210 J. A, Thomson — Rocks of Western Australia. 



LORIE (J.). " Fossile MoUusken von Curacao, Aruba unci der Kiiste von 

 Venezuela " : Samml. Geol. Eeichs-Mus. Leyden, ser. ii, Bd. i, 

 pp. 111-49, 1887. 



Salomon (W.). " Ueber angeblichen Untersilur in Venezuela": Monatsb. 

 deutsch. geol. Ges., 1909, p. 193 (shows that specimens described by 

 Drevermann were bought in U.S.A. and were not from Venezuela). 



SlEVERS (W.). "Das Erdbeben vom 26 Marz, 1812, an den Nordkiiste 

 Sudamerikas " : Mitt. Geogr. Ges. Hamburg, 1884, pp. 265-71. 



" Eeiseberichte aus Venezuela " : ibid., pp. 272-87 ; 1885-6, pp. 1-133. 



Venezuela, pp. viii, 359. Hamburg, 1888. 



" Karten zur physikalischen Geographie von Venezuela " : Petermann's 



Mitt., Bd. xlii, pp. 149-55, 197-201, 3 maps (1 : 3,000,000), 1896. 



"Das Erdbeben in Venezuela vom 29 Okt., 1900 " : Jahrb. Veroffnet. 



Geogr. Ver. Bonn, 1905, pp. 35-50. 

 Stevens (R. P.). "Geology and Mineralogy of Venezuela" : Proc. Acad. 



Nat. Sci. Philadelphia, 1868, pp. 303, 304. 

 Tate (R.). " Notes on the Geology of Guyana in Venezuela " : Quart. Journ. 



Geol. Soc, vol. XXV, pp. 343-50, 1869. 

 Wall (G. P.). "On the Geology of a part of Venezuela and Trinidad" : 



Quart. Journ. Geol. Soc, vol. xvi, pp. 460-70, 1860. 



IV. — The Classification of thk Hocks op the Western Australian 



GoLDFIELDS. 



By J. Allan Thomson, B.A., B.Sc, F.G.S. 



{Concluded from the April Number, p. 153.) 



Sedimentary Formations in the Goldjields. — Sedimentary rocks are 

 rare in all the goldfields south of the Gascoyne Kiver, if superficial 

 deposits of Tertiary or Recent age be omitted. It is true that 

 a sedimentary origin has at times been ascribed to the jaspers, and 

 still more commonly to the bands of graphitic schists within the 

 greenstones. Hand-specimens of the latter rocks and of slaty rocks 

 associated with the jaspers are indistinguishable from similar rocks of 

 sedimentary origin, and it is only by the study of the geological 

 occurrence of the bands that their derivation from igneous rocl<s 

 can be proved. It is probable, therefore, that many of the rocks 

 mapped as 'older sediments' by W. D. Campbell in Kalgoorlie ' and 

 Norseman^ are not sediments. There are, however, undoubted 

 sedimentary rocks between Kalgoorlie and Coolgardie, viz. the 

 Kurrawang conglomerates. The enclosed pebbles are largely jaspers 

 and porphyries, so that the formation of the conglomerates must 

 be posterior to the intrusion of the granites, and yet the matrix 

 is sub-schistose and the axes of folding are parallel to the general 

 direction of foliation of tlie district. The junction with the auriferous 

 series cannot be seen. From the plioto reproduced by Campbell, 

 it appears tliat there are similar conglomerates at Norseman.^ 



It is in the north-western goldfields the sedimentary series are 

 best developed and best exposed. Probably the oldest is a series 

 of highly inclined quartzites, conglomerates, quartz-schists, mica- 

 schists, etc., which is associated at Warrawoona with the basic 



^ Geological Map of the Kalgoorlie Goldfield, A. G. Maitland and W. D. 

 Campbell, Perth, 1902. 

 2 Bull, xxi, pp. 33-5, 1906. ^ Loc. cit., fig. 10. 



