Journal
of the

Royal Society of Western Australia
Vol. 42 Part 3

Rottnest Island: The Rottnest Biological Station and Recent Scientific Research

Edited by E. P. Hodgkin and K. Sheard

Foreword

The Rottnest Biological Station is an institu-
tion of which the State of Western Australia
should be truly proud. To Professor H. Waring
and Dr. E. P. Hodgkin of the Department of
Zoology. University of Western Australia, and
Dr. K. Sheard of the Division of Fisheries and
Oceanography, C.S.I.R.O., belong the credit for
bringing it into being. They deserve the thanks,
not only of scientific workers but also of the
people of the State as a whole, for their timely
recognition of the need and for the enthusiasm
and vigour which they brought to bear in its
fulfilment.

The station was established primarily to en-
able research to be carried out on the marine
and terrestrial fauna and flora of Rottnest
Island, and for the training of undergraduate
and post graduate students in essential field
disciplines.

Until now all research has been directed by
University personnel, with the exception of cer-
tain quokka population studies undertaken by

the Wildlife Survey Section of C.S.I.R.O. It is
our desire, however, that as trained personnel
become available, some part of the research
programme of the Fisheries Department will be
undertaken there.

I am particularly happy that as chairman
of the controlling committee I am able to keep
my Department in such close touch with the
work as well as the progress and development
of the station. In a State the size of Western
Australia, with myriad scientific problems but
only a small population and somewhat slender
financial resources, it is of paramount import-
ance that the most economical use be made of
all available personnel and finance. The only
real way of doing this is by the closest co-
operation between all agencies engaged in simi-
lar kinds of research. I believe that in the
Rottnest venture this desideratum is being
achieved.

A. J. FRASER,

Director of Fisheries , W.A.

9. — Introduction

Broadly speaking, biological advance comes
from either development of new techniques
with which to attack classical problems or the
exploitation of a previously inaccessible fauna
using classical and other techniques. In the
latter case the developments usually proceed
on a well-defined pattern. The forerunners
are the collectors and taxonomists who move
in to catalogue and list the animals in the
hitherto unknown field ; this is a continuing-
process which broadens into ecological studies of
various kinds. It is a phase of describing what
there is and what occurs. Sooner or later
people want to know “why?” and “how?" Then
the physiologists and biochemists of various
sorts take up the story.

The potential attraction of academic biologi-
cal work in Australia is its rich, little explored
fauna. This potential has never been fully
realised, chiefly because the distances to be
travelled from central laboratories to field areas
are prohibitive, particularly to University staffs
tied to teaching and administrative routines.
The existence of a local site such as that on
Rottnest Island with its attractive fauna, free
from predators and protected by statute from
man’s destructiveness, offers a way out from this
frustration if living quarters and simple labora-
tory facilities are available.

The various interim reports in this series show
how such a station has been established and
indicate the number and kind of programmes
that have been set in motion on ecological and
physiological themes. These reports not only
concern the work that has been attempted
< chiefly on the marsupial, Setonix brachyurus .
the quokka) but outline also a number of fields
where detailed work is worth while. The marine
problems are little touched at present, a limita-
tion in this regard being the absence of sea-
water aquaria for fish and crayfish work; so
far these have been beyond our financial re-
sources.

The choice of the quokka as a subject for
intensive multipurpose research was a logical
one. I had come to Australia with the express
purpose of working on marsupials, but quickly
realised the rarity within easy reach of the
metropolitan area of the numbers of individual
animals necessary for modern biological work.
In this context Rottnest Island as a research
area was a gift from heaven. As can be seen
from these reports, its large population of
quokkas provided not only a simple opportunity
for introducing techniques of modern biology to
students, but some very worthwhile problems in
vertebrate biology. The opportunities presented
by the Island for work in many other biological

65

fields are also evident, so that the Department
of Zoology is in the happy position on the one
hand of being able to cater for a wide range of
specialist activities, and on the other of main-
taining varied and worthwhile field courses for
its students.

Students and staff have reacted to these
opportunities with enthusiasm. At this point it
is important to emphasize that the station and
its facilities were not taken over ready-made
for research workers to walk into and use as a
base. Credit is given elsewhere to those who
translated an idea into a site and buildings.
There were many others whose enthusiasm and
labour made the building usable in the early
stages of the Rottnest studies. The present
day student and research worker likewise helps
where he can, but he should be aware that
there were others before him. A list of workers
contributing to Station activities 'research and
otherwise) is given at the end of these reports.
Of these the following tin alphabetical order)
were forerunners who should be doubly men-
tioned: J. Barker <nee J. Buttle), S. Barker,
George, Hodgkin. Lee, Littlejohn, Main, Mal-
colm (and Mrs. Malcolm), Milward, Rudeforth,
Sharman, Shield, and P. Woolley.

The form of these reports has been dictatec
by the necessity of fitting a large amount of
different- kinds of information into the one smal.
Journal part. Accordingly all references con-
cerning Rottnest Island have been collected ir
a separate Bibliography and only those outsido
this scope, but necessary to a particular report
have been included with that report. Also,
information with regard to individuals named ir
these reports has been given separately. There 1
has been some duplication but only where this
is necessary for clarity. Perhaps some helpeic
may have been overlooked in the rush of pre-
paration. If so I tender my apologies ir
advance.

In conclusion I would like to offer my per-
sonal thanks to all who have co-operated ir
this most rewarding venture. Elsewhere tho
financial contributions of the University, State*
Fisheries, and Australian Academy of Science*
are acknowledged. It is pleasing to me person-
ally to here acknowledge the moral support ano
generous financial backing of the C.SXR.Ot
Executive in the carrying out of our marsupiaj
research programme.

H. WARING,

Professor of Zoology.

10. — Rottnest Island as a Location for Biological Studies

The choice of Rottnest Island as a research
centre arises from certain obvious advantages,
e.g., the ease of access and the abundance of
the quokka, the marsupial around which so
much of the research has centred. The titles of
the accompanying papers could suggest that
there is nothing further to be said on the
problems inherent in an insular situation. This
may be so. yet. as will be mentioned below, the
solutions of problems attacked on Rottnest have
a potential application to continental situations
which would not usually be considered as hav-
ing anything in common with an island fauna.
It thus seems desirable to give the general back-
ground and aspirations of the research a little
more discursive treatment than will be given in
other papers of this series in order that the
full implications of the work can be appreciated.

Even a superficial acquaintance with the
terrestrial fauna of the western portion of Aus-
tralia poses a number of problems all of which
centre around the distribution of animal species
at the present, during the historical, the pre-
historical and geological past. Many of the
extant terrestrial animals especially the mam-
mals have disjunct or restricted distributions
which give every impression of being relicts of
wider ranges. Perusal of the records of occur-
rence in the historical past confirm their relict
nature for one soon discovers not only the wide
extent of the former range but also the number
of species which have become entirely extinct.
Commonly such range restriction and extinction
are ascribed to habitat destruction following the
advent of European-type culture in Australia as
well as the impact of introduced predators such
as foxes or herbivores such as rabbits. How-
ever, this cannot be the whole story for some

species of mammals apparently became extinc
before settlement was extensive and certain!?;
before foxes and rabbits were present. The
suspicion that European man with his associ
ates was not the sole agent of extinction i:
strengthened when one studies the cave deposit:
along the Western Australian littoral. Here, in
extensive deposits (mostly originating from ow
pellets though there are many remains of large:
animals), are an immense number of specimen:
of species which are either no longer found in
the vicinity or are entirely extinct.

Glauert was (1910, 1912, 1914. 1948) the firs
to work these deposits and more recently
Lundelius has surveyed caves over a much wide:
geographical area and, although this latte:
worker has as yet published no C14 dates, then
is every indication that faunal changes have
proceeded throughout the deposits to the super-
ficial zone and these must be considered
within historical times. Many of the bone. 0
collected by Glauert and Lundelius '1957) art*
con-specific with species now restricted to the
wetter south-east of Australia. The pre-historio
and geological evidence thus suggests that envir-
onmental factors, as opposed to man-made
habitat changes, have perhaps played an im-
portant part in the range reductions and
extinctions witnessed in the past 100 years or
so.

Students of climatic change have proposed this
mechanism repeatedly to account for disjuncl
or relict distributions in the Australian fauna
Some workers suggest a great aridity at about
5,000 years ago while others disagree and Tin-
dale points out that because of the uniqueness
and sensitivity of some relict populations the
climate could not have been much more arid

66

in the recent past than it is at present. The
apparent continuity of the process of species
extinction from Pleistocene time to the historic
past might be taken as supporting Tindale
U955). The question is open. However it is
quite clear that we will gain no real understand-
ing of the faunal depauperisation until some-
thing is known of the way species react to
deteriorating environmental conditions. As the
accompanying papers show, it is as a deterior-
ating environment that Rottnest oilers such a
valuable experimental “laboratory/’

But Rottnest is not the only such “laboratory”;
there are a number of other islands along the
W.A. coast extending from the vicinity of
Shark Bay to south of Esperance. These con-
tain relicts of Pleistocene faunal assemblages
which were cut off from the mainland with the
eustatic rise of the seas at the close of the
Pleistocene. Some of these islands, e.g., the
Abrolhos, contain fauna which is unknown on
the adjacent mainland but is found several
hundred miles to the south. Others, e.g., Rott-
nest, contain a fauna which is represented on
the immediately adjacent mainland. It is the
presence of a similar fauna on the adjacent
mainland that affords one of the great research
assets of Rottnest and this, plus the fact that
the Island is large enough for local island
populations to be developed, has meant that,
potentially, both intra-island populations as
well as island versus mainland populations could
be compared.

Clearly if Rottnest has been isolated since
the close of Pleistocene we might expect to find
some changes in the fauna. The headings under
which changes might be expected can be listed
as follows: —

<a> Those related to survival in a deterior-
ating environment.

i. No change but wide individual
tolerance which has not yet been
exceeded by island environment,

i.e., Rottnest animals similar to
mainland.

ii. A significantly different range of
tolerance in the island animals;
this presumably produced by
natural selection.

iii. A significantly different set of
ranges of tolerance within the
island population; this again pre-
sumably produced by selection.

(b) Those related to evolutionary differ-
entiation in geographical isolation.

i. Morphological differentiation.

ii. Genetic isolation, e.g., sterility in
island x mainland matings.

iii. Behavioural differences, e.g., male
call differences in frogs,

For a profitable analysis in terms of the fore-
going we need rather idealised animals which
are amenable to morphological, physiological
and experimental analysis. Fortunately, Rott-
nest contains four vertebrate species which, in
varying degrees, fulfil the ideal, these are: —

The quokka f Setcnix brachyurust and the
frogs Heleioporus eyrei, Hyla raniformis and
Crinia insignifera. The last mentioned species
affords a good illustration of the kind of popu-
lation changes which are possible. This species
is polymorphic with a phenotypic frequency of

the morphs on the mainland of: Striped, 0.37;
lyrate, 0.37: and patternless. 0.26. On Rottnest
patternless animals are not found and the re-
maining two morphs are equally frequent. In
this case, if we assume that individual morphs
and morph frequencies in the population have
an adaptive significance then we have a meas-
ure of the magnitude of the changes which may
be expected in other non-polymorphic popula-
tions. Nevertheless the principal research tar-
get has been the quokka which offers an oppor-
tunity for investigating the possible causes of
marsupial extinction which had been so wide-
spread during Quaternary time. There is no
doubt that the study has lived up to expecta-
tions and it is now possible to use the data in
hand as a basis for analogous reasoning when
studying other macropod marsupials.

So much for theorising and speculation. The
results, though not yet applicable directly to
studies of faunal extinction generally have
application to other fields, viz.: <i) Conserva-
tion and (ii) Pest Control.

(i) Conservation. — Many fauna reserves are
of necessity “islands” in the sense that they are
areas of country usually unwanted for either
agricultural or pastoral pursuits. Because of
their size and insular nature most will deterior-
ate as areas containing representative natural
habitats. To these situations the information
that is coming from the Rottnest studies, espe-
cially as that relates to marsupials, has an
application far wider than might be expected
when it is viewed simply as a study of an island
population (Main, 1956).

(ii) Pest, Control. — From the inception of
European settlement various marsupial species
have been regarded as pests. Usually this has
meant an active policy of extermination which
in most cases has been successful from the
settlers* point of view, with the result that the
offending species has become totally or locally
extinct. However, there are a few exceptions
to this state of affairs, especially under pastoral
conditions, where pest species have prospered
even under widespread hunting and poisoning
as well as in the presence of environmental
changes caused by gross pastoral over-grazing.
These successful species are the other side of
the problem of extinction and require as much
study as the threatened species. As a result
of the Rottnest work on a small amenable
species it is now possible to proceed in these
studies on the less amenable species knowing
that there are sufficient data from which general
research programmes can be formulated. Such
work has begun on the mainland.

A. R. MAIN.

References

Glaueri. L. (1910). — The Mammoth Cave. Rec. W. Aust.
Mus. 1: 11-36.

(1912). — The Mammoth Cave (contj. Rec.

W. Aust. Mus. 1: 39-46.

(1914). — The Mammoth Cave (cont.). Rec.

W. Aust. Mus. 1: 244-248,

(1948). — Cave fossils of the south-west. W.

Aust. Field Nat , 1: 100-104.

Lundelius, E. (1957). — Additions to knowledge of the
range of Western Australian mammals. W.
Aust. Field Nat. 5: 173-182.

Tindale, N. N. (1955). — Revision of the Ghost Moths
(Hepialidae), Part IV. Rec. S. Aust. Mus.
11: 307-344.

67

11. — History of the Kottnest Biological Station

The Rottnest Biological Station had its origin
in a visit that Professor Waring and I paid to
the Island in May, 1948, shortly after he arrived
in W.A. on first appointment. He at once
recognised the potentialities of the Island for
biological studies and especially the research
asset represented by the large quokka popula-
tion. We talked then about the possibility of
establishing a field station. The Island had been
the scene of active biological study before, as
evidenced by the Bibliography, and there had
been student camps under Professor G. E.
Nicholls. The last of these, in November, 1945.
was my first introduction to Rottnest. On that
occasion we used two bungalows in the settle-
ment, both as living accommodation and as
laboratories. 1 vividly remember the untidy
array of microscopes and other apparatus that
cluttered the kitchen table, the smelly collections
of marine animals we examined, and the happy
friendly relations between students and staff.

Physiological research on the quokka started
almost immediately in the Zoology Department
and another student camp was held in 1951.
However no further action was taken to estab-
lish a field station until 1953. In this year
Dr. K, Sheard undertook successful personal
negotiations with the Naval Officer-in-Charge,
W.A. for the lease of the naval barracks and
signal station near the central lighthouse. In
September the Navy agreed to lease the build-
ings to the State Department of Fisheries at
a nominal rental. This was finalised by the
Department of the Interior and a ten year lease
commenced on 21st December at an annual
rental of £1,

A committee of management, the Rottnest
Biological Station Committee, was set up under
the Chairmanship of Mr. A. J. Fraser, Super-
intendent of Fisheries for Western Australia.
This held its first meeting on 11th January,
1954. The other members at that time were
the Hon. Mr. L. F. Kelly. M.L.A., Minister for
Fisheries and Chairman of the Rottnest Island
Board with Dr. K. Sheard of the C.S.I.R.O.
Division of Fisheries, Professor H. Waring
representing the University, and Mr. B. K.
Bowen of the Fisheries Department as Secretary.
Subsequently Dr. J. M. Dunnet. of C.S.I.R.O.
Wildlife Survey Section, joined the Committee
(October, 1955 to July, 1956), Mr. T. Sten re-
placed Mr. Kelly as a representative of the
Rottnest Board, I took Professor Waring ’s
place, and in September, 1958, Mr. R. W. George
was appointed to represent the W.A. Museum.
The Committee meets auarterly. One meeting
a year is held at the Station.

When they were first leased the buildings
were little more than shells and. although in
fair condition, had had no maintenance since
they were vacated after World War II. Even
before the lease had been formally signed parties
of volunteers had started to put the building
in order, to paint, them outside and to install
essential furnishings and fittings. Since then
a great deal has been dene to maintain and
improve the buildings, much of it by the volun-
tary labour of those using the Station, their

friends and relatives, those attending annual 1
student camps, and by some of the technical
staff of the University who have spent part
of their holidays at the Station. Officers of the
State Department of Fisheries have assisted also.

Rottnest Island is a Reserve for recreation,
and is under the control of the Rottnest Island
Board. It is primarily a holiday resort and
each summer large numbers of visitors occupy
the bungalows of the settlement on Thompsons
Bay. There is nc private ownership of land
and no private transport is allowed. Lack of
transport would have severely handicapped work
at the Station and permission of the Board was
sought to use a vehicle. A second-hand Land
Rover was purchased and transported to the
Island in April, 1954, by the Army. It has
recently been replaced with a new vehicle.
Throughout the development of the Station we
have had the friendly co-operation of the Board
members, of its employees, and especially of
its Secretary, Mr. Jim Stark. Good relations
were cemented recently (February, 1959) when
Board members and Island residents were enter-
tained at the Station and told about research
conducted on the Island by the Zoology Depart-
ment. At the outset the Lighthouse Department
helped with transport; throughout we have
drawn on their supply of bore water, and suc-
cessive Light Keepers have acted as caretakers
to the Station.

All research projects are separately financed
(through University Research Grants, C.S.I.R.O.
Scholarships. Nuffield and Rockefeller Grants),
and hence this is not a worry to the Committee,
which has no funds directly at its disposal.

Development and maintenance have been fin-
anced by the participating organisations. On
the recommendation of Mr, E. M. Barker, at
that time Chairman of the Senate Finance Com-
mittee, the University made an initial grant for
the purchase of the Land Rover, a small lighting
plant and essential furnishing and now makes
an annual maintenance grant. Annual grants
from the State Fisheries Department have been
used to provide floor coverings, for the re-
current expenditure on painting and for other
outside facilities. C.S.I.R.O. has made available
a 32/250 volt lighting plant and for two years
supplied petrel to the Station. Mileage is
charged for the use of the vehicle but at present
no other Station charge is made.

From its inception the Station has been in
frequent use. During 1954 the principal users
were Sharman and Barker in their pioneer work
on quokka biology. In 1955 and early 1956,
Dunnet and his assistants spent much time
there making population studies of the quokka.
In 1957 and 1958, Shield and his team made
repeated visits to conduct their studies of quokka
nutrition. While these have been the regular
users of the Station many others have made
constant use of it for their investigations, as
will be evident from succeeding articles. The
first student camp was held in November, 1954,
and since then undergraduate training has been
a regular feature of the Station.

68

The Station has no resident staff: permanent
facilities are at present limited to ordinary
domestic requirements and a laboratory fitted
with light, power and water, but to which equip-
ment is brought from the mainland according
to the needs of particular work. The proximity
cf the Station to Perth and the University and
the accessibility of Rottnest by boat and aero-
plane, has thus made it possible to conduct much
valuable research at a relatively insignificant
cost. The policy of the management committee
is to facilitate in every way the academic study
of fauna and flora and the study of economically

12. — Geology of

Introduction

Rottnest Island lies on the continental shelf
along the western flank cf the Perth Basin. It
forms the northern termination of two parallel
chains of low islands and shallow reefs that
strike in a north-north-westerly direction from
the vicinity of the mainland south of Perth.
Both chains are composed mainly of Quaternary
aeolianite and represent major series of cal-
careous sand dunes which formed close to the
shore line when the sea-level was considerably
lower than at present. The eastern chain con-
sists of the Murray Reefs, Seal Island, Bird
Island, Point Peron, Garden Island, Carnac
Island and the Stragglers Reefs; the second
chain lies approximately two miles to the west
of the first and includes Coventry Reef. Hawley
Shoal and Casuarina Shoal. Gravity surveys
evening Meinesz 1948: Thyer and Everingham
1956) show Bouguer Anomalies cf between -65
and -70 milligals in the vicinity of Rottnest
Island and suggest that a thickness of about
20,000 feet of sedimentary rocks separates the
surface exposures from the underlying crystal-
line basement complex.

Recent contributions to our knowledge of the
geology of Rottnest Island have been made by
Teichert (1950) and Fairbridge (1954). The
present authors wish to acknowledge the valu-
able assistance of Mr. B. E. Balme, Dr. E. P.
Hodgkin. Mr. P. E. Play ford and Miss M. E.
Redman in the compilation of this review. Two
of us (C.W.H., E.W.S.K.) are currently engaged
in a study of the geology cf Rottnest Island.

Succession

All rock exposures on Rottnest Island are
thought to be of Quaternary age, but Tertiary
and Cretaceous strata were penetrated in the
Rottnest Island Bore. This bore was drilled near
the Rottnest Cemetery at a surface elevation of
approximately 10 feet above mean-sea-level. It
reached a total depth of 2,582 feet. A Lower
Cretaceous sequence of dark grey, sandy, glau-
conitic claystone and shale and dense sandstone
was penetrated between 2,185 feet and 2,582 feet:
this interval is correlated with the South Perth
Formation, known from bores in the Perth
Metropolitan Area. The overlying Kings Park

valuable organisms within the purview of State
Fisheries and C.SJ.R.O. The concern of the
Committee for the preservation of this unique
habitat led to an approach to the Australian
Academy of Science for funds to extend the
fenced enclosures. A grant was made and two
fences have been erected. In addition to work-
ers from the sponsoring bodies, a number of
visiting biologists have used the Station for
short periods and it is hoped that more may be
welcomed in the future.

E. P. HODGKIN.

Rottnest Island

Shale is a marine formation which extends from
933 feet to 2,185 feet. It consists of impure
sandstone, grey sandy shale, and thin beds of
impure limestone. Numerous fragmentary in-
vertebrates were recovered from the available
cores. Spore and pollen studies confirm the
correlation with the Middle to Upper Eocene
Kings Park Shale cf the Perth bores. Coarse-
grained, red, brown and yellow sandstone
occupies the interval between the base of the
“Coastal Limestone. ” at 233 feet, and the top
of the Kings Park Shale, at 933 feet. Samples
of this part of the section are not available for
study, but the unit may represent part of an
ancient delta of the Swan River. A thin un-
named formation cf late Tertiary or Pleistocene
age occurs below the “Coastal Limestone” in the
Public Works Department Swan River bores
directly to the west of the Fremantle Traffic
Bridge. It is perhaps of similar age and origin
to the sandstone beneath the “Coastal Lime-
stone” in the Rottnest Island Bore. Sandy
limestone extends from the top of the unnamed
sandstone formation, at 233 feet, to the surface
of the bore.

The Rottnest Island Bore, which is the second
deepest hole drilled in the Perth Basin, pene-
trated the thickest known section of the Kings
Park Shale. Comparison of the depths of
formations in the bores of the Perth area sug-
gests that the Mesozoic and Tertiary sections
in this area are faulted.

Exposures

All lithified strata exposed on Rottnest Island
are referred to the “Coastal Limestone.” They
consist predominantly of coarse-grained, cross-
bedded aeolianite and include minor develop-
ments of marine limestone. Fossil soils of
limited areal extent are fairly common in the
cliff sections west of Narrow Neck.

The aeolianite of the “Coastal Limestone” is
similar in composition to the sands on the pre-
sent day beaches of the island. It is composed
mainly of comminuted shells, calcareous algae,
Fcraminifera and other calcareous microfossils,
but includes rounded quartz grains and minor
amounts of heavy minerals. Quartz grains are

69

usually only minor constituents of the aeolianite,
but in some bands within the fossil dunes they
reach a high concentration.

An emerged coral reef in Salmon Bay, lithified
shell deposits at Geordie Bay, and the shell beds
around the margins of the salt lakes represent
marine incursions into the “Coastal Limestone”
during periods of higher sea -level. The fossil
soils are characterised by their massive structure
and the presence of the terrestrial gastropod
Bothriembryon. They formed fairly rapidly in
flat interdunal areas and do not exhibit signs
of soil maturity.

Soils forming at the present time are shallow
and immature. They show the initial stage in
soil formation, namely the accumulation of
organic matter near the surface.

Physiography

Rottnest Island is characterized by rolling
sand dune topography, and reaches a maximum
elevation of only 154 feet. Permanent drainage
channels are absent, but a number of swamps
form in favourable interdune locations during
winter (see n. 85 herein). The system of salt
lakes represents shallow arms of the sea which
were isolated in recent times, by bar and dune
formation near the present coast.

A striking physiographic feature of the Island
is the ubiouitous occurrence of narrow marine
benches situated a few feet above mean-sea -
level along the present coastline and around the
margins of the salt lakes. Previous authors
(Teichert 1950: Fairbridge 1954) have inter-
preted these features as remnants of low -water-
level marine benches formed during recent
eustatic still-stands or slow retreat of sea-level.
Benches at 10-11 feet above the present mean-
sea-level have been related to the “Flandrian”
sea-level of Europe, those at 5-6 feet to the

“Calaisian” and those at 2-3 feet to the “Dun-
kirkian.” Emerged coral reefs at Salmon Bay
and Stark Bay and shell beds around the lakes
yield unmistakable evidence of higher sea -levels.
However, studies in progress suggest at least
some of the low-water-level benches formed
during these periods of higher sea-level have
been either drastically remodelled or obliterated
by rapid erosion. Some of the benches around
the present coastline appear to owe their form
to surface induration of the aeolianite near the
upper limit of the splash zone, and it therefore
seems that they are unrelated to eustatic
phenomena.

A fall in present sea-level of approximately
five fathoms would link Rottnest Island to the
mainland as a peninsula extending through
Garden Island to Point Peron. Fossil pollen
and radiocarbon studies (Churchill 1959) in-
dicate that, approximately 5.000 years B.C., sea-
level stood five fathoms lower than at present.
The separation of Rottnest as an island is thus
a young geological event.

BRIAN F. GLENISTER, C. W. HASSELL and
E. W. S. KNEEBONE.

References

Churchill, D. M, (1959). — Late Quaternary eustatic
changes in the Swan River District. J. Roy.
Soc. W. Aust. 42: 53-55.

Fairbridge, R. W. ( 1954) .—Quaternary eustatic data for
Western Australia and adjacent states. Proc.
Pan-lnd. Ocean Sci. Conyr.. Perth, Sect, F:
64-84.

Teichert, C. (1950). — Late Quaternary changes of sea-
level at Rottnest Island. Western Australia.
Proc. Roy. Soc. Viet. 59: 63-79.

Tliyer, R. F., and Everingham, I. B. (1956). — Gravity
survey of the Perth Basin, Western Australia.
Bull. Bur. Miner. Resour. Aust, 33.

Veiling Meinesz, F. A. (1948). — Gravity expeditions at
sea, 1923-38, Vol. IV. (A. J. Mulder).
(Drukkerij Waltmann: Delft.)

13. — The Vegetation of Rottnest Island

Our earliest record of the vegetation of what
is now Rottnest Island comes from fossil pollen
and megascopic remains in swamp sediments
and dunes of late Pleistocene age. Apart from
species still feund on the Island, the past
occurrence of Eucalyptus (fomphocephala, E.
marginata , E. calophylla. Agonis, Casuarina.
Banksia, Macrozamia and Xanthorrhoea indi-
cates that a tuart woodland similar to that of
the present mainland once existed here. Since
then, rising sea-level and erosion have reduced
the area to an island, 7 miles long and 3 miles
wide. Consequent increase in wind exposure
and deterioration in rainfall have played their
part in rendering former habitats unsuitable for
tuart woodland. Thus the present vegetation
consists solely of elements of a coastal complex .

Supralittoral Vegetation

In comparison with the mainland, the strand
plants Cakile maritima and Arctotheca nivea,
and the fore-dune species Spinifex hirsutus and
Tetragonia zeyheri, are rare on the island. The

dominant plant of Rottnest fore-dunes is
Spinifex longifolius; associated with it are
Atriplex isatidea and the introduced Anthericum
divaricatum.

An entirely different suite (mostly of succu-
lents) occupies rocky shores: Carpobrotus
aequilaterus , Threlkeldia diffusa, Tetragonia
implexicoma, Sporobolus virginicus , Ercmophila
glabra, Nitraria schoberi, Enchylaena tomentosa,
Artlirocnevium halocnemoides , Salicornia aus-
tralis and Atriplex paludosa. Many of these
species are now abundant only on offshore stacks
and islets. Except at Cape Vlaming, excessive
browsing by quokkas in summer has exterminated
or impoverished most of the succulent-dominated
communities on the main island coast.

Coastal Dun? Vegetation

This is a fairly open formation of low, generally
microphyllous, shrubs, 1 to 5 feet high. Com-
position and height depend on wind exposure
and depth of sand over the consolidated dune.
The succession from sandy shores is usually

70

through Scirpus nodosus, Scaevola crassifolia
and Calocephalus brownii to Olearia axillaris.
The stony phase is pioneered by the dwarf shrub
Frankenia pauciflora , which, with decreasing
exposure, is replaced by taller shrubs; W estringia
dumpier i, Leucopogon insularis, L. parviflorus,
Acrotriche cordata and Boronia alata. On lee-
ward slopes most of these give way to Acacia
cuneata, Olearia axillaris , Myoporum insular e ,
Diplolaena dampieri, Melaleuca pubescens, and
Acacia rostellifera.

Interdunal Vegetation

In sheltered valleys and slopes, where the sand
is deep and the accretion of silt has enhanced
its water holding capacity, a scrub develops,
almost exclusively of Acacia rostellifera . Typi-
cally the formation is closed and from 10-20
feet in height. The liana Clematis microphylla
is common here. Undergrowth is sparse and
usually restricted to Stipa variabilis and
Acanthocarpus preissii.

This scrub was once far more extensive than
it is at present. As recently as the end of last
century, visitors could describe the vegetation
of Rottnest as “impenetrable” beyond the con-
fines of the eastern settlement. Today all that
remains of the scrub in the western half of the
island are a few isolated thickets of Acacia
rostellifera.

Where the scrub has gone, there now occurs
a low dense formation consisting almost
exclusively of sclerophyllous monocotyledonous
plants. The most characteristic species is
Acanthocarpus preissii, a fruticose, pungent-
leaved perennial, 1-3 feet high. It is usually
associated with a tussock grass, Stipa variabilis.
Less common are two other tussock grasses Poa
australis and Danthonia caespitosu, the sword
rushes Lepidcsperma gladiatum and L. resino-
sum, Conostylis candicans and a small grass-like
sedge, Carex preissii. Apart from annuals,
dicotyledonous species are uncommon and are
usually found <1> in disturbed areas (e.g.
Thomasia cognata /, (2) where the scrub has
recently disappeared <e,g. Didiscus caeruleus and
Guichenotia ledifolia >, or (3) where the lime-
stone is near the surface (e.g. Stackhousia
pubescens and Oxalis corniculata ) .

Recent research has shown that the status
of the Acacia depends on quokka grazing
pressure. Where the animals are abundant, the
Acacia is eaten out and replaced by communities
of herbs and low 7 shrubs that are resistant to
fire and generally unpalatable to quokkas.
Where quokkas are excluded by fences or where
their density is low, as in the Stark Bay hinter-
land, Acacia thickets expand into the surround-
ing Acanthocarpus- Stipa.

Thus Acanthocarpus- Stipa and Acacia scrub
are the end-points of a single sere, whose direc-
tion is controlled by the intensity of quokka
grazing. The present trend over most of the

Island is for Acanthocarpus to replace scrub,
which implies a recent increase in the abundance
of the quokkas The evidence for such an
increase and the factors responsible for it, have
been discussed by Storr (1957).

Limestone Ridge Vegetation

In the western two-thirds of the Island, the
consolidated dunes are usually covered by shallow
calcareous sands. At the eastern end of the
Island the dunes are frequently covered by finer
sands relatively rich in organic matter, which
support a closed formation comprising several
species of shrubs 5-15 feet high. Templetonia
retusa occasionally occurs in pure stands. More
often it is mixed with one or more of the
following: Pittosporum phillyrioides , Spyndium
globulosum, Beyeria viscose , Alyxia buxi folia,
Acacia rostellifera and Melaleuca pubescens.
Most of these species reappear on limestone
cliffs in sheltered bays. Undergrowth is sparse
and confined usually to Phyllanthus calycinus ,
Acanthocarpus preissii, Stipa variabilis and
Guichenotia ledifolia.

Swamp and Salt-lak? Vegetation

The various marsh communities form con-
centric zones around the lakes and swamps.
Except where the limestone is bare, the inner-
most zone is dominated by the samphires,
Arthrocnemum arbuscula, A. halocnem.oid.es ,
and Salicornia australis. During winter and
spring this zone is largely under water. In early
summer after the water has receded, certain
low creeping perennials renew their growth, viz.;
Hemichroa pentandra, Wilsonia humilis, Samolus
repens and Suaeda australis.

The next zone is dominated by the large
tussocky sedge, Gahnia trifida. Sometimes it is
mixed with or replaced by the erect sedges and
rushes, Scirpus nodosus. Hypolaena sp. and
Juncus viaritimus. Less frequently it is inter-
spersed with bushes of Arthrocnemum halocne-
moides. Atriplex paludosa or Myoporum visco-
sum. Wherever the soil is less saline and richer
in organic matter, a mat of grasses and herbs
covers the bare spaces between tussocks of
Gahnia. The mat is dominated by the perennial
grass Sporobolus virginicus.

As the land rises, the Gahnia is replaced by
Melaleuca pubescens, an erect or umbrageous
tree up to 40 feet high. It forms the only
dominant of a closed community in which
undergrowth is rare apart from the ascending
succulent Threlkeldia diffusa , and occasional
tussocks of Stipa variabilis. If the flats
surrounding the lake are extensive there is
a correspondingly broad zone of Melaleuca
pubescens, but where the land continues to rise
it gives way to Acacia rostellifera or Pittosporum
phillyrioides according as the soil is deep or
shallow over the limestone.

