The author first gave a sketch of the geological structure of the Australian continent, describing the rocks under the following heads:—
The frame work of Australia consists of three islands or groups of old rocks, with probably some additional ones in the northern parts.
On the western side we have the granitic and metamorphic range of Western Australia.
On the eastern side the great cordillera, consisting of granites, upper silurian rocks, and carboniferous sandstones of great thickness, containing valuable seams of coal.
In the centre of the south-west the South Australian group of palæozoic slates and sandstones.
Mesozoic rocks are not extensively found, unless a large part of the carboniferous rocks of New South Wales and Queensland should prove to be of triassic age.
The coal rocks of Victoria are triassic, and occupy a considerable area of that colony.
Professor McCoy has examined cretaceous fossils from the centre of Australia.
Marine tertiary rocks occupy a large portion of the interior.
Although trap rocks are found extensively in Australia, appearing to have broken through the sandstones in extensive sheets, no true sub-aerial craters have been discovered, except in Victoria, and there are no known active craters of eruption in Australia.
In considering these features of the different divisions of Australia in detail, the peculiar formation of the mountains, the remarkable features of the rivers, and the distinctive characters of the bush land, are very clearly described. Slight sketches, brief outlines of the explorations of Sturt and others into the interior and across the “island continent” to the Gulf of Carpentaria, are given; while a short account of a journey from Sydney to Adelaide in 1832, gives a direct personal interest to the paper, which concludes with the following contrast between Australia and New Zealand:—
“The most obvious contrast between Australia and New Zealand is that the former everywhere gives a nearly horizontal outline, while the aspect of the latter is towards the vertical. Consequently, in Australia the mountains are generally without grandeur, while New Zealand possesses some of the grandest, and at the same time the most varied mountain scenery in the world. Picturesque beauty in Australia is generally caused by rock scenery—scarps of sandstone, or huge bosses of granite, when they break the uniformity of the usual nearly level surface, have a pleasing effect. In the cañons of the Grove and the Cox, where deep valleys have been eroded from the sandstone, bounded by cliffs of great height, we have grand and wild effect, but cañons must be sought for; they do not strike the eye of a traveller as he passes through the country, and nine-tenths of the inhabitants of Sydney, although they daily see the Blue Mountains in the not very far distance, have never seen these deep and gloomy valleys, and hardly know of their existence. The open forest of
the usual country, the grassy glades, the timbered spurs of the western slope gently falling into open plains, are all entirely different from a New Zealand scene. The fiery glare of the mid-day sun glancing through the shadeless trees, and the rich purple hues of the sunset, are equally absent from the New Zealand landscape, or are modified and softened by the moister air of the ocean-surrounded colony. Although tree ferns and palms are well known in Australia, the regions where they are found bear no proportion in area to the mass of the country, so that they are practically unknown to the bulk of the inhabitants. Every New Zealander knows a tree fern, a cabbage tree, or a nikau palm. The New Zealand forest, particularly in the North Island, is of tropical aspect. Take a description of a South American jungle—it would fit in, word for word, for that of a New Zealand forest. The Australian bush stands by itself; it has a peculiar character, different from anything elsewhere. Australian lakes are few, and many of them shallow and liable to be dried up. In New Zealand the mountain lakes of Otago are equal to those of Switzerland or of Scotland, and in Canterbury and Nelson the continuation of these lakes to the N.N.E. offers scenery of the grandest description, although inferior in beauty to that of Otago. In the North Island, Lakes Taupo, Rotomahana, etc., with their geysers, hot water cascades, and deposits of silica, offer objects of beauty and interest which are unknown in Australia. New Zealand is a well watered, Australia a badly watered country. In the former colony one can hardly go for a few hundred yards without finding a stream, whereas, even in the better parts of Australia, the traveller may ride for a whole day before reaching a stream or a water hole. Australia has a continental, New Zealand an insular climate. Steady weather is the rule in Australia; in New Zealand constant change is the fashion. In Australia the mountain ranges only in one instance exceed 4,000 feet in height; in New Zealand Mount Cook approaches Mont Blanc in elevation, and heights of 8,000 feet are common. In the North Island are the volcanic cones of Mount Egmont, Ruapehu, and Tongariro, the two former about 9,000 feet in height. The small cones of Victoria are molehills in comparison, and are exceeded in height by numerous minor ones in the province of Auckland. In fact the New Zealand cordillera is on such a scale of magnitude that it would well form the backbone of a continent. The rivers of the provinces of Canterbury and Otago, if united on lower plains, might make a Ganges or an Indus, and the western rivers alone of the province of Wellington might, united, equal the Rhine or the Rhone. Such scenery as that of the sounds and harbours of the south-west coast of New Zealand—Milford Sound, Bligh Sound, Dusky Bay, etc.—is quite unknown in Australia. These deep inlets penetrate into the mountains, and cliffs several thousand feet in height look down upon the tiny ship which ventures into these solitary waters. In fine, geographically there are many points of resemblance between Aus-
tralia and New Zealand, while topographically there is great contrast. The flora and the fauna are, upon the whole, essentially different.”
Dr. Hector in remarking on Mr. Crawford's paper, mentioned the recently discovered diamond bearing deposits in the Mudgee River in New South Wales. The diamonds are found in abandoned gold workings, and must have been repeatedly overlooked by the diggers. Their immediate source is from a bed of conglomerate or cemented drift, small areas of which have been preserved by cappings of basaltic lava. According to Dr. Thomson, who had recently published an interesting paper on the subject, about 2,500 diamonds were obtained in the first five months of systematic working, and many thousands have since been collected. He recommended the study of Dr. Thomson's account to explorers for minerals in New Zealand, and especially in the north-west districts of the province of Nelson.
Mr. Hood remarked that one river only on the eastern slopes of the Australian Alps—the Clarence—contains the Murray Cod in abundance. He had noticed high pillars of basalt standing out in the central plains of Australia. He also stated that the Saurian remains from Australia bore considerable resemblance to those from New Zealand, but that the former were smaller.