The annual reports issued by the Water Supply Department of Queensland give detailed accounts of the annual and average rainfall over the whole of the colony, with the results of boring for artesian water, both privately and by Government. It is one of the most valuable and interesting reports issued, and with the rain maps accompanying it, conveys in a moment an accurate estimate of the average rainfall both on the coast and in the far interior. Beginning at Mackay, where the tropical rains commence, and following the coast line to Cape York, the record is higher than anywhere else in the colony, owing to the near approach of the high ranges to the coast. The maximum rainfall recorded in one year is reported at Geraldton, where 211.24 inches fell in 1894; Cairns can boast of 174.56 inches as its highest rainfall; this occurred in 1886. At Cape York, the average is 60.87; and at Mackay, 72.73 inches; these numbers give a general indication of the humidity of the climate on the east coast of North Queensland. As we advance into the interior a far different climate prevails, and the farther west we go, the lighter becomes the rainfall, till it would almost appear as if it scarcely ever rained in some places in the interior, which are not much raised above the level of the sea. At Birdsville, low down on the Diamantina River, on the borders of South Australia, the rainfall taken for three years, amounted to only 5.72 inches, and on the Mulligan, where for six years an average was taken, it amounted to only 5.77 inches. At Boulia, on the Burke River, the average for nine years was 13.54 inches.

Between these extremes of great dryness and excessive moisture, the intervening country shows a graduated increase or decrease as one approaches or recedes from the eastern coast. As very few water-ways exist to carry off surplus water, the drainage being often imperceptible to the eye, this seems a merciful dispensation of Nature, as under such conditions any great rainfall would place the whole country under a sea of water long enough for all animal life to become extinct. The water that flows down the usually dry channels of the western rivers southwards comes from the Gulf watershed, where the rainfall is much heavier, averaging at Cloncurry 20.80 inches. The amount of rainfall determines largely the nature of the fauna and flora of a country, and causes it to vary, even in the same latitudes. Between the high coastal districts and the vast rolling plains and downs of the interior these differences are so marked and distinct that they seem like two separate countries; climate, timber, herbage, and even animal life are so different in the two regions that it seems extraordinary such contrasts should exist in the same latitude in one country. All along the east coast, where the rainfall is heavy, we find forests of splendid hardwood and scrubs containing cedar and pine of gigantic growth. In the interior, the timber is as a rule dwarfed, hollow, and crooked; the principal timbers being the acacia family, such as the gidya, myall, brigalow, boree, etc. The grasses of the interior adapt themselves to the climate, and are of a far hardier growth than the coast grasses; one season without moisture does not impare their wonderful vitality; the salt bushes are the hardiest of all vegetation in the interior, and are of the greatest value to pastoralists. Birds are found on the coast that never visit the interior districts; while the galas and corellas are never found in a wild state near the coast. During the wet season in the summer months many seabirds migrate to the interior for a few weeks.

Accompanying the report of the Hydraulic Engineer is a coloured map showing the sites of artesian bores and tanks and the supposed area of the lower cretaceous or water-bearing strata, as well as the underlying impermeable palÆozoic rocks. The whole of Western Queensland may be said to belong to the lower cretaceous formation; here and there, where it has not been denuded by the action of the atmosphere, the desert sandstone may be found overlaying it. The whole of this vast area of water-bearing rocks has been proved by artesian bores, most of which are far below the level of the sea. The knowledge of the area of the water-bearing country in the interior is extending as additional bores are put down. Some of the bores within the known belt of the water area have been abandoned owing to causes that may be generally classified as accidents.