G. M. STORR, J. W. GREEN, and
D. M. CHURCHILL.

71

14. — Physiology of the Quokka

Investigations of physiological processes oper-
ating in the quokka have been carried out dur-
ing the last 10 years by a number of people in
various capacities and of different interests. As
a result, these studies have not followed a sys-
tematic sequence but are linked by the common
interest of the investigators in the marsupial
group. Therefore, rather than give a chrono-
logical account of the work done on the quokka,
the following summary uses broad headings
which group together investigations of related
physiological processes.

Digestion

Pew animals and no mammals form their own
alimentary cellulase to digest the cellulose
which encases plant cells. Consequently, those
mammals which use plant material as food rely
on unicellular organisms, which live in the
digestive tract, to digest the cellulose portion of
their food so that this substance can be made
available for the animals* needs. This is par-
ticularly important in the case of grazing herbi-
vores. Mammals can be divided into two groups
by the manner in which micro-organisms assist
them in this respect: the ruminants, in which
the stomach is divided into four pouches, the
first of these (the rumen) being the major site
of predigestion of food by micro-organisms, and
the non-ruminants, in which the stomach is a
single compartment, digestive micro-organisms
being contained in a relatively large caecum
and in the colon.

The quokka, like other macropods, is an herbi-
vorous animal of grazing habit. Moir, Somers,
Sharman and Waring (1954), and Moir, Somers
and Waring '1956) showed that in this animal
the problem of digesting plant material is largely
overcome by a type of “pregastric digestion”
which is similar, in many respects, to that which
occurs in ruminants. Thus, the stomach is
large and sacculated, has an oesophageal groove
and the proximal pouch contains bacteria which
attack and ferment the food. As in ruminants,
this bacterial action results in production of
volatile fatty acids which are absorbed mainly
frcm the fore -stomach. However, the stomach
of the quokka does not exactly resemble that of
the ruminant: it is not known if the oesopha-
geal groove functions as in ruminants and the
functions of the distal pouches of the quokka
stomach are unknown.

Two related characteristics of digestion in
ruminants are the slow rate of passage of food
through the alimentary canal and the small
proportion of fibrous food that remains un-
digested. In investigating these processes in the
quokka. Calaby (1958) observed that the rate of
passage of food through the digestive tract in
this animal is faster than in the ruminant but
slower than in the horse: also that the per-
centage of dry food digested by the quokka is
less than in ruminants but greater than in
rabbits. Thus, digestion of plant material in
the quokka is less efficient than in the domestic
ruminant although probably more efficient than
in non-ruminant herbivores.

Little is known of the essential food require-
ments of the quokka. In nitrogen balance trials,
using a mixture of equal parts of oaten and

lucerne chaff and ground sheep nuts, J. H.
Calaby i personal communication) obtained a
preliminary figure for crude protein require-
ments for maintenance of adult animals, of
approximately 3.5 grams per kilogram live body
weight per day. Further information on this
subject awaits future investigation.

Metabolism

General

The trend towards the specialised ruminant
type shown by studies on digestion in the quokka
are paralleled by some aspects of the metabolism
of this animal.

Moir et aL (1954, 1956) recorded that blood
volatile fatty acid (V.F.A.) and glucose levels
in the quokka are similar to those found in
ruminants, V.F.A. levels being higher and glucose
levels lower than those normally found in non-
ruminants; also V.F.A. was shown to be removed
from the circulation by the liver and other
tissues. These facts indicate that quokka tissues
may be like those of the ruminant in utilising
relatively large amounts of V.F.A. as an energy
source. However the relative importance of
V.F.A. and glucose in this respect are not yet
known.

Further studies by J. Barker (unpublished)
have shown that while normal blood glucose
values for the quokka are similar to those for
ruminants, feeding increases the blood glucose
level to a rather greater extent than occurs in
ruminants. However, intravenous injections of
insulin in the quokka depress the blood glucose
to very low levels which would not be tolerated
by non -ruminants, this without apparent effect
on the animal. This response is similar to that
which occurs in ruminants. On the other hand,
glucose tolerance times for the quokka are
similar to those for non -ruminants and much
shorter than those for ruminants. Finally, the
ability of the quokka to convert injected pro-
pionate to glucose is considerably less than that
of the ruminant although relatively greater
than that of the rabbit.

Thus, although the quokka is like the rumi-
nants in that it tolerates blood levels of
V.F.A. and glucose that would not be tolerated
by non-ruminants, some aspects of cell meta-
bolism in this animal must differ from that of
the ruminant, and full investigation of inter-
mediary metabolism in the quokka should be of
great interest.

Trace Elements

Cobalt and Copper . — Ruminants require cobalt
for the synthesis of Vitamin B,^ by micro-
organisms in the rumen. A higher intake level
of cobalt is necessary in ruminants than in non-
ruminants due to their poor faculty for absorp-
tion of Vitamin Bi* and to their requirement of
a high level of cobalt in the rumen liquor to
maintain a normal population of micro-
organisms. In cobalt deficiency, rumen levels
of cobalt are depressed. As a result, changes
occur in the population structure of the resident
micro-organisms and Vitamin B.-. production
falls below the minimal requirements of the
host. Thus the need for cobalt in ruminants is
indirect and cobalt deficiency is in fact a defi-

72

ciency of Vitamin B I2 . Ruminants become
cobalt deficient when grazing light land low in
cobalt and particularly when grazing coastal
sand dune country consisting largely cf wind
born shell fragments.

After Moir et al. showed that the quokka had
“ruminant-like” digestion, it was of in-
terest to determine whether cobalt deficiency
plays a part in limiting the numbers of quokkas
on Rottnest Island, an area which consists
entirely of sand dune formations and which has,
in the past, proved an unsuitable area for graz-
ing sheep. S. Barker (unpublished data) has
attempted to produce experimental cobalt defi-
ciency in quokkas. The basic diet used had a
cobalt level of 0.02 p.p.m. (dry weight basis).
This level is slightly lower than those found in
the few Rottnest plants that have been analysed
for cobalt. Although the liver cobalt levels in
the quokkas were, after several months, signifi-
cantly lower than those of control animals,
serum levels of Vitamin B, 2 did not approach
the lowest levels found by Shield ( 1958 > in the
Rottnest population during spring months. No
symptoms comparable with those exhibited by
Vitamin B, 2 deficient sheep were produced in
quokkas on these low cobalt intake levels. It is
therefore tentatively concluded that the quokka
is more efficient than ruminants with respect
to conversion of cobalt to Vitamin B )2 and/or to
absorption of Vitamin B (2 .

Copper deficiency occurs in ruminants under
two types of circumstance —

(1) a simple deficiency occurring in animals
grazing on copper deficient pastures;
and

(2) an induced deficiency occurring in
animals grazing pastures with normal
copper levels but also with high molyb-
denum and inorganic sulphate levels —
in this case an interaction between
these three ions reduces the availability
of copper to the animal.

By analysis of plants eaten by the quokka.
S. Barker (unpublished data) has shown that
Rottnest pastures are low in copper — the mean
level being less than 5.0 p.p.m. (dry weight
basis) — but field studies indicate that this in
itself is adequate for the quokka. Also, in cer-
tain areas of the island, plants have a high
molybdenum and inorganic sulphate content,
and field studies have shown that during the
summer, blood copper levels of animals in these
areas fall below the winter levels. It therefore
appears that when local population numbers
build up during the summer, reduction in blood
copper occurs in animals eating plants of high
molybdenum and inorganic sulphate content.
Preliminary experiments have indicated that a
Cu-Mo-SOi interaction does exist in the quokka
and further work on this problem is in progress.

Iron . — The mechanism of iron transfer from
the female quokka to the suckling joey is being
investigated by Kaldor. In eutherian mammals
that have been studied, uterine embryos obtain
iron for haemoglobin manufacture and iron
storage as a result of placental transfer and
such animals are born with a relatively high
blood haemoglobin concentration. After birth
the young are, for a time, dependent on the
maternal milk for further iron supplies but
eutherian milk has a low iron content. There-

fore, the young are largely dependent on their
own iron stores during the lactation period and
as these are not fully adequate for their needs,
a characteristic decline in blood haemoglobin
and in iron stores of the young occurs during
this period. Blood haemoglobin and iron stores
do not rise again until foods other than milk
are taken.

Preliminary studies on the quokka have
shown that, the blood haemoglobin concentration
is low in the young joey but rises throughout
pouch life and towards the end of this period it
is almost as high as the adult value. Storage
iron in the liver is maintained at a constant
high concentration during the corresponding
period. These findings indicate an unusually
high concentration of iron in quokka milk and
this was confirmed by analysis. How this high
output of iron in milk is maintained is the sub-
ject of work in progress as this is of great
theoretical interest since there is no known
mechanism for active secretion of iron into milk.

Water

Since Rottnest Island is an area where sum-
mer conditions are fairly prolonged and are
coincident with a limited natural water supply,
the quokkas living on the island might be ex-
pected to have some means of physiological
adjustment to varied water availability.

Bentley <1955) described the ability of the
quokka to concentrate its urine so as to maintain
a positive water balance when drinking salt
solutions as concentrated as 2.5'# NaCl. I How-
ever, most of his animals were not able to
maintain a positive water balance when drink-
ing sea water (equivalent to 3.3% NaClJ.l
Therefore, animals living on Rottnest Island
should be able to satisfy their summer water
requirements by drinking any available brackish
water, but while they may occasionally drink
sea water, it is unlikely that they could survive
over long periods with no other source of water.
This is borne out by Bentley’s field observations:
urine samples collected from animals on the
island during the winter were dilute while those
collected during the summer were more concen-
trated, but the degree of concentration of sum-
mer field samples did not indicate any severe
dehydration or show electrolyte concentrations
that would indicate that the animals were drink-
ing strong salt solutions. Therefore, animals
which survive the summer are able to obtain
sufficient water from their food and available
fresh or brackish drinking water to maintain a
positive water balance.

The structure of the quokka kidney was also
described by Bentley and his observations indi-
cated that the relative volume of reabsorptive
tubule tissue exceeds the normal value for most
other species. This may have physiological sig-
nificance in relation to the wide seasonal varia-
tion in kidney secretory function observed in
quokkas living in their natural habitat.

The possibility has been envisaged that if
some seasonal fluctuation in the state of hydra-
tion of island animals does occur, this might
be demonstrated by measurement of total blood
volume at different times of the year. Prelim-
inary work to test this was done by Ho (1958)
and further work is being carried out by Shield

73

and Woolley, but no definite information re-
garding seasonal changes is yet available. The
method used to assess total blood volume is the
Evan’s Blue (T1824) Dye method. Ho found
that the time for complete mixing of injected
dye in the circulation of quokkas is longer than
is usual for other mammals and that the plasma
volume per kilogram body weight is lower in the
quokka las in other marsupials that have been
tested) than in eutherian mammals.

Temperature Regulation

Another important aspect of quokka physi-
ology in relation to their environmental
conditions is that of temperature regulation.
Homoiothermy is a general feature of eutherian
mammals and is largely attained by evapora-
tion of water from the skin and or lung sur-
faces in hot ambient conditions, and by peri-
pheral vasoconstriction and shivering in cold
conditions. It was at one time thought that
many marsupials, including the quokka, were
not able to maintain a constant body tempera-
ture under conditions of gross changes in envir-
onmental temperature. That this is not true
of the quokka has been clearly shown by Bentley
• 1955) and Bartholomew (1956) who observed
very efficient homoiothermy in quokkas sub-
jected to high and low environmental tempera-
tures.

Under hot conditions, the animals’ respiration
rates rose considerably, and Bentley observed
that these increases were of the same order as
those that occur in eutherian mammals of simi-
lar size such as the cat and the rabbit. He
also described considerable sweating from the
fore and hind Daws, which he showed to be the
only skin areas containing sweat glands. Both
workers also described obvious salivation of
quokkas in hot conditions and Bartholomew
considered that evaporation of saliva, which the
animals spread over their limbs and tail as a
result of a “licking response to heat stress,”
was the major cooling factor. However, it is
difficult to distinguish the relative roles of sweat
and saliva in this respect since the behavioural
licking response would spread both sweat and
saliva to increase cooling by surface evapora-
tion. Bentley < unpublished data » has shown
that the licking response to heat stress is not
essential for maintenance of the homoiothermy
exhibited by these animals, by using circular
perspex collars that extended out from the neck,
to prevent licking. Under hot environmental
conditions, collared quokkas showed no increase
of body temperatures compared to quokkas
without collars; the paws became soaked with
sweat which spread up the limbs and evapora-
tion of this, together with the increased respira-
tion rate, provided adequate cooling for the
animals. It thus seems likely that the adjustable
methods for heat loss in the quokka under
natural conditions are largely a combination of
panting and evaporation of sweat and saliva
from parts of the body. These effects are en-
hanced by the behavioural pattern of licking.
The licking response is acquired early in life
(it was observed by Bartholomew in pouch
young) and this worker also showed that
homoiothermy develops in the quokka during
pouch life.

Bartholomew demonstrated that furred quok-
kas are also able to maintain their deep body
temperature at normal levels when subjected to
cold conditions with ambient temperatures as
low as -10 C. This ability was accompanied by
shivering and widespread peripheral vasocon-
striction.

No data are available on metabolic rate
changes in quokkas under hot or cold conditions.

Blood

Blood Groups

Blood group systems have been demonstrated
in several mammalian species and provide in-
teresting material for genetical studies. An
investigation of naturally occurring blood group
antigens and antibodies in the quokka was car-
ried out by Saunders <1958). The preliminary
findings indicate that differences occur between
individuals in this regard but further work is
necessary to elucidate the genetic mechanisms
involved.

Haemoglobin

It has been shown that differences between
individuals with respect to the type of haemo-
globin in the erythrocytes, occur in several
mammalian species. Such differences are gene-
tically controlled. From electrophoretic analysis
of quokka blood, Kirk has so far been unable
to demonstrate haemoglobin differences between
individuals of this species (unpublished data>.

Erythrocyte Electrolytes

In most mammalian species, potassium is the
predominant cation, sodium being present in
only small concentrations. However, in carni-
vores sodium is the predominant cation in
erythrocytes and in sheep, goats and possums,
different individuals have either high sodium
or high potassium erythrocytes.

Eadie (unpublished data) showed that quokka
erythrocytes are unusual in containing roughly
equal concentrations of sodium and petassium
and that pouch young arc not different from
adults in this respect; J. Barker • unpublished
data) confirmed this in studying the variation
of erythrocyte sodium and potassium distribu-
tion between individual quokkas and is at pres-
ent investigating other properties of these cells.

Endocrinology

Adrenal Physiology

The adrenal cortex produces hormones that
are essential to life in a wide range of vertebrate
species that have been investigated. When these
animals are adrenalectomised. they die after
varying periods of time < which are fairly char-
acteristic for each species' during which they
exhibit typical symptoms resulting from dis-
ruption of electrolyte, water and carbohydrate
metabolism. However, the North American
opossum, Didelphis virginiana, has been shown
to be unusually resistant to adrenalectomy and
there was thus the possibility that this might
be a characteristic of the marsupial group. This
hypothesis is not substantiated by the observa-
tions of Buttle, Kirk and Waring (1952> who
reported that adrenalectomised quokkas have a
short survival time (approximately two days)
during which typical symptoms of adrenal in-

74

sufficiency, such as loss of appetite, muscular
weakness, depression of blood glucose and plasma
sodium levels and elevation of plasma potassium,
occur.

Animals living under conditions of environ-
mental stress are very dependent on their
adrenal cortex secretions which aid the body
cells to cope with the additional functional re-
quirements imposed upon them by the stress
conditions. In such situations, the rate of
secretion of adrenal cortex hormones is increased
above normal and if the stress is severe and/or
prolonged the animals suffer from exhaustion
of adrenal function. A concommitant effect
with increased adrenal activity under conditions
of stress is depression of the ascorbic acid con-
tent of the adrenal cortex. These facts were
used by Herrick (unpublished data) in an in-
vestigation of variation of adrenal function in
quokkas at different seasons, in relation to
dehydration stress. Herrick's results indicated
that there was an increase in adrenal cortex
secretion in quokkas subjected experimentally to
severe dehydration. However, he obtained no
evidence of unusual adrenal activity or of
dehydration in wild animals caught on Rottnest
Island during summer or winter months.

The various investigations bearing on water
metabolism which have been mentioned provide
no evidence that dehydration stress is an im-
portant factor in population limitation among
the quokkas on Rottnest Island (and see the
report on Rottnest field studies in this part). It
may, of course, account for death of a small
number of animals which were not represented
in the samples obtained by the various workers.

Reproduction

Valuable contributions to the field of compara-
tive reproductive physiology have been made by
extensive investigations of reproduction in the
quokka, particularly since there is remarkably
little information of this nature concerning the
marsupial group.

Sharman <1954) commented on. and Waring,
Sharman, Lovat and Kahan <1955) described
the anatomy of the reproductive tract of the
female quokka. which is similar in all important
respects to that of other marsupials, and of the
pouch, which contains four nipples, and recorded
some observations on the birth and pouch life
development of the young. Thus, the animals
appear to be exclusively monovular, since
multiple births have never been recorded. New
born quokkas (which weigh approximately half
a gram) move into the pouch and attach to one
of the nipples which hypertrophies, along with
the mammary gland that supplies it, as the
foetus grows. Only the one nipple is used by
any one young during lactation. The sexes are
externally indistinguishable at birth and remain
so for about three weeks after which either
pouch or scrotum can be distinguished. The
young are born in an undeveloped condition,
but by the time they are about five months old.
their eyes are open and they are well covered
with fur. They remain permanently in the
pouch for a total period of about six months
after which they leave it for increasing periods
of time until they are finally too large to enter
it Even though no longer resident in the

pouch, they continue to feed from the elongate
nipple which often protrudes from the pouch,
until they are about 9-10 months old.

Sharman < 1955a) studied the oestrus cycle
of the adult female quokka. He observed that
the non -breeding part of the year ( period of
anoestrus) for quokkas in the wild lasts approxi-
mately from October to January. Towards the
end of January, the breeding season starts with
the commencement of oestrus cycles — these
animals are polyoestrus within the breeding sea-
son. As in many other species, domestication re-
sults in reduction and finally elimination of the
anoestrus period, in which case oestrus cycles
recur throughout the year and are only inter-
rupted by pregnancy and lactation. Each oestrus
cycle is about 28 days in length. The period of
behavioural oestrus in each cycle lasts for about
12 hours and is followed, within the next 24
hours, by ovulation, whether or not copulation
has occurred. Details of the changes in the
ovaries, uterus and vagina during the oestrus
cycle and the anoestrus period are given and
similarities between the cyclical changes in the
female quokka and those in Didelphis. Bettongia
and Dasyurus, the only other marsupials for
which detailed information is available, are
described.

Details of pregnancy and embryonic develop-
ment of the quokka were described by Sharman
(1955b), This account shows that the quokka
placenta is of the yolk sac type and that the
gestation period is about 26 days. After parturi-
tion, the female develops an oestrus condition
and ovulation occurs: copulation and fertilisa-
tion of the post partum ovum may occur at this
stage, but development of this zygote normally
proceeds only to the blastocyst stage. While the
first young remains in the pouch, the blastocyst
stays in a quiescent state, unimplanted in the
uterus which remains in an undeveloped state
of lactation anoestrus. If the pouch-young is
removed, the blastocyst becomes implanted and
starts to develop further, the uterus changes to
the pregnant condition and a second young is
eventually born.

This mechanism would account for the fact
that domesticated female quokkas have occa-
sionally been observed feeding two young at the
one time — one no longer resident in the pouch,
but still feeding from the exterior by the elong-
ate nipple to which it was previously attached,
and the other newly born and attached to a
different nipple. In such a case, the blastocyst
would have remained viable for at least five
months. However, this mechanism of delayed
birth is probably of value in the wild population
on Rottnest Island only in cases where the first
young of the season is, for some reason, lost
during earlier pouch life. By the time the first
young normally leaves the pouch, seasonal
anoestrus would, in most cases, have com-
menced in the wild carrying female and under
these conditions the quiescent blastocyst de-
generates.

Nerve Physiology

Studies are in progress by Collin on the con-
duction velocity in nerves from quokkas of diff-
erent size, in order to obtain data on the devel-
opmental aspect of nerve conduction.

75

Pharmacology

The effects of pltressin and pitocin (extracts
of the posterior lobe of the pituitary gland) on
blood pressure, have been studied in a wide
range of vertebrate species. Both drugs affect
blood pressure in all non-mammalian species
that have been tested, although the effects of
each varies in different species. The platypus, a
prototherian mammal, also shows blood pres-
sure changes with both drugs. No eutherian
mammal has been shown to exhibit a blood
pressure response to pitocin, while pltressin
causes a rise in blood pressure in these animals.
Similar responses to those of the Eutheria have
been demonstrated in the only two marsupials —
one being the quokka — that have been tested.
That this is true for the quokka was first shown
by Feakes and Waring (unpublished data) and
was later verified by Woolley (unpublished
data) .

These effects are of interest in relation to the
phenomenon of tachyphylaxis (or reduction of
response to a drug when serial doses of the
same amount are given over a period of time),
which has been demonstrated by the above
workers in relation to the effects of pitressin
on blood pressure in the quokka. Woolley is at
present investigating the mechanism by which
this tolerance is brought about.

In summary, it can be said that these investi-
gations on the quokka are of great interest in
relation to comparative physiology, since re-
latively little is known of physiological function
in the marsupial group. Several unusual mech-
anisms have been demonstrated and it is possible
that some, at least, of these will prove to be
characteristic of the macropod group.

S. BARKER and J. BARKER.

15. — Rottnest Field Studies Concerned with the Quokka

Rottnest Island is a study area of value to
field ecologists interested in the dynamics of
mammal populations. It is closed to recruit-
ment by immigration and to loss by emigration
such as occurs in continental populations in
response to climatic or seasonal change.

Its area is 4,700 acres, i.e., not so small as
to make it an extremely artificial study area.
The single species of indigenous mammal, the
quokka, is a herbivore with no carnivorous pre-
dator so that no complication in the way of
predator-prey relationship obscures the direct
relationship of the animals to the environment.
The animals are small (adult: 3.5kg), easily
caught, and relatively docile when handled. In
captivity they domesticate easily for experi-
mental work. Practically all the females have
one young per year, there being no observable
senescence in the population. Although accounts
of the early days of the colony indicate that
large numbers of the animals were shot for
sport prior to 1914, since that date the Island
has become a game reserve and with complete
protection the population has become virtually
a natural population with human checks re-
moved. All these factors add uo to the fact that
this Island and its indigenous quokka popula-
tion provide a relatively simple ecological situ-
ation. When it is realised that the search for
such situations has in recent years driven
ecologists to the simplified regions of the desert,
tundra and the steppes, it is fortunate that we
have so close at hand in Western Australia a
study area capable of producing a growing body
of fundamental research on a marsupial popu-
lation.

One of the fundamental questions of popula-
tion dynamics concerns the limiting factors of
population growth. Starvation and disease are
the causes most favoured by mammalogists.
Prolonged seasonal adversity in the form of
drought in hot deserts and blizzards in cold
deserts decimates populations seasonally or

periodically. Less frequently it can be demon-
strated that the fertility itself Is affected by
adverse conditions of food, water or disease and
this adjusts population numbers without the
spectacular death rate associated with the three
major limiting factors.

Since the original landing of Volckersen 300
years ago the journals of the various navigators
and naturalists indicate that the population of
the Rottnest Island quokka was dense enough
to elicit comment. Today the quokka numbers
are still large. The Island has been separated
from the mainland some 7 r 000 years according
to Churchill <1959) and one can speculate that
over the major part of this period the density
of the animals has been high.

What then are the natural limiting factors of
this population? Initially an attempt was made
to establish some correlation of death with sea-
son. If successful this would give a clue to the
probable cause. As no recently dead or mori-
bund animals are in evidence at any season
no pathological evidence can be sought to give
a lead to the immediate cause of death. In
fact animals in this condition are rarely found,
as the sick animals presumably seek shelter be-
fore becoming moribund and die unnoticed until
destruction of the vegetation reveals their skele-
tons. These are common on the Island. Hence,
as the only remaining evidence of natural
deaths, a large (600) collection of crania was
made in the hope that they would reveal some
seasonal pattern of death. It seemed upon
analysis that the major part, if not the whole of
the population deaths, takes place in the late
summer, i.e., March and April. This observation
gave a valuable lead because any limiting factor
had to be operative at or a little before this
period.

With an established season of death further
analysis of such a population could proceed on
two parallel lines. Either the biotic environ-
ment of the herbivore could be studied for the

76

effect of grazing, or the population of animals
themselves could be studied by extended samp-
ling, the knowledge of their clinical status pro-
viding an assessment of the factors contributing
to morbidity. Both these lines of attack have
been and are still carried on with the Rottnest
Island quokka population. Initially the latter
approach was used — an analysis of the physio-
logical status of the population through a com-
plete haematological survey extending over
some two years, with large samples of animals,
repeated periodically throughout the year. We
knew that semi-starvation in general produced
an anaemia and that this anaemia was prob-
ably of a special type — hyperchromic and mac-
rocytic. Summer dehydration, acute or chronic
was expected to produce the reverse picture —
a haemoconcentration. Generalised disease has
its own general indicators in raised white cell
concentrations and high sedimentation rates of
red cells whilst the evaluation of vitamin B, 2
deficiency is most easily determined by blood
serum bioassay. B 12 deficiency has not been
demonstrated in animals other than the sheep,
but seemed a possible limiting factor in this
case.

Two study areas have been selected on the
Island — one comprising the whole of the west
end of the Island; an area of some 500 acres
joined to the main island by a narrow isthmus,
whilst the other is located adjacent to Lakes
Bagdad and Pink and totals in all about 300
acres.

The West End study area contains no free
fresh water and the animals presumably satisfy
their water requirements from that contained
in their food. The other study area — Bagdad —
has an ample water supply all the year
around as a number of seepages around the
periphery of the salt lakes flow summer and
winter. To use two areas so dissimilar in their
available drinking water for a physiological
evaluation of the animals in each could show
whether dehydration operated as a limiting fac-
tor on the West End animals during the sum-

mer, when the mortality pattern appeared
constant all over the Island on the evidence of
the skull collections. Thus similarity of mor-
tality incidence in West End and Bagdad could
suggest that the lack of potable water on West
End was not a contributory cause there. How-
ever, it is a well known phenomenon! that
thirsty animals will not eat, so that chronic
water shortage leads to starvation which, rather
than dehydration, then becomes the proximal
cause of death. With this thought in mind the
similarity of the seasonal pattern of death in
the two study areas may relate to different
causes, that of the West End being primarily
mediated by dehydration. Inanition due to food
shortage in the presence of water and inanition
due initially to chronic water restriction, but
a really secondary starvation, present clearly
separable blood pictures.

The necessary experimental evidence came
from a colony of quokkas kept in the zoology
yards which had been subjected to water restric-
tion for a period of 6 or 7 months. The chronic
dehydration of the experimental animals pro-
duced, after some months of continued water
restriction, a blood picture which differed both
from acute dehydration and primary starvation:
on the one hand an anaemia in so far as the
haemoglobin and red cell concentrations fell
below the average of the control sample as did
the haematocrit values, and on the other, an
increase of the serum proteins, both albumin
and globulin, over those values in the control
animals which were maintained on a diet of
food and water ad. lib.

In the field under summer conditions the blood
picture was the same for both areas, giving
no evidence that either acute or chronic
dehydration supervened in the West End despite
the total lack of free fresh water.

With the demonstration by Moir, Summers
and Waring (1956) that the quokka was rumin-
ant-like, possessing a large stomach, and an
oesophagael groove very like that in the sheep
the question arose as to whether low cobalt

ROTTNEST ISLAND

WESTERN AUSTRALIA

1 Mile

77

values which had previously prevented the
establishment of sheep at Rottnest, also affected
the macropod population: in particular could
this act as a specific limiting factor to popula-
tion growth? Experimental work with sheep
had demonstrated that a drop in serum B,o
values paralleled a progressively developing
“coast disease,” overt symptoms of the disease
appearing at a definite low level of the serum
vitamin concentration in the experimental
animals. For this reason it was thought that a
haematological survey of the quokka population
over a complete season would reveal any defici-
ency comparable to that in sheep. We were
fortunate in having the haematology department
of the Royal Perth Hospital able to do all our B, >
assays. The survey was conducted during 1956-
57 and over the whole period for both study
areas a total of some 450 animals were assayed.
At no season did the Rottnest average Bia values
fall as low as those in “coasty” sheep. Instead
a seasonal variation in the quokka B, > level was
evident such that the maximum occurs in the
late summer, not the minimum which would
be expected to correspond to the mortality peak.
In addition statistical analysis revealed no cor-
relation with haemoglobin or albumin levels
with low Bi* levels as in the case of experimental
animals. Hence, taken together, the several
aspects revealed by the serum B,, assay indicates
that the soil cobalt deficiency 'low enough to
totally eliminate a eutherian ruminant, the
sheep, from the area) does not affect its mar-
supial analogue, the quokka.

The extreme control of the Island’s vegetation
by the quokka has been demonstrated in several
ways. In February 1955 fires burnt out the
whole middle of the Island. Immediately after-
wards the Zoology Department erected 25 animal
exclusion quadrats on various burnt areas. After
two years of subsequent regrowth the effect of
the quokka grazing was amply demonstrated
by the luxuriant growth inside a majority of
the quadrats and the poverty outside. The
immediate implication of this was that the
animal population itself was being primarily
controlled by starvation. Semi-starvation un-
complicated by disease has a fairly definite blood
picture 'Keys, Brozeck, Henschel, Michelson and
Taylor, 1950). There is a rather profound
anaemia of the order of 25 per cent, decrease in
the haemoglobin, red cell count, and haema-
tocrit. This anaemia is generally of the macro-
cytic, hyperchromic type. (Over a period of
some two years the seasonal anaemia of the
quokka during late summer has been of this
type, the blood picture corresponding to what
the World Health Organization (1951) regards
for humans at least as a severe semi-starvation
anaemia.) However, these figures are aver-
ages. Hence 50 per cent, of the population will
be below this value and some smaller percentage
will be in the pathological range of blood values
indicative of severe starvation. Parallel to the
decrease in formed elements of the blood was
a decrease in plasma proteins, with this effect
more marked in the albumin rather than the
globulin fraction.

All the foregoing considerations taken together
suggest that it is most probable that semi-star-
vation is the condition of the general Island

population with starvation the fate for some
proportion each year, as evidenced by the skull
data.

Starvation in mammal populations is rarely
unaccompanied by disease when population
numbers are high. As previously mentioned
no moribund animals were available for their
pathology to be determined and so other meas-
ures of disease were required. White blood cell
concentrations and the sedimentation rate of
red cells are general non-specific indicators of
disease. True, both these measures are affected
by conditions other than disease, e.g., diet and
pregnancy, but in general large variation in
sedimentation rates indicate tissue destruction,
whilst an increase in white cells indicates active
increase in phagocytosis. As a result of the
survey, cycles were found also in these two blood
measures. However, the trends were the oppo-
site to expectation on an hypothesis of seasonal
disease in the late summer. The white cell
counts on the average fell to low values during
this period — this being expected in starvation.
Similarly low sedimentation rate values were
found in the summer, this probably reflecting
the decrease in plasma proteins, which correla-
tion is known to exist.

Rectal temperatures of all animals captured
also follow a seasonal trend when plotted. An
average drop of some 2.5 °C. for the West End
animals occurs in the late summer as compared
to winter values. A control colony well fed and
watered on the mainland shows no comparative
drop during the summer. Studies on domestic
ruminants have shown that the heat of fermen-
tation as measured by body temperature rise
is appreciable after a meal. The quokka being
ruminant-like will have a digestion which will
also contribute this heat of fermentation to its
general metabolic heat. The relatively large
drop in rectal temperature at the summer season
possibly reflects the starvation, being the com-
bined effect of recession of fermentation and
the lowering of the metabolic rate consequent
upon starvation.

From this field survey it is seen that positive
indications exist only for starvation as the con-
trolling factor of population increase for the
Rottnest Island quokka (and see report on the
Physiology of the Quokka in this part). Other
factors either have contra-indications or no
evidence can be adduced for their effect. These
indications are over the study-years of 1955
through 1958, but no unusual seasonal or other
conditions which could make the study-years
non-representative have been discovered.

J. W. SHIELD.

References

Keys. A., Brozeck, J., Henschel, A.. Michelsen, O., and
Taylor. H, (1950). — “The Biology of Human
Starvation" (Univ. Minnesota Press:
Minneapolis, Minn.)

Joint F.A.O./W.H.O. Expert Committee on Nutrition
(1951). — Prevention and treatment of mal-
nutrition in times of disaster. World Health
Organization Technical Report Series No.
45. World Health Organization, Geneva 21.

r-

4 _>

p-jo' i — Exclosure iu Acacia thicket burnt February.
1955, north of Biological Station. Strong regrowth of
Acacia inside fence hides other species not. seen out-
side. Stipa and Thomasia clumps in foreground

Photograph. J. W. Shield

Fig. 2. — Exclosure at Barker’s swamp. Note the dense
regrowth of halophytes inside the fence. Suaeda is
abundant inside the fence but rare outside.

Photograph. J. W. Shield

Fig. 3. — Quokka. Flash-
light photograph of
young adult.

Photograph,
A. R. Main

Fig'. 4.— Wilson Bay. Wide intertidal platform with
outer part terraced. Small intertidal undercut. Note
cross bedding in aeolianite rock.

Photograph, E. P. Hodgkin

Fig 5.— Fish Hook Bay. Photograph taken through
deep intertidal undercut at entrance to bay. Low tide.
Pole height six feet.

