1852.] MURCHISON ON THE DISCOVKRY OF GOLD. 135 



gold, specimens of which they sent, the author wrote to Earl Grey, 

 Minister for the Colonies, in November 1848, referring to his antici- 

 pation as being about to be realized in a manner which might operate 

 a great change in the colony. From that time until the practical 

 establishment of the view on an extensive scale by Mr. Hargreaves in 

 1851, he developed the Australian phsenomena before the British 

 Association and the Royal Institution ; and, finally, he embodied his 

 views in the article entitled " Siberia and California," in the ' Quar- 

 terly Review,' 1850. 



Having next alluded to the diagrams illustrative of the subject 

 which he had exhibited, and to the useful new maps of the gold- 

 districts by Mr. Wyld*, the author spoke of a geological discovery 

 recently communicated to him by the Rev. W. B. Clarke, F.G.S., viz. 

 the existence of many fossils of known Silurian species, including Pen- 

 tamerus Knightii, and many shells and corals, on the flanks of the 

 dividing range of New South Wales. This discovery is important, for 

 it completes the resemblance of the Australian Cordillera (along which 

 Devonian and Carboniferous fossils had been found) with the Ural 

 Mountains ; the two chains being thus shown to be zoologically, as 

 well as lithologically, similar, and both to possess the same auriferous 

 ** constantsf." Such constants occur in many countries and have re- 

 cently been found to obtain in the prolongation of the Apalachian 

 chain into Canada, specimens of gold from whence were exhibited 

 by Mr. W. E. Logan, F.G.S. 



Sir Roderick entirely dissented from a theory propounded by Mr. 

 Clarke, — that the production of gold in certain meridional bands of 

 rock in both hemispheres has any fixed relation to four equidistant 

 meridians ; inasmuch as the exploration of Northern Asia or Siberia 

 has shown, that the greater proportion of Russian gold-ore is not de-> 

 rived from the Ural, but from numerous other similarly constituted 

 ridges, which occur at intervals throughout 70° or 80° of longitude. 

 The author concluded by recapitulating the data which he had 

 been enunciating for some years respecting the distribution of gold ^, 

 dwelling particularly on the facts which the labours of mankind 

 had established, that auriferous vein-stones in the parent rock had 

 been usually found to deteriorate in produce when followed down- 

 wards ; and that their originally richest portions having occurred in 

 the upper parts of the rocks, the most prolific gold-fields were 

 composed of the debris or drift, which in former ages had been abs- 

 tracted from the mountain-tops and distributed in gravel-heaps on 

 their sides. 



The author having further shown, that gold could only be abun- 

 dantly found along the back-bones or most ancient parts of the land 

 (more particularly in those countries which like Australia had never 

 been inhabited by civilized men), and had never been discovered in 

 any appreciable quantity in secondary or tertiary strata, it followed 



* Notes on the Distribution of Gold throughout the World. 8vo. London, 1852. 

 t See Discourse at the Royal Institution in March, 1850. 

 X See Trans. R. Geogr. Soc. vol. xiv. p. Ixiii. et seq. ; and Athenaeum Journal, 

 Nos. 920,1143,1167. 



