THE GOVERNMENT GEOLOGIST'S ANNUAL GENERAL REPORT.
As stated recently, a press of work at the Government Printing Office
rendered it impossible to issue the Government Geologist's report for 1888
punctually, and it was, therefore, decided to delay its production till
the report for 1889 was ready, and send out the two together. Somewhat
late in the year this has been done, but the delay was due, it is said, to
the amount of work the new Electoral Act entailed upon the Government
Department.
The reports, revised and extended by information since obtained, are those
which have from time to time appeared in the newspapers, and embraced the
various geological expeditions undertaken by Mr H. P. Woodward into
different parts of the colony during the years 1888 and 1889. Side by
side with these are number of papers, full of most important and
interesting information. The first is a historical account of the
geological work done by Mr Woodward's predecessors and others up to the
end of 1887. Up to that date, we are told, "very little had been done in
the way of a systematic geological survey... but when the enormous area of
the country, and the fact that geologists have only been engaged for short
periods arts [sic] taken into consideration, both the quantity and as well
as the quality of the work done by them is highly creditable." Following
upon this is a description of the geological configuration of Western
Australia. The sketch, for want of space prevents it from being more, is
well compiled, and conveys a mass of information to readers which,
although it is not all new, is almost as interesting as if it were. There
is one little statement, however, which may not meet with general
acceptance, namely that (speaking of cereals) "on the hills to the east of
Perth nothing is thought of a crop of 40 bushels to the acre."
The next part is a paper on the geognosy of the colony. Mr Woodward here
gives a most valuable and instructive description of the physical
geography of Western Australia, commencing with King Sound in the extreme
north, and taking the reader all along the western and southern coasts of
the colony until the eastern boundary is reached. First, one is invited
to look upon the King Sound country, with its large undulating plain of
sand, sandstone, and alluvial, which Mr Woodward conceives to belong to
the Mesozoic, rather than the Tertiary, age, as Mr E. T. Hardman supposed.
Then comes the Leopold range of hills, from 1,500 feet to 2,000 feet
above the sea level, and formed of the oldest rocks known in the district,
namely, quartzites, altered grits, schists, and gneiss, and flanked on its
south-western face by limestones of Carboniferous age. Passing onwards,
the gold bearing country is reached, the Great Autrim Plateau lying to the
Eastward, and extending into the Northern Territory. This is of great
interest, as the plateau is the only great lava flow known in Western
Australia. Both to the north and south of this table land, the Devonian
and Carboniferous rocks are well-developed, but on following the Ord River
further north, the crystalline rocks again outcrop at Mount Pill and the
Carr-Boyd Range. South of the district stretches the Great Sandy Desert,
and inland plateau, believed to be about 5000 feet above sea level.
Several large rivers have their sources on the western edge of this
plateau, and their action upon the rocks form deep gorges, through which
the waters flow upon "flats bounded by rough sandstone ranges, and on the
deep ravines through broken hills of schists, slates, sandstones,
quartzites, conglomerates, and amygdaloids containing trap dykes, into
large alluvial plains, with here and there bold, massive hills of
amygdaloids and small peaks of quartz, granite and ironstone around which
soft calcareous slates often rise to the surface but never from hills much
above the level of the plain."
The amygdaloids in many places of this wild country, which we are told,
extends to the sea coast where they are mostly fringed with mangrove
swamps, "split up into rough blocks which became red or black on the
surface, and then present the appearance of a huge heap of stones, without
a trace of soil or vegetation. They contain vast numbers of agates,
calcite crystals, and other enclosures so that it would be advisable to
prospect streams running through them for precious stones." Further to
the south-west the rivers rise in a large range running N.W. and S.E., and
rising to 2,800 feet above the sea level. This section of the country has
not yet been examined geologically, but it is reckoned to belong to
Carboniferous or Devonian age. The coast ranges are next described, as
far as Nickol Bay, and these, it is said, rising about 700 feet above the
sea, are rough, broken hills, composed of hornblende schists, quartzite,
conglomerate, shales, limestones, amygdaloids, with diorite, granite,
actinolite, and tourmaline dykes, and tourmaline dykes [sic], and lodes of
ferruginous copper ore and ironstone, quartz and jaspery veins." The
galenas, which have been shown to be rich in silver — and cupriferous
gossans of the district are pronounced well worth testing. With regard to
the gold in the district, that lying in the reefs is associated with
sulphide of antimony, which, in some places, is so abundant that it would,
Mr Woodward, says, be well worth starting some auriferous antimony mines.
