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work of the country, often cutting down through the older water-courses. Speaking of Gippsland, the author remarks that the streams "have scooped out deep valleys. The lofty hills have not been upheaved in isolated masses, but are the remains of formations which have been swept away by the slow action of water. If all the rock-formations could be restored and placed in the positions which they once occupied, Gippsland would be an immense nearly level plateau. As a familiar illustration, we may liken the mountains formed of palaeozoic rocks to the humps of earth left by the navvy when he digs a cutting. The grass on the surface of the hump shows what was once the height of the ground which has been removed; and the recent tertiary formations on the tops of the hills in Gippsland are evidence of the original height of the whole area. The rocks which once occupied the intervening spaces have been eroded by water; and the height of the hills above the valleys affords some hint as to the vertical extent which has been cut away." The author believes that Victorian surface-geology affords "an answer to those geologists who have urged that the greater amount of erosion everywhere has been effected by marine agency, and not by rivers, rains, and the wasting action of the atmosphere." And, indeed, no one can study the maps and sections in this volume without being convinced that the erosion of the present and of the old valley-system has been wholly a sub-aerial process.

Mining operations have done a good deal towards elucidating the older system of water-courses which were overflowed and buried beneath basalt. These water-courses or "leads," as the miners call them, contain richly auriferous "drifts," and they are accordingly explored and ransacked by shafts and adits. Thus, at Ballarat, the river Yarrowee must have had its course shifted considerably eastward by the overflow of basalt. Its old winding channel has been explored under the overlying basalt, and the channels of its tributary rivulets from the east have been followed under the bed of the present river.

From the shafts and the natural sections along the sides of the valleys, we learn that the volcanic phenomena continued to manifest themselves for a prolonged period. Showers of ashes and streams of basalt were thrown out at long intervals, during which gravel and sand were accumulated in the water-courses above the last erupted materials. Hence we now find sections where sheets of basalt alternate with stream-gravel and with layers of clay and ancient soil. As in Auvergne, the lapse of time which separated the oldest from the most recent volcanic rocks cannot but have been great. On the one hand, some of the basalt plateaux have been trenched by valleys several hundred feet deep, and fragments of the plateaux have been left isolated; on the other hand, there occur craters and cones of ash so fresh that not many centuries may have passed away since they ceased to be in eruption.

But the changes of level effected by the outpouring of volcanic rocks at the surface have not been the only causes at work in greatly modifying the drainage of the country. In comparing the water-courses with the quantity of water flowing in them, still more in examining the endless lines of water-course in which there is no water at all, we are forced to conclude that the rainfall must be much less now than it was in a very recent geological period. Over a large part of Victoria the ground is low and sandy; and there the streams which come down from the hills, after wandering hopelessly about among pools and scrub, disappear altogether, being partly evaporated and partly absorbed into the parched soil. Mr. Smyth mentions an interesting fact when he says that the old drainage system of the country can often be traced only by the vegetation. "The Murray pine, in the midst of small Eucalypti, marks distinctly the line of the ancient water-courses." "The beds of old lakes and tributary creeks can now be discovered in some places only by the timber which they bear." This general desiccation of the country points to some wide-spread geological cause. Possibly it may be due—in part at least—to a comparatively recent elevation of the northern part of Australia, whereby the northerly winds, having a broad belt of land to pass over, lose much of their moisture before they reach the high lands of Victoria and New South Wales. The want of an abundant and constant supply of water is in some parts of the colony a serious obstacle to improvement. In particular, it operates most prejudicially upon gold-mining; no pains ought to be spared, therefore, to prevent the destruction of timber, and to take every opportunity of planting it where it is likely to be of service.

In conclusion, the volume which Mr. Smyth has produced, though too bulky and too detailed for general readers, is a storehouse of information on the subject of which it treats, and will undoubtedly take its place as one of the standard works of reference for all that relates to the occurrence and the mining of gold. Arch. Geikie

THE want of special works introductory to the study of the botany of the principal tropical and southern countries of the globe has long been felt. The medical man, the student, and the amateur resident or travelling in India and our principal colonies, find it hard work to keep up or get up their botany by introductions and class-books founded on British plants, whilst the schoolmaster would find himself very much abroad who should attempt to teach his pupils Australian Botany by Henfrey's or Balfour's Introductions, or by Oliver's Elements. Hence the need of a series of works devoted to the teaching of botany with a special reference to the wants of the sojourners in foreign parts, and illustrated by the common plants to be found therein. With the exception of the admirable text-books of American Botany, of Asa Gray, we know of no work of the nature indicated, illustrative of any extra-European Flora. There was, indeed, some talk a few years ago of a series of such works, embracing all departments of Natural History, being authorised by the local governments of India,— but nothing has come from that quarter; and much as we then regretted the supineness of the Indian authorities in the matter, we no longer do so; for India could assuredly never have produced a work of so high an order as that whose title stands at the head of this notice, for a better considered