The Government have sunk a number of wells, while hundreds of flowing bores that now stud the great western country have been put down by private enterprise. The policy of the Government has been to determine the area within which artesian water may be hopefully searched for, and to provide water in arid country or on stock routes, and excellent results have attended the carrying out of this policy. The Winton bore is down in the lower cretaceous beds 4,010 feet, it gives a flow of 720,000 gallons of water a day, at a temperature of 192 degs.; the surface level is 600 feet above the sea; it will take about £8,000 to cover the total cost of sinking, etc. The Charleville bore has the largest flow of any Government bore, giving 3,000,000 gallons in the twenty-four hours, but some bores on Tinenburra, on the Warrego River, give as much as 4,000,000 gallons. About 800 private bores have been sunk in search of artesian water in the western area of Queensland; of these 515 give a total output of 322 millions of gallons in the twenty-four hours, and the total cost of them amounted to nearly £2,000.000. This expenditure made within sixteen years, is creditable to the energy and forethought of the western settlers. Some of the bores are not overflowing, and the water is raised by pumping, though the supply is inexhaustible. By the flow of water thus brought to the surface, the devastating effects of the periodical droughts have been minimised, and large areas have become available to profitable occupation that previously were waste country. The flow of this artesian water from the private and public bores is worth more to Queensland than a river of gold. They have completely changed the face of the country, and removed the anxiety of the stock owners towards the end of the season, when all surface water (except the most permanent lagoons) has dried up and formed mud traps to catch all weak stock that venture near them. These tiny perforations of the earth’s surface have helped to solve the difficulty of settlement on the western lands, where we find the rainfall diminishing as we go further west. As these little threads of water find their way across the plains and form into small ponds in the hollows, the wildfowl resort to them as if they were natural waters, while the bulrushes (typha angustifolia), soon follow and grow in masses, although these are only to be found round springs, and never in permanent lagoons or rivers. Some curious features are connected with the artesian water supply; sometimes the temperature is very high, that of the Dagworth bore reaching 196 degrees, while the pressure of the Thargomindah bore is over 230 lbs. to the square inch. The water supply tapped is perhaps beyond calculation, and up to the present time there is no indication of exhaustion.

The source of this enormous pressure of water that is capable of sending a jet over a hundred feet above the surface, is still unexplained, and many theories are afloat as to its origin; some of these go far afield for reasons for the great supply and strong pressure. The enormous rainfall on the coast ranges, where the intake probably occurs, and where the impermeable rocks approach the surface, carrying the water under the lower cretaceous, or more recent formation (which is shown to be the most extensive in Western Queensland), seems to be the most reasonable to adopt at the present time. These water-bearing strata must cover very large areas in Australia, for a bore at Tarcanina, near the south coast on the Great Australian Bight, is down over 1,000 feet below the level of the sea, and throws the water to a great height above the surface.

Mr. R. L. Jack, the Government Geologist, in a paper on artesian water in the western interior of Queensland read before the Australian Association for the Advancement of Science, in Brisbane, January, 1895, argues in a most convincing manner as to the source of artesian supplies of water, giving the intake or gathering ground at about 55,000 square miles, over a region where the mean average rainfall taken at thirteen meteorological stations along the line of outcrop, amounts to 27 inches annually, which is considerably greater than that of the interior of the downs country. The greater part of the rainfall is not carried away by the channels of the rivers, neither is it evaporated, but sinks through porous strata into the earth, and does not return except through springs or submarine leakage. The fact of all this great supply of water finding its way to the sea at great depths, shows what little effect a few bores can have on the enormous annual supply. It is an encouragement to extend the number of bores, which are so necessary to successfully settle the arid plains of the distant interior, in order to anticipate the waste of water.

The fact of an artesian bore diminishing its flow may be due to many causes other than shortage of supply, faults in the tubing or caving in of the strata may account for it. We have here the secret of successful settlement in inland Australia—an inexhaustible supply of water fit for all the wants of man.

The Normanton bore, practically on the edge of the Gulf, and sunk from a level of about 30 feet above the sea, struck artesian water at a depth of 1,983 feet, or 1,950 feet below sea level. This bore and the one at Burketown, both of which were successful in reaching artesian water, were put down by the Government during the time Mr. G. Phillips represented Carpentaria in the Legislative Assembly, 1893-5.

THE GRASSES AND FODDER PLANTS.

An enumeration of all the fodder plants and herbage common to North Queensland would require a long catalogue, as variety is Nature’s law in this case, and the western soil teems after the wet season with flowers, herbs, grasses, and fruits all more or less adapted for use as fodder. The prospect on the wide spreading plains after the early thunder showers in November and December is very refreshing to the eye that has been for months staring on the dry stalks of the Mitchell grass, or else on the brown bare earth. Trailing vines of the melon and cucumber family spread themselves in profusion, the fruit of which is eagerly sought after by stock. Convolvolus flowers and vines grow among the young green grasses, and many varieties of the compositÆ show in bright yellow their gleaming flowers, mingled with hibiscus of every hue. The growth of plant life is marvellous after the fall of soft rain on the warm rich soil. Portulaca, known as pigweed, is among the first of the plants to spring up, and grows in great masses; the seeds form a principal article of food for the birds that frequent the plains, the young plants are also used by stock, and are not despised by man in an emergency. All life, vegetable and animal, revives suddenly after the surface of the earth has been saturated with the life-giving element; frogs and locusts sing their songs of joy day and night; flies increase beyond conception, and mosquitoes and sandflies torment to distraction both man and beast.