The description of the country downwards as far as the Murchison, calls
for little comment. Many of the hills in the ranges of crystalline rocks
where this river rises, "are capped by horizontally embedded sandstone
intersected by numerous quartz reefs. They are surrounded by large
alluvial flats of red clayey loam and sand, which are broken in places by
bald red granite hills, evidently intrusive, which appears to extend in
lines or belts across this part of the country." The whole course of the
river lies, we are told, through country of nearly the same character, and
at it lower bend, the formation contains the mineral lodes, of which the
best known is the Geraldine lead mines.
The Victoria district, situated at the head of the Murchison and
Arrowsmith rivers has been the great centre of the mining interests of the
colony, most of the work done up to the present having been in that
portion lying between Geraldine and Geraldton. "The country consists of a
series of flat-topped hills or table-lands, and clay, sandstones, and
limestones of Cretaceous and Oolitic age. These, in many places, are
covered by sand-plains. Where streams occur they have cut through the
newer rocks, removing large portions and exposing the crystalline rocks,
of which granite is the most abundant, the others being chiefly mica
schists, gneiss and quartzite, with numerous dykes of diorite, granite,
and felstone." It is in this country that the rich lodes of lead and
copper occur, and may be traced for several miles by means of their clay
ironstone caps. Numerous quartz reefs are found as cross courses, and at
the point of intersection the two lodes have always proved extra rich,
although the reefs themselves do not carry any metal. "The most
remarkable thing about this district," observes Mr Woodward, "is the
finding of lead so abundantly in such a highly altered country, and this
can only be explained on the assumption that the infilling of the lodes
took place at a date more recent than that of the metamorplism of the
rocks." Further east, the Mesozoic rocks are well developed, forming a
great, sandy table-land, 40 miles wide through which the Greenough River
has channelled a course exposing their sections and also a series of
Carboniferous rocks beneath them. This river rises far to the eastward
among the crystallines and granite hills and alluvial plains of the
Murchison, and before emptying itself into the sea at Champion Bay, its
valley expands itself into a wide alluvial flat, between two lines of sand-
covered, limestone hills. About fifty miles from the coast, the Irwin
river rises in the crystalline range of hills of which Peterwangy is the
highest. As in the case of the Greenough, the Carboniferous series are
exposed by the action of the river cutting through the superincumbent red
clay, clay ironstone and ferruginous sandstone, the series being
represented by beds of clay, claystone, micaceous clays, limestones,
sandstones, and shales with gypsum, iron pyrites, and coal seams. This
series is believed to be of considerable thickness, as there is a steady
dip throughout towards the N.E. Lower down the river, where the clay beds
at the bottom of the series appear, "the valley opens out into large flat,
surrounded by broken flat-topped hills and undulating country of Mesozoic
age, the surface being covered with sand all the way down to the coast."