Photograph, E. P. Hodgkin

79

Fig. C. Central part of Ilottncst Inland. loosing west. April. 1954. Shows vegetation before the 1955 fire. Arrow

points to Biological Station, Photograph, A. R. Main

and right' "ofuoceTlIke^OaftnTn rwfn, Se ri r P entl ? e . a1 ^ Part of main Serpentine lakes. Note seepage area (top
° nz 01 upper lake » Gahma clumps adjacent to these, Melaleuca copse in foreground, Acacia top left Tuart

plantation top right. Photograph, A. R. Main

82

16. — The Birds of Rottnest Island

For its size (4,726 acres) Rottnest has a dis-
proportionately varied and abundant avifauna,
the reason for which is not hard to find. The
outstanding feature of the Island is its multi-
plicity of habitats: steppe, dune scrub, tall
scrub, samphire, salt-lakes, brackish swamps,
fresh-water soaks, sandy beaches, rocky coasts
and offshore islets and stacks. In addition there
are the man-made habitats of tuart plantations
and grassy clearings.

Systematic accounts of the birds of Rottnest
have been written by F. Lawson l Whitlock 1
<1905), Glauert (1929), and Serventy (1938).
In the present paper the birds will be discussed
under headings of major habitats.

Open Country

Steppe (dominated by Acanthocarpus and
tussock grass) is now the widest-spread plant
formation on the island. Its chief bird in-
habitants are the Pipit < Anthus novaezee-
laildiae) , White-fronted Chat ( Epthianura albi-
frons), Raven (Corvus coronoides) , Kestrel
<Fcilco cenchroides ) , and the introduced Pheas-
ant ( Phasianus colchicus) . A surprising absentee
is the Black-faced Wood-Swallow < Artamus
cinereus), which occurs in similar situations
along the mainland coast.

Scrub

As on the mainland, dune scrub (Olearia
axillaris etc.) supports very few species. Only
the Singing Honeyeater ( Meliphaga virescens )
is common here. The Spotted Scrub-Wren
fSericornis maculatus ) is now quite rare.

A more varied fauna occupies the tall scrub
( Acacia rostellifera , Templetonia retusa , etc.),
but as this formation is being rapidly replaced
by steppe most of its birds are declining. In-
deed, two species, the Brush Bronzewing (Phaps
elegans ) and the Rufous Whistler ( Pachyce -
phala rufiventris) have already disappeared
from the island, while the numbers of Golden
Whistler (P. pectoralis ) and Red-capped Robin
(Petroica goodenovii) are steadily decreasing.
The presence on Rottnest of the latter is re-
markable, for the opposite mainland is occupied
by the Scarlet Robin (P. multicolor), which is
replaced by goodenovii only in the drier country
north and east of the jarrah forest. The
Western Silvereye (Zoster ops gouldii ) alone is
abundant; significantly one of its major food
items is the purple fruit of Solanum simile, a
plant favoured by fire and disturbance generally.
Largely confined to the Templetonia scrub west
cf the salt-works is a small colony of Peafowl
' Pavo cristatus), descendants of birds liberated
from the Zoological Gardens about 1912. The
two introduced turtle-doves ( Streptopelia sene-
galensis and S. chinensis) are not strictly scrub-
birds; they favour isolated thickets and the
contiguous grassland.

Woodland

Woodland is a minor component of the vege-
tation of Rottnest and accordingly few birds are
found in it. The Fan-tailed Cuckoo ( Cacomantis

flab elli for mis > is a common visitor in winter and
spring to the groves of teatree ( Melaleuca pubes-
cens) on the eastern end of the island; whereas
around Perth its status seems to be merely that
cf a passage migrant. The wooded margins of
swamps and lakes are the principal habitat of
the Sacred Kingfisher ( Halcyon sancta) . Large
teatrees are the favourite roosting sites of
pheasants and ravens, the latter commonly
nesting in them. The widespread planting of
tuarts < Eucalyptus gomphocephala) has provided
a niche for the Western Warbler < Gerygone
fusca), which has recently become established
on the eastern end of Rottnest.

Lakes and Swamps

It is on or around the salt-lakes that one finds
the greatest concentration of birds. Throughout
the year certain of the lakes (especially Govern-
ment House and Serpentine) support enormous
numbers of brine shrimps ( Artemia salina),
which in turn provide abundant food for breed-
ing Silver Gulls (Larus novaehollandiae) and
Mountain Ducks < Tadorna tadornoides ) . The
Banded Stilts ( Cladorhynclius leucocephalus)
that visit the Island in summer feed exclusively
on these crustaceans.

The shores of the lakes are occupied in sum-
mer by huge flecks of birds that breed in northern
Asia; they are composed of the following species
(in order of decreasing abundance); Little Stint
( Calidris ruficollis). Curlew Sandpiper ( Calidris
ferruginea) , Turnstone < Arenaria interpres),
Sanderling ( Crocethia alba ) , Large Sand-Dotterel
( Charadrius leschenaultii) , Sharp-tailed Sand-
piper ( Calidris acuminata ), Hooded Dotterel
( Charadrius cucullatus), Greenshank < Tringa
nebularia) , and Golden Plover ( Pluvialis domin-
ica ). The only resident shorebird is the Red-
capped Dotterel (Charadrius alexandrinus ) .
Exposed shell-banks are the chief nesting site of
the Rottnest population of Fairy Terns < Sterna
nereis). The ubiquitous Welcome Swallow
(Hirundo neoxena) is most abundant in the
vicinity of the lakes, where myriads of flying
insects assure it of a regular supply of food.

Fresh and brackish waters support far fewer
species. Outside the breeding season the White-
faced Heron ( Notophoyx novaehollandiae) is a
common visitor to the Island. Grey Teal (Anas
gibberif rons ) are less frequent. Recently estab-
lished on Rottnest, the Banded Plover < Zonifer
tricolor/ usually breeds on grassy flats beside
fresh-water swamps. Rock Parrots ( Neophema
petrophila / drink at the soaks and obtain much
of their food (e.g. samphire seeds) in the vicinity,
but for nesting they resort to the offshore islets.

Coast and Islets

Much smaller numbers of limiccline birds are
found on the coast than around the lakes. Sandy
beaches are occupied by the Pied Oystercatcher
(Haematopus ostralegus/ and the Red-capped
Dotterel, both of which are resident, and a few
migratory species, especially the Little Stint,
Sanderling, and Large Sand-Dotterel. The
Turnstone. Grey Plover (Squatarola squatarola ) ,

83

and Whimbrel ..(Numenius phaeopus ) prefer
rocky shores. At low tide, Reef Herons
(Demigretta sacra) may be seen on the fringing
reefs.

Several marine species nest on offshore stacks
and islets, viz: Osprey ( Pandion haliaeetus >.
Silver Gull ( Larus novaehollandiae) , Crested
Tern (Sterna bergii) , Bridled Tern (S. anae-
theta), Caspian Tern ( Hydroprogne caspia ), Pied

Shag (Phalacrcccrax varius), and Wedge-tailed
Shearwater ( Puffinus pacificus) , though the
largest breeding colony of the last-named is on
the main island at Cape Vlaming. Non-breed-
ing but regular visitors to the seas off Rottnest
include the Gannet ( Sula serrator) and Arctic
Skua (S ter cor arias parasiticus).

D. L. SERVENTY and G. M. STORR.

17. — The Salt Lakes of Rottnest Island

The salt lakes cover some 500 acres at the
eastern end of the Island and separate the
settlement area from the main part of the Island.
At their highest level in August the four main
lakes and Garden Lake are continuous. However
water lies over the bar between Bagdad and
Herschell Lakes only very briefly, and in summer
not only does a bar separate Serpentine from
Government House Lake, but other smaller
portions of the lakes are cut off. Water passes
freely through the built up causeway between
Herschell and Government House Lakes.

The seasonal change in water level is marked.
The highest winter level (August) is 2.8 ft above
zero on the Fremantle tidal datum (fixed at
lowest low water). By March the level of Lake
Bagdad has fallen to -f0.5 ft (’57, ’58, *59),
Herschell and Government House Lakes to — 0.5
ft and the main Serpentine Lake to -f-1.0 ft
(’59). Monthly mean sea level varies from
2.8 ft in winter (June* to 2.1 ft in summer
(October to January); the lakes are thus below
sea level for most of the year.

The lakes have wide, gently sloping littoral
fringes and are of no great depth so that the
seasonal evaporation results in considerable con-
centration of the salts. Chlorinity figures for
the 1958-59 season are thus shown below: —

Lake

Approx.

Depth

Chlorinity. parts

i per thousand

1 4/9/58

26/11/58

9/2/59

22/3/i

Bagdad ....

ft.

s

43

51

67

63

Herschell ....

16

55

60

73

76

Garden

32

38

60

67

Govt. House

20

(55

70

84

83

Pink

27

46

158

183

There is considerable seepage into the lakes
and this shows as a film of water between high
and low lake levels. The principal areas of
seepage are shown on the map. Most are fresh,
with chlorinities between 0.5 and 3.0 ( '/oo, some
are brackish and one, on the north shore of Lake
Bagdad at its nearest point to the sea, approxi-
mates the chlorinity of sea water <19.0 %o).
The three small western lakes are shallow and
Negri and Sirius dry out each summer; from the
biological point of view they are best regarded

as brackish. The western part of Government
House Lake becomes cut off and may also dry
out; until recently the salt from this was
harvested commercially.

There is no macroscopic plant life in the salt
lakes apart from an algal film on the rocks
and the spheres of Botryoccccus macropogon
(Xanthophyceae) that are washed up on the
shores, Lamproth amnion macropogon (Charales)
grows in the brackish lakes.

The fauna of the lakes is very restricted in
number of species. Artemia salina is the prin-
cipal planktonic animal. It is present in the
three large lakes and Garden Lake but is par-
ticularly abundant in Government House Lake
where the water on the leeward side is often
coloured pink by the animals. Chironomid
larvae (Tany tarsus sp.) and the larvae and
pupae of an ephydrid fly are abundant in the
algal film cn the rocks round the lake margins
and at times free in the water. Hydrophillid
and dytiscid larvae and adults and the larvae
of a trichopteran Symphitcneuria wheeleri occur
seasonally. Isopods are common under loose
stenes.

The brackish water gastropod CoxieUa
striatula is abundant in lakes Negri and Sirius:
Macpherson (1957) records the type locality of
this species as ‘'Lake Ursula,” a name used by
Mr. Glauert for the seasonal pool in Rifle Range
swamp. The crab Brachynotus octcdentatus
occurs in brackish seepage at north Bagdad Lake;
this species is common in brackish waters along
the south coast of Western Australia. Chirono-
mid larvae, amphipods and ostracods are
common in the seepages.

There are extensive shell deposits round the
lake margins, both consolidated in the littoral
shelves and as unconsolidated material at up
to 12 ft above lake level. They are composed
largely of lamellibranchs; Katelysia scalarina
and Venerupis sp. appear to be the most abund-
ant, and Hormcmya sp. nov. is also plentiful.
Several species of gastropod are common, in-
cluding Notoacmea onychitis and three species
of the small Diala; Eubittium laioleyanum is
abundant in the upper part of some deposits
and this appears to have been mistaken for
Coxiella by Teichert (1950).

84

In many places there are undercut cliffs near
the lake edges similar to the intertidal undercuts
of the ocean coasts, and at the same level; they
are illustrated by Teichert ( 1950 > . The exist-
ence of these makes it certain that the lakes
were connected to the sea at a time when sea
level was little different from the present. Most
of the common species of the shell deposits still
live in coastal waters near Fremantle (principally

in the shelter of Cockburn Sound). Of the
others, many. e.g. Katelysia spp., are common
along the south coast of W.A. and a few are
known only from the north west (Shark Bay).
Most live in sand or silt but both Notcacmea and
Hcrmomya live on rocky shores. The fauna is
that of a marine gulf under stable conditions of
temperature and salinity (G. Kendrick, in lit.).

E. P. HODGKIN.

18. — Fresh Water and Brackish Water Swamps of Rottnest Island

These swamps lie in the eastern half of the
Island and, in comparison with the salt lakes,
have a very limited area. Most of the larger
swamps (Lighthouse, Salmon. Barkers, Bulldozer.
Bickley, Rifle Range and Parrakeet > are situated
in interdune depressions. Aerodrome Swamp
was however, originally part of Government
House Lake; it was isolated during the con-
struction of the aerodrome in 1943 and is now
much less saline. Corio Pool and the two small
Garden Pools lie adjacent to salt lakes and,
like the seepages round the lakes, appear to be
fed by a seasonally variable seepage. In addition
to these waters, there are some wells which act
as breeding sites for mosquitoes.

Two important factors affect the biology of
the swamps.

(a) Water is generally present only during
the winter; the ponds fill near the time of the
first heavy winter rains in May or June and the
last free water evaporates with the higher
temperatures of late October and November.
Pools in Bickley Swamp and Aerodrome Swamp
may retain water through summer and even in
the shorter lived swamps the soil remains moister
than in the surrounding dunes.

(b) The water of some swamps is brackish
and shows marked seasonal changes in salinity.

Apart from research on frogs and some
preliminary studies on dragonflies, no study has
been made of the faunal succession of the
Rottnest swamps. The frogs have been studied
by members of the Zoology Department as part
of investigations of the Western Australian
amphibian fauna, and the results will be
published elsewhere in the near future.

Collections were made from all the freshwaters
in October, 1958. Unfortunately, identification
of the material is still incomplete, but Table 1
shows the distribution of animal groups. It is
evident that not only is the total fauna a
restricted one, but that it differs from one swamp
to another. It is clear also that animals main-
taining populations in the temporary swamps
must show certain adaptive characters in relation
to the factors mentioned above, (a) They must
either aestivate as a drought resistant stage or
recolonise the ponds annually from the main-
land. All the Crustacea belong to groups known
to have aestivating eggs, with the exception of
the amphipod, which is the littoral rockpool
talitrid. Hyale rubra (kindly identified by Dr.
K. Sheard > . In contrast, larval dragonflies
' Anisoptera) cannot withstand drying and
annual recolonisation occurs; successful breeding
depends on rapid growth, but in years when the
ponds are short lived, breeding is frequently
unsuccessful (Hodgkin and Watson 1958). f'b)
They must be able to withstand some degree of
salinity; the capacity for osmoregulation being
important in the range of swamps inhabited.
Investigations of the fauna of the Rottnest
swamps must give valuable information relative
to adaptation to seasonal aridity and to salinity
and may also throw light on divergence from
the mainland swamp fauna.

D. H. EDWARD and J. A. L. WATSON.

Reference

Hodgkin, E. P., and Watson. J. A. L. (1958). — Breeding
of dragonflies in temporary waters. Nature
Loud. 181: 1015-1016.

19. — The Littoral Environment of Rottnest Island

Fauna and flora of the rocky shores of the
Island have been studied over many years and
are now fairly well known. Sandy bays and
beaches, and the abundant life of the sublittoral
rocks have, however, received little attention.
Zonation of the animal and plant life of the
intertidal limestone platforms, in relation to tide
levels and exposure to wave action, has been the
particular interest of the writers. Surveys have
been made over a number of years; the results
have been presented as theses (Marsh 1955, and
Smith 1952) and are in preparation for
publication.

Tidal range is small, maximum daily range
is about 3 ft and extreme range about 5 ft, sea
level being influenced by air pressure, water
temperature, and prevailing winds (Hodgkin and
Di Lollo 1958). Sea temperature varies remark-
ably little; it rarely exceeds 23° C or is less
than 18° C. The water is generally very clear
and estuarine water from the Swan River rarely
leaches the east end of the Island, even during
heavy winter rains.

Sandy bays and rocky headlands with inter-
tidal platforms alternate around the 20 miles of
coastline and narrow limestone bars, barely

85

TABLE I

LOCALITY

x:

- ?

X

X

x

80

Sq-

yd.

C 0

>

• /

-u>

(C

o

71

>

8

Y

— ^

jH

< S’.

•J1 — :

i";

•<

i ' r - H

1

5 = 55

? S ! S

£ X c* H

— < ^ <3

< X PH

25

15

Sp.

v d

1-2

Acre

1 -4 1

Acre s ".
yd.

1-5 2 0 1 0 0-4
Acre Acre Acre Acre

A PP

RON 1. MATE AREA

Scj.

yd.

4 -6 Acre

f '

CH LORINITY

' °/oo 18. X. 1958

0-6

1-2

1 -7

1 -8

2-4

2-6 3 1

4-4 4-8 7 0 Dry

(SEA-YVATER

19°/ 00 ) 26. XI. 1958

0-8

2-4

Drv

50

1 8-8

Drv

8-4 Drv 14-2 Dry

9. II. 1959

Dry

Dry

Dry

Dry

4-2

Dry

68-5 Dry Dry Dry

’* Chara " sp. 1

*

*

sc

*

s=

Sc

Sc Sc St

“ Chara ” sp. 2

1

=i< S 6

('/imoi/eton prorerum (R. Hr.)

*

A Q U A 1'IC

Eluded ••anademrs Michx.

*

1

Y E 0 E T A T 1 0 X

('russula nutans Thuuh.

*

if

❖

St ()

Hupp in mar Hi mu L.

s*e

if

if

—

St

s= 0

Lepiluenn preissU (Lclim.)

St

ANNELIDA :

OLIGOCHAETA sp.

S'

*

*

*

Sc

HYDRA! ‘ARINA :

// t/drachna sp.

*

<:

Ei/lais sp.

St

Diplodontus sp.

*

—

sp. 4

*

CLADOCERA :

Simoeephalus sp.

*

St

Moina sp.

*

*

•

Pseud omoina sp.

*

St

❖

1 *

St

OSTRACODA :

Ci/pris sp.

St

St

*

St

sp. 2

Sc

*

*

St

St

St s<

S< St

sp- *

St

St

St

sp. 4

#

sp. 5

St St

sp. 6

*

❖

COPEPODA :

sp.

*

*

St

St

St

S'

ISOPOD A :

sp. 1

*

sp. 2

S'

AM P1I IPO DA :

11 pale rubra

*

*

St

❖

St

St 5

ODONATA

Anar papuemis

*

V

()

s<

0

Aexhna brerixti/la

S=

I A UNA

Ileinieorduliu tan

*

*

()

()

Orthetrnm Caledonian in

o

A ustrnle.st.es nnnnloHHs

0

St

St

❖

*

1 1 EM 1 PTE R A :

V ELI 1 DAE.

*

G E LASTOPOR IDA E.

*

NOTON ECTTDAE. sp. 1

*

*

*

St

St

St

1 1

sp. 2

*

CORIXIDAE. sp. 1

*

*

St

*

sp. 2

St

COLEOPTERA :

DYTISCI DAE. (adults), sp. 1

*

St

St Si

Laneetes sp.

*

*

St

*

sp. 3

St

1

sp. 4

*

*

St

— .

sp. 5

*

*

*

St

*

*

Sc *

It hunt us sp.

St

St

St

DYTISCI DAE. (larvae), sp. 1

*

*

St

St

S' S'

sp. 2

*

St

St

sp. 8

*

.

HYDROPH1LIDAE (adult) sp.

St

s<

St S'

HYDROPH 1 LI DA E (larvae) sp. l

*

*

*

sp. 2

*

St

*

H AL1 PL 1 DAE. (adult) sp.

St

St

if *

II A LI PL I DAK. (larva) sp.

St

• 1)1 PTE R A :

CHI RON'O.M 1 DAE. sp. !

St

if

sp. 2

*

St

Sc

Proclarhus sp.

*

1

Ch. irommm oppositus

*

St

St

*

Cl LK'IDAE. Aeries australis

*

A ales cn in ptorhpnr/i us

Si

.1 dies sp.

SC

A n oph el e.s annuli pes

*

St

()

1

STRATIOMY1DAE sp.

*

*

*

St

St

St

St

St S' St

GASTROPODA :

CoricUa xtri alula

s

s

s

s S * —

(8 = shells only)

AMPHIBIA :

Cr i n i a i nsigni fern

0

()

0

Heleioporns ei/rei

()

O

0

o

0

()

()

0 0 0 0

_

Hpla moorei Copeland

()

O

o

o

= Collected 18. x. 1958. O = Collected prior to 18. x. 1958.

86

submerged, join headland to headland partially
enclosing many of the bays. The littoral
environment is made even more varied by the
different aspects of the coast; swell is mainly
from the SW., with winter storms from the NW.;
Cape Vlaming is almost continuously wave
beaten, whereas Thompson Bay is sheltered and
the sea often calm.

In the bays the water is generally not more
than 20 ft deep and the sandy floor bears exten-
sive stands of sea grasses; principally Posidonia
australis and Cymodoceci antarctica. The sea
grasses are heavily epiphytised by small algae
such as Polycera zostericola, Asperococcus
bullosus, Eryopsis plumosa and the corallines
Melobesia sp.. Jania micr arthrodia, and Coralline
cuvieri. No systematic study has been made of
the fauna; the foraminiferan Marginopora lives
on the sea grass and is washed up in great
numbers on some beaches, the sand anemone
Radianthus concmata, tectibranchs, and holo-
thurians may be common. The calcareous sand
varies from a fine white sand (e.g. west end of
Salmon Bay) to a coarse-grained material in
which the nature of the shell particles is readily
recognised under a hand lens te.g. Cape
Vlaming). The burrowing ghost crab Ocypode ,
the gastopod Oliva australis , and the sipunculids
cccur sporadically, and terebellids and other
burrowing polychaetes are common on beaches
relatively rich in organic matter. Again this
beach fauna has not been specifically studied.

Intertidal Platforms

The rocky shores have the characteristic
conformation of all limestone coasts of south
western Australia of the type described by
Fairbridge (1950): flat, intertidal platforms
which vary in width from a few feet up to a
hundred yards and in level from just below
mean L.W. to almost M.S.L., above this an
undercut hard rock face with an overhanging
“visor” 6 to 8 feet above the platform; the
platform terminates abruptly to seaward and is
generally undercut beneath, often deeply. In
places the intertidal undercut is replaced by a
sloping “ramp”, sometimes kept free of littoral
organisms by moving sand.

Zonation of fauna and flora is similar to that
of mainland coasts. A littoral zone above H.W.
is dominated by Melaraphe unifasciata and
Tectarius rugosus : below this two limpets,
Notoacmaea onychitis and Siphonaria luzonica ,
are dominant down to about M.S.L.; succeeded
by the limpet Patelloida alticostata in the lowest
part of the undercut and on to the platform.
The secondary organisms of the Patelloida zone,
two species of Patellanax , Melanerita, three
chitons, an anenome ( Actinia ) and a barnacle
(Tetraclitaf , vary in occurrence with shade and
exposure to wave action.

The rock immediately above platform level
often bears sparse communities of macroscopic
algae during the winter; Enter oviorpha sp., Ulna
lactuca, Chaetomorpha aerea , Cladophora spp.
and Porphyra umbilicalis are the chief com-
ponents. Within the rock surface a permanent
community of filamentous blue-green algae
extends from platform level to well above the
littorinid zone. The more encrusting blue-green,
Calothrix sp. is also widespread in this zone.

Both algal communities form the principal food
of the browsing molluscs and are also browsed
by the shore crab Leptograpsus variegatus.

Where the intertidal platform is narrow the
vertical zonation continues with no break to
below L.W.. and the Patelloida zone is succeeded
immediately by the lithethamnion zone, described
below, which extends to mean low water level.
M.L.W. is often marked by an abrupt line, the
upper limit of large algae, Ecklonia radiate and
Sargassuni spp. marking the sublittoral fringe.

On wide platforms the vertical zonation is
interrupted and there is a horizontal zonation
across the width of the reef. Because the
platforms lie at various heights in the intertidal
range, may or may not retain water, and have
different exposures to wave action, there is much
variation in the development of the zones on the
platforms. The following four principal zones
can be recognised:

Patelloida zone. — Considerable areas of plat-
form are grazed bare by P. alticostata;
nothing else lives in such places except
tufts of small algae on the limpets them-
selves, This is found particularly on
slightly higher parts of platforms from
which water drains at L.W.

Jania zone. — The coralline alga, Jania
fastigiata , forms extensive turf -like
masses which retain sand and form a
matrix in which large stands of C aider pa
cylindracea , Controceras clavulatum,
and Lauren cia heteroclada often occur.
Small crustaceans, polychaetes and other
worms abound in this turf. There are
usually few larger animals though the
gastropods of the brown algal zone are
sometimes common. This community
often covers wide areas of platform < e.g.
west of North Point), particularly where
shallow water lies on the inner parts at
low tide.

Zone of brown algae. — Bushy brown and red
algae often cover parts of the platform
over which water normally washes, even
at low tide. The dominant species are
the fucoids, Sargassuni spp., Cystophora
uvifera and Cystoseira abrotani folia,
and the red algae, Pterocladia capillacea
and Hypnea niusciformis. The fucoids
are often stunted and sterile for most
of the year. This algal community pro-
vides a suitable habitat for browsing-
gastropods of which the commonest are
Euplica bidentata. Pyrene spp. and
Senectus intercostalis.

Lithothamnion zone. — The term "litho-
thamnion” is used for the encrusting
coralline algae which form a thin or
thick cover to the rock. It is particu-
larly well developed where waves break
on the outer parts of the platform. With
it, and sometimes entirely replacing it
are the following browsing molluscs:
Onithochiton occidentalis, Clavarizona
hirtosa, Haliotis roei, Patelloida alti-
costata, Patellanax laticostata; of more
variable occurrence are the barnacle
Balanus nigrescens and the anemone
Isanemonia australis .

87

In exposed places this zone may be
10 or more yards wide while in more
sheltered places it may be only a narrow
fringe a foot wide bordering the edge
of the platform.

Interesting differences are shown in
the development of this “outer edge”
fauna. A high ridge at Cape Vlaming
constantly swept by heavy waves has
an exceptionally dense population of
Onithochiton, P. laticostata and Balanus
with small numbers of Clavarizona and
Patelloida. High platforms at the outer
edge of the main platform in less wave-
exposed places have the same species,
but dominated by Patelloida. On a low
level platform in the much more
sheltered waters at the west end of
Salmon Bay Haliotis is abundant and
Clavarizona largely replaces Onitho-
chiton; Patelloida , Patellanax and
Isanemonia are also common.

Zoogeography

The littoral fauna of the mainland coast from
the mouth of the Murchison River southwards
is predominantly Flindersian in its distribution.
The littoral fauna of Rottnest however includes
a considerable number of species which arc
Dampierian or found throughout the tropical
Indo-Pacific region. They are particularly
abundant on the platforms at the west end. A
few of these, especially the gastropods, occur
further south between Cape Naturaliste and
Cape Leeuwin, but most are rare or absent south
of Rottnest. These "tropical” species include:
Three species of Echinoidea i Echinometra
mathaei is particularly abundant*, six species of
Zoantliidea, an actiniarian. one coral, Pocillo-
pora damicornis, and seven species of Gastropoda.
In addition to these we have found ten species
of hermatypic coral in the sublittoral: they are
most abundant on the south coast where they
occur as scattered colonies. Pocillopora alone
forms a "reef”, near Parker Point, but this grows
on the limestone and there is no true reef
building. Associated with the Pocillopora are
crabs and gastropods not found elsewhere:
hermit crabs are also abundant.

Sublittoral

The intertidal platforms are deeply undercut
below low water These “sublittoral undercuts”,
pieces detached from the edge of the platforms,
and the "bars” across bays are the principal
rock surfaces accessible from the shore. The
algal flora is a rich one and is reasonably well
known systematically, mainly from the collec-
tions made by Preiss and Harvey in the vicinity
of Rottnest in colonial times. The fauna has
as yet received little systematic study. Distribu-
tion of fauna and flora in the sublittoral rocks
is known only from preliminary surveys with
face masks and self-contained diving apparatus.
The better illuminated surfaces are generally
covered by large algae over a lithothamnion
encrustation, though flat surfaces sometimes
carry a thick cover of Jania and other coralline
algae. The brown algae Ecklonia radiata,
Scytothalia dorycarpa, Scaberia agardhii and

Sargassum spp. are abundant, also the red alga
Metamastophora flabellata. On well illuminated
rocky substrata towards the sublittoral fringe
there is an abundance of Siphoneae, Dictyotales,
and Ceramiales.

In the undercut much of the rock surface is
again covered by encrusting coralline algae, but
leafy algae are sparse and confined to a few
Rhodophyceae in the more shaded parts.
Beneath the overhanging rock and further back
in the undercut the dominant organisms are a
great variety of sedentary animals. These
include many sponges (16 species being noticed
in a collection sent to Dr. M. Burton at the
British Museum); hydroids, zoanthids, alcyon-
arians, corals, and sometimes a rich growth of
the many coloured gorgonian Mopsella spp.;
Bryozoa; and simple and compound ascidians
(Kott 1952 and 1957*. Actively moving animals
are not abundant: those noted include nudi-
branch gastropods, ophiuroids and a great
variety of worms, under the lithothamnion,
sponges and ascidians. Heliocidaris is present
in the sublittoral of Thompson Bay, but the
"tropical” echinoids of the west end have not
been seen in the sublittoral.

The Crayfish

Panulirus longipes is the commercial crayfish
of W A.: in the year 1958 13-2- million lb. of
crayfish were taken. This yielded nearly 5
million lb. weight of crayfish tails worth £A2£
million for export to the U.S.A. Commercial
crayfish ermen operate from boats in water up
to 100 meters in depth, but the species is common
also on rocky shores around Rottnest and front-
ing the mainland from Dirk Hartog to Mandurah.
During the night the crayfish emerge on to the
intertidal platforms and graze on any plant or
animal material that projects above the general
level of the rock. They return before daybreak
to the sublittoral or to large pools in the
platform and hide in crevices in the rocks,
particularly in the undercut. Investigations by
George (1959) into the breeding and moulting
cycles and feeding habits were made partly on
Rottnest, and these add greatly to basic biological
knowledge of the crayfish.

In Rottnest waters the mature females moult
in June-July and mate a few weeks later, eggs
are discharged on to the pleopods in November-
December and fertilized (the spermatophore is
ruptured by scratching), eggs are released
in January-February and larvae hatch as
naupliosoma, after which the female moults
again. Tagging has shown that females breed
annually. Small immature “white crayfish”
have been tagged; when recaptured in the
following season most were still whites, but
some had normal red pigmentation proving that
the white crayfish is only a developmental phase
of P. longipes — contrary to the belief of many
fishermen (George 1958). Recaptures showed
a mean increase in carapace length of 0.3 in. or
12.5 per cent in those size groups.

E. P. HODGKIN. L. MARSH and G. G. SMITH.

Reference

Fairbridge, R. W. (1950).— The geology and geomor-
phology of Point Peron, Western Australia.
J. Roy. Soc. W. Aust. 34: 35-72.

88

20. — Population Studies in the Littoral at Rottnest Island

Preliminary studies have been carried out on
a common crustacean and a common mollusc
of the rocky shores.

Leptograpsus variegatus , — This species of rock
crab is ubiquitous throughout the rocky shores
of the temperate southern hemisphere. On Rott-
nest the females are carrying eggs externally
from September through the spring and early
summer until the end of February. Moulting,
as gauged by the feel of soft carapaces when
handling the animals, occurs at all seasons but
seems to increase in frequency just before and
just after the season when the females are carry-
ing eggs. The animals are omnivorous scaven-
gers. They have been noted eating dead fish
and limpets detached from the rocks, but they
appear to live mainly on the marine algae which
they pick from the rock with their pincers.

The natural habitat of these crabs is on rocky
surf -exposed shores and rocks just above the
water line. During the day they retire into rock
crevices or hide in rock debris. However they
are known to move about in the shadow during
the day but are extremely wary and retreat to
cover in a flash if approached by an observer.
At night the behaviour pattern is entirely
changed. When approached by an observer with
a flashlight the crabs in most instances remain
motionless or continue eating. Their capture
and examination is extremely easy under these
conditions.

As the specific name indicates, Leptograpsus
is noted for the individual colour variation which
ranges from a very dark blue to orange and a
light slate colour. By arranging some 200 of
these crabs in a colour sequence it was obvious
that this great variation in colour was not con-
tinuous but discrete. There were in fact only
two distinct colour groups the one a blue phase
and the other an orange grading into slate.
The latter phase contained a preponderance of
orange coloured males and, contrariwise, a pre-
ponderance of slate coloured females.

The study method used is to walk along the
reef platform at night with a flashlight in
several selected study areas and by this linear
traverse method score some 150-200 crabs for
colour phase, sex, place in the undercut
(whether in the splash zone, water, or on the
dry rock face). The linear sequence of such
observations is preserved. The study areas have
in most instances been marked with paint divi-
sion lines — generally the whole traverse is
divided into 10 subdivisions.

Analysis to date of these traverse scorings
has revealed several interesting facts. Firstly
the colour phases seem to have differing afifiini-
ties for the rock positions where they feed. Blue
phase crabs show a propensity to locate them-
selves higher up on the rock face whilst the
orange and slate colours have a tendency to be
found lower down on the wet rock face or actu-

ally in the water. Secondly, by subdividing the
traverse it has been possible to determine
whether the one phase tends to inhabit a certain
locality. This has proved the case; certain areas
have a stable population of one phase rather
than the other and this stability is maintained
throughout the season. One study traverse —
Wilson Bay — has been intensively worked over
a period of two years and the above results are
mainly from this place. However about 6 other
standard study traverses have been worked and
the analysis from all these places supported
that from Wilson Bay. It appears that the
orange/ slate phase prefers the wetter part of
its habitat. It inhabits the lower part of the
reef predominating where the undercut faces
open or broken water, i.e., those sections of
the traverse having a preponderance of orange
phase animals are generally those where the
surf breaking on the rock is more intense.

Here then we have a polymorphic species in
which the morphs have separate ecological pre-
ferences. These preferences are not absolute
ones but are only revealed and statistically
established after a large number of observations.
Perhaps this species is in the process of split-
ting into two species in an early stage of Dar-
winian evolution.

