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The Rev. W.B. Clarke, often called the Father of Australian Geology, traversed parts of the Shoalhaven in his expeditions. Clarke was fortunate to have an enthusiastic, well educated and intelligent correspondent in a local resident named Henry Moss who traversed much of the district, collecting specimens along the way, and contributed to Clarke’s knowledge of areas, such as Yalwal, that he did not personally visit. Here we reproduce three accounts of Clarke’s findings:
“The Rev. W.B. Clarke, of whose high standing as a geologist I have spoken above, has also been employed by the Local Government to prospect in various regions of the colony. The following are extracts from his Report on the district of the Shoalhaven River: -
‘There is a striking similarity between the Shoalhaven Ravine and the gullies in the basin of the Macquarie, and it is not therefore extraordinary that they should be considered both alike in auriferous character.
I found in the place where I camped three parties engaged in gold washing. Two cradles were at work. The persons now engaged in it amounted to eleven. So far as I could ascertain, about thirteen ounces of gold have been produced, besides one rolled lump of quartz, which weighs about three ounces, and is said to have been found in a spot, indicated by the finder, a few inches (eighteen) below the surface of the drift. It is singular, I think, that no other lump has been found.
I think there will be found much gold in and along the banks of the Shoalhaven. The gold already found is not local; it is flattened and worn by long friction amidst the hard boulders which fill the river bed, and I think it has been drifted from a considerable distance.
My opinion is, that the gold found in the Budawang Country, as along the Mongarlowe River, and the Wombagugga and the Tan-tu-li-an Creeks, is due to the presence of the hornblende. Hornblendic rocks are well-known sources of transmutations associated with the occurrence of gold. My time did not allow me to cross the Budawang Range; but I have information of the occurrence of gold in similar small quantities on the east side, in the feeders of the Clyde River, and about the head of the of the latter. I may add that I found gold in minute quantities along the Jembaicumbene Swamp, which occupies a depression in the granite, and at the Lagoon Flat at Bendoura, between it and the Shoalhaven, where a running creek flows over porphyry.’
From - An Historical and Statistical Account of New South Wales Vol II, J.D. Lang, 3rd ed., Longman, Brown, Green and Longman, London, 1852.
On the 5th October 1861 the following extract (written in 1851) was published in the Ilawarrra Mercury:
“Shoalhaven and Araluen Gold Fields.
(From Clarke’s Southern Gold Fields)
REPORT TO THE HON. COLONIAL SECRETARY.
Bungonia, 20th September, 1851.
I have the honor of communicating to you, for the information of his Excellency the Governor-General, the progress made in the geological exploraion of the country since my departure from Sydney, on the 12th instant.
Believing it to be the wish of his Excellency that my researches should be conducted in a regular plan, I considered it right to commence my operations where my former private survey of the country in the southern districts terminated.
I therefore took my departure from Marulan, and have devoted the present week to a careful examination of the creeks and ranges lying between that place, Jacqua Creek and the Shoalhaven River. Having in view an enquiry into the probable auriferous character of that district.
In the neighborhood of Marulan the principal rocks are phorphyritic, supporting masses of of conglomerate and sandstone, which have been hardened at the places of contact and much disturbed. The base of the porphyritic rocks is a petro-silex, and abundance of hornblende is mixed with the felspar. In some cases the base is so predominant as to give the rock the character of a cornean; in others the admission of small quantities of mica gives it a granite constitution. In this phase it occurs near Glenrock, which also passes into syenite. A few miles east of Marulan this rock is flanked by limestone, inclined at a very high angle, the contact with the igneous rock being marked by the occurrence of a thick band of quartz rocks. The limestone is intersected also by quartz rock and a rich ore of iron, which occurs in bands also. The dip of these rocks is from 52 to 62 degrees N.N.W., and the first mass of limestone has its summit 289 feet below Marulan (by my barometrical measurement). Marulan itself is more than 2,000 feet above the sea; by former calculations I made it 2,058 feet. The porphyry on which the church stands is 2,104 feet (by the same calculation) above the sea.
The presence of quartz rock in all the other rocks named above, is very remarkable. The porphyry is itself studded by rounded grains of crystalline quartz, which sometimes is almost predominant; and veins of quartz, perfectly white and opaque, run through the porphyritic rocks with the exception of the concretionary syenitic granite at Glenrock. I do not find that this quartz is auriferous, but the country is strewn with fragments of quartz, and these are so abundant as to attract the attention of the most unobservant. They are seldom rounded, and by their distant rectilinear forms show that they have been broken up from intersecting bands and veins.
I made a journey to the gullies running into the Shoalhaven, a little below Glenrock Creek.
