566 



(b) The less altered Lower Silurian rocks are sandstones, 

 slates, shales^ and mudstones, with a few beds of conglomerate 

 and breccia. Graptolites are so abundant in tlie shales as to 

 make them carbonaceous. Over twenty-four species have been 

 recorded,* and in addition the brachiopods Siphonotreta Qnicula, 

 McCoy, and Lingula, and a sponge, Protospoiujia. Two phyllo- 

 pods have also been recorded — Hymenocaris ^alteri, McCoy, and 

 Lingulocaris McCoyi, R. Etheridge, Junr.f 



(3) In South Australia at the Mount Macdonnell Ranges, jSIr. 

 H. Y. L. Brown has described^ § rocks which Mr. R. Etheridije, 

 Junr., considers to be Lower Silurian, as lyiniij unconformably on 

 Cambrian (?) strata. 



The Lower Silurian rocks consist of sandstone, quartzite, and 

 shale, with thin bands of fossiliferous limestone. The following 

 fossils have been recorded and described from these rocks by Mr. 

 R. Etheridge, Junr.|| ^ :— 



Stems of Crinoids. 



Asaphus (MegalasjnsJ Thorntoni, R. Etheridge, Brown's Leigh's 

 Creek and Hergott Springs Reports, 1892, p. 8, pi. i. 



Asajjhus illarensisj spec, nov., R. Etheridge, Additional Silurian 

 and Mesozoic Fossils from Central Australia, p. 5, pi. i. fig. 1, 



Urthis leviensis, R. Etheridge, Junr., Brown's Leigh's Creek 

 Report, 1891, pp. 13-14, pi. i. figs. 5-7, and Additional Silurian 



* " Prodromus of the Palteontology of Victoria," by Frederick McCoy, 

 Decade I. pp. 5-20, pi. i. and ii. ; ibid. Dec. II. pp. 29-37, pi. xx. ; ibid. 

 Dec. V. pp. 39-41, pi. l. 



+ Records Geol. Survey New South Wales, Vol. iii. Pt. 1, t. 4, fig. 2. 



:{: South Australia. Report on the Coal-bearing Area in the Neighbour- 

 hood of Leigh's Creek, by H. Y. L. Brown. By authority. Adelaide, 

 1891. p. 13. 



§ South AustraHa. Further Geological Examination of Leigh's Creek 

 and Hergott Districts, and General Geology of the Finke River, by H. Y. 

 L. Brown. By authority. Adelaide, 1892. p. 7. 



II Loc. cit. Brown's Report, 1891, pp. 9-14, pi. i. and loc. cit. Brown's 

 Report, 1892, pp. 8-9. 



H South Australia. Additional Silurian and Mesozoic Fossils from 

 Central Australia, by R. Etheridge, Junr., H. Y. L. Brown, Government 

 Geologist. By authority. Adelaide, 1893. pp. 5-S and plate, figs. 1-13. 



