Reviews—Stanford’s- Geography—Australian Geology... 425 
only the scarps of the inland plateau. This rule applies also to the 
third grand division, viz. Westralia. 
The second grand division also runs south and north from the 
southern sea to the Gulf of Carpentaria, and is described as the region 
of the Great Plains, formed, Professor Gregory thinks, by subsidence. 
A large portion of this is less than 500 feet above sea- -level; the 
shores of Lake Eyre are said to be 39 feet below that level. It is, in 
fact, an extensive basin whose further submergence would tend to 
convert the continent of Australia into two separate islands. The 
greater part of this depressed area is occupied by rocks of Cretaceous 
age as determined by their fossils. 
The third grand division is lar ger than the other two combined, aid 
consists of an endless series of upland plateaux of moderate elevation 
up to about 2,000 feet, much of which is practically a desert. This 
immense mass consists to a great extent of Archean rocks associated 
in the north-east with a wide stretch of older Palseozoics, though 
parts of the interior may be still unexplored. It appears to have 
been unsubmerged, like peninsular India, for a long period, and has 
a fringe of newer rocks on its western margin, in which the early 
settlements of Western Australia are situated. The mineral resources 
of this and the two other grand divisions of the Australian continent 
may be gathered from Professor Gregory’s separate notices of the 
individual Colonies. 
New South Wales.—As previously noted in considering the character 
of the East Australian highlands, the south-eastern corner is com- 
posed of Archean and Lower Paleozoic rocks, mostly striking north 
and south. ‘These older rocks gradually decrease in height as they 
are followed northwards, until they disappear below the Upper 
Paleozoic rocks which contain the great coalfields. To the north 
of this area the older rocks reappear and are continued to the Queens- 
land frontier. The mountains result in the main from the dissection 
of plateaux by river-action. These are in a very youthful stage of 
dissection, and their marvellous gorges and cliffs—expressions of 
youth—provoke the wonder of the beholder by reason of their diverse 
forms. The lavas of Tertiary age, which occur in some places, also 
lend themselves to this kind of scenery, and there are peaks west of 
the Blue Mountains which consist of trachyte and andesite. On the 
east side of the mountain-system the coastal plains have an average 
width of 40 miles, though in the valley of the Hunter River the 
width reaches.150 miles. The western plains, on the other side of 
the mountain-system, include some of the largest true plains in the 
world. They are mostly dry, but sometimes in places so flooded that 
steamers have been known to discharge their cargoes 25 miles away 
from the main channels. 
As regards the geological structure of New South Wales, Professor 
Gregory observes that the block of older rocks was divided into two 
parts in Middle Paleozoic times by the great valley now occupied by 
the basin of the Hunter. This basin was filled with Carboniferous 
sediments, which were deposited upon the upturned edges of pre- 
existing strata. In contrast to the north and south strike of the older 
rocks, these Carboniferous beds strike from east to west. Referring 
