553 



THE OCCURRENCE OF RADIOLARIA IN PALEOZOIC 

 R0CK8 IN N.S. WALES. 



By Professor T. W. Ed(;eworth David, B.A., F.G.S. 



(Plates xxxvii.-xxxviii.) 



CONTENT.S. 



1. Bibliographj-. 



2. Localities and (reologieal horizons of ladiolaiian rocks in N.S.W. 



3. Macroscopic and microscopic description of the radiolarian rocks. 



4. Sumn)ary. 



5. Deductions. 



1. Bibliography. 



The finst reference known to me as to the occurrence of radio- 

 larian rocks in Austraha is in a paper by Dr. G. J. Hinde, 

 F.R.S.* 



This rock was obtained by Capt. Moore, of H.M.S. " Penguin," 

 about 1891, from Fanny Bay, Port Darwin. "The rock in question 

 is of a dull white or yellowish white tint, in places stained reddish 

 with ferruginous material; it has an earthy asp'ect like that of 

 our Lower White Chalk, but it is somewhat harder than chalk, 

 though it can be scratched with the thumb-nail. There are no 

 signs of stratification, and it appears as a fine-grained homo- 

 geneous material." Under the microscope the groundmass is 

 seen to be made up of minute granules and mineral fragments, 

 isotropic for the most part, being probably amorphous silica. 

 The minute grains, however, and angular particles polarize : 

 some appear to Ije quartz, others rutile. The organic structure 



^ Q.J.G.S. Vol. x!iv. Xo. 194. May 1st, 1893. Dr. G. J. Hinde. Note 

 on a Radiolarian Rock from Fainiy Ray, Port Darwin, Australia. 