The coast-line from the Murchison to the Moore river is described as
consisting for the most part of Tertiary and Recent deposits, the salt
lagoons and swamps being separated from the sea by sandstone or limestone
of varying height up to 300 feet. A series of flat-topped ranges, rising
600 ft. above the sea, run parallel to the shore, and are built of
horizontally bedded sandstone, ferruginous claystone and mottled limestone
containing Mesozoic fossils. Further south the country is slightly
altered, and fossils of Cretaceous age are found. Here numerous
stalactitic caves and underground watercourses exist. Inland, between the
Yarra Yarra Lakes and the south branch of the Irwin called the Lockier
river, there are long ranges of crystalline rocks in which rich patches of
mineral lodes occur, but owing to the expense of cartage they have not
been worked up to the present. A little further eastward there is another
low range of similar rocks, named the Herschel Range, which Mr Woodward
says is evidently the northern extension of the Darling Range, and extends
from the lakes just named northward to the Murchison. It forms the
Eastern boundary of the Carboniferous and Mesozoic rocks, but it is
impossible to say at present whether the deposits with which it is capped
belong to the same series. "Eastward of this an undulating and gradually
ascending plane is found, broken here and there by hills and also by
alluvial flats upon which lie ranges of crystalline rocks having numerous
quartz reefs. A remarkable feature of the flat other large masses of
granite rising, sometimes, to considerable elevation above the surface."
"The central and eastern districts embrace the coast line between the
Moore and the Murray Rivers, and include the Darling Range." The
formation comprises "a range of cliffs of coralline and shelly limestones,
calcareous sandstone containing Recent and Tertiary shells, and where the
rivers have removed these beds, large drifting hills of marine sand
occur." A white silicious sand proved, a short distance below, to be a
compact red sandstone destitute of organic remains, overlies these
formations, and beneath this are found calcareous sandstones and gritty
conglomerates, or as near Perth, oyster beds and other estuarine deposits,
proving it to be of very recent date. "Immediately underlying these coast
beds, and running in a parallel line between them and the Darling Range,
are beds of clay, supposed by Mr Gregory to be of Cretaceous age, and to
be an extension to the south of the beds of this age, which are exposed at
the Moore River, and extend as far south as Gingin. On the Western edge
of this clay chalybeate springs rise. A trial bore in this formations
struck, at a depth of 170 ft., a stratum of black shale containing
fragments of coal or lignite, and a great deal of iron pyrites. Overlying
this clay and resting against the foot of the hills, are beds of white
sand, ferruginous conglomerates, and decomposed rock debris, in which have
been found many pieces of different ores and fragments of garnets and
other crystals." Continuing his description of the Darling Range, Mr
Woodward says that "flanking the main granitic range a beds of clay slate,
mica schist, and flaggy sandstones, which, near the Murray, dip 60 deg. to
70 deg. to the W. and strike 10 deg. E. of N., while on the Canning the
strike is N. and S. and the dip vertical. To the north these beds change
into micaceous sandstones, containing quartz veins, numbers of which,
together with diorite and porphyry dykes, occur along the western face of
this range and are often associated with metallic ores, though none large
or rich enough to pay have at present been found." "This range, which
rises to 1,800 ft., is principally composed of hard crystalline rocks,
e.g., granite, syenite, porphyry and gneiss, containing numerous dykes of
granite, diorite, serpentine, quartz veins, and ironstone lodes, covered
for the most part with cappings of red clay and clay ironstone which in
places rest on large deposits of very pure kaolin, ferruginous sandstones,
grits and conglomerates, nodular clay ironstone and sand, sometimes as
much as 40ft in thickness, and as high as 800ft above sea level." In the
absence of sufficient data to confirm the opinion that the beds are
Devonian, they may be considered provisionally as Mesozoic. The character
of the rocks change on penetrating well into the range, but they are still
traversed by numerous quartz reefs and ironstone lodes.
At the north bend of the Avon, veins of quartz, and rich lodes of magnetic
iron yielding iron of great purity, are found.
To the eastward, we are told, the country is chiefly a large undulating
plain of sand, but "more to the east the sand almost entirely disappears,
giving place to large clay and loam flats with bold bare and red granite
hills and extensive red clay alluvial plains, with salt and gypsum
deposits which continue to about 119 degrees East longitude, when a line
of low ranges makes its appearance containing numerous quartz reefs and
ferruginous lodes, some of which have proved very rich in gold. The
country here is a good deal broken and of comparatively slight elevation,
unlike most of the interior, which is a high table-land, and this may be
the result of extensive denudation arising from the fact that most of the
drainage of a large portion of the interior passes over this area, which
would also account for the ridges of the older rocks beneath being exposed.
