siting of a pa. Each is
surrounded by near-vertical, 30-40 m high, cliffs on three sides, and
connected by a narrow neck of land to the remainder of the island.
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The pa on Hokoromea (site 4) was defended by a ditch constructed
across the narrowest point, which has a steep, natural scarp on its
northern side. A series of terraces on higher slopes of the headland were
undoubtedly man-made, and although no shell midden or artefacts were
found, the pa may have been occupied for at least a short period of time.
Evidence for a pa at the northern end of Atihau is less certain. There
appears to be a shallow ditch on the south side, but no terracing or
midden was seen on the headland itself. However, much of the area is
presently covered in low scrub, and such features could have been
obscured.
The main hill on Burgess Island does not seem to have been a pa,
although the upper slopes were substantially modified during construction of the lighthouse and associated facilities, and any prehistoric
earthworks could have been destroyed. No pa site was identified on
Fanal Island.
Midden
Very little shell midden was found on the islands (none was seen on
Burgess), and much of it may have been eliminated through the acid
action of leaf litter, fires, and natural erosion. Burgess Island is known to
have been fired at frequent intervals from the early 1920's, and
vegetation on the Knights Group was probably also burnt off at various
times (Wright 1980). The presence of goats, sheep, and cattle almost
certainly resulted in the destruction of some sites on Burgess Island.
The relatively common midden on Fanal Island is probably a reflection
of minimal European interference with the environment in historic
times, and frequent visits by mutton-birding parties. Shellfish species
recorded include Cookia sulcata, Nerita melanotragus, Haliotis iris
(paua), Thais orbita, Haustrum haustorium, Lunella smaragda, Perna
canaliculus (mussel), and Paphies australe (pipi); Spring-Rice (1980) also
noted the presence of Cellana sp. Fish bone was found at several sites.
With the exception of pipi, and possibly Perna, all of these species could
have been obtained on the island itself.
Well-rounded cobbles (up to 30 cm diameter) associated with shell
midden at various sites on Fanal Island, and also on the Knights Group,
are inferred to be hangi stones. Of two cobbles collected on Fanal, one is
probably an andesite and the other appears to be a rhyolite or dacite.
Andesite does not occur naturally on the island (Browne & Greig 1980),
and the hangi stones were most likely obtained from Burgess Island or
the Knights Group.
Mutton-birding areas
Spring-Rice (1980) showed the location of six ancient mutton-birding
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areas on her map of Fanal Island, and in January 1984 obsidian flakes
and pieces, as well as minor shell midden, were found at or in close
proximity to three of these (Pahuhunui, Haukawakawa, and
Harakekeroa). No terracing was seen at these sites, but Spring-Rice
recorded a series of five terraces near Arawii, at the eastern end of the
island (Fig. 2). Other sites on the island with scattered obsidian and shell
midden, particularly those lacking associated terraces (e.g. site 12),
could also represent former birding areas. The abundance of obsidian
flakes and pieces and well- rounded cobbles (hangi stones?) at site 8
suggests this may have been an important area for the preparation and
cooking of mutton birds.
No mutton-birding areas have been identified on other islands in the
Mokohinau group, although obsidian flakes (and shell midden) found at
site 6 on Atihau, and two sites (2, 3) on Hokoromea could be related to
birding activities.
Agricultural areas
Judging from the presence of rounded pebbles in dark top soil covering
the topographically-subdued southwestern part of Burgess Island, much
of this area was probably cultivated in prehistoric times (Fig. 1). Water
would have been available year-round from a natural spring on the
western slopes of Lighthouse Hill.
The central part of Hokoromea may also have been cultivated,
considering the large number of well-rounded pebbles found there. It is
possible that much of the relatively flat, central part of Atihau was
cultivated too. However, the lack of water would have virtually
restricted the growing of crops to winter months. No evidence of
cultivation has been found on Fanal Island, although Spring-Rice (1980)
recorded a single raised-rim pit which could have been used for storing
kumara, and it is possible that a large (100 x 30 m) terrace situated
nearby was cultivated.
OBSIDIAN
Nature of deposits
The existence of obsidian on Fanal Island was first reported by
Fleming (1950), and Browne & Greig (1980) described an agglomerate
composed of obsidian blocks up to 40 cm diameter forming a "discontinuous carapace over much of the island". A type section for their
Agglomerate Member (of Fanal Formation) was designated at a bluff on
the south side of the highest point (Mataa, SO7/0435 8265) (Fig 3.)
Re-examination of the type locality revealed a minimum of 8-10 m of
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Fig.3. Bluff on south side of Mataa, Fanal Island, type locality of Browne & Greig's
(1980) Agglomerate Member. Weathered rhyolite in the upper part of bluff
contains large obsidian "blocks".
highly weathered, crudely flow-banded rhyolite with numerous blocks of
obsidian conformably overlying flow-banded rhyolite (Fig. 4). Flowbanding in the upper unit dips about 70° north. The underlying rhyolite
is flow-folded, but layering locally also dips 70°N. The obsidian blocks are
up to 50 cm diameter (but mostly 10-20 cm), and flow-banding in the
obsidian is sub-parallel to that of the enclosing rhyolite (see also Browne
& Greig, fig. 2). Hence the "agglomerate" does not represent an air-fall
deposit, but probably a partially autobrecciated glassy rhyolite flow. The
presence of abundant obsidian blocks up to 80 cm diameter around the
northern side of Mataa indicates that the obsidian unit dips slightly
northward overall, and is about 20 m thick.