Melanerita melanotragus. — The black peri-
winkle Melanerita melanotragus abounds on the
limestone surf rocks about mean sea level over
the whole of Rottnest. It has attracted interest
as an experimental animal for population
studies because of several of its attributes. The
variation in size of individuals of the various
colonies throughout the island is great. In
areas where there is a low density the animals
tend to grow to a large size and where the con-
centration is high they are of a relatively small
average size. Moreover these average sizes and
the population size compositions have not
changed over a period of 5 years. Four experi-
mental populations have been divided into 5
size classes over this period by seiving through
standard mesh screen; all populations appear
to be maintaining their size composition. Fur-
ther w T ork is devoted to determining whether
this stability is environmental or genetic, or
whether the fortuitous initial density of animals
is the controlling factor.

Some five years of marking of individual
animals indicates that the extreme age of the
animals can probably exceed 15 years. In addi-
tion this work has shown that although in
general the animals are restricted in their move-
ments they can move up to 16 feet over the rock
face in one night.

The studies are proceeding mainly with the
aid of student labour; further work is to be
devoted towards establishing life tables for the
several study populations.

J. W. SHIELD.

89

21.— Student Training at the Rottnest Biological Station

At the present time the Station is used only
by the Zoology Department for regular student
training although staff and students of other
University departments use it from time to time.
Training is at three levels: postgraduate, during
the third year of the degree course, and at the
beginning of the second year.

Postgraduate

Participation in research projects discussed in
other parts of this report has formed a large
part of the training of Honours. M.Sc. and Ph.D.
Candidates. The Station has been the base for
their field operations with the island fauna their
main research material. No separate account of
this aspect of student training is required here.

Population Ecology

At the end of their third year course students
spend a week at the Station making a practical
study of the dynamics of animal populations.
This is regarded as an integral part of the
Zoology course and a short written examination
has been included during the last two years.
The fact that staff and students live and work
together the whole time effectively counteracts
any tendency to take the course light-heartedly
after the major examination tension has ended.
There are opportunities both for fun and re-
laxation and for stimulating discussion as a
result of common interest in the problems
studied. For staff this is often also an oppor-
tunity to evaluate the results of the years teach-
ing. sometimes with outspoken criticism from
students, and to plan future teaching and
research programmes.

The ordinary laboratory course necessarily
presents the student with the animals he is
studying as individuals. Whether it be in the
study of systematics, comparative anatomy, or
physiology, the animal is usually treated as a
unit, representative perhaps of a family, class,
or phylum, but rarely as one of a population of
similar individuals. In this field course emphasis
is laid throughout on a study of quantitative
attributes of populations of animals: reproduc-
tive rates, mortality rates, immigration and emi-
gration rates, age structure, and total numbers
in the populations.

The methods used are those which have yielded
research results in population studies. The same
species of animal, and in many cases the same
populations, have been studied in successive
years and the results obtained form part of
research programmes discussed elsewhere in this
report.

The statistical knowledge necessary to the
working of the various estimates is ” acquired
through a series of lectures in biological statisti-
cal methods given during the third-year course.

The principal animals studied are:

1- — Jewel beetles, Castiarina hopei, on
flowers of the “Rottnest daisy.” Random
samples are captured on discrete daisy
patches, marked, released, and recap-
tured over successive days, with the

object of determining adult life span,
adult recruitment rates, and population
total numbers.

2- — The black periwinkle, Melanerita
melanotragus, on intertidal rocks. This
has proved ideal for student exercises
in estimation of population size be-
cause estimates made by the mark and
return method can be immediately
checked by a total physical count.

3. — The whelk, Dicathais aegrota, on inter-

tidal rock platforms. Samples attracted
to baited traps are marked, returned,
and recaptured. “Latin square” evalua-
tion of captures makes it possible to
study food preferences and distribution
on the platforms.

4. — The rock crab, Leptograpsus variegatus,

is caught by hand at night on intertidal
rocks for estimation of total population
and habitat preference of the three
colour phases. The size of the popula-
tion is determined by the method of
removal of one sex and a subsequent
count to reveal a change in sex ratio
from which a population size estimate
is made.

5. — The quokka; estimation of population

size by ear tagging and return, and a
measure of relative abundance by visual
counts on a regular circuit.

Second-year Camp

This is held over four days immediately before
the start of first term and all students entering
the second year course in Zoology are required
to attend. The camp has two main aims: first
to enable staff and students to get to know one
another in the friendly atmosphere of a camp,
and second to introduce students to living rep-
resentatives of the various phyla.

The marine environment is the richest source
of material and receives most attention, but
collections are also made in the salt lakes to
shew the restricted fauna of a specialised en-
vironment, and students assist in aspects of the
quokka research programme. Animals collected
are brought, back to the laboratory and are
identified as far as possible with standard texts,
by means of simple keys, and sometimes by
reference to original literature. In most cases
no attempt is made to run them down to species,
the emphasis being rather on learning to
recognise the broad systematic position of the
animals and to know hoiv to identify them.

The second year course has an ecological
background, but animals handled in the systema-
tics course are of necessity often preserved. The
emphasis in this introductory camp is on seeing
as many kinds of animal as possible alive in their
natural environments. Attention is constantly
drawn to the relationship of the animals to their
physical environment and to one another.

E. P. HODGKIN and J. W. SHIELD.

90

22. — Rottnest Island Board

Background

For many years Rottnest had provided a
secure place of confinement for native prisoners,
but as farming areas developed on the mainland
and the country became more settled so the
need for such a place grew less urgent. At the
same time the Island was used as a desirable
place of recreation by the fortunate guests at
the Government House shooting parties but no
members of the public were allowed to land
without permit. A flush of money at the time
of the gold rush in the eighteen-nineties en-
abled the building of several ministerial cottages
along the Thompson Bay front.

First mention of the possibility of a wider
recreational use seems to have come from the
Speaker of the Legislative Assembly after his
first taste of island hospitality. In 1905 he urged
the development of the Island as a tourist
resort. Immediate steps were taken to survey
the position, and a most extravagant plan of
works emerged. Only strong outside pressure
prevented the subdivision and sale of 300 blocks
of land on the Island to provide finance for
this.

Vice-regal support for a wider use was positive
as will be seen from the following extract from
a minute dated March 1907, from the office of
His Excellency Admiral Sir Frederick Bedford:

(1) The Island should be declared a Public
Park and recreation ground for ever. It
is very desirable to avoid the idea
getting about that the Island is being
exploited for the benefit of the few
men, who at this time could afford to
buy or rent plots to build.

(2) That the natural beauty of the Island
shall not be disturbed more than is
absolutely necessary.

(3) Better communication with mainland.

(4) That it should be made more attractive
by planting trees and making roads.

Further opposition killed any idea of sub-
division, and the government began some small
building development in the area of the present
barracks. A change of government swung the
location of settlement in the opposite direction
towards Bathurst, but before much could be
done the impact of World War I held up all
progress while during a long term stay of
prisoners -of -war much was destroyed of what
little building had been attempted.

On 12/5/17 the Island was gazetted a Class A
Reserve under “The Permanent Reserves Act,
1399,“ and a Board appointed under the Chair-
manship of the Colonial Secretary (Mr. H.
Colebatch). As it received no subsidy, the Board
immediately found itself in financial difficulty.
To this day the Board functions under the same
condition and under the same anxiety. In order
to arrive at some measure of assistance, the
experiment was tried of establishing a new
prison camp in the valley between Lakes
Herschell and Bagdad, for good conduct
prisoners. This however proved unsuccessful
and after three years, 1922 saw the departure

of the last prisoners, white and black. (The Boys’
Reformatory in the present Hostel had ceased
to function in 1901.)

Present Constitution

The Board today functions under the Parks
and Reserves Act, and in status is a statutory
body free of any departmental authority. With
its freedom of function however, it remains free
of subsidy so that its very limited resources
come from rents, leases and landing fees. One
exception is the recent establishment of water
catchment area and storage of approximately
one and a half million gallons — a project quite
beyond the resources of the Board and met by
the government of the day.

The Board is presided over by a Minister of
the Crown (in 1958, Mr. Kelly — Minister for
Lands and Agriculture) and its personnel con-
sists largely of experts in the field of building
and architecture, engineering, roadmaking and
law.

The duties of the Board embrace:

(a) The extension of residential facilities.
(b> The maintenance of existing buildings.

(c) The maintenance and extension of
services — water, sewerage, lighting and
power.

(d) Administrative.

(e> Beautification of island, particularly in
the restoration of trees.

(f> Development of recreational services,
(g) Protection of the Island’s natural re-
sources.

The Island administration is in the hands of
the Managing Secretary, who is resident there.

Biological Aspects

On the one hand the Island presents a
wonderful potential for natural life, with its
sheltered valleys, its many protected bays, its
very large expanse of wide shore reefs and its
delightful system of salt lakes. Unhappily on
the other hand it is a typical example of the
human flair for destruction of natural resources.
Decades cf bushfire destruction — much of it de-
liberate to disclose game — have reduced half
the Island to bare heath. Present day control
in this respect has been offset by protection
of the indigenous quokka, which has now in-
creased very greatly in population to the extent
that natural regeneration of unprotected vege-
tation is practically impossible.

The protection of the crayfish from illegal
fishing is a major problem with such a long
shore line and with settlement so firmly estab-
lished at one end. At the moment the spear
fishermen are suspect of large scale disturbance
if not depletion of marine life in the pools and
reef areas. The birds appear to be comparatively
free from disturbance and the eye of the visitor
is delighted with the sight of the many aquatic
birds about the lakes. An occasional peacock
and the small population of pheasants are des-
cendants of those introduced in the year 1912.
There is also a well established population of
small land birds.

91

Re-afforestation

Over the last three decades the Board has
been actively engaged in an attempt to restore
some of the lost vegetation. The main indigenous
trees of the Island include; Callistris robusta
(Rottnest Pino; Melaleuca pubescens (Rottnest
Tea Tree) ; Acacia rostelli/era ( Rottnest Wattle) ;
Pittosporum phillyraeozdes (Native Pittosporum) ;
Templetonia retusa (a shrub).

As early as 1886, a grant of £50 for the estab-
lishment of a pine plantation allowed the
experimental planting of 500 trees of several
types in the Bathurst area. Reports in 1889
indicated an almost complete failure due no
doubt to the combined influences of soil
deficiencies, wind, drought and the attacks of
animals.

There was no revival of effort till 1907 when
200 trees were planted at Mt. Herschell and 600
near Bickley Swamp. Before the onset of
summer practically all with the exception of a
few aloes were lost. Later still more care and
watering developed the magnificent avenue of
Moreton and Sydney figs and olives through the
settlement and the large pines to be found in
the older parts of the settlement.

It rested with the late Dr. W. Somerville to
bring to bear the conviction and energy neces-
sary to force successful results.

A disappointing start in 1929 stressed the need
for a local nursery. From 1932 onwards the
story is one of continual progress. After experi-
menting with native trees from the mainland,
the outstanding result was the discovery of the
hardihood and quick growing qualities of the
Tuart (Eucalypt us gomphocephala) . Somerville’s
book “Rottnest Island” from which much of this
information was taken, shows photographs of
trees planted by Italian prisoners-of-war in 1942.
After seven years these trees had reached a
height of 55 feet. Between 1934 and 1944 he was
responsible for the raising and planting out of
5,000 tuarts in the plantation near the head of
Serpentine Lake. At the same time there was
developing to the north of the settlement a large
plantation for use as a camping area. Alto-
gether during eleven years it was estimated that
41 acres of plantation and 210 chains of line
planting had been effected. Planting has con-
tinued at the approximate rate of five to six
hundred trees per year. The present beautifica-
tion of the settlement area stands as a memorial
to Somerville, who was also largely responsible
for the original planning of the beautiful Univer-
sity grounds at Crawley. As an example of the
experimentation that went on. the following still
exist on the Island, E. gGmphocephala (Tuart),
Ficus macrophylla and F . Australis, Araucarea
cxcelsa (Norfolk Is. Pine), Agonis flexuosa
(Peppermint), E. erythrocorys , E. meliodora, E.
camaldulensis, E. torquata, Casuarina glauca
and C. stricta (Sheoaks), Ceratonia siliqua
(Carob Bean), Olea europea, Melea azedarach
(Cape Lilac), Pinus halepensis (Aleppo Pine),
P. pinea, P. canariensis (Canary Island Pine),
Cupressus sp., Washmgtonia felifera, Pheonix
canariensis.

Present Activity

Somerville’s phase of activity resulted in the
beautification of the settlement. The next stage

of development (now under way) consists of
the effort to replace valley groves and to line
the main tourist roads with ouick growing trees.
Line planting along the north road across the
lakes has reached the sealed road and is expected
to reach the central light-house next season.
In order to re-establish valley groves it is
necessary to enclose areas for protection of
young trees against the auokka, and in this pro-
ject there are to date six large fenced areas and
a number of small areas all planted with trees.
The first two have reached the stage when next
season the fences will be removed to fence two
fresh areas. Happily, sales of quokkas to over-
seas zocs have gone a long way towards financing
these ventures. In general the policy is to try
and preserve the balance between native and
exotic, for which reason emphasis in 1958 was
given to Tea Tree and special attention in 1959
will be devoted to Rottnest Pine.

As an example of the scale of planting being
attempted, this season’s planting (1958) is a
record planting cf 1250 trees, mostly line and
plantation. Experimental planting has included,
Native Pittosporum (indigenous), E. lehmanii,
E. calaphylla. and palms, unnamed, from U.S.A.
With the help of public donations following dis-
astrous fires a few years ago, the nursery has
been enlarged and reorganised. Leading from
the nursery an avenue of young trees show
examples cf the types now being used.

Scientific Use of the Island

It is appropriate arid very desirable that the
unique features of the Island should be available
to scientific study and experiment. In 1930 the
then State Apiculturist (Mr. W. Lance) estab-
lished an apiary for the breeding of pure Car-
niolan Queens, and this is now a well established
project.

In more recent years the Biological Committee,
representing Fisheries Department, University
Department of Zoology, and K. Sheard have
found it possible to establish permanent quarters
in the centre of the Island. Apart from what
help the Board can offer in the matter of labour,
there is little that it can do to help such highly
specialised bodies. There are however fairly
frequent occasions when good turns can be
offered from both directions. At all times in
both the apicultural and the biological fields,
relationships with the Board and Board Manage-
ment have been excellent. From the beginning
the Eoard was represented at Biological Section
meetings. In the early stages, its Chairman
attended to represent the Board and in latter
times his place has been taken by the Board
member most interested in the biological field
(Mr. T. Sten). The same relationships exist
with the Departments of Agriculture, Forestry
and other bodies to whom the Board must turn
from time to time for expert advice. It is not
to be expected that the full scientific potential
has yet been exploited, and it is to be hoped
that the Island will be able to make an even
greater contribution in this direction in the
future.

T. STEN.

92

23. — Bibliography

(Publications containing references to Rottnest Island)
Compiled by D. L. Serventy and K. Sheard

Alexander, W. B. (19141. — The history of zoology in West-
ern Australia. Part 1. — Discoveries in the
17th Century. J. W. Aust. Nat. Hist. Soc. 5:
49-64. | Refers to the visits of Volckersen in

1658 (p. 52) and Vlaming in 1696 (p. 54).]

(1916). — History of zoology in Western Aus-
tralia. Part, 2.— 1791-1829. J. <fc Proc. Roy.
Soc. W. Aust. l: 83-149. I Observations of
Peron’s naturalist, Bailly, translated on
p. 100; P.P. King's visit on p. 123.]

(1917). — History of zoology in Western Aus-
tralia. Part 3. — 1829-1840. J. & Proc. Roy.
Soc. W. Aust. 3: 37-69. I Visits of early

settlers referred to on pp. 39, 68. |

(1920). — Crested Penguins in Western Aus-
tralia. Emu 19: 295-296. [Eudyptes chry so-
come on Rottnest I.]

(1932). — Emu 3 2: 128. | Letter to Editor

about Cormorants on Rottnest. Island, West-
ern Australia. 1

Ashby, E. < 1929.) .—Contributions to the fauna of Rottnest
Island No. 2. Polyplacophora. J. Roy. Soc.
W. Aust. 15: 47-54.

Bartholomew, G. A. (1956). — Temperature regulation in
the macropod marsupial, Setonix brachyurus.
Physiol. Zool. 29: 26-40.

Eentley, P. J. (1955). — Some aspects of the water meta-
bolism of an Australian marsupial Setonyx
brachyurus. J. Physiol. 127: 1-10.

Buttle, J. M., Kirk, R. L., and Waring. H, (1952).— The
effect, of complete adrenalectomy on the
wallaby Setonyx brachyurus. J. Endocrin.
8: 281-290.

Calaby, J. H. (1958). — Studies on marsupial nutrition II.

The rate of passage of food residues and
digestibility of crude fibre and protein by
the quokka, Setonix brachyurus (Quoy and
Gaimard.) Aust. J. Biol. Sci. 11: 571-580.

Campbell, A. .7, (1890). — A naturalist in Western Aus-
tralia — Rottnest Island. Australasian (Mel-
bourne). May 10: 936.

Carrigy, M. A., and Fairbridge, R. W\ (1954). Recent
sedimentation, physiography and structure
of the continental shelves of Western Aus-
tralia. J. Roy. Soc. W. Aust. 38: 65-95.

Churchill, D. M. (1959). — Late Quaternary eustatic
changes in the Swan River District. J. Roy.
Soc. W. Aust. 42: 53-55.

Clark, J. (1929). — Contributions to the fauna of Rottnest
Island. No. 3. The ants. J. Roy. Soc. W.
Aust. 15: 55-56,

Clarke, J. R. (1948). — Anatomy of the quokka Setonix
brachyurus (Quoy and Gaimard) Part I. —
External morphology and large intestine.
J. Roy. Soc. W. Aust. 33: 59-150.

Cotton, B. C. (1929). — Contributions to the fauna of
Rottnest Island. No. 4. Western Australian
Seplidae. J. Roy. Soc. W. Aust. 15: 87-94.

Dunnet, G. M. (1956). — A population study of the
quokka, Setonix brachyurus Quoy &
Gaimard (Marsupialia). I. Techniques for
trapping and marking. C.S.I.R.O. Wildl.
Res., 1 73-78.

Dunnet, G. M. and MacLean, L. (1956). — Whimbrel on
Rottnest in winter. W. Aust. Nat. 5: 72.

Erickson, R. (1951). — Quokka feeding on introduced
snail and stink wort. W. Aust. Nat. 3: 41.

I Setonix brachyurus eating Helix pisana and
Inula graveolens.\\

Fairbridge, R. W. (1954). — Quaternary eustatic data for
Western Australia and adjacent states.
Proc. Pan-Ind. Ocean Sci. Congr. Perth, Sect.
F: 64-84.

Ford, J. R. (1958). — Occurrence of Fork-tailed Swift in
the south-west, 1956, W. Aust. Nat. 6:
106-107. | Apus pacificus observed January. I

George, R. W, 11958). — The status of the "white” crayfish
in Western Australia. Aust. J. Mar. & Freshw.
Res. 9: 537-545

Glauert, L. (1926). — A list of Western Australian fossils.

Supplement No. 1, 1925. Bull. Geol. Surv.
W. Aust. 88: 36-71. | Pleistocene mollusca

listed from Rottnest I.]

(1929). — Contributions to the fauna of Rott-
nest Island. No. 1. Introduction and
vertebrates. J. Roy. Soc. W. Aust. 15: 37-46.

(1947). — A Rottnest puzzle. W. Aust. Nat. 1:

22. | Discussion of L. Freycinet's statement

(in Peron’s "Voyage de Decouvertes aux
Terres Australes", 1, 1807 : 188-189) that two
macropod marsupials occurred on Rottnest
I ; a recording error inferred through con-
fusion with the Tammar on Garden I.|

(1951). — Recent, records of the Oarfish.

W. Aust. Nat. 2: 195-196. [ Regalecus glesne

in December 1950.1

Glauert, L. and Jenkins, C. F. H. (1931 ) .—Contributions
to the fauna of Rottnest Island, No. 7.
Notes on the Banded Stilt (Cladorhynchus
leucocephatus) with a description of its eggs.
J. Roy. Soc. W. Aust. 17: 1-6.

Hale, H. M. (1948). — Australian Cumacea. No. 14 Further
notes on the genus Cyclaspis. Rec. S. Aust.
Mus. 9: 1-42. I Includes a number of species
of this Crustacean genus taken with a sub-
marine light-trap in Thompson Bay.]

(1949). — Australian Cumacea. No. 15 The

Family Bodolriidae (cont.). Rec. S. Aust.

Mus. 9: 107-125. | Species from Thompson
Bay.]

(1949). — Australian Cumacea. No. 16 The

Family Nannastacidac. Rec. S. Aust. Mus. 9:
225-245. | Species from Thompson Bay.l

(1951), — Australian Cumacea. No, 17 The

Family Diastylidae (cont.). Rec. S. Aust.

Mus. 9: 353-370. |. Species from Thompson
Bay.]

Hodgkin, E. P. (1959). -Catastrophic destruction of the
littoral fauna and flora near Fremantle,
January 1959. W. Aust. Nat. 7: 6-11. | Mor-

talities due to combination of exceptionally
low tides and summer heat; Rottnest reefs
discussed.]

Hodgkin, E. P. and Di Lollo, V. (1958).— The tides of
south-western Australia. J. Roy. Soc. W.
Aust. 41: 42-54.

Jackson, A. (1931). — The Oligochaeta of south-western
Australia. J. Roy. Soc. W. Aust. 17: 71-136.
Kilpatrick, A. G. ( 1932 ) .—Birds of Rottnest Island, W.A.
Emu 32: 30-31.

King, P. P. (1826). — "Narrative of a Survey of the Inter-
tropical and Western Coasts of Australia”:
London l Description of a visit on January,
14, 1822 (summarised by Alexander 1916,

p. 123).]

Kott, P. (1952). — The Ascidians of Australia I.

Stolidobranchlata Lahille and Phlebo-
branchiata Lahille. Aust. J. Mar. Freshw.
Res. 3: 205-333.

(1957). — The Ascidians of Australia. II,

Aplousobranohlata Lahille: Clavelinidae

Forbes & Hanlv and Polvclinelac Vcrrill.
Aust. J. Mar. Freshw. Res. 8: 64-110.

Lawson, F. (1905). — A visit to Rottnest Island. W.A.

Emu 4 : 129-132. | Commonly cited elsewhere

under Whitlock. F. Lawson. Gives detailed
account of bird-life.)

MacLean, L. and van der Heyden, L. (1956). — Sooty
Oystercatcher at Rottnest. W. Aust. Nat. 5:
119.

MacPherson, J. H. (1957). — A review of the genus
Coxiella Smith, 1894, sensu lato. W. Aust.
Nat. 5: 191-204. | Coxiella striatula (Menke)

from Lakes Ursula and Bagdad.]

Main, A. R. (1956). — The role of pure research in con-
servation. W. Aust. Fish. Dept. Fauna Bull.
1: 12-15.

Mathews, W. H. (1930). — Contributions to the fauna of
Rottnest Island. No. 6 Notes on the Odonata
and Neuroptera. J. Roy. Soc. W. Aust. 16:
41-44.

McArthur, W. M. (1957). Plant ecology of the coastal
islands near Fremantle, W.A. J. Roy. Soc.
W. Aust. 40: 46-64.

McCrum, E. and Slater. P. ( 1955).— Record of the Silver-
grey Petrel from Rottnest, W. Aust. Nat. 4:
192.

Mertens, R. (1958). — Neue Eidechsen a us Australien.

Senck. biol. (Frankfurt am Main), 39 (1/2):
51-56. |pp. 52-53. Trachydosaurus rugosus
konowi subsp. nov., from Rottnest I.]

93

(1958). "Quer durch Australien. Biologische
Aufzeichnungen liber eine Forschungsreise".
Senckenbergiana. Ipp. 41-45, biological
impressions of Rottnest I.]

Michaelsen, W. and Hartmeyer, R. ( 1907-30) .-“Die
Fauna Sudwest-Australiens. Ergebnisse der
Hamburger sudwest-australischen For-
schungsreise 1905." (5 vols.) (Gustav

Fischer: Jena.) [Rottnest I. was a collecting
station for invertebrates. A general account
of the Island and its environment by W
Michaelsen appears in l (1), 1907: 12-21 I

Moir, R. J, Sharman. G., Somers, M., and Waring, H
1 1954),— Ruminant-like digestion in a mar-
supial. Nature, Loud. 173: 269-270.

Moir, R. J., Somers, M.. and Waring, H. (1956). — Studies
in marsupial nutrition I. Ruminant-like
digestion in a herbivorous marsupial
( Setojiix brachyurus Quov Gaimard).

Aust. J . Biol. Sci. 9: 293-304,

Nicholls, A. G. (1942). — Marine Copepoda from Western
Australia. 1. Littoral Harpacticoids from
Rottnest Island. J. Roy. Sue. W. Aust.. 27:
135-141.

Nicholls, G, E. (1929 1 . — Some new species of Stenetrium
from Western Australia. Proc. Linn. Sue.
N.S.W. 54: 361-374.

(1933).- The composition and biogeographical

relations of the fauna of Western Australia .
Rep. Aiist. Ass. Advanc. Sci. No. 21: 93-138.
[The brine shrimp. Parartemia zietziana and
the isopod, Haloniscus salina. recorded from
salt lakes. I

( 1939. — The Prophliantidae. A proposed

new family of Amphipoda, with description
of a new genus and four new species. Rcc.
S. Aust. Mus. 6: 309-334. I Crustacea, Amphi-
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Bathurst Point,]

Peron, F. and de Freycinet, L. ( 1807-1816) .- Voyage de
Decouvertes aux Terres Australies. Paris, 3
vols, [Natural History of Rottnest 1. dis-
cussed vol. 1, pp. 187-190.1

Rayment, T. (1934). — Contributions to the fauna of
Rottnest Island. 8. Apoidea. J . Roy. Soc.
W. Aust. 20: 201-212.

Reid, D. (1949). — Crested Terns and Silver Gulls nesting
at Green Island, Rottnest. W. Aust. Nat. 2:
21 .

(1950).— Nesting of the Pied Cormorant off

Rottnest I. W. Aust. Nat. 2: 69. [Dyer’s 1. 1

Roewer, C. F. ( 1929) .—Contributions to the fauna of
Rottnest Island. No. 5 Opiliones in the
Western Australian Museum. J. Roy. Soc.
W. Aust. 15: 95-98.

Sadleir, R. M. (1958). — An observation on the drinking
of Trachysanrus rugosus. W. Aust. Nat. 6:
152-153,

Sedgwick, E. H. (1958). The introduced Turtledoves in
Western Australia. W Aust. Nat. 6: 112-127.

I Status of Streptopclia chinensis and S.
senegalensis reviewed. ]

Serventy, D. L. (1929). — Records of Cladocera (Crustacea)
from the south-west province of Australia.
J. Roy. Soc. W. Aust. 15: 63-69. I Records
Daphnia thomsoni describes Daphniopsis
pusilla from Rottnest I.J

(1938). — Birds of the islands off Fremantle,

Western Australia. Emu. 37: 265-268. [Breed-
ing and visiting land birds listed. 1

(1948). — The birds of the Swan River District,

Western Australia. Emu 47: 241-236. [Rott-
nest species included.!

(1949). — The spread of the Mediterranean

snail ( Helix pisana ) on Rottnest Island. W.
Aust. Nat. 2: 38-42, maps. [Introduced

between 1925 and 1927; distributional surveys
of 1936 and 1947 mapped. Competition with
native Bothriembryon bulla discussed,]

(1951). — Inter-specific competition on small

islands. W. Aust. Nat. 3: 59-60. (Discussion
of distribution problems of macropod
marsupials on Rottnest and Garden Is. and
the survival of only one species on each.]
Serventy, D. L. and Storr. G. M. (1959). — The spread of
the Mediterranean Snail on Rottnest Island
—Part II. W. Aust. Nat. 6: 193-196.

Serventy, V. N. (1950). — Fairy Terns on Rottnest Island.

W. Aust. Nat. 2: 126-128 (map.)

Serventy, W. R. (1947). — Wedge-tailed Shearwater at

Rottnest I. W. Aust. Nat. 1 : 44. [Puffinus
pacificus recorded breeding on Green I.]
Sharman, G. B. (1954). — The relationships of the quokka
(Setonix brachyurus). W. Au.sf. Nat. 4:
159-168. I Anatomy: measurements of skulls. I
(1955a). — Studies on marsupial reproduction

II. The oestrous cycle of Setonix brachyurus.
Aust. J. Zool. 3: 44-55.

(1955b). — Studies on marsupial reproduction

III. Normal and delayed pregnancy in
Setonix brachyurus. Aust. J. Zool. 3: 56-70.

Somerville, W. ( 1949 > .—“Rottnest Island.” (Rottnest
Board of Control.)

Stokes, J. L. (1846). — “Discoveries in Australia.”: London.

[Vol. 11. p, 128, p. 516. et seq.. brief descrip-
tion of the environment in 1840 and 1843.'

Storr, G. M. (1957). — Second record of a Gannet ringed
in New Zealand. W. Aust. Nat.. 5: 230-231
[ Sula serrator ringed as fledgling in Hauraki
Gulf, N.Z., hatched in November, 1955:
recovered Strickland Bay November 1956;
apparently came ashore during previous
month.]

Storr, G. M. and Dunnet, G. M. (1955). — Fork-tailed
Swifts over Cockburn Sound and Rottnest.
Island. W. Aust. Nat. 5: 22-23. \Apus

pacificus .]

Teichert, C. (1950). — Late Quaternary changes of sea-
level at Rottnest Island, Western Australia
Proc. Roy. Soc. Viet. 59: 63-79.

Teichert, C. and Serventy. D. L. (1947) .—Deposits of
shells transported by birds. Amer. J. Sci.
245: 322-328. [Shell middens of Gabianus
pacificus on Rottnest I. wduch might be
mistaken for marine shell beds. I
Thomson. J. M. 1 1951). —The fauna of Rottnest Island

X. Anthuridae. J Roy. Soc. W. Aust. 35: 1-8.
Waring, H., Sharman. G. B., Lovat, D. and Kahan M.

(1955). — Studies on marsupial reproduction

I. General features and techniques. Aust.

J. Zool. 3: 34-43. I S&tonix brachyurus .]
Wheeler. W. M. (1934). — Contributions to the fauna of

Rottnest Island, Western Australia. No. 9—
The ants. J. Roy. Soc . W. Aust. 20: 137-163.
Whittell. H. M. (1941). — A review of the work of John
Gilbert in Western Australia. Emu 41: 112-
129. [Refers to a visit to Rottnest by John
Gilbert, James Drummond and Ludwig
Preiss in 1839. J

Whitlock, F. Lawson ( 1947).— Cuckoo Bees ( Crocisa ) at
Bunbury. W. Aust. Nat. 1 : 44-45.

Williams, G. (1940). — Contributions to the fauna of
Rottnest Island. 11. Pvcnogonida of West-
ern Australia. J . Roy. Soc. W. Aust. 25:
197-205.

Theses lodged at the Department of Zoology. University of Western Australia.

Bentley, P. il953>. — Some aspects of the water meta-
bolism and kidney histology of the mar-
supial ( Setonix brachyurus) .

Buttle, J. M. (1951). — Adrenalectomy of the quokka
Setonyx bracliyuris, with particular reference
to its effect on serum sodium and potassium
levels.

Clarke, J. R. (1950). — Anatomy of the quokka, Setonyx
brachyurus , Part 1. External morphology
and large intestine.

Cohen, J. (1956). — Histological techniques employed in
a study of the stomach of the quokka,
Setonyx brachyurus.

George. R. W. (1959).— The biology of the Western Aus-
tralian commercial crayfish. Panulirus lon-
gipes. A study of the taxonomy, ecology,
female reproduction, larval development,
growth and phylogenetic relationship of the
P. longipes.

94

Ho, D. K. H. (1957). — Blood volume of the quokka,
Setonyx brachyurus using Evans blue d”e,
T.-1824.

Marsh, L. (1955). — Ecology of the Western Australian
limestone reefs.

Sadleir, R. M. (1958). — Comparative aspects of the
ecology and physiology of the Rottnest and
Byford populations of the quokka, ( Setonix
brachyurus Quov and Gaimard).

Saunders. L. (1958). — Marsupial serology.

Shield, J. W. (1958). — Aspects of field ecology of the
quokka.

Storr, G. M. (1957). — Quokkas and the vegetation of
Rottnest Island.

Storr, G. M. (1958). — Microscopic analysis of faeces and
its application in a study of the diet of
quokkas on the west end of Rottnest.

Wilson, A. M. ( 1957).— Anatomy of the quokka. Part II.
The musculature and skeleton.

Thesis Icdged at the Department of Botany ,
University of Western Australia .

Smith, G. G. (1952). — A contribution to the algal
ecology of the Cockburn Sound and Rottnest
areas.

List of Research Workers and Other Persons Mentioned in Reports

Arnold, Jennifer M.. B.Sc. (W.A.) Dept of Land Research
and Regional Survey, Canberra. (R.s ZD
U.W.A. > ' ”

Barker, Jennifer M.. M.Sc. (W.A.) Senior Tutor
Physiology Dept., U.W.A.

Barker, S., B.Sc. (W.A.) Rockefeller Fellow, Z.D., U.W.A.

Bartholemew, G. A., Ph.D. (Harvard) Professor of
Zoology. University of California. (Fulbright
Fellow. Z.D., U.W.A.)

Bennetts, W. H. D.V.Sc. iMelb.) Principal, Animal
Health and Nutrition Laboratory, Dept, of
Agriculture, Perth,

Bentley, P. J., B.Sc, (W.A.) Lecturer, Physiology Dent..
U.W.A.

