[Proc. Rot. Soc. Victoria, 29 (N.S)., Pt. I., 1916]. 



Akt. IV. — Tlie Pideontological Sequence of the Lower Ordoviclan 

 Mocks in the Castlrmaive District. 



Part I. 



By \V. J. HARRIS, B.A. 



(With Plate I.). 

 [Read 11th May, 1916]. 



Victorian economic geology, more particularly in so far as it is 

 concerned witii the origin and occurrence of auriferous lodes, is so 

 intimately associated with the folding of palaeozoic strata and the 

 resulting problems, that any reliable guide to the order of super- 

 position of the various beds is likely to be useful. The absence of 

 conglomerates and other well defined bands deprives geologists of 

 benchmarks, that would be of assistance in working out the folding 

 of the rocks in localities Avhere good exposures are wanting. Re- 

 cognition of the part certain favourable beds play in the enrichment 

 of lodes, more particularly at Ballarat, and to a lesser extent at 

 Bendigo, Daylesford, and elsewhere, has accentuated the importance 

 of obtaining a working knowledge of the stratigraphical relations 

 of the rocks of these localities. In the absence of this knowledge 

 even expert opinion is liable to err. Mr. E. J. Dunn states that 

 " the South Eureka rocks appear to loe well up in the Castlemaine 

 zone . . . Spring Gully apj^eai's to be still higher. . . . The 

 Fryerstown belt is in the Castlemaine zone."i These three localities 

 seem on palaeontological evidence to be all Upper Bendigonian, and 

 hence much more favourable for quartz mining than the above makes 

 them apiDear. The i-esearches of Dr. T. S. Hall and others have 

 resulted in the subdivision of the Victorian Lower Ordovician rocks 

 into four series — Lancefield, Bendigo, Castlemaine and Darriwil, in 

 ascending order. The relations between the three lower series are 

 clearly shown in several areas, and are generally known, but, though 

 the Darriwil series is recognised as somewhat above the Castlemaine 

 series, its exact stratigraphical position has remained in doubt. 

 This paper includes, among other efforts, an attempt to co-ordinate 

 the Castlemaine and Darriwil series. 



1 Dunn, E. J., Rec. vol. iii., part ii., Geo). Surr. Victoria. 



