582 CASTS OF RADIOLARIA IN PRE-CAMBRIAN ROCKS, 



these localities are A'eiy well adapted foi' preserving macroscopic 

 fossils, had they ever existed in them. 



(iii.) The evidence on the whole is decidedl} in favour of the 

 existence of radiolaria in Pre-Cambrian rocks in South Australia. 



(iv.) Such I'adiolaria appear to differ very little in size from 

 the forms described from Palfeozoic, Mesozoic, Tertiary and Post- 

 Tertiary rocks, as their diameters appear to range from about -1 

 to '22 mm. 



(v.) Forms allied to Carpospluera and Cenosplicera, and possiljlj' 

 to Cendlipsis, appear to have been represented in Pre-Cambrian 

 time. 



We desire to express our thanks to Mr. Stanley Fi-aser, the 

 manager of the South Australian Portland Cement Company, at 

 Brighton, who has kindly given all the help in his power to 

 facilitate our researches at Brighton. We have also to thank 

 Mr. W. Lewis, of Bi'ighton, for kind guidance and assistance. To 

 Mr. J. W. Jones, the Conservator of Water, we are much indebted 

 for the excellent arrangements which he made for our geological 

 examinations of Crystal Brook and Ardrossan. We also desire 

 to thank for much useful aid given us in the field the following : 

 Mr. Hicks, Mr. C. C. Buttfield and Mr. E. S. A. Willis. Mr. 

 W. S. Dun, the Librarian and Assistant Palaeontologist to the 

 Geological Suiwey of N.S. Wales, we also desire to thank for 

 having obligingly supplied us with most of the references quoted 

 in the bibliography. 



EXPLANATION OF PLATES. 



CasU of Radiolaria from Pre-Camhriaii (? ) Bocks, Brighton and Gryxtal 

 Brook, South AuntraUa. 



(All the figures X 200.) 



Plate xxxix. 



Fig.~. 1 and .S.— Internal cast of form perhaps allied to Caiposj^hnra, from 

 black chert, Crystal Brook. 