Bowen, B. K„ B.Sc (W.A.) R.O., State. Fisheries Dept.,
V/.A. Secretary. Rottnest Biological Station
Committee.

Calaby, J. C., R.O., C.S.I.R.O., Wildlife Survey, Canberra.
A.C.T. ( Z.D., U.W.A.)

Churchill, D. M., B.Sc. (W.A.) R.S,, Botany Dept.,

U.W.A.

Cohen, June, B.Sc. (W T .A.), (R.S., Z.D., U.W.A.)

Collin, R., M.Sc.. M.B.. B.S. (Syd.), B.Sc. (Oxon.) Senior
Lecturer. Physiology Dept., U.W.A.

Dunnet, G. M., B.Sc., Ph.D. (Aber.) Lecturer. Dept, of
Zoology, Marisehall College, Aberdeen, Scot-
land. (R.O.. C.S.I.R.O., Wildlife Survey,

W.A.)

Eadie, J. F., B.Sc. (W.A.). (R.S., Z.D., U.W.A.)

Edward, D. H. D., B.Sc. (W.A.) R.S., Z.D.. U.W.A.

Finch, M. Eileen, M.Sc. (W.A.) Lecturer. Z.D., U.W.A.

Fraser, A. J., Director of Fisheries, Chief Warden of
Fauna. Dept., of Fisheries and Game. W.A.
Chairman. Rottnest Biological Station
Committee.

George, R. W.. B.Sc. (W.A.), Ph.D. (W.A.) Assistant
Curator. W.A. Museum, in charge of Inverte-
brates. ( R.O., C.S.I.R.O., Division of

Fisheries and Oceanography, W.A.) Member,
Rottnest Biological Station Committee.

Glauert, L., B.A (W.A.) Director of the W.A. Museum
until 1957.

Glenister, B. F.. B.Sc. (W.A,), M.Sc. IMelb.) Ph.D.

(Iowa) (Senior Lecturer, Geology Dept.,

U.W.A.)

Green, J., B.Sc. (Adel.) Curator of Herbarium. Univer-
sity of New England, Armidale, N.S.W. (Asst.
Government Botanist, Dept, of Agriculture,
W.A.)

Harris. A. C., Conservator of Forests. Forests Dept ,
Perth.

Hassell, C. W., B.Sc. (W.A.) R_S.. Geology Dept., U.W.A.

Herrick, E. H., B.Sc. (Kans.), Ph.D. (Harvard) Professor
of Zoology. University of Kansas. (Fulbright
Fellow, U.W.A.)

Ho. Dorothy. B.Sc. (W.A.) Dietician, Royal Perth Hos-
pital. ( R.S.. ZD., U.W.A.)

Hodgkin, E. P.. B.Sc. (Mane.), D.Sc. (W.A.) Reader,
Z.D,, U.W.A. Member, Rottnest Biological
Station Committee.

Kahan, Margaret, B.Sc. (W.A.). (R.S., Z.D , U.W.A.)

Kaldor, I., M.D. (Budapest) Senior Lecturer Physiology
Dept., U.W.A.

Kelly, L., M.L.A., Minister for Fisheries, W.A., 1953-1959,
and Chairman, Rottnest Island Board.

Kirk, R. L., M.Sc. (Birm.), D.Sc. (W.A.) Reader, Z.D.,
U.W.A.

Kneebone, E. W. S., B.Sc. (W.A.) R.3., Geology Dept.,
U.W.A.

Lee, A. K,, B.Sc. (W.A.) Z.D., University of California,

Los Angeles. (R.S.. Z.D., U.W.A.)

Littlejohn, M. J., B.Sc., Ph.D. (W.A.) Z.D., University

of Texas; as of Oct. 1959 Z.D., University of
Melbourne. (R.S., Z.D, U.W.A.)

Lovatt, Dorothy. B.Sc. (W.A.). (R.S., Z.D., U.W.A.)

Main, A. R., B.Sc., Ph.D. (W.A.) Senior Lecturer, Z.D.,
U.W.A.

Main, Barbara A.. B.Sc.. Ph.D. (W.A.) R.S., Z.D., U.W.A.

Malcolm. W. B„ B.Sc. (Syd.), Ph.D. (W.A.) R.O.,

C.S.I.R.O., Division of Fisheries and
Oceanography, Cronulla, N.S.W. (at ZD.,
U.W.A.)

Moir, R. J., B.Sc. (Agric.) (W.A.) Senior Lecturer,
Institute of Agriculture, U.W.A.

Marsh. Loisette M.. M.A. (W.A.) R.S., Z.D., U.W.A.

Milward. N. C., B.Sc. (W.A.) R.S., Z.D.. U.W.A.

Nicholls, G. E. (Deceased), D.Sc. (Lond.), A.R.C.S.,
Professor of Biology, U.W.A. 1921 to 1947.

Perry, D. FI., Officer-in-Charge, Metropolitan District,
Forests Dept., W.A.

Royee, R. D.. B.Sc. (Agric.) (W.A.) Senior Government
Botanist, Dept, of Agriculture, W.A.

Rudeforth, B F., B.Sc. (W.A.) Laboratory Manager,
Z.D., U.W.A.

Sadleir, R, M.. B.Sc. (W.A.) R.S.. Z.D.. U.W.A.

Saunders, Lynette M., B.Sc. (W.A.) R.S., Z.D.. U.W.A.

Serventy, D. L.. B.Sc (W.A.), Ph.D. (Cantab.) Principal
Research Officer. C.S.I.R.O., Wildlife Survey
Section, W.A.

Sharman, G. B.. B.Sc. (Tas. ) Senior Lecturer, Z.D.,
University of Adelaide. (Nuffield Research
Fellow. Z.D.. W.A.)

Sheard. K.. D.Sc. (W.A.) Senior Research Officer,
C.S.I.R.O., Division of Fisheries and
Oceanography, W.A., Member. Rottnest
Biological Station Committee.

Shield, J. W., M.Sc. (W.A.), Ph.D. (W.A.) Senior
Lecturer, Z.D.. U.W.A.

Stark, J., Secretary, Rottnest Island Board.

Sten, T. B.A., O.B.E., Dip. Ed.. M, A. (W.A.) Member of
Rottnest Board and formerly Superintendent
of Teacher Training, W.A., Member, Rottnest
Biological Station Committee,

Storr. G. M.. B.Sc. (W.A.) R.S., Z.D., U.W.A.

Summers, Margaret B . B.Sc. (W.A.) Pathology Dept..

Fremantle Hospital. (R.S.. Z.D.. U.W.A.)

Waring, H., M.Sc. (Liv.j, D.Sc. (Aber.). F.A.A., Professor
of Zoology, U.W.A.

Watson, J. A. L., B.Sc. (W.A.) Z.D., University of

Cambridge. (R.S., Z.D., U.W.A.)

Woolley, G., M.Sc, (W.A.) R.O.. Physiology Dept.. U.W.A

Woolley, Patricia A.. B.Sc. (W.A.) Research Assistant
I C.S.I.R.O. ) , Z.D.. U.W.A.

Abbreviations. — 'C.S.I.R.O. Commonwealth Scientific
and Industrial Research Organization; R.O.
Research Officer: R.S. — research student; U.W.A.

University of Western Australia; Z.D. - Zoology
Department.

In each the present address is given first where
that has changed; that during the course of the
contribution second, in brackets.

95

TEN FATHOMS

SHOALS, THREE FATHOMS

NORTH

POINT

MONDAY ROCK

DUCK ROCK

POINT

fjJJV

CLUNE

ROTTNEST ISLAND

PARAKEET ISLAND

PARAKEET

BAY

LONG REACH
BAY

LIGHT

BATHURST POINT

PARAKEET

SWAMP

GEORD/E

BAY

ARMSTRONG ROCK \

ARMSTRONG POINTS

FREMANTLE

GAGE ROADS

R/FLE RANGE
Q SWAMP

% OLD
ll CATCHMENT

MUSHROOM ROCK

**

ARMSTRONG HILL

PADBURY'S

FLAT

CHARLOTTE POINT

tf'CARNAC I

==-MT. a / \ V

"!!L CHELL VchVnt \

CITY OF YORK BAYj

SETTLEMENT

A BARE hill

LAKE BAGDAD

GARDEN
' LAKE i

THOMPSON BAY

COCK BURN

LAKE NEGRI

HERSCHELL LAKE

GARDEN

ISLAND

SOUND

LAKE S/R%

crayfish

Rock,

MUD OR
\ PINK
\t*LAKE

SALT

WORKS

JETTY

BARKER'S.
SWAMP C

GOVERNMENT

HOUSE

\\ LAKE

FORBES HILL

|PT. PERON

NATURAL JETTY.

BULLDOZER

SWAMP

OR/O POOL

HILLIP

SCALE OF MILES

C TUART
^ PLANTATION
WL I t

B/CKLEY

SWAMP

ii5°4o\fc

STARK

BAY

BIOLOGICAL
RESEARCH STATION

LOCALITY MAP

BICKLEY

BAY

• LIGHTHOUSE

SWAM,

LIGHTHOUSE SWAMP

ROCKY

BAY

SALMON SWAMP //

J BICKLEY POINT

Jubilee rocks

ff A w HITE hill

>-*^ATERson
HENRIETTA ROCKS

ABRAHAM

POINT

OAN ISLAND

CELIA'S ROCKS

MARJORIE

BAY

LADY

CAPE HAYWARD

" ^ ^ ~J//NA NCY^Af

MUNT3 CAMfyfjT COVE

^/fj&QREEN ISLAND

THE BLUFF

MABEL | (I
XOYE /

PORPOISE

w

\\ A CONICAL HILL

\\

_\\

KING HEAD

STRICKLAND BAY

SALMON BAY

DYERS ISLAND
(SEAL ISLAND)

MARY
CO YE

CATHEDRAL ROCKS

VERA ROCKS

WILSON

BAY

£ RADAR HILL

SALMON POINT

CAPE VLAMING

POCILLOPORA REEF

RADAR REEF

PARKER POINT

PARKER

ROCK

LEGEND

SCALE OF MILES

•*••••■ • • •• ••

LARGE EXCLOSURES
INTERTIDAL PLATFORMS
COASTAL ROCK
SEEPAGE AREAS

ROTTNEST ISLAND

POINT

115° 30'E

TOTAL AREA

4726 ACRES

Journal
of the

Royal Society of Western Australia

Vol. 42 Part 4

24. — The Effect of Frequent Burning on the Jarrah (Eucalyptus marginata)

Forest Soils of Western Australia

By A. B. Hatch*

Manuscript received — 24th February, 1959

An examination of the surface soils from
regularly burnt firebreaks and adjacent pro-
tected compartments in the jarrah forest of
Western Australia showed no differences in
the following analyses; pH, total soluble salts,
organic carbon, nitrogen, exchangeable metal
ions and exchangeable hydrogen.

It has been shown that, the temperatures
of these controlled burns are of the order of
320-450'C., and the forest soil Is not exposed to
any prolonged high temperatures.

If the burning does cause any temporary
loss of organic matter and inorganic nutrients
from the immediate surface soil these losses
are replaced by natural leaching of the follow-
ing year’s leaf fall.

Introduction

In the fire protection of the jarrah ( Eucalyp-
tus marginata ) forest in Western Australia
regular controlled burning of strips of forest
along railway lines, main roads, etc. is carried
cut to reduce the fire risk to adjacent areas of
forest. This burning is normally carried out
during the latter spring months and the first
half of December, and the frequency of burn-
ing of these firebreaks varies from annually to
every third year, depending on the litter fall
and the fire risk involved.

The forest country adjacent to the breaks has
been protected from fire as completely as pos-
sible for periods ranging from 15 to 25 years,
and has an Ao horizon ranging from 4i - 6i
tons per acre (oven dry weight). By contrast
the firebreaks have only a sparse accumula-
tion of litter, which is regularly removed by
burning.

The aim of this study was to compare the
chemical properties of the two groups of sur-
face soils, and to ascertain what changes had
taken place in the surface soils as a result of
the regular burning.

Location

The samples were collected from several areas
in the Dwellingup Forest Division, which forms
part of the prime jarrah forest of Western
Australia.

*Forests Department, Dwellingup, Western Australia.

Climate

The jarrah forest region experiences a typical
Mediterranean climate, with ccol wet winters
and hot, dry summers. The average annual
rainfall at Dwellingup is 50.88 inches, spread
over 134 days. The rainfall distribution shows
a marked winter maximum, 81 per cent, of the
annual rainfall occurring during the months
May to September. The mean monthly tem-
peratures vary from 69.7°F. in February to
49.4 U F. in July.

Soils

The soils are typically lateritic gravelly soils
with a shallow dark grey gravelly sand overly-
ing deep yellow brown very gravelly sands. Lat-
erite boulders occur frequently throughout the
profile.

Experimental

Surface soil samples, <0-3i") were collected
during January, 1954, from twelve pairs of
adjacent areas, using a constant volume soil
sampler. The areas were selected for similarity
of topography, soil and forest vegetation. Details
of the fire history of these areas are shown in
Table I.

TABLE 1

Experimental Areas
Fire History

Location.

Fire History.

Com- Firebreak,
partment.

1. Amphion, Compt. 6 ....

1932

Triennially.

2. Curara, Compt. 5

1930

Annually.

3. Curara. Compt. 8

1937

Triennially.

4. Holmes, Compt. 1

1929

Annually.

5. Holmes, Compt. 3 ....

1934

Annually.

6. Holmes, Compt. 11, Plot

li

1934

Triennially.

7. Holmes. Compt. 11. Plot

13

1934

Triennially.

8. Holmes, Compt. 12 ...

1934

Triennially.

9. Holmes. Compt. 14 ...

1935

Triennially.

10. Marrinup, Compt. 4 ....

1938

Annually.

11. Mt. Wells, Compt. 10

1931

Frequently.

12. Teesdale, Compt. 2 . ..

1939

Triennially.

In the soil sampling, twenty-seven individual

samples were collected from each of the burnt
and unburnt areas, and combined to give three
composite samples from each treatment.

97

In the laboratory the samples were air dried,
and then passed through a 2 mm sieve. The fine
earth fractions were analysed for pH, total
soluble salts, organic carbon, nitrogen, exchange-
able metal ions and exchangeable hydrogen.

In the analysis of the soil samples, most of
the methods used were those described by Piper
(1942), but at a result of recent investigations a
newer method was used for the determination
of the exchangeable metal ions. These were
extracted by leaching with neutral normal
ammonium acetate, and the calcium and mag-
nesium determined by titration with E.D.T.A.
after destruction of the ammonium acetate.
(Bond and Tucker 1954 and Hutton 1954).
Potassium and sodium were estimated by the
EEL flame photometer i Hutton and Bond unpub-
lished data) after the ammonium acetate had
been removed by gentle ignition.

Analytical Data

The means for the two groups of surface soils
are tabulated in Table II, and in addition the
individual means for pH, nitrogen and exchange-
able calcium are shown in Tables III, IV, and V.

TABLE II

Analytical Data

Surface Soils (0-31") from, Protected Compartments and
Regularly Burnt Firebreaks

Means

P .05
Difference

Analysis

Compart-

ment

Fire-

break

Difference

for

Signifi-

cance

pH

Total Soluble Salts (%)

6*27

6-38

—0-11

0-21

0016

0-015

+ 0 001

0-005

Organic Carbon (%)

2-96

3-00

—004

0 • 64

Nitrogen (%)

0-125

0-128

— 0 003

0 • 025

Exchangeable Cations

Calcium m*e. %, %

3-92 67

4-23 69

—0-31 —2

1-25 4-9

Magnesium rn.e.%,

/o _ . . • ■

1-35 24

1-42 23

— 0 07 +1

0-46 3-3

Potassium m.e. %,

0/

0

0-11 2

0 10 2

+ 0-01 0

0-03 0-4

Sodium m.e. %, %

0*35 7

0 • 34 6

+ 0-01 +1

0*11 2-6

Exchangeable Metal

Cations

5*73 100

6 • 09 100

—0-36 -

1-67 —

Exchangeable 1 lydro-

gen (pH 8-4)

12-00

10-97

+ 1-03

2-70

Total Exchange Ca-

pacity m.e. % ....

17-73

1706

+ 0-67

4-05

Per cent. Metal Iron

Saturation

32-1

35 • 5

—3-4

4-4

It is evident from the data that this regular
light burning has had no significant effect on the
surface soil properties examined.

Both groups of soils are mildly acid, and low
in soluble salts. Organic carbon values are
relatively high, but nitrogen values are low,
giving wide C/N ratios of 24 and 23 for the
compartments and firebreaks respectively. These
wide C/N ratios are related to the litter fall in
the jarrah forest, which is very high in carbon
and has a C/N ratio of approximately 100.

In both groups of soils the cation exchange
capacity is almost solely dependent upon the
organic matter present in the surface horizon,
and is relatively low. Calcium is the dominant
exchangeable cation in the surface, averaging
two thirds of the total exchangeable metal ions.

Magnesium is next in importance and potassium
and sodium are only of minor importance in
the total exchangeable metal ions.

Exchangeable hydrogen values (to pH 8.4) are
relatively high, and the soils are moderately
unsaturated, the percentage metal ion saturation
being 32.1 and 35.5 per cent, for the compart-
ments and firebreaks respectively.

Discussion

There do not appear to be any Australian
data available on the effects of fire on the
Eucalypt forest soils, and it is difficult to com-
pare the jarrah forest conditions with those
quoted by overseas workers.

From a study of the literature it appears to
be generally accepted that a very hot fire, such
as a slash burn, where fire temperatures are of
the order of 850 °C. for a prolonged period, has
a significant effect on soil properties. Under
these conditions there is usually a decrease in
organic matter, loss in nitrogen and increase in
pH in the surface soils.

However, opinions differ very widely when
considering the effects of light and moderate
burns on the soil properties.

One group of workers claim that burning has
a detrimental effect on the soil. Amongst these
are Worley (1933) who stated:

(i) that burning destroyed humus.

(ii) that resultant ash from the burn, containing
small amounts of essential elements such as
copper and manganese, is easily lost through
leaching and a general impoverishment results.

Freise (1939) claimed that repeated burning
had an unfavourable effect on the physical and
biological properties of the soil, and Elwell and
Fenton (1941) stated that burning caused a loss
of soil nitrogen, destroyed organic matter and
increased soil and water losses.

A second group of workers believe that burning
has no significant effect on the soil. Amongst
these are Alway and Rost (1928) who suggested
that burning appears to be neither beneficial nor
detrimental to the soil, and Blaisdell (1953), who
claimed that light and moderate burns do not
affect soil properties.

TABLE III

Analytical Data

Surface Soils (0-31,") from Protected Compartments and
Regularly Burnt Firebreaks

pH

Values

Location

Mean

Compart-

ment

Values

Firebreak

Difference

Amphion, Convpt. 6 ....

6-47

6-54

0-07

Curara, Compt. 5

6-27

6-48

—0-21

Curara, Compt. 8

6 • 26

6-47

—0-21

Holmes, Compt. 1

6 -57

6-50

+ 007

Holmes, Compt. 3

5 • 85

5 • 93

—0-08

Holmes, Compt. 11, Plot 11. ..

6-19

6-27

—0-08

Holmes, Compt. 11, Plot 13. ..

6 • 49

6 17

+ 0-32

Holmes, Compt. 12

6-16

6 • 34

— 018

Holmes, Compt. 14

6-24

6 • 36

012

Mariinup, Compt. 4

5 • 72

6-27

0*55

Ml . Wells, Compt . 10

6-47

6-86

—0-39

Teesdale. Coiup » 2

6-54

6-41

+ 0-13

Means

6-27

6-38

—0-11

P -05 difference for significance

= 0-21.

Each value shown is the mean of three composite samples.

98

The third group believe that light and
moderate burning has a favourable effect on
the forest soil. One of the most important
papers in this group is that of Heywood
and Barnette (1934), who showed that soils
frequently subjected to fire were consistently
less acid, and had higher percentages of ex-
changeable calcium and total nitrogen. Also
Burns (1952) found that moderate burning
benefited the mineral soil chemically, and pro-
bably had a favourable effect on the forest floor,
and in 1955 Vlamis, Schultz and Biswell demon-
strated by means of pot experiments that light
burning increased the nitrogen power of the
soil fourfold, and in addition tended to increase
the phosphorus supplying power of the soil.

high temperatures in the controlled burn. In
connection with this work it has been shown by
Heywood (1938), that in the Longleaf Pine re-
gion of Southern U.S.A., the heat from the
majority of forest fires is insufficient to im-
poverish the soil, and that the slight heat which
enters the soil during the fire may even favour
plant nutrition.

TABLE V

Analytical Data

Surface Soils ( 0-3 }>") from Protected Compartments and
Regularly Burnt Firebreaks
Exchangeable Calcium
Mean Values
(m.e.% & %)

TABLE IV

Analytical Data

Surface Soils (0-3h") from Protected Compartments and
Regularly Burnt Firebreaks
% Nitrogen Values

Mean Values

Locatic n

Difference

Compart-

Firebreak

ment

Amphipn, Compt. 6 ....

0-120

0- 132

0-012

Curara, Compt. 5

0-122

0-144

0-022

Curara, Compt. $

0-152

()■ 179

0 022

Holmes, Compt. 1

0 • 090

0-122

- 0 032

Holmes, Compt. 3

0-121

()■ 1 15

• ()• 000

Holmes. Compt. 11. Plot 11 ...

0-079

0-097

- 0-018

Holmes, Compt. 11. Plot 13...

0-097

0-157

0-000

Holmes. Compt. 12

0- 137

0 • 095

+ 0-042

Holmes, Compt. 14 ....

0-100

0 ■ 1 42

0-042

Marrimip, Compt. 4

0 • 1 70

0-094

+ 0-082

Mt. Wells. Compt. 10

0-122

0- 120

0 • 004

Teesdale. Compt. 2

0-184

0 132

0-052

Means

0 125

0-128

—0 • 003

P • 05 difference for significance
Each value shown is the mean

= 0-025.

of three composite samples.

It is evident that the data for the jarrah
forest soils strongly supports the second group of
workers in that there were no significant dif-
ferences in the surface soil properties exam-
ined.

With regard to the effect of the control burn
on the forest crop it has been shown by Harris
‘1956) that the best of the older jarrah sap-
lings are found alongside the old bush tram-
ways, where fires were set by the locomotives
as often as a fire would run. In addition Lon-
eragan, (unpublished data) and Harris (1956)
have shown that there is no significant differ-
ence in girth increments between saplings on
regularly burnt firebreaks and protected com-
partments.

In considering the effects of the controlled
burnings of the jarrah forest soil there are sev-
eral factors which appear to be related to the
lack of differences between the two groups of
soils.

Firstly, the temperature of the burn is not
high, and in some experiments carried out at
Dwellingup, it was found that the temperatures
of a controlled burn were of the order of 320°-
450' C. for tw r o and three year old litter. Sec-
ondly, the litter on the firebreak consists mainly
of leaves and fine twigs, and thus burns rapidly.
Therefore, the soil is not exposed to prolonged

Location

Compartment

Firebreak

Amphion, Compt. 0

3-08

67

5-08

66

Curara, Compt. 5

4-34

69

3-11

63

Curara, Compt. 8

5-66

71

8-34

72

Holmes, Compt. 1

.... 1 2-78

72

3-58

73

Holmes, Compt. 3

3 • 58

65

3-80

66

Holmes, Compt.. 11, Plot 11

1 -65

58

1 • 96

62

Holmes, Compt. 13, Plot 13

2-47

63

4-41

69

Holmes, Compt. 12

.... j 4-69

66

5 • 08

76

Holmes, Compt. 14

Marrimip, Compt. 4

3-13

63

3 • 56

68

5-34

65

3 • 27

73

Mt. Wells, Compt. 10

4 • 69

77

3 • 32

71

Teesdale. Compt. 2

5 • 58

75

5-24

69

Means

3-92

67 • 6

4-23

69 0

I* -05 difference for significance 1*25 m.e. % and 4 -9%,
Each value shown is the mean of three composite samples.

In addition the controlled burning is carried
out during the latter part of the year, and the
maximum leaf fall in the jarrah forest occurs
during the months of January, February and
March. In jarrah regrowth forests the leaf
fall during this period may amount to between
12 and 15 cwt. per acre (o.d.wt.), and this leaf
litter contains the following amounts of in-
organic nutrients; 0.77% calcium, 0.240% mag-
nesium, 0.252% potassium and 0.473% nitrogen.

The fresh leaf litter on the forest floor of
the firebreak is exposed to at least one winter’s
leaching by the rainfall, and it has been shown
by Hatch <1855> that jarrah leaf litter loses
one third of its oven dry weight during the
first winter. This loss in weight includes the
majority of the inorganic actions and a con-
siderable amount of readily soluble organic com-
pounds, and evidently this accession of nutri-
ents and organic compounds from the litter is
sufficient to replace any losses in the immediate
soil surface which may be caused by the
burning.

In field inspections of the firebreaks
and compartments, the chief differences ob-
served were the absence of a thick A1 horizon
in the firebreak soils and also the undergrowth
vegetation appeared to be much sparser in the
firebreaks.

Conclusion

It is evident that the practice of regularly
burning selected firebreaks in the jarrah forest
has had no significant effect on the soil pro-
perties examined, and the results support the
conclusions of Alway and Rost (1928) and
Blaisdell (1953).

99

Also, from the above data, it would appear
that the Departmental policy of prescribed con-
trolled burning, which is primarily based on
practical and economic considerations related to
the present stage of development of this State,
is unlikely to cause any soil deterioration to
take place.

Acknowledgments

Acknowledgments are made to Mr. A. C. Har-
ris, Conservator of Forests for his assistance
and advice in this work, and to Mr. W. R. Wal-
lace, who was in charge of the Forests Depart-
ment’s research activities when this project
was carried out.

References

Alway, F J., and Rost, C. O. (1928). — The effect of
forest fires upon the composition and produc-
tivity of the soil. Proc. First lnt. Congr. Soil
Sci. 3: 546-576.

Blaisdell, J. P. (1953). — Ecological effects of planned
burning of sagebrush grass range on the upper
Snake River Plains, Tech. Bull. U.S. Dep. Agric.
1075.

Bond, R. D., and Tucker. B. M. (3954). The titration
of calcium with ethylenediamine tetra -acetate
in the presence of magnesium Chem, & Ind.
(Rev.) 40: 1236.

Burns, P. Y. (1952). — Effect of fire on forest soils in the
pine barren region of New Jersey. Bull. Yale
Univ. Sell. For. 57.

Elwell, D. H. A., and Fenton, F. A. (1941).— The effects
of burning pasture and woodland vegetation.
Bull. Okla. Agric. Exp. Sta. B-247.

Freise, F. W. (1939). — Investigations on the conse-
quences of burning on tropical soils. Tropen-
pflanser 42: 1 - 22 .

Harris. A. C. (1956). Regeneration of jarrah (Eucalyp-
tus marginata) . A ust. For. 20: 54-62.

Hatch. A. B, (1955). — The influence of plant litter on
the jarrah forest soils of the Dwellingup Region
— Western Australia. Leafl. For. Bur. Canberra
No. 70

Heyward, F. (1938). — Soil temperatures during forest
fires in the Longleaf Pine Region. J. For. 36:
478-491.

Heyward. F., and Barnette, R. M. (1934).— Effect of fre-
quent fires on chemical composition of forest
soils in the Longleaf Pine Region. Bull. Fla.
Agric. Exp. Sta. 265.

Hutton, J. T. (1954). — The titration of calcium and
magnesium by E.D.T.A. Divisional Report 9/54,
Part C., C.S.LR.O, Division of Soils, Adelaide.

Piper, C. S. (1942). — ’‘Soil and Plant Analysis.” (Univ.
Adelaide.)

Vlamis, J.. Schultz. A. M., and Biswell. H. H. ( 1955). —
Burning and soil fertility. Calif. Agric. 9, No. 3:
7.

Worley, F, P (1933). — Forest fires in relation to soil
fertility. Nature, Lond. 131: 787-788.

100

25. — Jurassic Stratigraphy of the Geraldton District, Western Australia

By P. E. Playford*

Manuscript received — 21st April, 1959

This paper is a detailed account of the
stratigraphy, structure, and petrology of the
Jurassic sediments of the Geraldton district.
These sediments are almost horizontal and
were deposited on an Irregular, weathered
surface of Precambrian gneisses and granu-
lites. The Jurassic sediments are divided into
seven formations, of which the lower six form
two groups. They are, from the base up. the
G reenough Sandstone and Moonyoonooka Sand-
stone (making up the Chapman Group), the
Colalura Sandstone, Bringo Shale. Newmarra-
carra Limestone, and Kojarena Sandstone
(making up the Champion Bay Group), and
the Yarragadee Formation. The age of the
Chapman Group has not been definitely
established owing to lack of 1'ossiL evidence.
It consists oi continental fiuviatile sandstones
and is tentatively placed in the Lower Jurassic,
though all or part of the group may be Upper
Permian or Lower Triasslc. The Champion
Bay Group consists of marine sediments of
Middle Jurassic age. One formation, the New-
marracarra Limestone, is very fossiliferous, and
has been accurately dated as Middle Bajocian.

The flat-topped hills of the Geraldton dis-
trict are usually capped by laterite, which is
often overlain by sand. These hills are rem-
nants of the well-dissected Victoria Plateau.
The laterite in the district formed after uplift
and dissection of the plateau. Both the Pre-
cambrian granitic rocks and the Jurassic sedi-
ments (especially the Newmarracarra Lime-
stone) have undergone extensive alteration be-
neath the laterite.

The major structural feature of the area
is the Geraldton Fault, which is known to have
had a throw since the Jurassic of 750 to 800
feet, and a total throw of at least 1.500 feet.
Minor faults, cutting both the Jurassic sedi-
ments and the Precambrian rocks, have also

been noted in the area.

Contents

Page Xo.

Introduction ....

101

Physiography ....

103

General Geology

104

Precambrian

104

Lower Silurian (?)

105

Upper Permian or Lower Triassic.

105

Jurassic

105

Laterite and Sand-Plain

106

Quaternary Superficial Deposits

107

Jurassic Stratigraphy

107

Chapman Group

107

(i) G reenough Sandstone

108

(ii) Moonyoonooka Sandstone

1 09

Champion Bay Group

115

(i) Colalura Sandstone ....

1 15

(ii) Bringo Shale ...

117

(iii) Newmarracarra Limestone ....

118

(iv) Kojarena Sandstone ....

121

Yarragadee Formation ....

122

Structure

123

References

124

*West Australian Petroleum Pty. Limited, Perth,
Western Australia. Formerly Department of Geology,
University of Western Australia, Nedlands, Western
Australia.

Introduction

Location of Area

Geraldton is situated on the coast of Western
Australia, about 230 miles north of Perth, the
capital city. It is a port on Champion Bay,
serving the surrounding agricultural and mining
districts.

During this investigation an area of approxi-
mately 400 miles around Geraldton was exam-
ined in reconnaissance (see Plate 4), and a de-
tailed survey was carried out on approximately
14 square miles in the vicinity of Bringo, a
small railway station 19 miles from Geraldton
on the line to Mullewa.

Purpose of Investigation

The marine Jurassic sediments of the Gerald-
ton district have been known since the middle
of the last century, and were until compara-
tively recently the only known exposure of
marine Jurassic in Australia. Nevertheless no
detailed geological investigation of the area has
been undertaken previously, due largely to the
lack of any economically important deposits as-
sociated with the sediments. The objects of the
present survey were firstly to map a small area
of the Jurassic sediments in detail, establishing
the rock units present, collecting fossils, and
carrying out a laboratory examination of the
sediments; secondly to map a larger area in
reconnaissance, measuring stratigraphic sections
throughout, and obtaining information on the
lateral extent of the rock units. The overly-
ing lateritic deposits and underlying Precam-
brian metamorphic rocks were also studied.

This paper was originally submitted in March,
1953. as part of the requirements for the degree
of Bachelor of Science with Honours at the
University of Western Australia. Since then,
part of the Geraldton area has been re-exam-
ined by Mr. S. P. Willmott and myself during
the course of a regional geological survey of the
Perth Basin on behalf of West Australian Pet-
roleum Pty. Limited. Some alteration to the
original manuscript has been necessary as a re-
sult of this additional work.

Methods of Study

The area around Bringo which was examined
in detail (see Plate 5), was mapped using verti-
cal aerial photographs, on a scale of four
inches to the mile. In this area every outcrop
was visited and examined. The reconnaissance
survey (Plate 4) was carried out using the army
topographical maps on a scale of one inch to
the mile. For this survey all outcrops were not
visited, but roads and important tracks in the

101

area were covered by motorcycle, with visits to
significant exposures. The regional map was
completed in Perth using vertical air-photos
loaned by the Army Survey Corps.

The Bringo railway cutting < Plate 6 > was
mapped on a section prepared from measure-
ments supplied by the Engineer’s Department.
Western Australian Government Railways.

A petrological examination was carried out
in the laboratory of samples collected mainly
from the area mapped in detail. This analysis
consisted of mechanical analysis, sphericity and
roundness determinations, and mineralogical
study of the disaggregated sediments, supple-
mented by thin section work. Chemical
analyses were carried out on the phosphatic
rocks to determine their content of P 2 0.>.

Macro-fossils were identified from the litera-
ture and the ammonites were sent to the late
Dr. W. J. Arkell.

The army one -mile grid system is used on the
geological maps of the Geraldton and Bringo
areas respectively (Plates 4 and 5). Localities
mentioned in the text are referred to this grid.
Taking Bringo as an example, the east- west
reading is 75.9 and the north-south reading is
36.5, then the grid reference is given as
(759365). In the same way the grid reference
for “Moonyoonooka” homestead is obtained as
(708325).

