THE VICTORIAN NATURALIST 71 
Glenelg are the Chetwynd, Wando, Stokes, and Crawford, all enter- 
ing on its left bank, the country on its right furnishing no stream 
of any importance. The Surrey, Fitzroy, and Eumeralla, are small 
rivers, unconnected with this main drainage area, flowing directly 
into the ocean on the eastern side of Portland Bay. 
In the region lying between the Glenelg and the Mallee Scrub, no 
river or even creek of any but the most insignificant size is found, 
as the country is almost a dead level, the slight slope which exists 
being towards the Murray. Here, however, are a number of small 
lakes, generally brackish, often full in winter, but sometimes for 
years together, perfectly dry. The principal are the White Lake, 
Boorropki, Wallace, and Mitre Lakes. 
The whole district is a deeply interesting one, comprehending as it 
does so many formations, ranging from pleistocene to silurian, with 
their accompanying intrusive and metamorphic rocks. <A very large 
part of it is occupied by tertiary strata, particularly in the South 
and West, where marine limestones prevail, yielding an extensive 
and interesting suite of fossils, which, when fully collected and 
examined, will afford data for classifying these beds in the order of 
their deposition. Towards this end, much has already been done by 
a few earnest workers, but in a new country, where so many fresh 
forms are continually brought to light, the task is likely to engage 
the attention of geologists for a long time to come. At the present 
moment, a considerable diversity of opinion exists as to their relative 
age, the celebrated Muddy Creek deposits, for example, from which 
upwards of 300 species of mollusca are known, being placed by sone 
authorities much lower down in the tertiary scale than they are by 
others. It is not possible to establish any equivalence of age for our 
tertiary beds with those in Europe and America, as the fossils, 
though presenting a generally similar facies, are seldom, if ever, 
identical, so that the terms miocene, oligocene, and eocene when 
applied to Australian strata must be understood to refer to their 
geological sequence only. 
Professor Tate, of Adelaide, has devised a classification into 
Upper, Middle, and Lower Murravian, quoting the Muddy Creek 
beds in the first of these divisions, a position not quite in accordance 
with views held by Victorian geologists, but which he has adyanced 
sound reasons for assigning to them. 
Overlying many other formations, is a deposit of iron stone gravel, 
red in color, and of no great thickness anywhere, but most nen anh 
able for its ‘persistence through very wide areas. It forms a von- 
spicuous feature in the landscape, extending over hill and dale, and 
coating every escarpment and cutting as far as the eye can reach. 
In the heath and serub lands, it is hidden from view by another and 
still more recent deposit, namely, loose sand, which, spreading in 
broad belts throughout the counties of Follet and Lowan, and 