On the plains, the first vegetation to spring up is the sensitive plant, spreading its delicate foliage over the surface, the leaves closing during the heat of the day, and opening in the evening. The small creeping plant said to be poisonous to stock (Euphorbia Drummondi), appears immediately after rain. The climbing vine (Capparis lucida), which bears a sub-acid fruit not unlike passion fruit, at this time of year gives out its white flowers and fruit at the same time. The scent of the innumerable flowers on the plains, the tender herbage, the young grasses sending their seed stalks several feet high, and all the soil covered densely with vegetation and herbage suitable for stock present a picture to the eye, so utterly opposed to that which prevailed but a few weeks before the advent of the rains, that the spectator can scarcely believe it to be the same country. The seeds of some plants will remain dormant for years, and then suddenly spring up in profusion; for instance, the plant commonly known as peabush, a leguminous annual (botanically Sesbania aegyptica), has only a periodical growth, and at such times, varying for many years, it covers the plains in such rank masses that the stockriders get quite bewildered when searching for stock through its scrublike density; for several years after this abundant growth, the plant will scarcely be noticeable; it is said that every three years is a peabush year, but the writer cannot support the theory, as he can only call to mind four or five really bad peabush seasons in a period of thirty years. The seeds which fall to the ground in great quantities form the sustenance for flocks of pigeons and other birds, but much seed must also fall down the cracks of the earth and bide their time for a chance of springing into life. The flowers of this plant grow in lilac and yellow on the same stalk. Cattle are fond of it when young, and mustering stock in a peabush year has many extra difficulties on account of the prolific growth of this intermittent annual. It will sometimes grow to a height of fifteen feet, and in swampy places is so dense that it is difficult to keep even a few horses in sight when driving through it; after it dries and the seeds fall to the ground, the stalks break off, and the sweep of the water over the plains during the succeeding year gathers these dry stems against the trees in enormous masses like small haystacks, and there they remain until a bushfire reduces them to ashes. The masses of peabush carried down creeks and watercourses at certain seasons will yet prove a source of danger to railway and road bridges when such structures come to be built on the western plains comprising the watersheds of rivers flowing into the Gulf of Carpentaria. Though peabush grows strongly on flooded ground, it can be found of a sturdy growth on ridges or high plains or downs during a favourable year, especially where water lodges between ridges. It is an ancient and historical plant, for the flowers that composed the wreath found on an Egyptian mummy of ancient date, when softened and opened with warm water, were found to be identical with the flowers of the peabush of the Flinders River and western plains of North Queensland.

The native pastures have not been improved by the introduction of stock; the evils of overstocking and the want of bushfires to keep down the under-growth, have in some districts deteriorated or exterminated some of the best of the fodder grasses. The best of all indigenous grasses is known as Mitchell grass, a perennial of strong growth, and capable of resisting the driest weather; there are many varieties of this grass, which is found only on the plains and downs of the interior. It possesses the faculty of shooting green from the old stalks at the joints, and taking up moisture, renewing its youth again. The Mitchell grass grows in isolated strong bunches, and its presence is a sure sign of a fattening country. The following are the best known varieties:—

“Astrebla pectinata,” common Mitchell grass, growing in erect tussocks of two or three feet high.

“A. triticoides,” wheat-eared Mitchell grass; this plant is taller and coarser than the last, attaining a height of four or five feet.

“A curvifolia,” or curly Mitchell grass; plant forming erect tufts one or two feet high, the leaves narrow and much curved.

“A. elymoides,” weeping Mitchell grass; plant decumbent, the stems several feet long.

The blue grass (Andropogon sericeus), is an annual of soft rapid growth, with a branching seed-stalk that breaks off and is blown by the wind in masses into waterholes; the blacks use the fine seeds of this grass for food.

“Anthistiria membranacea,” called the Flinders or Barcoo grass, is an annual of a reddish colour, found all over the western plains. It is soft and brittle, breaking easily off to fall on the ground, when stock will pick it up; it makes excellent hay, keeping sweet for years, and is one of the most fattening grasses.