Historical Review

The Geraldton district was one of the
earliest parts of Western Australia to be set-
tled, and in the early 1850’s several sheep sta-
tions were established in the area covered by
this report. Such stations as “Newmarracarra,”
“Tibradden,” “Ellendale,” and “Sandspring”
were soon flourishing in an area which proved
to be among the richest pastoral districts in
Australia. It is not surprising that the richly
fossiliferous rocks of the area attracted the at-
tention of these early settlers, and as a result
several fossil collections were sent to England.

The first to record the Jurassic age of these
fossils was Moore (1862), who examined speci-
mens forwarded by a Mr. Clifton, and also those
sent by F. T. Gregory to the Geological Society
of London. Moore expressed the opinion that
the fossils were referable to the Upper and
Middle Lias of the English succession. Earlier.
A. C. Gregory (1849), J. W. Gregory (1849), F.
von Sommer (1849). and F. T. Gregory <1861>
had written brief accounts of the geology of the
district, but none had recognized the Jurassic
age of the sediments.

The Reverend W. B. Clarke < 1867 ) published
a paper on fossils he had been sent from the
Moresby Range, near Geraldton. His conclu-
sion was that “Taking the general aspect of
these fossils, and the occurrence of such forms
as Avicula Munsteri, Ostrea Marshi, and Am-
monites Moorei, it is almost certain that the
nearest representative of the formation is the
Inferior Oolite.” This conclusion is held to the
present day, the Newmarracarra Limestone
being considered to be of Bajocian (“Inferior
Oolite”) age, though it has been further nar-
rowed down to the Middle Bajocian.

Further palaeontological papers on fossils
from the Geraldton area were published by
Neumayr (1885), Crick (1894), Etheridge (1901,
1910), and Chapman (1904. a and b).

The first geologist to map the Geraldton dis-
trict at all thoroughly was W. D, Campbell
(1907), who published a geological map of the
Greenough River district, with accompanying
notes. This map shows the broad distribution
of the Jurassic sediments, Precambrian rocks,
and laterite, but the notes give little information
on the stratigraphy of the area.

Further work on the area by Campbell (1910)
was published as part of his outstanding con-
tribution to the geology of Western Australia —
“The Irwin River Coalfield and the adjacent
districts from Arrino to Northampton.” This
report embraced an area of about 2,000 square
miles, and included the area covered by the
present survey. However. Campbell was mainly
concerned with the Permian sediments of the
Iiwin River district, and his report contains no
detailed information on the stratigraphy of the
Jurassic sediments.

The next palaeontological paper was by F. W.
Whitehouse (1924), who examined fossils col-
lected by Professor W. G. Woolnough from a
railway well near Bringo. He named several
new species, and on evidence supplied by am-
monites, suggested a Middle Bajocian age for
the fauna. This dating was confirmed by Spath
(1939), who described a small collection of am-
monites from the Geraldton area. He considered
that they were referable to either the Sauzei
Zone or the Sowerbyi Zone (Middle Bajocian)
of the European succession.

The geological survey of the Irwin River and
Eradu coal basins (Permian) by Johnson, de la
Hunty, and Gleeson <1954 > overlaps the present
reconnaissance in the vicinity of Wicherina.
However their paper gives little information on
the Jurassic sediments.

The field work for the present investigation
was undertaken in December 1951, January,
February, June, August and November 1952, and
March 1953, a total of 17 weeks being spent in
the field. The laboratory work was done during
the academic year of 1952.

Since the present paper was submitted as an
Honours thesis in 1953 two papers have been
published dealing with the Jurassic sediments of
the Geraldton area. The first (Arkell and Play-
ford 1954), deals primarily with the ammonities
of the Newmarracarra Limestone, which are
described in that section of the paper written
by Arkell. He considers the fauna to be Middle
Bajocian in age. and to correlate, at least in
part, with the Sowerbyi Zone of the European
succession. The Sauzei and Humphriesianum
Zones of the Middle Bajocian may also be pre-
sent The other section of the paper, by my-
self, summarizes the stratigraphy of the Jurassic
sediments. In “The stratigraphy of Western
Australia” by McWhae, Playford, Lindner,
Glenister, and Balme (1958). the latest informa-
tion on the Jurassic sediments of the Geraldton
area is given in summary form.

Acknowledgments

During this investigation ready assistance and
advice were given by Dr. R. W. Fairbridge and
Dr. A. F. Wilson, and I wish to express my sin-
cere thanks to both. I am also indebted to Pro-
fessor R. T. Prider for his interest and advice.
Other members of the Geology Department,
University of Western Australia, gave valuable
support and encouragement, for which I am
grateful.

Since the paper was first written, Dr. R. O.
Brunnschweiler, Mr. S. P. Willmott, Dr. J. R. H.
McWhae, Mr. D. Johnstone, and Mr. M. H. John-
stone have given valuable assistance in a number
of ways, for which I wish to extend my thanks.

Physiography

General

The Geraldton district is situated in the
northern part of the Perth Basin. It falls
within the Greenough Natural Region of Clarke
(1926), the South-West Physiographic Division
of Jutson (1934), and the Greenough Block
Subregicn of the Swan Coastal Belt (Physio-
graphic Region) of Gentilli and Fairbridge
(1951).

The country to the east of Geraldton con-
sists of the remnants of a plateau dissected by
the Greenough and Chapman Rivers, leaving
flat-topped hills of Jurassic sediments, often
capped by laterite. and underlain by Precam -
brian granitic rocks. The western margin of
the dissected plateau is marked by the Gerald-
ton Fault Scarp (Jutson 1914). This scarp is
deeply dissected and has retreated several miles.
It is fronted by a coastal plain, 3 to 10 miles
wide, which slopes gently to the sea.

In those areas where the rivers have cut
through the sand-covered plateau, there are
rich pastoral properties supporting large num-
bers of sheep. Cereal crops are also grown,
being most successful in the drier years, while
there are numerous market gardens on the
coastal plain.

The climate of the area is characterized by
an annual rainfall of 15 to 20 inches, nearly all
of this falling in the winter months. Summer
temperatures are high, with the maximum often
over 100 °F.

The natural vegetation has been largely re-
moved in the valleys of the Chapman and
Greenough Rivers, but on the granitic and Ju-
rassic areas it apparently originally consisted
predominantly of “Jam” < Acacia acuminata ),
“York Gum” ( Eucalyptus foecunda , var. loxo-
pheba), “Needle Bush” ( Hakea recurvata). and
“Shecak” (Casuarina) . There is a marked
change of vegetation on the sand-plain, which
supports a low scrub, including stunted species
of Acacia and Banksia , with occasional “Christ-
mas Trees” (Nuytsia floribunda).

River Systems

The Geraldton district is drained by two main
rivers, the Greenough and the Chapman. An-
other so-called river, the Buller, is in reality
little more than a creek. Like most Western
Australian rivers they are intermittent, only
flowing after heavy rain.

The Greenough River rises 130 miles north-
east of Geraldton, and only the lower part of
its course lies within the area examined. In
this part of its course it receives two main tri-
butaries, Wicherina Brook and Colalura Brook,
the latter draining the area surveyed in detail.

Upstream from the road crossing near Ellen-
dale (890232) the Greenough River flows
through Jurassic sediments in a series of large
ingrown meanders, with undercutting along
high cliffs and prominent slip-off slopes. These
ingrown meanders continue upstream in the
Eradu district, and as suggested by Johnson, de
la Hunty and Gleeson (1951), they indicate a
rejuvenation of ? river which had reached the
“old age” stage of development. This rejuvena-
tion must have occurred following uplift of the
plateau in late Tertiary times. The Murchison
River, 80 miles to the north, shows even clearer
evidence of rejuvenation. West of the Green-
ough Block (Precambrian granitic rocks) it
flews in a deep, narrow gorge with well-de-
veloped incised meanders.

For 10 miles south of its mouth the Green-
ough River flows over a rich flood-plain known
as the Greenough Flats. These flats are divided
into two parts by a low sand-covered ridge of
Coastal Limestone, which is parallel to the coast.
(This ridge is about three miles inland and re-
presents consolidated coastal sand dunes of
Pleistocene age.) The river flows between the
ridge and the present dunes, following them
north for 10 1 miles before breaking through to
enter the sea. This northerly deflection of the
river is due to the strong prevailing south-
south -west winds which sweep the coast. The
picturesque trees along the Greenough Flats,
bent over almost parallel to the ground, testify
to the constancy and strength of these winds.
Sand carried by the resulting northerly long-
shore drift, combined with the slow migration
of sand dunes, has caused the meuth of the
river to migrate northwards, as its cld mouth
is progressively filled in.

As first pointed out by Jutson ( 1914 > Rudds
Gully probably represents an abandoned course
of the Greenough. This gully breaks through
the Pleistocene dune limestones and is up to 90
feet deep, but today it carries only a small creek
which seldom flows. It seems very likely that
during the Pleistocene the river emptied into
the sea at Rudds Gully, flowing north behind
the Pleistocene dunes just as today it flows be-
hind the present dunes.

The Chapman is much smaller than the
Greenough. It divides into two branches near
“Narra Tarra”, and these are known as the
Upper Chapman and East Chapman branches.
The Upper Chapman rises 35 miles north of
Geraldton, and the East Chapman rises near
Northern Gully.

Victoria Plateau

The Victoria Plateau was named by John-
son et al. (1951), who defined it as the dissected
plateau bounded on the east by the Darling-
Fault, and on the west by the Geraldton Fault
and the high sea cliffs north of Geraldton.

103

In the Geraldton district the Victoria Plateau
has been deeply dissected by the Greenough
and Chapman Rivers, leaving large remnants
such as the Moresby Range. The surface of the
plateau is covered by sand overlying laterite,
generally at shallow depth. The laterite itself
outcrops along the edges of the plateau, or in
those places where the sand has been removed
by erosion.

The surface of the plateau shows only minor
undulations, and averages about 800 feet above
sea-level.

Hills

The most conspicuous hills of the Geraldton
district are flat-topped (buttes and mesas), their
outline being due to the resistant nature of the
laterite cap overlying soft Jurassic sediments.
The laterite cap is generally flat, though in some
cases it shows a sloping surface.

The Moresby Range is made up of a series of
parallel, elongated mesas and buttes, trending
north-north -west, and standing about 200 feet
above the surrounding plain. Laterite, some-
times overlain by sand, caps most of the range,
though in places this has been removed by
erosion, and Jurassic sediments outcrop at the
top. The western edge of the range is the re-
treated scarp of the Geraldton Fault, and the
eastern margin is due to dissection by the Chap-
man River, which parallels the range.

Those hills of Jurassic sediments which are
not capped by laterite have a rounded outline,
and examples of these are found typically in the
area mapped in detail.

Springs

Springs are common throughout the area
examined. Some issue at the unconformity be-
tween the Jurassic sediments and the Precam-
brian rocks, and these are generally brackish
or salt. Others, either fresh or brackish, are
found in the sediments at the contact between
sandstone and shale, or limestone and shale.
The latter type has a widespread development
east of Bringo, where limestone overlies black
shale.

Much of the rain falling on the sand-plain
sinks in, there being very little run-off, and the
water often reappears as fresh-water springs
beneath the underlying laterite.

General Geology

Precairibrian

Precambrian metasediments outcrop over a
large proportion of the area, though exposures
are generally poor. These recks have undergone
high-grade regional metamorphism, and consist
of granitic gneisses and granulites, which are
characteristically garnetiferous.

The petrology of the Precambrian metasedi-
ments has not been intensively studied, though
thin-sections of some of the most typical rock
types have been examined.

The gneisses are the most abundant of the
Precambrian rocks present in the area. They
are usually medium-grained, uniformly banded,
and almost invariably carry garnet. Sillimanite

is sometimes present, usually as a minor acces-
sory. Some of the gneisses also contain cor-
dierite. Typical examples of the gneisses are
specimen No. 34797 (University of W.A. Geology
Dept, registered number), which is a quartz-
orthoclase-andesine-garnet gneiss, and specimen
No. 34798, which is a quartz-microcline-oligo-
clase-garnet-cordierite gneiss.

Several types of granulite have been noted
in the area, but they have not all been examined
microscopically. Most have a composition simi-
lar to that of the granitic gneisses, and at
several localities the granulites and gneisses
grade into one another. Other types are inter-
bedded with the gneisses and include char-
nockitic granulites, hornblende granulites, and
garnetiferous quartzites.

The metasediments are cut by pegmatites, and
at several localities by quartz veins, which are
probably associated with pegmatites.

At a few places in the area the gneisses and
granulites are intruded by dolerite dykes. The
one crossing the area mapped in detail is at
least 2 2 miles long, stretching from a quarry at
<746361) to (728325). near Spion Kop. The
strike of 26° closely parallels that of the dyke
swarm of the Northampton district, 30 miles to
the north, where the dolerite dykes have intro-
duced lead, copper, and zinc into the gneisses.

I-ineation is seldom pronounced in the
gneisses, but readings have been taken at three
widely separated localities (635426, 774356,

811215). The strike of the lineation is rather
constant, averaging 335°, while the angle of
plunge varies from 12° south to 70° north. This
north-north -west tectonic trend is usual in the
West Coast Province of Prider (1952).

Throughout the area the foliation of the
gneisses varies little from a northerly strike and
easterly dip. and they are probably isoclinally
folded.

The contact between the Precambrian rocks
and the Jurassic sediments is very irregular,
and east of the Geraldton Fault the elevation of
the unconformity above sea-level varies from
about 250 feet near “Narra Tarra” and “White
Peak” to 717 feet at Mt. Davis.

Although the Precambrian basement rises
gradually from west to east, this rise is not uni-
form. There are irregularities in the surface
of the unconformity, which existed as hills and
valleys at the time when the Jurassic sediments
were deposited. The basal formations of the
Jurassic are found to pinch out against these
buried hills, so that the lower the elevation of
the unconformity, the greater is the thickness
of the sediments.

The metasediments beneath the unconformity
are frequently deeply weathered, the felspars
being completely kaolinized to depths of 100 feet
or more. This is particularly well seen in vari-
ous small railway cuttings near Bringo. How-
ever most of this remarkable depth of weather-
ing is believed to be associated with lateritiza-
tion, and was not present in Jurassic times.
Similar deep weathering of metasedimentary
rocks beneath laterite is known in many other
places in Western Australia. Nevertheless a
certain amount of weathering of the Precam -

104

brian rocks is believed to have occurred in
Jurassic times. The basal formation of the
Jurassic succession, the Greenough Sandstone,
is made up of highly weather granitic material,
and is believed to be locally derived.

Lower Silurian (?)

There are a few exposures of the Tumblagooda
Sandstone in the area west of Wicherina. These
are the southernmost known outcrops of this
formation, which is best known along the Mur-
chison River on each side of the Greenough
Block. The Tumblagooda Sandstone is probably
of Lower Silurian age.

The exposures of Tumblagooda Sandstone near
Wicherina consist of fine- to very coarse-grained,
grey to yellow, well-sorted sandstone, which is
partly silicified. The sandstone is crudely to
well -bedded and sometimes shows cross-bedding.
Scattered well-rounded pebbles and cobbles of
quartz and quartzite are a feature of these ex-
posures of the formation. At the large water
tank 24 miles west-south-west of Wicherina
Dam, many pebbles and cobbles have weathered
out of the formation and are scattered over the
surface.

The relationships between the Tumblagooda
Sandstone and the over-lying Jurassic sediments
cannot be seen in the exposures near Wicherina.
However 54 miles north of Northern Gully (off
the map) the Lower Jurassic Chapman Group
can be seen resting unconformably on the Tum-
blagooda Sandstone. The Tumblagooda Sand-
stone overlies the Precambrian granitic rocks
unconformably. Only one satisfactory dip could
be measured in the exposures of the formation
near Wicherina, at ( 879400 >. There the unit is
crudely bedded and cross-bedded, but it appears
to strike 140°, and dip 15 west.

The only fossils known from the Tumblagooda
Sandstone are invertebrate tracks, which in-
dicate an early Palaeozoic age. However there
is evidence to suggest that the formation is at
least in part of Lower Silurian age, though it
may extend down into the Ordovician. This
dating is indicated by the fact that the forma-
tion appears to underlie conformably the Middle
Silurian Dirk Hartog Limestone in the Dirk
Hartog 17B bore (McWhae et aL 1958).

The exposures of the Tumblagooda Sandstone
near Wicherina are only a few feet thick. How-
ever on the Murchison River it appears that the
unit is at least 6,000 feet, and probably exceeds
10,000 feet in thickness. It is probably present
at depth throughout most of the Perth Basin
and is believed to be a continental fluviatile
deposit laid down following the first major
period of movement along the Darling Fault, in
Lower Silurian or late Ordovician times.

Johnson et al. (1954) correlated the exposures
of Tumblagooda Sandstone near Wicherina with
the Enokurra Sandstone of the Yandanooka
Group, which is exposed 60 miles to the south-
south -east. However the exposures near
Wicherina have now been shown to be essentially
continuous with those of Tumblagooda Sand-
stone extending down from the Murchison River,
and the correlation with this formation cannot
be seriously doubted. The lithological similarity
with the Enokurra Sandstone is quite strong,
but this is not sufficient to establish correlation.

Indeed it is now believed that the Yandanooka
Group is distinctly older than the Tumblagooda
Sandstone.

Upper Permian or Lower Triassic

Sediments of Upper Permian or Lower
Triassic age were first discovered in 1956 in
cores from the Geraldton Racecourse Bore
(569307). This bore was drilled with Calyx
equipment in 1896-98 and some of the cores
were preserved by the Geological Survey of
Western Australia. A core from 1,470 feet in
this bore was found to contain the uppermost
Permian or lowermost Triassic ammonoid
Xenaspis.

The formation was named the Kockatea Shale
by Playford and Willmott in McWhae et al.
(1958). It consists of partly calcareous, light
grey shale, grading into siltstone, with subor-
dinate interbedded medium- to coarse-grained
sandstone.

In the Geraldton area the Kockatea Shale is
known with certainty only from the Geraldton
Racecourse. Municipal, and Station Yard bores.
In the Municipal Bore the unit is 1,091 feet thick
and overlies Precambrian gneiss, while in the
Racecourse Bore it is 1,131 feet thick, without
having reached the base of the formation. In
both bores the Kockatea Shale is overlain by
Jurassic sediments.

Dr. Glenister. who has examined the
ammoniod Xenaspis from the Racecourse bore,
favours a Tatarian (uppermost Permian) dating
for the formation ‘McWhae et al. 1958 >. On the
other hand Mr. B. E. Balme, from a study of
the spore, pollen and microplankton assemblages,
believes that it is more likely to be lowermost
Triassic. though he does not rule out the Tata-
rian dating.

Although the Kockatea Shale is not definitely
known to outcrop in the Geraldton area, it could
conceivably be present. The Greenough Sand-
stone. which is tentatively dated as Lower Juras-
sic, shows lithological similarity to parts of the
Kockatea Shale, and they may be partly equiva-
lent. The only certain exposures of the Kocka-
tea Shale in the Perth Basin are found near the
junction of Kockatea Gully with the Greenough
River.

Jurassic

In the Geraldton District Jurassic sediments
are known to extend from the northern end
of the Moresby Range as far south as Mt. Hill,
and both marine and continental deposits are
found in this area. The marine transgression
is known to have extended inland at least as far
as Eradu, on the Greenough River.

Although a Jurassic age is proved for the
marine sediments, one formation being accur-
ately dated as Middle Bajocian, there is no
direct proof as to the age of the continental
deposits, though they are tentatively placed in
the Lower Jurassic.

In summary the sequence, from top to bottom,
is as follows:

Yarragadee Formation. — Alternating sand-
stone and micaceous siltstone, with beds of clay-
stone, shale, and conglomerate.

Thickness: 51 \ feet (plus).

105

Champion Bay Group:

Marine sandstone, shale, and limestone making
up the following formations:

Kojarena Sandstone. — Brown ferruginous
sandstone, partly fossiliferous, with some clay-
stone and shale near the top.

Thickness: 33 feet.

Newmarracarra Limestone . — Yellow to grey,
massive, richly fossiliferous limestone. The
limestone is subject to irregular alteration, and
may be replaced by hematite, or leached of
calcium carbonate, leaving a residue of its clastic
impurities.

Thickness: 16 to 38 feet.

Bringo Shale . — Black shale, with thin yellow
phosphatic beds. Phosphatic nodules often found
at the top. Dwarf pelecypods occur at several
horizons.

Thickness: 0 to 8 feet.

Colalura Sandstone. — Predominantly brown to
black ferruginous sandstone, rarely grading into
yellow sandy claystone. Abundant fossil wood
is characteristic, and small oval nodules are
frequently found. Both nodules and fossil wood
are sometimes phosphatic, but are usually re-
placed by limonite. Marine fossils rarely pre-
sent.

Thickness: 0 to 28 feet.

Chapman Group:

Continental sandstone and arkose, with sub-
ordinate shale, siltstone, and claystone, mak-
ing up the following formations:

Moony oonocka Sandstone . — Predominantly
yellow fine-grained felspathic sandstone and ar-
kose, with subordinate shale, siltstone. and con-
glomerate. Well-bedded, with cross-bedding and
current ripple-mark common. Ferruginous con-
cretions are characteristic, fossil wood is quite
abundant, and fossil leaves are very rare.

Thickness: 0 to 120 feet.

Greenougli Saridstone . — Mottled red, white,
yellow, and purple argillaceous sandstone, poorly
sorted, with subordinate shale, siltstone, clay-
stone, and conglomerate. Poorly bedded, and
containing rare fossil wood.

Thickness: 0 to 280 feet.

In the area examined, the total exposed
thickness of the Jurassic and questionable
Jurassic eediments probably does not exceed 550
feet. No single section exposes as much as this.
The thickest section measured is at Wokatherra
Hill at the northern end of the Moresby Range,
where about 430 feet of sediments are exposed,
the upper portion of the Champion Bay Group
and the Yarragadee Formation being missing.
The upper section is exposed in the Bringo rail-
way cutting, but there the Precambrian base-
ment is so high that nearly all the Chapman
Group is excluded, and the total section is only
115 feet thick.

Jurassic and associated lowermost Cretaceous
sediments are widespread in the Perth Basin,
and may exceed 8,000 feet in thickness. They
are predominantly continental sediments, the

only marine Jurassic outside the Geraldton area
being found in the drainage area of the Hill
River, 100 miles south of Geraldton.

Laterite and Sand Plain

A considerable part of the area is covered by
laterite, which is often overlain by sand. These
deposits, which have a widespread development
throughout Western Australia, are generally con-
sidered to be fossil soil horizons, formed during a
more pluvial period, probably in late Tertiary
times. Laterite may have been deposited under a
humid climate of seasonal rainfall as an illuvial
soil horizon zone of fluctuation of the w r ater
table. The sand-plain which is frequently found
overlying laterite is believed to be the fossil
eluvial horizon.

The laterite is up to 20 feet thick, and outcrops
as large massive slabs around the sides of hills,
giving rise to “breakaways.” The laterite show's
an irregular cellular structure, in some places
partly concretionary. The weathered surface is
yellowish brown in colour, while freshly broken
surfaces are mottled in various shades of browm,
yellow', and red.

The laterite consists of hydrous and anhydrous
oxides of iron and aluminium, together with
quartz and minor amounts of other insoluble
minerals. The quartz present is usually of sand
grade, though some large, rounded pebbles are
occasionally found.

Overlying the laterite, wherever erosion is not
too severe, deposits of quartz sand are found,
w*hich are light grey to w 7 hite on the surface, and
yellow' at depth. This sand, which is probably no
more than 20 feet thick anyw'here in the area,
is believed to be essentially in situ, though it
may have undergone some redistribution,
filling small depressions in the surface of the
laterite.

Many of the hills in the Geraldton district
w^hich are capped by laterite are flat-topped,
though the surface of the laterite is by no
means invariably horizontal. It may show* dips
of anything up to 10° , as at Mt. Hill. Sloping
laterite is also well seen on the three adjacent
hills Sheehans Hill, Wizard Peak, and Browms
Table. It is also found that, in general, the
laterite slopes towards the present river valleys,
indicating that the general features of the
present drainage system w'ere already established
at the time w'hen the laterite w*as forming.

The surface of the laterite in the Geraldton
district show's considerable variations in eleva-
tion, To the east, where there are large
remnants of the old plateau, the laterite (or
the overlying sand) is usually more than 800
feet above sea-level, reaching 863 feet near
Kojarena, and 821 feet at Mt. Julia. However,
laterite ( in situ > at “Amuri Park” is 350 feet
above sea-level, while in the gravel pit at (644317)
it is only 210 feet above sea-level. It is clear
that laterite in the Geraldton area did not
form on a low -lying peneplain of the type postu-
lated by Woolnough ( 1918 > . It formed on a land
surface already uplifted and eroded, the drain-
age system found today having been already
established during the period of laterization.
This is discussed in more detail by Playford
(1954).

106

The effects of laterization in the Geraldton
area are found to extend to considerable depths
below the laterite itself. These effects are most
apparent with the Precambrian granitic rocks
and the Newmarracarra Limestone. The gra-
nitic rocks are found to be completely kaolinized
to depths of more than 100 feet below the
laterite. The upper part of this weathered zone
is typically mottled white and various shades of
red and brown, and is commonly known as the
mottled zone. The lower part is simply white
due to kaolin, and is known as the pallid zone.

Many of the structures and textures of the
original rock are preserved in its kaolinized
equivalent, particularly in the pallid zone. Thus
gneissic structure is frequently clearly visible,
and in the Bring o cutting, the original ophitic
texture can still be detected in a thin dolerite
dyke, despite the fact that the felspars are
completely kaolinized.

The Newmarracarra Limestone is completely
altered to depths of 80 to 100 feet beneath
laterite. It is either replaced by hematite or
simply leached of its calcium carbonate, leaving
a residue of the clastic impurities. In those
places where the rock is clearly altered lime-
stone it has been mapped as Newmarracarra
Limestone, but wherever there is uncertainty, or
it approaches normal laterite in appearance, it
has been mapped as laterite.

Alteration of the Newmarracarra Limestone
by lateritization has been discussed fully in
papers by Playford (1954) and Arkell and Play-
ford (1954), and will only be summarized here.

Newmarracarra Limestone replaced by hema-
tite is free of calcium carbonate, and varies in
colour from deep red to almost black. Moore
(1870) gave analyses of two blocks of the hema-
tite and they contained 49% and 56%, of metallic
iron. The hematite was probably derived by
leaching of the overlying ferruginous Koj arena
Sandstone.

Fossils are often very well-preserved in the
hematite rock, either as moulds or as replace-
ments. However, in some areas, e.g. in parts of
the Bringo cutting, the hematite rock shows a
concretionary structure, and fossils are wholly
or partly destroyed.

A leached zone is usually present between the
hematite rock and the solid limestone. It has
formed by removal of calcium carbonate,
followed by compaction of the remaining
insoluble clastic impurities. Its composition is
usually that of sandy, silty claystone, and it is
generally yellow in colour. This zone contains
few fossils, those which are present being inter-
nal moulds of ammonites and pelecypods. The
material of these moulds was apparently low in
calcium carbonate, so that they were not des-
troyed during leaching.

The best exposure of the leached zone and
associated hematite rock is in the Bringo cutting.
There it can be seen that they are not sharply
separated, one grading irregularly into the
other.

In the field the relationship between limestone
outcrop and elevation of laterite is quite
apparent. Wherever the undulating surface of
the laterite is closer than about 90 feet to the

base of the Newmarracarra Limestone, the lime-
stone is completely leached. Exposures of
unaltered limestone are only found where the
laterite is more than about 90 feet above the
base of the formation.

The other sediments also show the effects of
lateritization. though not so clearly as the
Newmarracarra Limestone. The mottled zone is
frequently visible close to laterite in all forma-
tions, and beneath this there may be a bleached
zone, though this is seldom exposed, as removal
of the iron oxide cement of many of the sand
stones makes them friable.

A feature which is believed to be associated
with laterization is the occasional silicification
of sediments. Near Mt. Hill, about J-mile west
of the summit, the sandstones of the Chapman
Group are silicified to a depth of 50 feet or
more. These sandstones are at an unknown
depth below the original laterite surface, which
is known to have been very irregular here, for
laterite occurs on the north flank of Mt. Hill,
more than 100 feet below the summit, yet it does
not occur on the summit itself.

Quaternary Superficial Deposits

In addition to laterite and sand- plain, other
superficial deposits have a widespread distribu-
tion in the area, but have not been studied in
any detail. These deposits include surface
travertine, Coastal Limestone, Recent sand
dunes, and alluvium. All are of Quaternary age.

The deposits of travertine are found in small
patches throughout the area, where they are
exposed to erosion, giving rise to surfaces
covered by fragments of the white, lime-rich
rock.

Alluvial deposits have been spread over most
of the coastal plain, and inland around the
margins of the Victoria Plateau. Alluvial sand
deposits are commonly found around remnants
of the plateau, the sand having been washed
from the tops of the hills where it previously
covered laterite.

Alluvial deposits are exposed in several parts
of the Bringo cutting in old valleys cutting
through the Koj arena Sandstone and Yarra-
gadee Formation.

Jurassic Stratigraphy

Chapman Group

The name Chapman Group was introduced
by Playford, in Arkell and Playford (1954), for
the continental sediments lying between the
unconformity with the Precambrian rocks and
the disconformity with the overlying Champion
Bay Group. It was named after the Chapman
River. The group was originally considered to
be made up of two formations, the Greenough
Sandstone and the Moonyoonooka Sandstone, but
was expanded by Johnstone and Playford (in
McWhae et al. 1958) to include the Minchin
Siltstone, which lies at the base of the group in
the Northampton-Hutt River area. As this
formation is not exposed in the Geraldton area,
it will not be discussed further in this paper.

The age of the Chapman Group is uncertain
owing to the lack of satisfactory fossils for
dating. It is not even certain that the forma-
tions of the group form a continuous sequence.

107

However the three formations are tentatively re-
garded as being of Lower Jurassic age, keeping
in mind that one or more could be Lower Trias-
sic or Upper Permian.

(i) Greenough Sandstone

the sandstone seems to be merely reworked,
highly weathered granitic material, and it is
frequently only the relic gneissic structure in
the weathered Precambrian, or the presence of
a few quartz pebbles in the sediment, which
serves to distinguish them

Definition. — The name Greenough Sandstone
was proposed by Playford, in Arkell and Play-
ford (1954), for the unit of sandstone with
minor shale, claystone, and siltstone, lying be-
tween the granitic rocks and the Moonyoonooka
Sandstone in the area east of Geraldton. The
name was taken from the Greenough River, the
largest river flowing through the area.

The type section of the Greenough Sandstone
is on “Moonyoonooka” property, at 28° 47’ 4” S.,
114° 48’ 3” E. <722319). The following is a
description of this section.

Moonyoonooka Sandstone. Comformably over-
lying —

Greenough Sandstone (90')

Thickness

feet

(6) Sandstone. clayey, mottled grey,
white, yellow, red. and purple; in
places grades into sandy claystone;
top marked by a 3" bed of hard, fer-
ruginous claystone with purplish

bands .. 45

(5) Conglomerate, intraformational. mot-
tled grey, yellow, and red; contains
angular and rounded fragments of
clay in a matrix of course sand ... 5

(4) Claystone, mottled red and white,

massive . .... ... .... .... 1\

(3) Sandstone, clayey, yellow, mottled
red and white; contains scattered
fragments of angular and rounded
claystone: fills scour channel in

underlying shale, conglomeratic at
base; bleached and hardened along

joints 11

(2) Shale, white to yellowish, mottled red,
yellow, and purple; massive clay-
stone at base, but otherwise shaly;
lenses of sandstone found in the
uppermost two feet; hard ferrugin-
ous beds up to \' f thick common

throughout 23

(1) Sandstone, conglomeratic, felspathic,
brown to reddish brown, ferruginous,
contains poorly rounded quartz peb-
bles up to 6" in diameter; a few fel-
spar pebbles, and occasional boulders
of weathered gneiss at the base 5

unconformably overlying Archaean gneiss
(weathered) .

Lithology. — The Greenough Sandstone is typic-
ally a mottled red and white argillaceous sand-
stone, which is medium to coarse-grained, and
is very poorly sorted and poorly bedded. Lenses
of siltstone, claystone, and shale are present in
the formation, with occasional quartz pebble
conglomerates. Lenses of intraformational con-
glomerate occur rather commonly throughout
the section, and cut-and-fill structure, giving
rise to local unconformities, has been noted at
several localities. Cross-bedding is rarely de-
veloped in the sandstones, which are usually
massive, with no bedding visible. Sand grains
show little or no rounding, but quartz pebbles
are sometimes well-rounded.

It is often difficult to recognize the exact
position of the unconformity, as the weathered
Precambrian rocks frequently appear to grade up
into the Greenough Sandstone. This is because

One of the most distinctive features of the
formation is its mottled colouring, red and
white being most common, but shades of grey,
yellow, blue, purple, and brown are also found.
Black or dark grey sediments have not been
found in this formation. The origin of this
mottling is not definitely known, but most of
it is certainly secondary, as it transgresses the
bedding. Along joints it is often found that
the sandstone is both irregularly bleached and
hardened. However much of the mottling does
not seem to be connected with joint planes,
though it is almost certainly secondary, and due
to circulating ground waters. Since the sand-
stones are mottled even when hundreds of feet
below laterite, there appears to be no connection
with the mottled zone which is found immedi-
ately beneath laterite.

The mineralogy of the formation is very
monotonous. Quartz and clay minerals, pro-
bably mainly kaolinite, together with a little
muscovite, are usually the only ‘ light” minerals.
Felspar is rare, only being found near the base
of the formation. The heavy mineral suite is
also very restricted. Zircon is by far the most
abundant of the non-opaque minerals, with
minor amounts of anatase, monazite, tourma-
line, and rutile. The extreme rarity of meta-
morphic minerals (kyanite, staurolite, and
garnet) is very noticeable, as they are much
more abundant in the other formations.