Large obsidian boulders up to 50 cm diameter are also found at various
other places (Fig. 2), which suggests that the obsidian unit was formerly
distributed over much of Fanal Island. Although it is remotely possible
that some large blocks were carried from the north end of the island to be
worked elsewhere, the abundance and large size of boulders at several
localities suggests this is unlikely. Only a few of the many large boulders
on the slopes above the eastern landing show any sign of being worked.
Boulders near site 10, and most of those at site 12, also show little or no
sign of having been worked. A l l of these occurrences, therefore, are
regarded as natural deposits.
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Fig.4. Closer view of bluff showing irregular obsidian "blocks" (dark patches) in
weathered, flow-banded rhyolite. Flow-banding in the obsidian is sub-parallel to
that of the surrounding rhyolite.
No natural obsidian deposits were found on the other islands,
although some perlite and glassy rhyolite outcrops along the southeastern cliffs of Burgess.
Physical characteristics
Fleming (1950, p. 267) described the Fanal Island obsidian as
"greenish black, slightly amygdaloidal, more opaque and less
homogeneous than Mayor Island obsidian, lacking perfect conchoidal
fracture". A l l of the obsidian seen by the writer is black, although on
surfaces parallel to the flow-banding it may appear medium to dark grey
in colour (Rock-colour chart). The obsidian is grey in transmitted light.
Most of the obsidian is weakly to strongly flow-banded, and material
from Mataa may be more strongly flow-banded than that from other
localities. The obsidian contains abundant, small (0.5-2 mm) crystal
inclusions composed of quartz and/or feldspar, but no spherulites.
Although the Fanal Island obsidian is dense and glassy it has an
imperfect conchoidal fracture, and produces few well-formed flakes.
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Nevertheless, many flakes and pieces have sufficiently sharp edges for
cutting and scraping purposes, as attested by the high percentage of
used flakes at site 8.
Obsidian artefacts
A l l except one of the obsidian flakes and pieces found on Burgess
Island and the Knights Group were clearly derived from the deposits on
Fanal Island. One flake (Z3735/1) from site 1 on Burgess Island
evidently had a different source. It is semi-translucent (smoky grey in
transmitted light), very vitreous, has a perfect conchoidal fracture, and
lacks crystal inclusions. A remnant of pitted cortex on one side indicates
that it was struck off a pebble from a colluvial, rather than an alluvial or
beach deposit. Overall, the obsidian is similar to that described by Atwell
(1973) from Whangaparapara, on Gt Barrier Island, and probably came
from a Gt Barrier source.
A l l of the flakes collected from the Knights Group and Burgess Island,
with the exception of Z3737 show some sign of edge-wear, which
suggests they were probably used for cutting and/or scraping purposes.
The one "foreign" flake (Z3735/1) also shows considerable evidence of
use. Of the 8 flakes collected from site 8 on Fanal Island 5 showed
definite edge wear. Used flakes were also reported by Spring-Rice (1980)
from Arawii.
Obsidian cores were found at sites 9 and 10 on Fanal Island.
DISCUSSION
Exactly when, and for how long, the Mokohinau Islands (at least
Burgess Island) were occupied by Great Barrier Maoris is unknown, but
the archaeological evidence suggests the islands were home to a
relatively small group (<100?) for only a short period of time, perhaps
50-100 years. The lack of terracing, storage pits, and midden on Burgess
Island is particularly notable, although it is possible some features
(especially midden) were destroyed during European occupation (18831980). The pa on Hokoromea is the only obviously fortified site, and may
have been occupied for a short time. A token effort was apparently also
made to strengthen the natural defences of the northern headland of
Atihau, but there is no evidence it was ever used as a pa. In view of the
limited fortifications there was either a small population living on
Burgess Island and the Knights Group, or no significant threat to the
local inhabitants.
Archaeological sites on Fanal Island seem to be almost exclusively
related to mutton-birding activities, including the manufacture of
obsidian flakes for butchering purposes. It is unlikely there was any
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permanent occupation because of the very limited water supply
particularly during summer months (Wright 1980). Although some
kumara may have been grown and stored for use by parties stranded
during stormy weather, visiting groups (presumably from Great Barrier
brought a small supply of food (pipi, mussel?) with them to supplement
whatever was available locally. The presence of terraces on various parts
of the island suggests that temporary shelters were built to accommodate those involved in mutton-birding, and possibly also for storage.
Fanal Island was undoubtedly also visited by the Maoris living on
Burgess Island and the Knights Group, both for mutton birds and to
obtain obsidian. Andesite hangi stones found on Fanal must have been
transported from Burgess during such visits. These people could also
have made occasional voyages to Great Barrier to obtain various items
not available on the Mokohinaus.
ACKNOWLEDGEMENTS
I thank Roger Grace for assistance in the field, and Nigel Prickett for reviewing the
paper. Typed by Pearl Matthews.
REFERENCES
Atwell, E.G. 1973: Archaeological sites, Great Barrier Island. Tane 19: 157-165.
Browne, G . H . & Greig, D.A. 1980: Geology of Fanal Island (Motukino), outer Hauraki
Gulf, North Auckland. Tane 26: 7-19.
Fleming, C.A. 1950: The geology of the Mokohinau Islands, North Auckland. Part 1 —
general geology. Transactions of the Royal Society of New Zealand 78 (2-3): 255-268.
Sandager, F. 1889: Observations on the Mokohinau Islands and the birds which visit them.
Transactions of the New Zealand Institute 22: 286-294.
Spring-Rice, W. 1980: Fanal Island (Motukino) archaeological survey and historical
account. Tane 26: 99-105.
Wright, A . E . 1980: Auckland University Field Club scientific trip to the Mokohinau
Islands, May 1979. Introduction and Acknowledgements. Tane 26: 1-6.
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