The varieties of the indigenous grasses that cover the great western plains are innumerable; all are more or less eaten by stock, even the triodia or spinifex that is looked on as a desert grass, and of a formidable and forbidding nature. Spinifex is a very drought-resisting plant, and in times of great scarcity and extreme drought, when all other grasses have dried out and been blown away, the spinifex is there with its erect spiney leaves, possibly bitter to the taste, but still life sustaining to stock, as has been proved in many a severe drought. It grows on sandy sterile ridges, and seems to adhere to the latest geological formation, the sandstone or cainozoic period; it is found on ridges adjacent to alluvial flats where the richest herbage and grasses are found in abundance.

Kangaroo grass (Anthistiria ciliata), is found mostly in coastal districts, and although a good pasture grass when green, it soon dries and requires burning.

There are two prominent varieties of spear grass in the north, the worst being the black spear grass (Andropogon contortus), which grows in sandy spots along the banks of creeks, or on sandy ridges; it is not of much use as a fodder grass, but becomes a terrible scourge to sheep when ripe and seeding. The seeds are barbed, and as sharp as needles, and having once entered the skin they work into the bone, causing intense annoyance and irritation, and ultimately death. The other spear grass (Andropogon Kennedeyii), not so dangerous, but of little use to stock, is a coarse-growing, strong grass, seven or eight feet high, with a reddish bloom, and strong seeds that penetrate saddlecloths and clothes in countless hundreds.

Herbage fills the spaces between the tufts of grasses soon after the rains, and the plains develop a dense growth of pasturage; but after continued dry seasons, all herbage disappears, and the grasses follow in time, until very little is left except the roots, and a few of the more hardy salsolaceous plants. These form a striking feature in the economy of Nature in the plain country, the salt bushes are ever present in one variety or another, and help to keep stock in health and condition. The various species of “Atriplex” abound, and being very drought-resisting, they are reckoned amongst the most valuable fodder plants. Sir Thomas Mitchell was the first to make salt bush known after his first expedition over sixty years ago.

“A. Nummularia,” passing under the curious vernacular of “Old Man Salt Bush,” is truly grey enough. Some of these plants have been propagated in north-west America with great success, turning the barren alkali lands that were never known to grow anything, into valuable pastures. Tons of seeds are raised annually for Utah, Arizona, and other States. In Africa the salt bushes are cultivated from seeds and even cuttings, and their value is acknowledged everywhere. They endure scorching heat, live without rains, are eaten by all kinds of stock, proving nutritious and wholesome to them, are easily raised from seed, and can, with a little care, be propagated from cuttings.

The blue bush (Chenopodium), is common all over the Gulf of Carpentaria watershed, growing in swampy spots where water lies; it is a great favourite with all kinds of stock, and is getting scarce owing to its being eaten out so much.

Wild rice (Oryza sativa), grows in swampy places throughout the Gulf country; the grain is well-defined, but small; all stock are fond of it, when green; it grows to a height of three or four feet. The rice of commerce is the produce of cultivated varieties of this grass.

Edible shrubs are extremely plentiful, and are of great value when grass becomes too dry to be nutritive. A peculiar feature in the vegetation of the western plains is the “roley-poley,” which is called in America the “tumble weed.” This is an annual of quick growth after rains, growing in a spherical form from a common root; when the stem dries, it breaks off close to the ground, and the ball of dried vegetation is driven by the winds over the plains at a furious rate, topping the fences, and piling up against them in masses. It causes the greatest consternation to horses as it is driven across the downs. It possesses no virtue as a fodder plant.

FOSSILS OF ANCIENT AUSTRALIA.