Stratigraphic relationships. — In the Gerald-
ton district the Greenough Sandstone rests un-
conformably on the weathered, irregular sur-
face of the Precambrian rocks, and is overlain
conformably by the Moonyoonooka Sandstone.
In the Hutt River-Bowes River area, near
Northampton, the Greenough Sandstone rests
with a slight disconformity on the Minchin
Siltstone.

The contact between the Greenough Sand-
stone and the Moonyoonooka Sandstone is ex-
posed at the type section, where it is clearly
defined, but this contact has seldom been ob-
served elsewhere owing to the poorness of out-
crop. In this section the mottled argillaceous
sandstone and sandy claystone of the Green-
ough Sandstone are overlain conformably by a
black shale containing numerous lenses of grey
sandstone and conglomeratic sandstone. As
black and dark grey sediments are not known
in the Greenough Sandstone, this shale is as-
signed to the next formation, the Moonyoo-
nooka Sandstone, which in some areas con-
tains significant amounts of dark shale.

Distribution and thickness. — The distribution
of the Greenough Sandstone is limited by the
elevation of the Precambrian basement, and if
this rises higher than about 530 feet above sea-
level, the formation pinches out. Since the

108

basement rises gradually, though irregularly,
from west to east, the formation thickens to
the west.

At Wokatherra Hill, the most northerly and
most westerly section studied, the greatest
thickness of the Greenough Sandstone, 280 feet,
has been measured. The formation has thin-
ned to 60 feet at Appa Hill, and pinches
out near Grant Siding. Outside the area exam-
ined the formation is known to reach a maxi-
mum thickness of 310 feet, at Kings Table Hill.

The formation is absent over a large part of
the area examined, for around Bringo, “Tib-
radden,” “Sandspring,” and “Minnenooka,” the
Precambrian is sufficiently high to exclude it.

Exposures of the Greenough Sandstone are in
general poor, for the sediments are usually
weakly lithified. In the area mapped in detail
the most typical outcrops of the Greenough
Sandstone occur on two small hills at (69834),
though the type section is the only continuous
section exposed. Other good outcrops of the
formation are found on “White Peak” property,
along the western flank of the Moresby Range,
and in a few railway cuttings near Grant
Siding.

Fossils and age. — The only fossils which have
been found in the Greenough Sandstone are
rare, poorly preserved fragments of wood.

The age of the formation has not been defi-
nitely established owing to the lack of fossil
evidence, but it is tentatively placed in the
Jurassic. However it may be Lower Triassic or
Upper Permian in age.

Environment of Deposition . — The Greenough
Sandstone is considered to be a fluviatile sedi-
ment deposited around elevated areas in the
Precambrian rocks. Most of the sediment is
probably locally derived, having undergone little
transportation.

A continental, fluviatile origin of the sedi-
ments is indicated by the following features: —

(a) Marine fossils are absent, the only
fossils which have been found being
fragments of wood.

(b) Individual strata are laterally imper-
sistent, a characteristic feature of
fluviatile deposits.

(c) Typical colours found in the formation
are red, yellow and brown. The colour-
ing matter is ferric oxide, which is
normally reduced under marine, paludal,
or lacustrine environments, and is best
preserved under non-reducing fluviatile
environment.

(d) Subaerial exposure of the sediments is
indicated by the prevalence of intra-
formational conglomerates and breccias.
They indicated hardening and cracking
of clays due to exposure to the air.
followed by scouring of flood-waters,
incorporating the hardened blocks in
the succeeding sediment. Local uncon-
formities are often associated with the
intraformational conglomerates, and
these are known to be quite typical of
fluviatile deposits.

The sediment making up the Greenough
Sandstone is believed to be largely locally derived
from the nearby granitic hills. It fills valleys in
the irregular surface of the Precambrian rocks.
The sediment is almost unsorted, having a
kaolinitic cement, and closely resembles the
weathered granitic rocks both in composition
and appearance. Rounding of sand grains and
the bedding are always poor, confirming that
the sediment has undergone little transporta-
tion.

Economic Aspects. — The Greenough Sandstone
has been used to a limited extent as a building-
stone, and as such it is rather well-suited. The
mottled colouring is attractive, and as it is never
strongly consolidated, it is easy to work.

Small quarries have been opened at “White
Peak” and “Moonyoonooka” Stations for the
purpose of extracting this stone.

( ii > Moonyoonooka Sandstone

Definition. — The name Moonyoonooka Sand-
stone was introduced by Playford, in Arkell and
Playford (1954), for the continental sediments,
predominantly felspathic sandstones and arkoses,
between the Greenough Sandstone, or the Pre-
cambrian rocks, and the overlying marine
Colalura Sandstone. The name is taken from
“Moonyoonooka” Station, which embraces a
large part of the area mapped in detail (Plate 5).
Moonyoonooka is also the name of a small rail-
way station on the Geraldton-Mullewa line.

The type section of the formation is on
“Moonyoonooka” Station and overlies the type
section of the Greenough Sandstone. It com-
mences in a creek bed at 28° 47' 18" S., 114 47'
36" E. (714315), and continues up a hill to
(714313). The following is a description of this
section: —

Colalura Sandstone. Disconformably over-
lying—

Moonyoonooka Sandstone (103')

Thickness

Feet.

(6) Arkose and felspathic sandstone, very
fine- to medium-grained, partly silty,
chiefly yellow, occasionally white and
grey; contains some thin interbedded
shales and siltstones; well-sorted, and
usually well-bedded; shows cross-
bedding. current ripple-mark, and oc-
casional mud-cracks; some thin intra-
formational conglomerates are present;
ferruginous concretions are common,
barite concretions rare; fossil wood
common in the centre of ferruginous
concretions; one fossil leaf found 66

(5) Sandstone, medium-grained. brown
ferruginous. massive; outcropping

prominently Va

( 4 i Interbedded shales and fine-grained,
cross-bedded felspathic sandstone;
variegated yellow, grey, and white;
some beds have incrustations of
water-soluble salts 11

(3) Shale, black, carbonaceous, contain-
ing indeterminable plant fragments .... 5

(2) Sandstone. conglomeratic, brown,
ferruginous, massive, lenticular, out-
cropping prominently. with well-
rounded quartz pebbles; contains
rare fossil wood l

(1) Shale, black, carbonaceous, with
lenses of brown sandstone, sometimes
felspathic. conglomeratic, and con-
taining rare fossil wood: sandstone
lenses most abundant near the base,
where they are several feet long, and
on the average 3 in. thick 19

conformably overlying Greenough Sandstone.

109

Lithology. — The Moonyoonooka Sandstone con-
sists for the most part of poorly consolidated
felspathic sandstones and arkoses, which are
predominantly yellow, but also white, grey, red,
and brown. These sandstones are well-bedded,
often very thin-bedded, and both cross-bedding
and current ripple-mark are commonly found.
In the area mapped in detail these indicate a
current direction, which though variable, is pre-
dominantly from the south-east.

The sandstones are usually fine- to very fine-
grained, and contain lenses of shale, siltstone,
coarse sandstone, and conglomerate, which are
dove-tailed together, conglomerate sometimes
cutting through shale. The lenticular nature of
these beds is very noticeable. The shales are
usually white, grey, or black in colour, while
the coarse sandstones and conglomerates are
usually brown. Intraformational conglomerates
are sometimes found, together with rare mud-
cracks.

The sand grains for the most part show little
rounding, though an occasional rounded grain is
found, and in conglomerates the quartz pebbles
and granules may be well-rounded.

Small ferruginous concretions are rather
characteristic of the formation. These vary
considerably in shape, but the most typical are
subspherical, and from one to six inches in
diameter. The outer surface is usually yellow
in colour, but may also be brown or dark red.
The centres of the concretions usually consist
of yellow, grey, or green unconsolidated powder,
surrounded by a hard limenitic shell. They
have apparently formed by the decomposition
of pyrite or marcasite. Some contain a piece
of limonitized fossil wood, which was once prob-
ably pyritic or marcasitic.

A few barite concretions have been found
weathered out of the formation, both in the
type section, and at (723300*. It was not pos-
sible to fix accurately the horizon from which
they were derived.

The Moonyoonooka Sandstone shows a vari-
able assemblage of minerals, which is in marked
contrast to the Greenough Sandstone with its
monotonous suite. The “light” minerals con-
sist of quartz, felspar, and muscovite. Felspar
is usually present in sufficient Quantities to
designate the sandstones as felspathic, and fre-
quently there is sufficient to call them arkoses.
The felspar, which is usually rather fresh, con-
sists almost entirely of microcline and ortho-
clase, though odd grains of albite and oligoclase
have been noted. Altogether 27 samples, col-
lected over a wide area from this formation,
have been examined microscopically to de-
termine their felspar content. Of these, 13 were
felspathic sandstones (10 to 24% felspar), 11
were arkoses (25% or more felspar), and three
were auartzose sandstones (less than 10%. fels-
par). A noticeable feature of this examination
was that of six samples from the type section,
five were arkoses. and the other was a fels-
pathic sandstone.

Muscovite flakes are frequently present in the
sandstones, in quantities up to 5%. The flakes
occur along the bedding planes, so that the
sandstones split readily along these planes.

Among the non-opaque heavy minerals, kya-
nite and tourmaline are the most abundant,
while staurolite, rutile, and zircon are well re-
presented. There are minor amounts of other
non-opaque minerals present. The most notice-
able feature of the assemblage is the abundance
of the metamorphic minerals kyanite and
staurolite. and the relatively low percentage of
zircon. This is in marked contrast to the Green-
ough Sandstone, where zircon is comparatively
abundant, while kyanite and staurolite are very
rare.

Stratigraphic Relationships. — Over most of
the area studied the Moonyoonooka Sandstone
rests conformably on the Greenough Sandstone.
However in those places where the Greenough
Sandstone pinches out against hills in the Pre-
cambrian rocks, the Moonyoonooka Sandstone
rests unconformably on these rocks.

The Moonyoonooka Sandstone is overlain dis-
conformably by the Colalora Sandstone, the
basal formation of the marine succession. This
disconformity has little relief and is best seen
in the Bringo cutting, where the phosphatic
sandstone of the Colalura Sandstone rests on
typical Moonyoonooka Sandstone, whose bed-
ding planes are truncated at the surface of con-
tact (see Plate 1, 1).

Distribution and Thickness. — The Moonyoo-
nooka Sandstone has been recognised from near
Kings Table Hill in the Northampton area to
Mt. Hill. It extends inland as far as the Bringo
cutting.

Throughout the area examined, wherever the
Moonyoonooka Sandstone rests on Greenough
Sandstone and not the Precambrian rocks, its
thickness varies little from 110 feet, the thick-
est section measured being 118 feet at (713296),
and the thinnest is 80 feet near Spion Kop
(828326). The formation pinches out in those
areas where the elevation of the Precambrian
rises higher than 640 feet above sea-level.

The type section is the best known exposure
of the formation. Another good outcrop is at
(723310), where it has been exposed by gully-
ing combined with landsliding. Other typical
exposures occur at The Twins (608410), at Spion
Kop (728327). and near “Woolanooka” (782337).

Fossils and Age. — Fragments of wood are the
only fossils commonly found in the Moonyoo-
nooka Sandstone. These are sometimes present
in the centres of ferruginous concretions.

One fossil leaf has been found near the top
of the type section, but this is poorly preserved
and is of doubtful value for dating. Dr. A. B.
Walkom is of the opinion (in a written com-
munication) that it could be a leaf of the Lin-
guifolium type, which would indicate a Meso-
zoic age, perhaps Jurassic or Rhaetic.

Owing to the lack of satisfactory fossil evi-
dence it has not been possible to date the Moon-
yoonooka Sandstone, but it seems best con-
sidered as Lower Jurassic. It is probably
equivalent to part of the Cockleshell Gully
Sandstone of the Hill River area, and this
formation has been dated as Lower Jurassic.

110

Ill

Fig.

PLATE 1.

1— Disconformity between Moonyoonooka Sandstone (beneath hammer) and Colalura Sandstone (about 18 inches
thick) exposed in the Bringo cutting. The Colalura Sandstone is overlain conformably by Bringo Shale.
Note truncation of bedding at the disconformity

2. — Exposure of Colalura Sandstone, showing abundant fossil wood enclosed in a matrix of ferruginous, con-
glomeratic sandstone. The scale is 6 inches long.

112

PLATE 2.

1. — Newmarracarra Limestone with numerous Trigonia moorei.

2. — Newmarracarra Limestone with several specimens of Pecten cinctus.

113

- *L

PLATE 3.

1 - — Tlie western end of the Bringo cutting, showing Jurassic sediments and kaolinized granitic
gneiss (right centre). Note the two small west-dipping faults cutting the Jurassic
sediments.

2. — Small anticline exposed in the Yarragadee Formation near the eastern end of the Bringo
cutting.

114

Environment of Deposition. — The Moonyoo-
nooka Sandstone is believed to be a continental
fluviatile deposit. It shows the following fea-
tures indicative of fluviatile deposition, many
of which are also shown by the Greenough
Sandstone:

(a) Fossil wood is present and one fossil
leaf has been found, while marine
fossils are absent.

(b) A prominent feature of the formation
is the lenticular nature of individual
beds, with sandstones, conglomerates,
and shales dovetailing together in in-
tricate fashion. This points strongly
towards fluviatile deposition. The
coarse sediments represent the channel
deposits, and the finer-grained sedi-
ments the flood-plain deposits, while
the dark shales represent deposits of
small lakes and swamps on the flood -
plain.

(c) The characteristic colour of the forma-
tion is yellow, a typical colour of fluvia-
tile deposits which accumulate under
non-reducing conditions, permitting
preservation of such colours as red and
yellow, which are due to ferric oxide.

(d) Intraformational conglomerates and
breccias testify to the subaerial ex-
posure of the beds.

(e) Cut-and-fill structure is present where
coarse sandstones cut through shale or
fine-grained sandstone.

(f) The abundance of cross-bedding and
current ripple-mark throughout the
formation is evidence of the shallow-
water nature of the deposit.

(g) Arkose, though not invariably a fluvia-
tile sediment, is most typically deposited
under the fluvial environment, so that
the prevalence of this sediment, to-
gether with felspathic sandstones, sup-
ports the suggested mode of origin of
the formation.

It is considered that following deposition of
the Greenough Sandstone, which rapidly filled
major depressions in the surface of the Pre-
cambrian rocks, the Moony oonooka Sandstone
was spread over a broad flood-plain, above
which some basement hills still projected,
though the relief was much less than when the
Greenough Sandstone was being deposited. The
Moonyoonooka Sandstone is very well-bedded
and well-sorted, in marked contrast to the
Greenough Sandstone. This is because the
Moonyoonooka Sandstone has been transported
further than the Greenough Sandstone, and
has been spread layer-on-layer by successive
floods, whereas the Greenough Sandstone is lo-
cally derived.

The prevalence of fresh potash felspar in the
Moonyoonooka Sandstone indicates that erosion
of the source area was sufficiently rapid to pre-
vent decomposition of this mineral. Rather
rapid erosion is also indicated by the rich heavy
mineral suite, which includes such relatively
unstable minerals as sphene. The extreme
rarity of garnet in the non-opaque suite is evi-
dence that the sediment must have been trans-

ported a fairly considerable distance, for the
local granitic rocks are rich in garnet. As the
abundance of felspar and other metastable
minerals is very marked in the Moonyoonooka
Sandstone, garnet would also have been com-
mon had the sediment been locally derived.

It is likely that deposition of the Greenough
and Moonyoonooka Sandstones, and indeed of
all the continental Jurassic and Lower Cre-
taceous continental sediments in the Perth
Basin, was controlled by movement along the
Urella and Darling Faults. These sediments
are believed to have been laid down in front of
the active faults, and to have been derived by
erosion of the area of steep, youthful topo-
graphy near the fault scarps. The Urella Fault
is believed to have been the dominant fault
in Jurassic times in the area north of Coorow,
while from about Coorow to the south coast the
Darling Fault is the main fault. It is import-
ant to note that no Jurassic sediments are
known in the area east of the Urella Fault.

Champion Bay Group

The name Champion Bay Group was intro-
duced by Playford, in Arkell and Playford
(1954), for the Jurassic sediments overlying the
Chapman Group. The group is made up of four
formations, the Cclalura Sandstone. Bringo
Shale, Newmarracarra Limestone, and Koja-
rena Sandstone. Playford and Willmott (in
McWhae et al. 1958) redefined the Ko.iarena
Sandstone, placing the upper part of the forma-
tion as previously understood by Playford in
the Yarragadee Formation. The latter forma-
tion is not included in the Champion Bay
Group.

The Champion Bay Group is of Middle Ju-
rassic age. One formation, the Newmarracarra
Limestone, is accurately dated as Middle Ba-
jocian, and the other formations are probably
also of Baiocian age.

(i) Colalura Sandstone

Definition. — The name Colalura Sandstone was
introduced by Playford, in Arkell and Playford
(1954), for the sandstone unit resting on the dis-
ccnformity with the Moonyoonooka Sandstone
or the nonconformity with the Precambrian
rocks, and overlain conformably by the Bringo
Shale or the Newmarracarra Limestone. The
formation is named after the Colalura Brook
(770330), which drains the southern part of
the area surveyed in detail, and flows into the
Greenough River.

The type section of the Colalura Sandstone is
at Spion Kop (28° 46' 44" S., 114° 48' 24" E.).
The following is a description of this section:

Laterite (lateritized Newmarracarra Lime-
stone) overlying —

Colalura Sandstone (8 to 12')

Thickness

feet

(1) Sandstone, very coarse- to medium-
grained. conglomeratic. yellowish
brown, ferruginous, coarsely cross-
bedded, containing a few thin clay-
stone beds; several horizons rich in
fossil wood and limonitic nodules 8-12

disconformably overlying Moonyoonooka
Sandstone.

115

Lithology . — The Colalura Sandstone consists
almost entirely of sandstone, with minor
amounts of claystone, siltstone, and shale. The
sandstone is frequently conglomeratic, and
varies in colour from black and brown to
yellowish -white, a dark brown being most
common. Sand grains may be appreciably
rounded or unrounded, and their cement is
usually ferruginous, but is sometimes calcareous.

A striking and characteristic feature of most
exposures of the unit is the presence of abundant
ferruginous fossil wood (see Plate 1, 2), and to
a lesser extent of oval-shaped ferruginous
nodules, generally about 2-inch long. The wood
varies in size from logs 3 feet long, to minute
fragments. The nodules and some of the fossil
wood are believed to have been originally phos-
phatic, and to have been ferruginized during
weathering. They are still phosphatic in the
exposures of Colalura Sandstone in the Bringo
cutting and near “Woolanooka” (780238).

The phosphatic nodules, which are dark
brown in colour, have a pronounced concentric
structure, and frequently contain a nucleus of
greyish clay. It is possible that this structureless
clayey interior is of coprolitic origin, and the
nodule has grown by concentric addition to
this nucleus. In the nodules which have been
replaced by limonite. this concentric structure
is lost, though the clay centres remain.

The nodules are apparently syngenetic
(formed before burial in sediments), for the
insoluble residue left after treatment of the
nodules with acid is fine clay or sand, despite
the fact that the nodules are themselves enclosed
in a coarse sand.

The abundant limonite in the Colalura Sand-
stone is probably not entirely secondary, for
even in the Bringo cutting where the nodules
are still phosphatic, the cementing agent in the
sandstone is limonite, with perhaps some hema-
tite, and the nodules themselves contain some
ferric oxide. The reason for the complete
replacement of the nodules by ferric oxide is not
certain, but it may well be connected with later i-
tization.

Stratification is usually absent in the sand-
stones, though they are sometimes coarsely
cross-bedded. The sorting of the sandstones
usually appears to be poor owing to the large
amounts of fossil wood and nodules present —
these may make up as much as 50% or more of
the rock by volume. However, the sand remain-
ing after treatment of the rock with acid is
often found to be quite well-sorted.

In the Bringo cutting the Colalura Sand-
stone shows a well-marked facies change from
the typical brown sandstone with no marine
fossils but abundant dark brown fossil wood and
phosphatic nodules, to a yellowish sandy clay-
stone with abundant marine fossils, and
occasional fossil wood and phosphatic nodules.
The nodules and fossil wood in this claystone
are different in appearance from those in the
sandstone, and they also contain a higher per-
centage of PjsOs. The phosphatic wood is yellow,
and the cell structure is clearly visible, even to
the naked eye. This fossil wood contains as much
as 32.9% of P 2 O.S, whereas the fossil wood in the
sandstone from the cutting contains only as

much as 1.47% of P 2 O 5 . The nodules in the
claystone are yellowish and many have a black
coating giving them a high surface lustre. In
shape they are similar to the typical brown
nodules, and they usually contain a clayey
nucleus, though the outer layer shows no pro-
nounced concentric structure. These nodules
have as much as 23.8% of P 2 Ch, while the dark
brown nodules from the sandstone contain up
to 6.1%.

The cementing material of the Colalura Sand-
stone is occasionally calcareous, as at the
locality near “Woolanooka” (780238), and at
(873307), near “Sandspring.”

In some localities the sandstone is stained
black by manganese oxide. This is seen well in
the Bringo cutting, where the sandstone and
claystone of the formation show some black
patches due to a thin coating of manganese
oxide.

The “light” minerals in the sandstone remain-
ing after treatment with acid consist of rounded
and angular grains of quartz, and smaller
amounts of felspar and muscovite. The per-
centage of felspar was not sufficient to designate
any of the samples examined as being felspathic,
but it is higher than in any formation other
than the Moonyoonooka Sandstone. Only potash
felspar has been recognized, and the percentage
is highest in the finer-grained sandstones, one
sample containing 8%>.

The heavy mineral suite is rather variable,
the most distinctive feature being the abundance
of the metamorphic minerals kyanite. stauro-
lite, and garnet. The nature of the heavy
mineral suite seems to vary according to the
underlying rock. In the Bringo cutting the
Colalura Sandstone rests on both the Moony-
oonooka Sandstone and the Precambrian
gneisses. The heavy mineral residue from the
formation at this locality is remarkable for its
unusually large content of garnet, which forms
more than 50%. of the non -opaque minera ls.
The Precambrian gneisses of this area are very
rich in garnet, and the Colalura Sandstone in
the Bringo cutting no doubt derived its garnet
from this source. On the other hand, specimens
examined from localities distant from granitic
areas, where the formation overlies thick
deposits of Moonyoonooka Sandstone, contain
little or no garnet. These specimens are found
to contain considerable quantities of kyanite
and staurolite, which were probably derived bv
the reworking of the underlying Moonyoonooka
Sandstone, which is rich in these minerals, but
contains little garnet.

Stratigraphic relationships . — The Colalura
Sandstone usually overlies the Moonyoonooka
Sandstone, being separated by a disconformity
which shows little relief. In places however, it
overlies the Precambrian rocks, as the Moonyoo-
nooka Sandstone lenses out against buried hills.
Conformably overlying the Colalura Sandstone
is either the Bringo Shale or the Newmarracarra
Limestone.

Distribution and thickness . — The Colalura
Sandstone is a thin, discontinuous, but persistent
formation at the base of the marine section
throughout a large part of the Geraldton district.

It is known to extend from near Howatharra
Siding (north of the map) to Mt. Hill, and has
been recognized as far east as “Sandspring”
(873307).

The Colalura Sandstone is absent over part of
the area, but where present it ranges up to 28
feet in thickness at (725340). Most exposures
are only about 2 feet thick.

As the Colalura Sandstone is often well-
consolidated, exposures of the formation are
quite frequent, in the form of large slabs, which
may migrate some distance down the hill-slopes.

Fossils and age. — As already described, the
Colalura Sandstone is rich in fossil wood. Marine
fossils have also been found in the formation at
several localities. The most important of these
is the Bringo cutting, where a claystone unit
in the formation contains numerous marine
fossils, preserved as moulds. Another locality
where fossils are abundant is at (715325), where
they are preserved as moulds in a coarse-grained
ferruginous sandstone.

The following is a list of fossils which have
been identified from the Colalura Sandstone:
The pelecypods Astarte cliftoni, Astarte sp,.
Ctenostreon pectiniformis , Lopha cf. marslii ,
Trigonia moorei, Ostrea sp., Oxytoma cf. decern -
costa , and Isognomon sp., and the belemnite
Belemnopsis sp.

There are also several unidentified species of
pelecypods and gastropods, and one echinoid
spine, a shark tooth, a reptilian tooth, and a
reptilian vertebra were found in the Bringo
cutting.

All the species which have been identified are
also present in the Newmarracarra Limestone,
which is known to be of Middle Bajocian age,
and it seems probable that the Colalura Sand-
stone is also Bajocian in age.

Environment of deposition. — The Colalura
Sandstone represents the basal shallow-water
deposits of an advancing sea. The clastic con-
stituents were largely derived by reworking from
the underlying Moonyoonooka Sandstone and
the Precambrian rocks. A shallow-water en-
vironment of deposition is indicated by the
coarseness of the sandstone and the large-scale
cross-bedding. Moreover, it is difficult to visua-
lize such large quantities of wood being in-
corporated in the sediment except under very
shallow water conditions.

The source of all the fossil wood in the forma-
tion is not easy to explain. If it has been carried
in by rivers, then the sediments carried by those
rivers would tend to mask the wood. It is pos-
sible that the wood represents the vegetation
which was growing on the low-lying flood-plain
of the Moonyoonooka Sandstone, which was en-
gulfed as the sea advanced. Against this hypo-
thesis is the fact that no fossil stumps have been
found embedded in situ in the Moonyoonooka
Sandstone.

The origin of the phosphatic nodules in the
formation is not known. However the occurrence
of these nodules immediately above the dis-
conformity with the Moonyoonooka Sandstone

is not unexpected, as phosphatic zones are com-
monly found elsewhere in the world in associa-
tion with unconformities.

(ii) Bringo Shale

Definition. — The name Bringo Shale was first
used by Playford, in Arkell and Playford (1954),
for the black shale which overlies the Colalura
Sandstone or the Precambrian rocks, and under-
lies the Newmarracarra Limestone.

The type section is exposed in the Bringo cut-
ting (766364, 28° 44' 54 S., 114° 50' 54" L.) The
following is a description of this section:

Newmarracarra Limestone. Comformably over-
lying —

Bringo Shale (7 feet)

Thickness
Ft. In.

(5) Shale, black, becoming yellow in the
uppermost foot; phosphatic nodules
resting on top; several layers contain-
ing small pelecypods 2 6

(4) Claystone. yellowish brown, phos-
phatic, concretionary 2

(3) Shale, black; rich in small pelecypods 6

(2) Claystone, yellowish brown, phos-
phatic, concretionary .... .... 4

(i) Shale, black; abundant small pelecy-
pods at the base 3 6

conformably overlying Colalura Sandstone.

Lithology. — The Bringo Shale consists of black
shale with thin yellow phosphatic beds. A layer
of phosphatic nodules is present at the top of the
unit, at the contact with the Newmarracarra
Limestone. The shale contains some small car-
bonaceous fragments of wood and a few beds of
marine fossils.

The yellow phosphatic clay beds are only a
few inches thick, and show pronounced con-
cretionary structures. The phosphate content
averages 3.3% of F-O, The phosphatic nodules,
which are not common, are flattened, smooth,
bulging, asymmetrical bodies, which are up to
6 inches long, and 2 inches thick. They show
only a poorly defined concentric structure. The
upper surface of the nodules often shows a
series of small pits. Sections show that these
pits cut through the concentric structure of
the nodules, indicating that they are secondary,
and it seems possible that they were formed by
boring organisms. Another feature of the outer
surface is a series of cracks which penetrate
about i-inch into the nodules. These are sub-
parallel, and are apparently shrinkage cracks
produced when the nodules solidified. The
phosphate (P2O5) content of the nodules varies
from 7.6% in the Bringo cutting to 26.8% near
“Sandspring”.

Stratigraphic relationships. — The Bringo Shale
rests conformably on the Colalura Sandstone, or
unconformably on the Precambrian rocks. Both
relationships are visible in the section exposed
at the Bringo cutting.

Overlying the Bringo Shale is the Newmarra-
carra Limestone. A layer of phosphatic nodules
at the contact between the formations suggests
an interval of non-deposition, so that they are
probably separated by a diastem, though they are
essentially conformable.

117

Distribution and thickness. — The Bringo Shale
has a rather limited distribution. It has been
traced at the surface from the Bringo cutting
to near “Sandspring” <872307), and as far south
as (848249 ). It is probably present in bores in
the Eradu area, underlying the Koj arena Sand-
stone, and resting on the Lower Permian Irwin
River Coal Measures.

The Bringo Shale appears to have been de-
posited only in the restricted environment ly-
ing to the east of Precam brian ridges. Thus
the unit is present in the Bringo cutting section,
to the east of a Precambrian ridge which
reaches its highest point near Bringo Station,
but it is absent on the western side of this
ridge, in the Grant Siding — “Moonyoonooka”
area (see section A-B, Plate 5. and Fig. 1.)

No section of the formation has been seen
which is more than 8 feet thick, and where it
rests on the Colalura Sandstone it is usually
about 7 feet thick. At the type section the
thickness is 7 feet, near “Sandspring” (872307)
it is 8 feet, and at (848249) it is 5 feet.

The Bringo Shale is poorly exposed through-
out the area examined. The best section is the
Bringo cutting, but elsewhere there is no con-
tinuous section exposed.

Springs commonly issue at the contact be-
tween the Newmarracarra Limestone and the
Bringo Shale, and the running water often ex-
poses the shale to some extent. A typical ex-
ample is found one mile east of Bringo (775358),
where there is a good spring of fresh water is-
suing at the contact between the two forma-
tions.

Fossils and age. — The only fossils which have
been found in the Bringo Shale are those from
the type section. At this locality there are sev-
eral layers in the shale which are rich in
dwarfed pelecypods, predominantly a species of
Meleagrinella, together with some oysters. Rare
gastropods, and guards of Belemnopsis are also
found. Balme (1957) has described a small as-
semblage of fossil spores and pollen grains in
a sample of the formation from the Bringo cut-
ting.

The Bringo Shale is believed to be of Bajocian
age. The layer of phosphatic nodules at the
top of the formation indicates a probable gap in
sedimentation prior to deposition of the Middle
Bajocian Newmarracarra Limestone, but this gap
was probably only of very short duration.

Environment of Deposition . — The Bringo Shale
was deposited in an environment having re-
stricted circulation, resulting in anaerobic con-
ditions on the bottom. Under such conditions
the benthonic fauna is absent or restricted, and
the action of scavengers in eliminating organic
material derived from the surface waters is pre-
vented. Nearly all black shales in the geological
record are believed to have formed in this way
(Twenhofel 1950).

As the Bringo Shale contains several layers
with dwarf benthonic pelecypods. and as no iron
sulphide has been found in the shale, restriction
of circulation was apparently not complete, and

there were periods when the bottom was quite
well-oxygenated. However, as the benthonic
fossils are only found in relatively thin bands,
with black unfossiliferous shale in between, the
conditions w’ere apparently anaerobic during
most of the time when the shale was accumu-
lating.

The cause of the stagnation is to be found in
the irregularity of the surface of the Precam-
brian rocks. It is clear in the Bringo cutting
that the shale has accumulated in a barred
basin on the eastern side of a hill or ridge of
Precambrian rocks. On the western side of this
ridge the Bringo Shale is absent, as this area
w : as apparently part of the open ocean, with free
circulation, at the time when the shale was
accumulating in the restricted environment to
the east of the ridge. It is not knowm wdiether
the ridge was below r sea- level w T hen the shale
w r as deposited. If it w T as submerged, the depth
of water must have been small, so that free
connection with the open ocean w^as prevented.

Some change must have occurred in the con-
ditions of circulation following deposition of the
Colalura Sandstone. In the Bringo cutting sec-
tion this formation contains a rich benthonic
fauna w r hich clearly grew under normal condi-
tions of free circulation. It is possible that
during Colalura times there w : as free connection
with the open ocean through some opening
winch w’as barred before deposition of the Bringo
Shale commenced. Alternatively the restriction
may have followed a slight relative fall in sea-
level, making the bar more effective.

The phosphatic nodules at the top of the
formation may have been deposited in the form
of a gel. This is suggested by their flattened,
irregularly rounded shape, which is typically like
that of a gel mass, and also by the presence of
skrinkage cracks on the outer surface of the
nodules. These may have formed as the gel
contracted on solidification.

(iii) Neivmarrctcarra Limestone

Definition . — The Newmarracarra Limestone
was defined by Playford, in Arkell and Playford
(1954 ). The formation overlies either the Bringo
Shale, the Colalura Sandstone, the Moonyoo-
nooka Sandstone, or the Precambrian rocks, and
underlies the Koj arena Sandstone. The name is
taken from “Newmarracarra,” a well-known
pastoral property in the Geraldton district.

The name “Newmarracarra” had previously
been used in a stratigraphic sense by Glauert
(1926), who defined the “Newmarracarra Beds”
as the fossiliferous beds exposed in the “Nineteen
Mile” (later Bringo) railway cutting, from W'hich
the fossils described by Whitehouse (1924)
were obtained. Actually Whitehouse’s fossils
were probably obtained from a railway well
near Bringo, but in either case they certainly
came from the limestone, and Glauert’s name
must be used in reclassification.

Teichert (1947), apparently independently,
proposed the name “Newmarracarra Series” for
all the marine sediments of the Geraldton dis-
trict, but Glauert’s earlier usage clearly has
priority.

The type section of the formation is on Round
Hill, near Grant Siding (729351, 28° 45' 31" S.,
114° 48’ 23” E.) The following is a description
of this section: —

Kojarena Sandstone. Conformably overlying —
N ewmarracarra Limestone

Thickness

Feet.

