THE DESERT SANDSTONE. 295 



worthless grasses, mainly Spinifex, and is thickly covered with 

 rather stunted timber. 



" Opals form the chief commercial product of this formation. 

 They occur in nodules of ferruginous siliceous sandstone and 

 siliceous ironstone. Although the majority do not exactly meet 

 the definition of " precious opal " insisted on by jewellers, they 

 are not less beautiful. A change in popular fancy, or the 

 eradication of prejudice, is all that is required to make the 

 Queensland opals as valuable as the most appreciated gems from 

 Hungary. Among their chief sources are the Opal Range, the 

 Winton, the Mayne River, the Canaway Range, Bulgroo, 

 Nickavilla, and Listowel Downs. A fine collection is to be 

 displayed by Mr. Bond at the Exhibition. 



" The Desert Sandstone attains a thickness of 300 to 400 feet 

 on the West slopes of the Coast Range. In the west of the colony 

 however it dwindles to 50 or 60 feet. The Desert Sandstone 

 affords a most impressive instance of denudation. The most casual 

 observer, standing on the edges of one of its table-lands, cannot fail 

 to be struck with the obvious former connection of the terrace-edged 

 tablelands which meet the eye on all sides. This formation, 

 geologically so new, is left only in isolated fragments, and does 

 not cover in Queensland one-twentieth part of the area over 

 which it once extended. 



" The Desert Sandstone has yielded little but plant remains, 

 chiefly fragments of silicified wood. Mr. Norman Taylor, late of 

 the Geological Survey of Victoria, who accompanied Hann's 

 Exploring Expedition, however, found in it at Battle Camp, near 

 Co'oktown, some fossils which Mr. R. Etheridge, Senr., described 

 as ' a Hinniles like H. velatrix, and an Ostrea like 0. sowerbyi, 

 Eth.' Mr. Etheridge, however, thought that the fossils were 

 drifted specimens lying on the surface ; which Mr. Taylor assures 

 me was not the case. In confirmation of Mr. Taylor I have the 

 unquestionable testimony of Mr. A. C. MacMillan, that he 

 himself had seen fossils in the locality referred to by the former 

 gentleman. In any case, however, the fossils are insufficient by 

 themselves to determine the age of the deposits. 



" In his paper on the Geology of Queensland, the late Mr. R. 

 Daintree first referred in 1872 to a series of rocks occurring at 

 Maryborough, and containing fossils which, in the appendix to 

 Daintree's paper, Mr. ■ Etheridge, Senr., named as follows : — 

 Cyprina expansa, Eth. ; Trigonia nasuta, Eth. ; Crenulata 

 gibbosa, Eth. ; shell resembling Lucina (Codallia) percrassa, 

 Stol. ; Culcullcea robusta, Eth. ; C. costata, Eth. ; Nucula 

 quadrata, Eth. ; N. gigantea, Eth. ; Tellina inaricvburiensis, Eth. ; 

 T. sp. / Avicula alata, Eth. ; Natica lineata, Eth. ; Panopcea 

 sulcata. Eth. 