The Australian continent has undergone great changes during the past geological ages, and most probably has been connected in remote times with part of Asia, and not unlikely with South America by some now submerged land. But whatever the connection may have been in the very distant past, it has been shut off from the larger northern land masses at so remote a period that the higher forms of mammals have not found their way to it, as in Africa and South America. Great changes have taken place in the continent itself. It is supposed that, at one time, in what is called the cretaceous or chalk age, a great sea spread from the north right across from what is now the Gulf of Carpentaria, covering immense tracts of level plain country in the interior of Australia, including Western Queensland, and part of New South Wales, so that the western half of the continent was separated from the eastern at least in the northern parts. Gradually the land rose and great lakes were formed in the interior, especially in the region of Lake Eyre, and a growth of vegetation sprang up of a more luxuriant type than is to be found now in those western parts, otherwise the enormous animals, such as the giant diprotodon, huge extinct kangaroos, birds larger than the moa, as well as crocodiles and turtles, could never have found sustenance to multiply in such numbers as their fossil remains testify they did in nearly every part of central Australia, and in the interior of North Queensland. In this sea, which washed the base of the mountains on the west, was deposited the sandy formation which has become the level inland plains. From some cause so far unknown, the land became desiccated, the lakes lost their freshness, and became great salt pans, the vegetation and the animals dependent on it became extinct, until a dry and arid region was produced, with a river system that fails to reach the sea, but becomes absorbed in the great sandy interior. The smaller types of marsupials of a hardier nature and capable of removing to greater distances for food, maintained their existence, while the giants of a similar race have left only their bones embedded in the drift to testify to the mighty changes that Nature has wrought out in the past ages. Fossil diprotodons of gigantic size and struthious birds rivalling in stature the New Zealand moa, are found in Central Australia. At Lake Callabonna in the great salt Lake Eyre basin, there are hundreds of fossil skeletons of these animals, many of which have been removed to the Adelaide Museum. In that locality they are found most frequently on the surface of the dry salt lake, and have been preserved by a natural coating of carbonate of lime; the bones are found at various depths.

Nearly the whole of interior Australia, including Western Queensland, is one vast cemetery of extinct and fossilised species, scattered along the surface, or buried deep in cement or drifts, and in clays hidden beneath the present surface formation. The open plains of the Upper Flinders disclose great deposits of marine fossil shells, belemnites and ammonites, and also remains of extinct animals. On the Lower Leichhardt River, in the Gulf of Carpentaria, forty or fifty feet beneath the alluvial deposits forming the banks of the river, and firmly embedded in the hard cement, which is an ancient drift formed of water-worn stones in an ironstone clay, are found the bones of innumerable extinct gigantic species of animals that found sustenance and multiplied in enormous numbers over the Gulf country in some far back pre-historic age. On the Walsh River are found large numbers of fossils, mostly shells of the ammonite species. The bones that have been buried for countless ages in these ancient drifts are well preserved, and are not very dissimilar in appearance to the bones of animals dying recently on the surrounding plains, although they are completely fossilised and changed into the appearance of stone. The utter extinction of these gigantic species, comprising diprotodon, nototherium, and zygomaturus, and other species, grasseaters and flesheaters alike, can only be accounted for by a great change of climate, and great and long-continued droughts, reducing the herbage and causing the remaining living animals to crowd into the drying-up lagoons and lakes, there to become bogged in thousands, and die as the stock die in the waterholes after a long drought. Some of the fossils are those of animals of a gigantic size, much larger than any existing native animals; the teeth found are twice the size of an ordinary bullock’s, and the jaws carrying them are of enormous size and strength. There are remains of alligators over thirty feet long, and turtles of much greater dimensions than any existing in the present day. The vegetation in the marshes and territory forming North Queensland must have been of a luxuriant and tropical description in those days to have supported such large types of marsupials—animals that would require a more abundant moisture, larger rainfall, and heavier foliage, than are now to be found on the western slopes of the ranges. Deeply interesting is the study of the ancient forms of life that roamed over the densely-wooded marshes of the interior, when the flora represented a type found now only along the rich alluvial banks of the rivers on the east coast.

GEOLOGY OF QUEENSLAND.

The following facts are summarised from the geology of Queensland written by Mr. Daintree, as the result of his investigations, whilst prosecuting the search for new goldfields on behalf of the Queensland Government in the northern portion of their territory, as also from the official reports of the Geologist of Southern Queensland, and other sources.

The consideration and history of the different formations will be taken in their sequence of time, as far as the stratified or sedimentary rocks are concerned. The igneous rocks will be described under the various groups of Granitic, Trappean, and Volcanic.

Alluvial.—Fresh-water deposits skirt all the present watercourses, but the accumulations are insignificant on the eastern watershed, except near the embouchures of large rivers, such as the Burdekin, Fitzroy, etc. On the shores of the Gulf of Carpentaria, however, and in the south-western portions of the colony, where the watercourses have scarcely any fall, and where in seasons of excessive rain the country is nearly all inundated, fluviatile deposits are very extensive. Though the dense lavas of the Upper Burdekin (volcanic outbursts of a late Tertiary epoch) are traversed by valleys of erosion, in some cases 200 feet deep, and five miles broad, yet very narrow and shallow alluvial deposits skirt the immediate margin of the watercourses draining such valleys. It is only near the mouths of the larger rivers that any extent of alluvium has been deposited, and even these areas are at the present time in seasons of excessive rain, liable to inundation, showing that little upheaval of this portion of Australia has taken place since the last volcanic disturbances terminated.