"A marked feature on the S.W. coast is the chain of tidal lakes and inlets
and swampy alluvial deposits which follow the coast, sometimes connected
with the sea, and others separated by the sand-hills. The bars across the
mouths of most of the rivers keep them fresh for a great part of the year,
although they are not running rivers, but merely estuaries with the waters
standing at sea level. There is plenty of evidence to prove that this
coast is rising rapidly, in addition to the fact that many old colonists
remember when land at Fremantle, now quite above the water level used
daily to be covered by the tide."
"The south-western division is almost identical with the foregoing until
Bunbury is reached." Between Capes Naturaliste and Leeuwin, there is a
line of range of crystalline rocks rising parallel to the Darling Range
and flanked towards the sea by limestone cliffs. Between the ranges, a
distance of some 30 miles, is a stretch of country consisting of sand,
loams, clay and gravel, in which lignites of good quality have been found.
"This southern portion of the Darling Range is of a highly crystalline
character, the rocks being mostly granite and gneiss with dykes of diorite
and feldspar, and quartz veins, all of which, as in the northern section,
are capped with deposits of clay, clay ironstone, and sandstone."
Columnar basalt makes its appearance at Bunbury, and events in places as
far south as Cape Beaufort. "From this point to Albany the coast has bold
granite headlands, indented by a number of inlets into which the rivers
draining the South coast flow, often forming large alluvial deposits... "
North of Albany stands the Stirling Range, about 50 miles long, running
east and west, and attaining its greatest elevation in Kyenerup, a peak
3,500 feet above sea level. The rocks "consist of quartzite, sandstone
ferruginous slaty sandstones, and slate, with quartz reefs striking east
and west, with a variable dip. The country between this range and Albany
is entirely granite, large masses of which rise through the sand, with
which a good deal of it is covered. At the foot of the Stirling Range
gold has been found, which gave a good return on assay, but was not worked
at a profit."
Eastward the coast presents a series of bold granite headlands as far as
Cape Arid, overlaid by fossiliferous Mesozoic rock, which extending far
into the interior, disappears beneath Giles' Great Victoria Desert.
"From Cape Arid to the boundary of the colony, a great mass of limestone
rises, presenting an almost vertical face, from 300 to 400 ft in height,
to the Great Australian Bight.... This great table-land extends some 200
miles into the interior: it has no rivers, but the rainfall soaks into the
porus [sic] limestone, and is discharged at the base of the cliffs. The
rock is very interesting from a geological point of view, being very
largely composed of fossils."
GEOLOGY.
The next part of the report consists of a highly interesting description
of the geology of the colony. Hitherto, Mr Woodward says, it has
generally been imagined that the formations to be found in Western
Australia were limited in number, and that the rocks were for the most
part either granite or sand; but that this was quite erroneous he proves
by furnishing a table of strata, showing the various formations now known,
and which, he says, will probably be much extended when all the country
has been thoroughly examined. Following upon this is a description of the
characteristics of each geological period as far as at present known.
