Suggestions upon the Origin of the Australian 
Flora. 
Continued from page 212. 
By SPENCER Moorg, B.Sc., F.LS. 
Our scanty knowledge of the geology of the West Australian 
desert has recently been materially added to by Mr. Victor Streich,! 
who traversed the southern part of the desert lying between Mount 
Squires on the eastern border and Yilgarn on the west. Mr. Streich 
finds that Mesozoic rocks, covered in many places by abundant tertiary 
deposits, extend from Mount Squires as far west as Queen Victoria 
Springs, except in one place where Palaeozoic cliffs were seen. The 
rocks regarded as Mesozoic are clay, jasper-rock, conglomerates, and 
quartzite sandstone, and they are assigned to this age on lithological 
grounds alone, there being no fossils in them, but their lithological and 
stratigraphical features being the same as in the typical area outside 
the western colony. West of Queen Victoria Springs there are 
quartzite ridges, and at the Fraser Range hornblendic schists are met 
with. From the Fraser Range towards Lake Lefroy and the Hampton 
Plain, that is in the Coolgardie district, a series of metamorphic rocks 
are met with, the country having a general elevation of 1200 to 1500 
feet above sea-level, while to the west lies an immense high plateau, 
1300 to 1400 feet above the sea, terminating at the steep western 
escarpment of the Darling Range; there are several formations in this 
plateau, the granitic and the flanking schistose being the most con- 
spicuous. The sandy flats covered with efflorescent salts on this 
plateau represent, Mr. Streich thinks, depressions of the granitic uplands 
in which has been accumulated the saline matter remaining over from 
isolated parts of the ocean. In the north-western part of this plateau 
the Crystalline hills are capped with desert sandstone, which directly 
overlies the granite and is invariably horizontally bedded. .Fossils were 
not found in this sandstone, which Mr. Streich considers to be probably 
identical with the similarly named formation of Central Australia. 
1 “The Geology of the Elder Expedition,” Zransactions of the Royal Society of South 
Australia, vol. xvi. 
274 