The meteorological or climatic conditions during this period were nearly identical with those of the present time, heavy rains during the summer months causing violent floods, removing seaward the aËrial decompositions and denuded materials from year to year.

What lapse of time is represented during this period of erosion is a matter of speculation, but it seems certain that the mollusca of the present creeks were also the inhabitants of the waters during the whole period of denudation since the last volcanic eruption.

From the Gulf of Carpentaria in the north, to Darling Downs in the south, however, the fossil remains of extinct mammalia have been found in breccias and indurated muds, which are the representatives of the beds of old watercourses through which the present creeks cut their channels. At Maryvale Creek, in latitude 19 deg. 30 sec. S., good sections of these old brecciated alluvia occur. The fossils from this section, as determined by Professor Owen, are “Diprotodon Australis, Macropus titan, Thylacoles, Phascolomys, Nototherium,” crocodile teeth, etc.

Imbedded in the same matrix occur several genera of mollusca undistinguishable from those inhabiting Maryvale Creek.

The fact of these older alluvia forming both the bed and the banks of the present watercourse, goes to prove that Diprotodon and its allies inhabited the Queensland valleys when they presented little difference in physical aspect or elevation from that of the present time. The crocodile (Crocodilus Australis), however, had then a greater range inland than it has now. A study of these Diprotodon breccias leads to the conclusion that the remains are chiefly entombed in what were the most permanent waterholes in seasons of excessive drought, and that the animals came there in a weak and exhausted state to drink and die, just as bullocks do under similar conditions at the present time.

No human bones, flint flakes, or any kind of native weapons have yet been discovered with the extinct mammalia of Queensland.

CAINOZOIC.

Desert Sandstone.—On the eastern branches of the Upper Flinders and elsewhere, fine sections are exposed of lava resting on horizontal beds of coarse grit and conglomerate, which lie in turn unconformably on olive-coloured and gray shales with interstratified bands and nodules of argillaceous limestone containing fossils of cretaceous affinities. I have called this upper conglomerate series “Desert Sandstone,” from the sandy barren character of its disintegrated soil, which makes the term particularly applicable.

Without doubt, it is the most recent widely-spread stratified deposit developed in Queensland. The denudation of the “Desert Sandstone” since it became dry land has been excessive, but there still remains a large tract “in situ,” and all the available evidence tends to show that this “Desert Sandstone” did at one time cover nearly, if not quite, the whole of Australia. The journals of the two Gregory’s description of the new settlement of Port Darwin, all bear evidence to the continuity of this so-called “Desert Sandstone” over all the extended areas investigated by them.

Augustus Gregory’s description of the sandstones of the Victoria River agrees with those of the “Desert Sandstone” of Queensland, the specimens from either locality being undistinguishable the one from the other, while the same barren soil, the same hostile spinifex, the same fatal poison plant, mark its presence from Perth to Cape York.

In Queensland, the upper beds are ferruginous, white and mottled sandy clays, the lower being coarse alternating grits and conglomerates; the extreme observed thickness has not exceeded 400 feet. A characteristic view of the upper “Desert Sandstone” beds is shown in Betts’ Creek, on the Upper Flinders. Whether these are marine, lacustrine, or estuarine deposits, there is hardly sufficient evidence to show.

What may be the value of this “Desert Sandstone” for free gold, is at present unsolved; but the very nature of its deposition seems to preclude the idea that that metal will be found in paying quantities, except where direct local abrasion of a rich auriferous veinstone has furnished the supply.

MESOZOIC.

Cretaceous.—As early as 1866 a suite of fossils was collected by Messrs. Sutherland and Carson, of Marathon station, Flinders River, and forwarded for determination to Professor McCoy, in Melbourne. They were never figured, but his manuscript names are as follows:—

In company with Mr. Sutherland, who supplied McCoy with the before-mentioned materials, Mr. R. Daintree visited the Upper Flinders, and carefully collected the fossils from three localities, viz., Marathon station, Hughenden station, and Hughenden cattle station.