Thus, under the heading of "Recent and Tertiary Rocks," are described the
alluvium of lake basins, river valley gravel and estuarine deposits, sand
plains, raised beaches, ancient river gravel and lake basins (in which at
Bridgetown, it is reported, bones of the Diprotodon, a gigantic fossil
animal closely related to the kangaroo, have been found), limestones and
clays of various formations. In describing the cretaceous beds, which are
well-developed in the flat-topped coast range from Gingin to the
northward, Mr Woodward refers to a very singular agency which is at work
altering the appearance of the country. He says, "Both here, and in other
places, a great deal of work is done, vastly altering the appearance of
the country, by what may appear to many people at first sight to be a
perfectly ridiculous agency, viz., the white ants; but after passing over
the plains, or through the thickets, where their hills are so numerous
that it is difficult to drive amongst them, the immense amount of their
work can be better appreciated. The clay cemented with resinous matter
with which they build their nests is as hard as brick, and when these fall
to pieces they form clay flats almost impervious to water, and so hard
that it will bear a great deal of traffic without being cut up. The work
of these insects can be studied in all stages, first in the thickets where
they are commencing work, then in the more open country where they have
got the upper hand of the timber, next on the plains where half the hills
will be found deserted, and lastly on the clay flats where they have
almost entirely disappeared, and the scrub has begun to grow again.
Another remarkable thing about these nests is the amount of iron they
contain, for when a tree has been burnt in which they have built a nest,
there will be found at its base a mass of iron clinker, looking just as if
it had come out of a furnace."
The Palæozoic or Primary rocks described, are the Carboniferous, Devonian,
Silurian, Archœean and Metamorphic, and the Igneous rocks (volcanic and
plutonic) are also dealt with. The next annual report will, if possible,
contain a list of the minerals and fossils of the country.
MINERAL WEALTH, &C.
Following upon the geological sketch is an account — partly historical,
and partly descriptive — of the mineral wealth of the colony. Both have
already appeared in print, in another form. "Every day," Mr Woodward
says, "news of fresh discoveries of gold and other valuable metals is
coming in. There are, however, two great obstacles standing in the way of
these discoveries being immediately turned to account, viz.: — Want of
capital, and the construction that has been put on the Mining Regulations.
Of these the first will be removed as soon as the out. side [sic] mining
world is assured of the genuineness of these finds, and that there is
really a good field for investment here; and the second as soon as the
Government strictly enforces all its regulations, as up to the present it
has been too lenient, and of this advantage has been taken, to the
detriment of the real interests of the colony, both in the floating of
companies, and by the holding of areas without fulfilling the labour
conditions." The mineral deposits described are gold, lead, copper, tin,
iron, antimony, zinc, manganese, mica, asbestus [sic], kaolin, coal, and
graphite. In conclusion of this part of the report, Mr Woodward says,
"sufficient evidence has now been brought forward to show that this is
decidedly a mineral country, and when we take into consideration the vast
size of the colony and the small number of inhabitants, and consequently
the small amount of prospecting that can possibly have been done up to the
present, there cannot be any doubt but that many more, and, perhaps, far
richer deposits of valuable minerals, may be found; but as we have already
discovered more than we can at present use, what is now needed is the
incoming of enterprising people with money from other parts of the world
to assist in developing this known mineral wealth. It is often asked by
persons in other places, why, if we have such wonderfully rich deposits,
we do not work them all ourselves instead of offering them to others, and
to this the answer is that as there are not sufficient people here with
money to work more than one or two mines efficiently, while at the present
time they are trying to develop a hundred, and as a natural consequence
failures are occurring on every side."
A summary of work done in 1888 and 1889 follows, and this consists of the
reports which has been forwarded from time to time by Mr Woodward to the
Government, and which have appeared already in the newspapers.
Mr Woodward proposes issuing a geologically coloured map of the whole
colony at the end of the year, as by that time he hopes to have examined
most of the settled country. For information of the interior he will have
to depend upon that which can be gained from reports and maps of explorers.
In the preparation of his report and in his work of the past two years, he
has, he says, being greatly assisted by the work done by his predecessors,
and amongst those mentioned are Messrs. A.T. and F.T. Gregory, Messrs. H.
Y. L. Brown, E.T. Hardman, and H.E. Victor, Rev. C. G. Nicolay, and the
late Mr W. Knight, while the department of the Surveyor General, both
under the late Capt. Roe, and present head, the Hon. John Forrest, has
done much in elucidating the Geology of this immense country....