(4) Limestone, light yellow-grey, sandy,
hard, massive, outcropping in large
slabs; few fossils 2

(3) Limestone, light yellow-grey, weather-
ing greyish white, hard, massive, out-
cropping in large slabs; richly fossil i-

ferous ... 8

(2) Limestone, light yellow-grey, clayey,

soft, massive; richly fossiliferous ... 21

(1) Limestone, light yellow -grey, sandy,
clayey, hard, massive, outcropping as
large slabs, richly fossiliferous .... 2

disconformably overlying Moonyoonooka
Sandstone.

Lithology. — The Newmarracarra Limestone,
where it has not undergone secondary altera-
tion, usually consists of limestone composed of
entire or little-broken shells. It has a variable
content of clastic impurities, and rarely grades
into a calcareous sandstone.

The limestone is generally massive, hard, and
smooth-weathering, outcropping as large slabs
which frequently break off, and tend to migrate
down the sides of hills making it difficult to
say when the slabs are in situ.

The colour of the limestone varies from yellow
and grey to red, the most usual being yellow,
frequently weathering grey. The red coloration
is secondary, and is due to the presence of finely
divided hematite in the rock.

The limestone has been subjected to a great
deal of secondary alteration throughout the
area examined. Over the most of this area a
large part of the limestone has been either re-
placed by iron oxide (mainly hematite), or
leached of calcium carbonate, leaving a residue
of its clastic impurities. Only in the small area
around the type section near Grant is the lime-
stone thought to be unaltered throughout, and
even there it is possible that the sandy claystone
overlying the limestone outcrop is really leached
limestone. The leached zone is found between
the hematite and the unaltered limestone, and
the thickness of alteration is very variable. This
alteration of the limestone is connected with
lateritization, and has been discussed already.

The limestone is often stained red by hematite
without complete removal of calcium carbonate.
This is not connected with lateritization and is
often found where the limestone overlies Bringo
Shale, with springs issuing at the contact.

The insoluble residue from the limestone
consists of clay, rounded grains of quartz, a
little felspar, an occasional flake of muscovite,
and a small quantity of heavy minerals. The
percentage of these clastic impurities is usually
rather high, most samples being sandy, argil-
laceous limestones. The quartz sand present
is rounded, having an average roundness of
about .29. This value is considerably higher
than that for sand in the other formations, and
indicates relatively prolonged abrasion of the
sand.

It is noticeable that the percentage of clastic
impurities in the formation rises to the east,
as those elevated areas in the Precambrian
rocks still projecting above the earlier sedi-
ments are approached. For example, on the
road from Northern Gully to “Tibradden”
(836367). there is an outcrop of cross-bedded
calcareous sandstone at the base of the lime-
stone, and all the limestone is very sandy. The
formation abuts a buried hill of Precambrian
rocks near this locality, and almost certainly
pinches out against this hill. On the other
hand the base of the limestone to the west (as
at (690297), which is several miles from such
elevated Precambrian areas) is comparatively
free of clastic impurities.

The high sand content around the granitic
hills is probably not due to erosion of these
hills when the Newmarracarra Limestone was
accumulating. This is indicated by the fact that
the quartz grains are comparatively well-
rounded. and must have undergone rather pro-
longed abrasion before deposition. They could
not have been abraded to any great extent
while the shells were accumulating, for these
show little evidence of wear. It is probable
that the sand was rounded while the Colalura
Sandstone and Bringo Shale were being de-
posited. During this time the sea probably did
not cover the granitic hills, and rounded beach
sands may have accumulated around these is-
lands or promontories. The rounded sand now
found in the limestone may represent this sand
which was redistributed during deposition of
the Newmarracarra Limestone.

The most striking feature of the heavy min-
eral suite is the unusually large quantity of
epidote present, as this mineral is only found
in small quantities in the other formations.
Otherwise the heavy mineral assemblage is
rather like that of the Colalura Sandstone,
with a fairly high percentage of metamorphic
minerals, including garnet.

Stratigraphic relationships. — The Newmarra-
carra Limestone was deposited in different parts
of the area on either the Bringo Shale, the
Colalura Sandstone, the Moonyoonooka Sand-
stone, or the Precambrian rocks. The contact
with the Precambrian rocks is a nonconformity,
and that with the Moonyoonooka Sandstone is a
disconformity. The contact with the Bringo
Shale and the Colalura Sandstone is believed to
be essentially conformable, though the units may
be separated by a diastem.

The Newmarracarra Limestone is overlain con-
formably by the Kojarena Sandstone.

Distribution and thickness. — Unaltered New-
marracarra Limestone has a very limited dis-
tribution in the Geraldton district, the most
extensive outcrops being found in the area map-
ped in detail. Elsewhere outcrops are very
sporadic, as the limestone has been largely
altered by lateritization. The hematite rock
and underlying leached zone can be readily re-
cognized as altered Newmarracarra Limestone
in the field, and have been mapped as such.
On the other hand, the intensely altered lime-

119

stone close to true laterite is not readily re-
cognized, and for mapping purposes has been in-
cluded in the laterite.

Owing to the irregular alteration, the thick-
ness of limestone is very variable, the thickest
exposures being near Round Hill, where up to
33 feet of unaltered limestone are exposed.
Elsewhere the formation is invariably altered
to some extent, so that at least the upper part
is replaced by hematite or simply leached of
calcium carbonate. Because of the irregular
leached zone, which causes compaction of the
formation, it is not possible to give accurate
primary thickness of the limestone at those
localities where it has been altered. The thickest
section which has been measured is at (690297',
where the formation is about 38 feet thick. At
this locality there are about 28 feet of limestone
and 10 feet of altered limestone. Nearly all of
this alteration is in the form of hematite, and
the leached zone is very thin. In the Geraldton
Racecourse bore the formation may be 47 feet
thick (from 186 feet to 233 feet).

At the Bringo cutting the unaltered limestone
is up to 5 feet thick, but passes both laterally
and vertically into leached limestone (see Plate
6). The leached zone is up to 8 feet thick, and
is overlain by as much as 9 feet of hematite
rock. The contact between the leached and
hematite-replaced limestone is not well-marked,
each grading gradually but irregularly into the
other. At this locality the formation is only
17 feet thick, and has compacted considerably
owing to the thick leached zone.

Exposures of the Newmarracarra Limestone
extend from near Howatharra Siding on the
Geraldton-Northampton line (off the map) to
Mt. Hill. It is known to lense out to the east,
and has been recorded during the recent Wapet
survey as far inland as U miles south-east of
Eradu Pool on the Greenough River. It is ab-
sent from bores around Eradu itself, though
both the Koj arena Sandstone and the Bringo
Shale are apparently represented there.

The Cadda Formation of the Hill River area,
100 miles south of Geraldton. is a facies equiva-
lent of the Newmarracarra Limestone. The
Cadda Formation contains a high percentage of
sandstone and siltstone in addition to limestone,
and is also not as richly fossiliferous as the
Newmarracarra Limestone.

Fossils and age , — The Newmarracarra Lime-
stone is richly fossiliferous. and fossils are usu-
ally well-preserved, though they are frequently
difficult to extract owing to the toughness of the
matrix. In addition to the abundant marine
fossils, fragments of wood up to about 2 feet
long are not uncommon in the limestone.

The most abundant fossils are the pelecypods,
and of these Trigonia moorei is by far the most
common. This species is found, perfectly pre-
served, in great abundance thoroughout the
formation, indeed some parts are composed
almost entirely of masses of this shell (see Plate
2 , 1 ).

The ammonites, which are of prime import-
ance in dating the formation, are seldom found
in any abundance, though there are at least
23 species known. The species most commonly

found is Fontannesia clarkei and large numbers
of this species were collected in the debris from
rabbit-burrows in the area about one mile
south-east of Bringo. The ammonites have
recently been the subject of a detailed study by
Arkell (in Arkell and Playford 1954), and he
has concluded that the Newmarracarra Lime-
stone can be referred to the Sowerbyi and per-
haps Sauzei and Humphriesianum Zones of the
European Middle Bajocian.

The following is a list of fossils which have
been recorded from the Newmarracarra Lime-
stone. It must be understood that most of
these fossils were described many years ago, and
many of the names, particularly of the genera,
need revision. These forms marked with an
asterisk, e.g. *Cristellaria cultrata , have not been
figured or properly described from the Newmar-
racarra Limestone. Their occurrence has
merely been recorded, and there is some doubt
as to whether some of them are really present.
The Ostracoda. originally described by Chap-
man (1904a), were recently discussed by Kel-
lett and Gill (1956), and they point out that the
fauna needs complete re-study. It is certain
that all the fossils which have previously been
described as coming from the Geraldton dis-
trict are from the Newmarracarra Limestone.

Foraminifera (Chapman 1904a, Moore 1870).
Bulimina gregorii, Cristellaria costata var. com-
pressa, C. costata var. seminuda, *C . cultrata, C.
daintreei, C. decipiens. C. cf. limata, C. promi-
nula, C. rotulata . C. subalata, Discorbina rosa-
cea , Flabellina dilatata, Haplophragrnium neco-
cornianum > Marginulina compressa, M. solida,
Polymcrphina burdigalensis, P. compressa, P.
gutta, Textularia crater, Truncatulina ivuellers-
torfi. Vaginulina intumescens, V. lata, V.
schloenbachi var. interrupta , V. strigillata.

Echinoidea (Whitehouse 1924). Cidaris sp.

Vermes (Clarke 1867, Moore 1870. Etheridge
1910). Serpula conformis, *Serpula spp.

Byozoa (Whitehouse 1924). ■Berenicea cf.
archiaci.

Brachiopoda (Clarke 1867, Moore 1870,
Etheridge 1910). Rhynclionella variabilis,
* Rhynchonella spp.

Pelecypoda (Clarke 1867, Moore 1870. Ether-
idge 1901, Maitland 1907, Etheridge 1910,
Glauert 1910, Whitehouse 1924. Teichert 1940).

* Area sp., Lopha marshi, * Avicula inaequivalvis ,
Ctenostreon pe.ctiniformis , Ciicullaea inflata , *C.
oblonga, C. semistriata, C. tibraddonensis ,
Meleagrinella sinuata , Grypliaea spp., -H in-
nit es sp., *Lima proboscidea Sowerby, L. punc-
tata, Modiola maitlandi , *Mytilus cf. gygerensis,
*M. sp., *Nucula sp., Ostrea tholiformis , Ostrea
spp. Oxytoma decemcosta, * Pecten calvus, P.
cinctus, *P. cf. frontalis, P. greenoughensis, *P.
valoniensis, :: P. spp.. *Pema sp., Plicatula sp.,
Radula duplicata, Radula sp., Trigonia moorei,
■Gresslya donaciformis, *Myacites liassianus, M.
sanfordii, Pholadomya ovulum, Astarte apicalis,
A cliftoni, *Cardium sp., *Cypricardia sp.,
*Isocardia sp., * LUcina sp.. * Opis sp.. * Panopaea
rugosa, *P. sp., *Tancredia sp.. Teredo australis ,

* Unicar dium sp.

Scaphopoda (Clarke 1867). *Dentalium sp.

120

Gastropoda (Clarke 1867, Moore 1870, Ether-
idge 1910). * Amberleya sp., *Phasianella sp.,
Pleurotomaria greenoughensis, *Pleurotomaria,
sp .*Trochus sp., Turbo laevigatus, * Turbo sp.,
Cerithium greenoughensis, *C. sp., *Chemnitzia
sp., *Nerinc tea sp., Rissoina australis.

Nautiloidea (Crick 1894). Nautilus perorna-
tus.

Belemnoidea (Clarke 1867, Moore 1870, Crick
1894. Whitehouse 1924). Belemnites canalicula-
tus, * Belemnites canhavii, *B. sp.. Belemnopsis
sp.

Ammonoidea (Arkell and Playford 1954).
Sonninia playfordi, Witchellia australica, Fon-
tannesia fairbridgei, F. clarkei, F. whitehousei,
F. spp., Otoites woodwardi, O. antipodus, O.

( ?TrilobiticerasJ depressus , 70. australis,

Pseudotoites leicharti, P. fasciculatus , P. cham-
pionensis, P. robiginosus, P. emilioides, P. brun-
nschweileri, P. spitif omits, P. semiornatus, P.
spp., Zemistephanus corona , Z. armatus, ?Z
spp.. Stephanoceras ( Stenunatoceras / cf. sub-
coronatum, S. ( S J aff. triptolemus.

Ostracoda (Chapman 1904a, Kellett and Gill
1956). “Cytliere” lobulata, “ Cytheropteron ”
australiense, “Loxoconcha” elongata, “L.” jur-
assica, Procytlieridea sp.

Environment of deposition. — The Newmarra-
carra Limestone is built up for the most part
of the remains of shallow-water benthonic
organisms, predominantly pelecypods, which ac-
cumulated on the bottom of a shallow, warm
sea. Currents introduced a certain amount of
clay, silt, and sand, but the fact that these fos-
sils show little evidence of wear, and the pele-
cypod valves are often closed, indicates that
these currents were not very strong. There was
also a certain amount of drift wood in the sea,
which on becoming waterlogged, sank to the
bottom and was incorporated in the limestone.

Following deposition of the Bringo Shale,
there must have been a further subsidence (re-
lative rise in sea-level) before deposition of the
Newmarracarra Limestone. This subsidence ex-
plains the change in environment from one of
restricted circulation during deposition of the
Bringo Shale, to one of open circulation for the
Newmarracarra Limestone. By covering or in-
creasing the depth of water over the elevated
Precambrian ridges, the region east of these
ridges obtained good circulation.

(iv) Kojare7ia Sandstone
Definition. — The name Koj arena Sandstone
was first published by Playford in Arkell and
Playford (1954). He defined it as the Jurassic
sediments, mainly sandstones, which overlie the
Newmarracarra Limestone in the Geraldton dis-
trict. The name is taken from Koj arena, a
small railway siding on the Geraldton-Mullewa
line. However, the limits of the formation have
since been revised by Playford and Willmott in
McWhae et al. (1958), the upper part of the
formation as previously understood being in-
cluded in the Yarragadee Formation.

The type section of the Koj arena Sandstone
is in the Bringo railway cutting (28° 44' 54" S.,
114° 50' 54" E.). The following is a description
of this section:

Yarragadee Formation. Conformably over-
lying —

K of arena Sandstone (33')

Thickness

feet.

(2) Sandstone, reddish brown, the lower
half being mottled grey, brown, and
yellow; bedding indistinct; marine
fossils in a lens up to 6 inches
thick, 19 feet above the base 31

(1) Claystone, greyish white, mottled red;

poorly bedded 2

conformably overlying Newmarracarra Lime-
stone.

Lithology. — The Koj arena Sandstone is com-
posed predominantly of brown ferruginous
sandstone, with a little claystone at the base.
The sandstone is medium- to coarse-grained,
and is generally very well-sorted. The unit is
poorly bedded to massive, though cross-bedding
is sometimes present.

The sandstones are composed of subangular
grains of quartz, with little or no felspar, and
small quantities of heavy minerals. Compared
with the preceding marine formations the
heavy mineral suite is marked by an increased
percentage of the ultra-stable minerals zircon
and tourmaline, and a corresponding fall in the
quantity of metamorphic minerals.

Stratigraphic Relationships. — The Koj arena
Sandstone is found overlying the Newmarra-
carra Limestone, with apparent conformity,
throughout most of the area examined. In one
area near Wicherina (945350) the Newmarra-
carra Limestone is sometimes overlain directly
by the Yarragadee Formation, while in bores
around Eradu (to the east of the area covered
by Plate 4) the Kojarena Sandstone appears to
rest on the Bringo Shale. Further north, near
the mouth of Kockatea Gully, the Kojarena
Sandstone disconformably overlies the Upper
Permian or Lower Triassic Kockatea Shale.

The Kojarena Sandstone is overlain, with ap-
parent conformity, by the Yarragadee Forma-
tion.

Distribution and Thickness. — The Kojarena
Sandstone is the most widely distributed of the
Middle Jurassic marine formations. It extends
from Howatharra Siding (off the map) to Mt.
Hill, and inland it is found all along the valley
of the Greenough River north and south of
Eradu and the lower reaches of Kockatea Gully.
The unit is probably present in the Geraldton
Racecourse Bore between 154 and 186 feet.

In the area around Eradu the unit probably
reaches its thickest development. The thick-
ness from bores and exposures in this area is
probably about 110 feet, whereas in the Gerald-
ton area it does not exceed 33 feet, the thick-
ness of the type section. It is not present in
the 47 i mile peg bore (off the man) which is
situated close to the Urella Fault. In this bore
the Yarragadee Formation rests directly on the
Kockatea Shale.

121

Fossils and age. — The Kojarena Sandstone con-
tains few fossils. In the Bringo cutting section
at 20 miles 5 chains from Geraldton, there is a
thin fossiliferous lens up to 6 inches thick
containing moulds of marine fossils. At several
other localities, such as Round Hill and H miles
east-north -east of Eradu, a few similar marine
fossils have been found. Those which have been
identified are Trigonia moorei , Cucullaea sp..
Isognomon sp.,and Belernnopsis sp. These fos-
sils are also present in the underlying New-
marracarra Limestone, which is of Middle
Bajocian age. As the two formations are com-
formable, it is likely that the Kojarena Sand-
stone is also of Bajocian age.

Fragments of wood occur occasionally in the
unit, and worm tubes are also sometimes found.
Environment of deposition. — The Kojarena
Sandstone is interpreted as being a shallow-
water marine deposit. The presence of marine
fossils in typical sandstones of the formation
shows the marine origin, and the high degree of
sorting probably indicates that it was deposited
below wave-base. It represents the final phase
of the Middle Jurassic marine cycle.

Yarragadee Formation

Definition. — The Yarragadee Formation was
first named “Yarragadee Beds” by Fairbridge
(1953). He used the name for exposures of
sandstone and siltstone on Yarragadee property,
7 to 8 miles north of Mingenew. His usage was
followed by Johnson et al. (1954). The name
was raised to formation rank by Playford and
Willmott (in McWhae et al. 1958). They
included the “Monksleigh Beds” of Fairbridge
(1953) in the formation. Fairbridge’s type
locality of the “Yarragadee Beds,” li miles
south-south-east, of Yarragadee Homestead, is
retained as the type of the Yarragadee Forma-
tion. However, the section exposed there is
complicated by faulting (it. is adjacent to the
Urella Fault), and a satisfactory section cannot
be measured.

The section of Yarragadee Formation exposed
in the Bringo railway cutting is proposed as a
reference section for the formation in the
Geraldton area. This section is as follows:

Yarragadee Formation (511)

Top of formation not exposed, overlain by
Quaternary deposits.

Thickness

feet

(13) Sandstone, silty, coarse-grained, light

yellowish brown; poorly sorted 1

(12) Claystone, white, unbedded, lenticu-
lar.' ... l /z

(11) Sandstone, silty, coarse-grained. Light

yellow-brown, unbedded, poorly sorted. 2

(10) Claystone, silty, white, unbedded;
contains rare cannon-ball concretions;

lenticular IV 2

(9) Sandstone, silty, coarse-grained, con-
glomeratic in part, light yellow-brown
unbedded, poorly sorted; quartz grains

subangular 8

(8) Claystone, greyish white, unbedded,

lenticular .... .... 1

(7) Sandstone, medium-grained, yellow-
brown, weil-sorted, unbedded; quartz
grains are sub-angular; contains a few
dark brown cannon-ball concretions ... 3

(6) Siltstone, sandy, with some inter-
bedded fine-grained silty sandstone

and claystone; variegated yellow,
white, and red, thinly-bedded, partly
cross-bedded; contains some thin
ferruginous bands and cannon-ball

concretions 6 y 2

(5) Shale, silty in part, grey, grading
into siltstone, white to light grey:
contains a few thin jarositic bands 5V 2

(4) Siltstone. sandy, white to yellowish
white, thinly bedded to fissile, grading
into fine-grained silty sandstone; con-
tains thin beds of grey claystone,

which is partly carbonaceous 6

(3) Claystone, dark grey, carbonaceous,
grading into siltstone; poorly bedded,
containing carbonaceous wood frag-
ments; yellow jarositic beds, irregular
in shape, are present; an efflorescence
of minute gypsum crystals is present
in places .... .... .... .... .... 5£

(2) No exposure, due to channel filled

with alluvium ... ... .... .... 4

(1) Claystone. sandy, silty, greyish white
to grey, mottled pink, poorly bedded,
weathered; contains few thin yellow-
brown ferruginous beds 7

conformably overlying Kojarena Sandstone.

Lithology. — The Yarragadee Formation is an
interbedded sequence of sandstone and siltstone,
with lesser thicknesses of shale, claystone, and
conglomerate. The sandstones are mainly poorly
sorted, and are very coarse- to medium -grained.
They are partly felspathic, though the felspar
is usually kaolinized at the surface. Exposures
of the sandstones are commonly white, with
a mottled red-and-yellow colouring. The silt-
stones are micaceous, and are usually white at
the surface, though in the subsurface they are
often dark grey and carbonaceous. Bedding in
the sandstones is generally poor, though cross-
bedding is sometimes developed. The siltstones
are often thinly bedded to fissile.

Stratigraphic relationships . — In the Geraldton
area the Yarragadee Formation rests with ap-
parent conformity on the Kojarena Sandstone,
and the top is eroded or capped by laterite.

Distribution and thickness. — The Yarragadee
Formation is known to extend from near Howa-
tharra Siding in the north to the Moore River
in the south. In the Geraldton-Mingenew area
it is known to extend no further inland than
the Urella Fault. It seems that no Jurassic sedi-
ments occur to the east of this fault, which is
believed to have been active in Jurassic times.

Exposures of the formation are sporadic, and
are generally thin. Individual beds in the unit
are markedly lenticular, and the differential
compaction associated with this results in very
variable dips.

No exposures of the Yarragadee Formation in
the Geraldton area are more than 80 feet thick,
and it is doubtful if more than 100 feet of the
formation is present in this area. However a
study of the Dongara, Yardarino, Mingenew,
and Moora bores shows that the unit probably
exceeds 4,000 feet in thickness in the deepest
part of the Perth Basin, near the Darling Fault.

Fossils and age. — The only fossils known from
the Yarragadee Formation are plants, but none
have been recovered from exposures of the

formation in the Geraldton area. However
in the type area of the formation, 64 miles
north -north-west of Mingenew, there are
numerous well-preserved fossil leaves in a
white siltstone. Walkom (in McWhae et ah 1958)
has reported the following forms from
this locality: Otozamites bengalensis , Otoza-
mites feistmanteli, Otozamites bechei, Otoza-
mites cf. bunburyanus, Araucarites cutchen-
sis , Pagiophyllum sp. Brachyphyllum ex-
pansum, Elatocladus plana, and Retinosporites
indica. Walkom considers that these fossils are
of Middle or Upper Jurassic age. However Balme
(1957, and written communication) has ex-
amined samples from the Mingenew bores and
from a shaft only 2 miles north-west of the
type locality, and he finds a probable Lower
Cretaceous spore and pollen assemblage. These
samples are in a similar stratigraphic position
in the formation to Walkom 's fossil leaves.
Balme has also reported on the palynology of
samples from the Yarragadee Formation in
the Dongara. Yardarino, 474 mile-peg, and
Moora bores. These suggest that the unit
ranges from Middle Jurassic to Lower Creta-
ceous in age, with no evidence of a break with-
in the unit.

Environment of deposition. — In the Geraldton
area the Yarragadee Formation is believed to
have been deposited under continental, fluvia-
tile conditions, associated with movement along
the Urella Fault. A continental environment
of deposition is indicated by the rapidly altern-
ating lithologies, the lenticular nature of in-
dividual beds, the lack of marine fossils and
presence of plant fossils, and the variegated
colouring of the unit.

Continental sedimentation is frequently as-
sociated with faulting, which results in con-
tinuing elevation of the source area. As the
Yarragadee Formation is not known to occur east
of the Urella Fault, it seems quite likely that
this fault was active during Jurassic times.
The Urella Fault dies out to the north, and
in this area the Yarragadee Formation thins,
and eventually disappears. The Urella Fault
also dies out to the south, but there the Juras-
sic and later movement is taken up by the
Darling Fault.

Structure

The Jurassic sediments of the Geraldton dis-
trict are practically horizontal, showing only very
small dips, measured in terms of a few feet per
mile.

The base of the Newmarracarra Limestone is
taken as a marker horizon, and in the area
mapped in detail this is found to decrease in
elevation from 660 feet above sea-level in the
Bringo cutting to 539 feet at (690297). This is
a fall to the south-west of just over 20 feet per
mile, equivalent to a dip of only about 1/5 .
This is the maximum regional dip found any-
where in the area, and is apparently due to
differential compaction over the sloping Pre-
cambrian basement. In the Bringo cutting the
limestone is only 14 feet above the Precambrian.
whereas at (690297) there are about 220 feet of
sediments beneath the limestone.

The major structural feature of the Geraldton
area is the Geraldton Fault. It was named by
Jutson (1914), and has also been referred to as
the “Moonyoonooka Fault” (Woolnough and
Somerville 1924). The evidence for the exist-
ence of the fault is based on geomorphology and
the deep bores at Geraldton. The fault itself
is not seen at the surface.

Geraldton is situated on a coastal plain which
is backed by a dissected scarp of Jurassic sedi-
ments overlying the Precambrian basement.
Jutson suggested that this is a retreated fault
scarp. The scarp in itself is not sufficient
evidence for the existence of a fault, but the
hypothesis is confirmed by two deeo bores in the
Geraldton area — the Racecourse and Municipal
bores. The Racecourse bore was drilled with
calyx equipment in 1896-98, and was aban-
doned at a depth of 1,531 feet without reaching
basement. Some of the cores were preserved
from the bore, and these have been examined.
The section in the bore is interpreted as: 0-53
feet, Quaternary; 53-400 feet, Jurassic: 400-1,531
feet, Lower Triassic or Upper Permian (Kockatea
Shale). A few cores were retained from the
Newmarracarra Limestone, which is believed to
be present between 186 and 233 feet. As the New-
marracarra Limestone is flat-lying in its area of
exposure (east of the bore) and the nearest
exposure is about 540 feet above sea-level, the
throw of the fault since the Jurassic can be
expected to be of the order of 750 feet. However,
the throw on the fault at the unconformity be-
tween the Kockatea Shale and the Precambrian,
is believed to exceed 1,500 feet, based on the
depth of this unconformity in the bore and its
elevation at the surface. Hence it seems likely
that there were two distinct periods of movement
along the Geraldton Fault, the first during the
Lower Triassic or late Permian, or between the
Lower Triassic and the Jurassic, and the second
after the Middle Jurassic.

The Geraldton Municipal bore struck granite
at 1,435 feet. As the Racecourse bore was still
in sediments at 1,531 feet, the unconformity must
dip east. i.e. into the fault.

It is difficult to position the fault accurately
owing to the lack of outcrop on the coastal plain.
Hence the position of the fault shown on the
map must be regarded as being only approx-
imate.

In the Bringo cutting a series of small faults
are exposed which fracture both the Precambrian
and the overlying Jurassic sediments. They are
normal faults, throwing down to the west, with
the downthrown block usually dipping east
(Plate 3. 1 and Plate 6). There are seven of
these faults, the largest throw on any of them
being only four feet, and the total throw about
14 feet. The faults tend to die out in the soft
Jurassic sediments, sometimes passing into
monoclines. These faults cannot be traced either
on the ground or on air-photos, and are probably
only local features. They may have formed when
movement occurred along the main Geraldton
Fault, Their age is evidently pre-laterite, for
the contact between the hematite rock and the
leached limestone (which are products of
lateritization) is almost unaffected by the fault-
ing.

123

One small pre-Jurassic fault was also noted
in the cutting, displacing a vein in the Pre-
cambrian rocks.

Minor faulting has also been found in the
Chapman Group sediments exposed in a cliff-
face near “Ellendale” (895228). At this locality
a west-dipping normal fault, having a throw
of about five feet, is clearly visible.

At the eastern end of the Bringo cutting there
is a small faulted anticline < Plate 3, 27. The
faults are apparently due to tension at the
crest of the anticline, and a small block
of sediments has fallen between them. As there
is no evidence of compressive movements else-
where in the area, this anticline may well be
due to folding over a tilted fault block at depth.
Alternatively it may have formed by differential
compaction over a buried ridge of Precambrian
rocks.

At (724298) a series of well-developed land-
slides is visible. The sides of the hills around
this locality are steep, and the hills are capped
either by laterite or by Newmarracarra Lime-
stone. The unconsolidated sandstones and shales
of the Moonyoonooka Sandstone have failed, re-
sulting in four main faulted blocks and many
minor ones. They are classical examples of
landslides, with the typical concave outline at
the top of the hill, and a series of back-tilted
blocks. The complex manner in which the
Moonyoonooka Sandstone has been faulted
during this landsliding can be seen in a nearby
gully (723300) where the formation is well-
exposed. The total throw of the landslides is
about 170 feet.

References

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124

CONTENTS OF VOLUME 42

Part 1 (published 19th March , 1959)

1. The Potential of Some Native West Australian Plants as Pasture Species.

Presidential Address, 1958. By A. J. Millington 1

2. Permian Stratigraphy of the Woolaga Creek Area, Mingenew District,

Western Australia. By G. Playford ... .... .... 7

Part 2 (published 2nd June, 1959)

3. A New and Distinctive Species of Eriachne R. Br. (Gramineae) from

Western Australia. By M. Lazarides 33

4. Tertiary Sediments at Coolgardie, Western Australia. By B. E. Balme and

D. M. Churchill 37

5. Topographic Relationships of Laterite near York, Western Australia.

By M. J. Mulcahy 44

6. The Status of Yarra singularis and Geotria australis (Petromyzontidae) .

By R. Strahan 49

7. Late Quaternary Eustatic Changes in the Swan River District. By D.

M. Churchill 53

8. Notes on the Fabric of Some Charnockitic Rocks from Central Australia.

By Allan F. Wilson .... 56

Part 3 (Rottnest Island: The Rottnest Biological Station and
Recent Scientific Research. Edited by E. P. Hodgkin and K.

Sheard) ( published 15th August, 1959)

Foreword. By A. J. Fraser .... 65

9. Introduction. By H. Waring 65

10. Rottnest Island as a Location for Biological Studies. By A. R. Main 66

11. History of the Rottnest Biological Station. By E. P. Hodgkin 68

12. Geology of Rottnest Island. By Brian F. Glenister, C. W. Hassell, and E.

W. S. Kneebone 69

13. The Vegetation of Rottnest Island. By G. M. Storr, J. W. Green, and D.

M. Churchill 70

14. Physiology of the Quokka. By S. Barker and J. Barker 72

15. Rottnest Field Studies Concerned with the Quokka. By J. W. Shield .... 76

16. The Birds of Rottnest Island. By D. L. Serventy and G. M. Storr 83

17. The Salt Lakes of Rottnest Island. By E. P. Hodgkin 84

18 Fresh Water and Brackish Water Swamps of Rottnest Island. By D. H.

Edward and J. A. L. Watson .. 85

19: The Littoral Environment of Rottnest Island. By E. P. Hodgkin, L.

Marsh, and G. G. Smith 85

20. Population Studies in the Littoral at Rottnest Island. By J. W. Shield 89

21. Student Training at the Rottnest Biological Station. By E. P. Hodgkin

and J. W. Shield 90

22. Rottnest Island Board. By T. Sten 91

23. Bibliography. Compiled by D. L. Serventy and K. Sheard 93

List of Research Workers and Other Persons Mentioned in Reports 95

Part 4 (published 21st October, 1959)

24. The Effect of Frequent Burning on the Jarrah (Eucalyptus marginata)

Forest Soils of Western Australia. By A. B. Hatch 97

25. Jurassic Stratigraphy of the Geraldton District, Western Australia. By P.

E. Playford 101

The Royal Society of Western Australia Incorporated

Council 1958-1959

President
Past President
Vice-Presidents

Joint Hon. Secretaries

Hon. Treasurer
Hon. Librarian
Hon. Editor

E. P. Hodgkin. D.Sc., F.R.E.S.

A. J. Millington. D.Sc. (Agric.)".

R. T. Prider, B.Sc., Ph.D., M.Aust .I.M.M.,

F.G.S.

N. H. Brittan, B.Sc., Ph.D.

D. P. Drover, B.Sc., Ph.D.

L. E. Koch, B.Sc.

R. D. Royce, B.Sc. (Agric.).

G. G. Smith, M.Sc.

J. E. Glover, B.Sc., Ph.D.

Alison M. Baird, M.Sc.

C. F. H. Jenkins, M.A.

R. J. Little.

L. W. Samuel, B.Sc., Ph.D., F.R.I.C., F.R.A.C.I.
A. C. Shedley, B.Sc., Dip.For.

A. R. Tomlinson.

A. F. Wilson, D.Sc., F.G.S.

K. Sheard. D.Sc.

Council 1959-1960

President

R. T. Prider, B.Sc., Ph.D., M.Aust.I.M.M
F.G.S.

Past President

E. P. Hodgkin, D.Sc., F.R.E.S.

Vice-Presidents ....

N. H. Brittan, B.Sc., Ph.D.

D. P. Drover, B.Sc., Ph.D.

Joint Hon. Secretaries

R. W. George, B.Sc., Ph.D.

L. E. Koch, B.Sc.

Hon. Treasurer

A. C. Shedley, B.Sc., Dip.For.

Hon. Librarian

G. G. Smith, M.Sc.

Hon. Editor

J. E. Glover, B.Sc., Ph.D.

C. F. H. Jenkins, M.A.

R. J. Little.

M. J. Mulcahy, B.Sc.

R. D. Royce, B.Sc. (Agric.).

L. W. Samuel, B.Sc., Ph.D., F.R.I.C., F.R.A.C.I.

N. S. Stenhouse, B.Sc.

D. W. Stewart, B.Sc. (For.).

A. F. Wilson, D.Sc., F.G.S.