584 W. H. HUDLESTOF OK WEST-ATTSTKALIAN 



the geology of West Australia as far north as the Gascoyne river 

 in latitude 25° S. 



Speaking of the Darling Eange and the country to the eastward, 

 Mr. Gregory says that the principal portion of West Australia 

 consists of an undulating table-land of syenitic granite, which has a 

 western face rising abruptly from a plain of small elevation to a 

 height of from 800 to 1200 feet above the level of the sea, gradually 

 ascending, for 200 miles to the eastwards, to 1400 or 1600 feet, and 

 even as high as 2000 feet. Two diagrammatic sections were given, 

 one, about 40 miles in length, in latitude 32° S., where the edge of 

 the syenitic granite is about 20 miles from the coast. The crystal- 

 line rock, which in this latitude forms the western edge of the 

 Darling range, is represented as being penetrated by numerous 

 " dykes " of " serpentine," porphyry, and quartz. 



The second seetion is about 200 miles in length from west to cast, 

 and may be said to include the entire valley of the Gascoyne river, 

 in latitude 25° S., from its sources to the sea. From this section we 

 learn that the outcrop of the crystalline rocks in this more northern 

 region is about 90 miles from the coast, instead of 20 miles, as was 

 the case on the more southern parallel, and furthermore that there is 

 no such abrupt rise as occurs immediately to the east of the Swan 

 river, in the higher latitude. On the contrary we learn that about 

 the confluence of the Lyons and Gascoyne rivers, a very consider- 

 able thickness of palaeozoic rocks reposes, as it were, on the flanks of 

 the crystalline group, and thus serves to moderate the sharpness of 

 the declivity. Annexed is a copy of Mr. Gregory's second section 

 (fig. 2, p. 585). 



The paper and sections by Mr. Gregory must, then, be regarded 

 as having laid the foundation of West Australian geology south of 

 the parallel of the Gascoyne river, and, indeed, fully up to that 

 river, whilst the collecting of Mr. Forrest, the present surveyor, has 

 been limited to the regions upon, and to the north of, the Gascoyne 

 river; as indicated in the map which accompanies this report. 

 Beyond the fact that he has discovered a range, or, more properly 

 speaking perhaps, a sort of continuous outcrop, trending N.N.W. for 

 nearly 150 miles, which has yielded an interesting suite of Carbo- 

 niferous fossils, there does not seem to have been any noteworthy 

 discovery *. This fact, however, is in itself one of considerable im- 

 portance, as it places the existence of a large sweep of Carboni- 

 ferous rocks beyond the possibility of a doubt ; whilst, owing to the 

 poverty of the collection exhibited by Mr. Gregory, which only con- 

 tained one coral (referred to Cyatliophyllum), two or three species of 

 Spirifer and Productus, and a few Encrinital stems brought from 

 the Irwin river along with coal, the age of the coal-bearing beds of 

 that river had even been questioned. Moreover, as will be seen 

 subsequently, the Forrest collection is extremely interesting from a 



* In his letter to Sir Charles Nicholson, dated Perth, Nov. 4, 1882, he speaks 

 of having collected many fossils, some of which he had forwarded to England. 