At Marathon, which is some forty miles further down the Flinders than Hughenden, there is, close to the homestead, an outcrop of fine-grained yellow sandstone, which has been quarried for building purposes, and below this, to the edge of the waterhole supplying the house, is a series of sandstones and argillaceous limestones, containing numerous organic remains. These were submitted to Mr. Etheridge for examination and correlation, the result of which appears in the appendix to his work. The Hughenden cattle station is twenty miles further up the Flinders than the Hughenden head station. Here hundreds of Belemnites are strewn over the surface of the two ridges which front the cattle station huts, but they are rarely found in the soft shales which crop out from under an escarpment of “Desert Sandstone.” The lithological character of these cretaceous strata is such that decomposition is rapid; the resulting physical aspect being that of vast plains, which form the principal feature of Queensland scenery west of the Main Dividing Range; but that the “Desert Sandstone” has extended over all this country is evidenced by its existence either in the form of outliers, or as a marked feature “in situ” in all main watersheds, or by its pebbles of quartz and conglomerate, which are strewn everywhere over the surface of the plains. The height of the watershed between the Thomson and Flinders Rivers is locally not more than 1,400 feet above sea level, and as the former river has to travel as many miles before reaching the sea, it is easy to understand why, in a country subject to heavy tropical rains at one period of the year, followed by a long dry season, the river channels are ill-defined, and vast tracts of country covered by alluvial deposits. Down the Thomson and its tributaries, these mesozoic rocks are known to extend, though much obscured by flood drifts. That this portion of the mesozoic system extends throughout the whole of Western Queensland to Western Australia is also more than probable, hidden, however, over large areas by “Desert Sandstone.”

Mineral Springs.—There is one other subject of practical interest connected with the great mesozoic western plains, and that is the occurrence of hot alkaline springs, which suggest the possibility of obtaining supplies of water on the artesian principle over some portion at least of this area.

At Gibson’s cattle station, Taldora, on the Saxby River, a tributary of the Flinders, a spring of hot water rises above the surface of the plain, and its overflow deposits a white encrustation, which on analysis by Dr. Flight, under the direction of Professor Maskelyne, afforded:—

Apart, therefore, from the 5.552 per cent. of chloride of sodium, the deposit consists of sequi carbonate of soda or native “Trona,” and as such is used by the settlers for culinary purposes, etc.

PALÆOZOIC.

“Carboniferous.”—Whilst the affinities of the southern coalfield of Queensland are mesozoic, a northern field, of even larger extent, has a distinct fauna more resembling the PalÆozoic Carboniferous areas of Europe.

The Dawson, Comet, Mackenzie, Isaacs, and Bowen Rivers drain this carboniferous area; and numerous outcrops of coal have been observed on these streams. No commercial use, however, has yet been made of any of these deposits, as the measures generally are too far inland to be made available until the railway system of the country is extended in that direction.

“Devonian.”—From the southern boundary of Queensland up to latitude 18 deg. S., a series of slates, sandstones, coral limestones, and conglomerates extend to a distance 200 miles inland; these are sometimes overlain by coal measures, sometimes by volcanic rocks, and consequently do not crop out on the surface over such districts. North of latitude 18 deg. S., however, over the Cape York Peninsula, this series (so far as we have any evidence), is absent, granites and porphyries capped by “Desert Sandstone” forming the ranges on the eastern, and their abraded ingredients the sandy ti-tree flats, those on the western side of that inhospitable tract of country, a never-ending flat of poor desert-looking sandy ti-tree country, stretching away to the shores of the Gulf of Carpentaria.

In the limestone bands, which form the lower portion of the series, corals are very numerous; in fact, the limestones, where little alteration has taken place, are a mass of aggregated corals; and as this class of rock has resisted aerial destruction better than the associated slates and sandstones, the barriers thus formed mark the trend of the rock system to which they belong, in a very picturesque and decided manner; their bold, massive, and varied outline chiselled into the most delicate fretwork by Nature’s hand, is relieved by a wealth of richly-tinted foliage, unknown in the surrounding bush; and the eye jaded with the monotony of the eternal gum tree turns with delight to the changing tints and varied scenery presented by these barrier-like records of the past. This class of country is very much in evidence at Chillagoe. On the track from the Broken River to the Gilbert diggings, Devonian rocks several thousand feet thick may be observed, as they are continuous in dip, without being repeated, for at least five miles across the strike, with an average inclination of 60 deg.