In crossing the ridges I found the limestone passing into statuary marble, white and crystalline, just where it comes into contact with slate; having between itself and the latter, a thick mass of quartzite, and a little distance above the point of contact a band of ironstone. Just in advance, towards the east of this junction, schistose rocks, interstratified by grey quartzite, make their appearance; they are reddish, grey, and blue in colour, but very soft, except in the lower parts of the creeks, where the stratification is seen to advantage, and they obtain considerable hardness. The descent of the spurs between the creeks is very steep and laborious, owing to the crumbling nature of the slate. The whole of the detritus is local.
I did not, on this occasion, descend to the Shoalhaven, the day being too far advanced, and there being in sight, from the spot whence the river could be distinctly seen, no gold-diggers at work.
The dip of the rocks, after passing the marble. became reversed, being E.S.E., at an angle of 52 degrees.
Many of the creeks have been prospected, but without success.
I next proceeded to examine the range of sandstone, and conglomerate, running from Mount Otway, whence building stone is procured, across the bush towards the limestone previously mentioned, and upon which, and upon the syenitic knolls, outliers repose in advance of the main range. These outliers are frequently thrown off from the igneous masses at an angle of 50 degrees to the west. The latter have transmuted the former.
Between Marulan and this place similar accidents have occurred, the general level of the country falling somewhat, and the porphyritic, as well as other rocks, being covered by a vast detritus of broken up conglomerate and quartzites.
On the road to Goulburn, at Collin’s Flat, when the waters of Bungonia Creek are drained the porphyry, which is intersected by quartz rock of considerable whiteness, and at the point of intrusion is decomposed, throws off thick beds of fossiliferous sandstones and conglomerate at an angle varying from 19 to 28 degrees, having a westerly dip. (These beds appear by the fossils to be of the age of the upper part of the lower Silurian formations; the height of this swampy flat is about 1,880 feet above the level of the sea.
In the neighborhood of Lumley and Inverary I found, for the first time, on this journey, a basaltic rock. The trap there forms a high and tolerably level range, having at Jacqua, on one flank, a mass of conglomerate and sandstone, much distorted and broken, and dipping to W.N.W., at angles varying from 54 to 65 degr. and on the other, at Inverary Quarry, a hard, yellowish, fine sandstone, dipping 68 degrees to E.S.E.
The intrusion of the trap has produced metamorphic results, and in one place a singular magnetic pisolitic iron ore in particles not larger than a pea, which are cemented by various crystallized minerals.
Iron is a prevalent metal in these rocks, but a few miles to the westward copper ore occurs in more or less abundance.
From Inverary I made a visit to the Shoalhaven River, passing the night in an oppossum rug on the rocks of the left bank. The descent to and the ascent from the river is most difficult and not devoid of danger.
The first part of the way lies along the beds of the deep gullies that drain the higher country. On the banks of these ravines the peculiar stratification of the slates and quartzites is beautifully developed, and some of the most remarkable examples of highly inclined, contorted, and concretionary beddings are exhibited. The windings of the creeks present to view the joints, cleavages, and beds in admirable detail, and a walk through them is worth the toil.
In rainy weather these creeks must be almost impassable, but they are quickly drained, and even during the late high westerly winds the water has rapidly diminished.
In some places ferruginous springs have formed, at an earlier epoch, a conglomerate, cementing the local fragmetary detritus, which conglomerate now stretches across the valleys at a higher level than the present bottom of the creek running therein.
Some idea may be formed of the little probability of much occupation of the Shoalhaven River in this vicinity, if I state that the only possible access is on foot, all supplies having to be taken down on the shoulders, or in the hand of the pedestrian, who has to pass for some distance along a spur of a range, which at the narrowest point is first one foot then one inch in width, being formed by the almost vertical edge of a quartz band; and this surmounted, the descent is down a smooth slope of more than 1,200 feet vertical, the incline being, by measurement on the spot, from 20 to 32 degrees - a difficult path to climb in returning. Some of the slopes of the opposite ranges are 47 and 60 degrees.
The Shoalhaven in this place has no banks unoccupied by ledges or fragments of very hard and sharply inclined rocks; and during floods, as evidenced by the drift, the whole ravine must be occupied by water at least 30 feet above the present level. On the right bank, the highly inclined and contorted alternations of slate and quartzite descend without any talus into the water. Bars are formed by the connexion of the opposite faces of rock, and at these bars the water falls in slight rapids, heaping the sides of the ravine with a thick deposit of broken slate and quartz. The latter mineral has played a very considerable amount in the features of these formations; for the quartzite is crossed by innumerable thin veins and threads of white quartz, which do not always pass through the intermediate slate. I saw several instances in which the slate contained embedded quartzite, and vice versa quartzite entangling slate. It is plain, therefore, that the schistose rocks (slate and quartzite) are of contemporaneous formation and that the white quartz is younger......” CONTINUED
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