234 
NATURE 
[ Dec. 30, 1869 
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 palaozoic 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 inter- 
vening 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-aérial 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 auri- 
ferous “ drifts,’ and they are accordingly explored and 
ransacked by shafts and adits. Thus, at Ballarat, the 
‘river Yarrowee must have had its course shifted con- 
siderably 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 quan- 
tity 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 ina very recent geological period. 
Over alarge 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 dis- 
covered 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 pro- 
duced, 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 
OLIVER’S INDIAN BOTANY 
First Book of Indian Botany. By Daniel Oliver, F.R.S., 
F.L.S., Keeper of the Herbarium and Library of 
the Royal Gardens, Kew, and Professor of Botany in 
University College, London. With numerous I!lus- 
trations. Small 8vo. pp. xii. and 394. (London: 
Macmillan and Co, 1869.) : 
HE 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 