Although on the Broken River and its tributaries a breadth of thirty miles with a length of sixty miles, is occupied by a persistent outcrop of Devonian strata, gold has only been discovered in remunerative quantities in a small gully, where a trapdyke has penetrated the PalÆozoic rocks of the district.

The following districts, however, where Devonian rocks prevail, have been the centres of gold mining enterprise:—Lucky Valley, Talgai, Gympie, Calliope, Boyne, Morinish, Rosewood, Mount Wyatt, Broken River, portion of Gilbert.

In every case here cited, the country is traversed by trap rocks of a peculiar character, either diorite, diabase, or porphyrite; and tufaceous representatives of these are also found interstratified in the upper portion of the same formation, and occasionally throughout the other beds.

At Gympie, the auriferous area is confined to veins traversing a crystalline diorite, or within a certain limit of its boundary, marked by the presence of fossiliferous diabase tufas.

Whatever may have been the solvent and precipitant of the nobler metals in the auriferous veinstones associated with trap intrusions, all other but hydrothermal action may safely be eliminated, the very nature of the reefs, composed as they are of alternating layers of a promiscuous mixture of quartz, calcspar, pyrites, etc., affording unmistakable evidence on this point. The gold also contained in the trap dykes themselves is always accompanied by pyrites, both (according to Daintree), hydrothermal products separating out during the cooling down of the trap intrusions. Auriferous lodes, occurring in areas where hydrothermal action has attended trap disturbances of a special character in Queensland, are generally thin—to be estimated by inches rather than feet; but taken as a whole they are far richer in gold than those enclosed by sedimentary rocks.

GRANITIC.

Outcrops of granite extend along the eastern coast of Queensland from Broad Sound to Cape York, and inland as far as the heads of streams running direct from the inner coast range to the sea.

Very little rock of this character is met with west and south of the Dividing Range which separates rivers flowing to the eastern and northern coast, and those trending south to the Murray or Cooper’s Creek.

The granites of Queensland vary very much in their crystalline texture, passing from true granites into porphyry and quartz porphyry.

TRAPPEAN.

Much stress has been laid on the value of certain intrusive trap rocks as specially influencing the production of auriferous veinstones in Queensland.

The petrology of these may be divided into four type classes:—1. Pyritous porphyrites and porphyries. 2. Pyritous diroites and diabases. 3. Chrome iron serpentines. 4. Pyritous felsites.

VOLCANIC.

Whilst the older trappean rocks have apparently had so much influence on the disturbance and fracture of the sedimentary strata older than the Carboniferous, and by a secondary process have evidently been centres of mineralising action, the volcanic seem to have played the most important part in determining the elevation and present physical outline of north-eastern Queensland. The main outbursts of lava have taken place along the Dividing Range which separates the eastern and western waters, and therefore on the line of the highest elevation of the country. The more northern volcanic areas, are probably contemporaneous with the upper volcanic series of Victorian geologists, so extensively developed in the western districts of that colony. These have issued from well-defined craters still in existence, and are probably of Pliocene Tertiary age.

The southern areas, viz., Peak and Darling Downs, etc., are older, agreeing with the lower volcanic of Victoria, which have been ejected through fissures, and have in no case a very extensive flow beyond the lines of fracture through which they issued. These may be referred to the Miocene Tertiary epoch. The rock masses forming both the upper and lower volcanic are basic in character, and may be all termed or grouped under the general term “dolorites.”

The volcanic soils of Queensland are those best adapted for the grazier and agriculturist.

To epitomise:—With the exception of the McKinlay Ranges, a line drawn parallel to the eastern coast, at a distance of 250 miles, would include all the palÆozoic, metamorphic, granitic, trappean, and volcanic rocks represented in the colony, both coal groups lying within the same area.

The mesozoic and cainozoic systems occupy the surface area to the westward. The volcanic rocks follow the line of greatest elevation on the main watershed at altitudes from 1,500 to 2,000 feet above sea level. The chief granitic mass extends from Broad Sound to Cape York, with an occasional capping of “Desert Sandstone.” Westward from the Dividing Range, “Desert Sandstone” and the cretaceous and oolitic groups alternate one with the other to the extreme limit of the colony.

AREA OF FORMATIONS.

Estimating the entire extent of the colony at 600,000 square miles, a rough approximation to the areas occupied by the different geological formations is as follows:—