Suggestions upon the Origin of the Australian 



Flora. 



Continued from page 212. 



By Spencer Moore, B.Sc, F.L.S. 



Our scanty knowledge of the geology of the West Australian 

 desert has recently been materially added to by Mr. Victor Streich, 1 

 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 Eange hornblenclic schists are met 

 with. From the Fraser Eange 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 Eange ; 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," Transactions of the Royal Society of South 

 Australia, vol. xvi. 



274 



