75 



ON THE ORIGIN OF MINERAL VEINS, WITH SPECIAL 

 REFERENCE TO THE BAROSSA DISTRICT, SOUTH 

 AUSTRALIA. 



By Gavin Scoular, Corresponding Member. 



[Read March 19, 1878.] 



ABSTRACT. 



The author commenced by enquiring into the primary condition of 

 our planet, citing the opinions of the ancients and Laplace's nebulous 

 theory of the earth's origin. He then sought to prove that the sources 

 of our present accessible metallic deposits have never at any period of 

 the earth's history been deep-seated. Treating of the metalliferous 

 rocks of the Barossa District, he writes — "In the absence of fossil 

 remains or a much stricter investigation of lithological identity than has 

 heretofore been prosecuted, it would be mere waste of words were I to 

 attempt to state unreservedly to what particular formation the rocks 

 constituting the Barossa Range belong. The slender evidence upon 

 which the Rev. J. E. Tenison Woods identifies them with the Silurian 

 is not sufficiently conclusive. And though twelve years have past since 

 the publication of the " Geol. Observ. in S. Australia," the rocks in 

 question are still " unresolved." Mr. Selwyn, in his geological sketch of 

 his tour in South Australia, states that " it is impossible in the absence 

 of fossil remains to determine to what series the rocks belong ; they may 

 be of Silurian or Devonian age." Regarding their physical and litho- 

 logical features the author writes, " They have undergone in many parts 

 a considerable amount of metamorphism, and now repose at high angles 

 of inclination. The rocks for a considerable distance both to the east 

 and west of the junction of Victoria Creek and the South Para River 

 have nearly all an easterly dip ranging from 50° to 60°, and in some 



