364 GEOLOGY AND PETKOLOGY OF THK GREAT SERPEXTISE BELT OF N'.S.W., 



APPENDIX. 



Lower Carboxiferous Limesto.ve Fossils prom New South Wales. 



By Frederick Chapmax, A.L.S., Palaeontologist to the Natioual Museum and 

 Lecturer on Palaeontology, Melbourne University. 



(With Plate xxiv., figs. 1-8.) 



A tew months ago Dr. W. X. Benson forwarded for my inspection a rock 

 specimen composed largely of tlie eorallum of a species of Chaetetes, from the 

 parish of Moorowarra, New South Wales. Accompanying: these were some thin 

 slides of other limestones from New South Wales, including three apparently new 

 polyzoa and some interesting oolitic structures. At Dr. Benson's re(|uest I have 

 written the following notes on these minute fossil remains. 



PLANTAE. 

 CYASOPllYCEAE (Blue-green Algae.) 

 Genus G I R V A X E L L A Nicholson and Etlieridge. 



GiRVAXELLA .SP. 



Description. — The granules forming an oolitic limestone from the Lower 

 Carboniferous, represented in the present collection, are circular to ovoid in sec- 

 tion. In many eases the filamentous growth ot' which they are formed enwraps 

 adventitious particles near their periphery, as distinct from the nuclei, and which 

 ai)parently were wasiied against the grains during the process of their formation. 

 This precludes any idea of a mere chemical deposition, as it denotes a tiiread-like 

 thallus, free at the extremity during its winding- growth and ready to tangle on 

 to surrounding fragments. 



The structure of the thallus in these oolitic grains is clearly that of Girvan- 

 ella, although the preservation is such as to present some difficulty in their study 

 under high powers. The thallus consists of a fine tube, whilst here and there in 

 its course are indications of strings of minute globular cells, proliably repro- 

 ductive. 



The nuclei upon which the pellets are moulded consist of shell-fragments, 

 pieces of Polyzoa, ossicles (arm and .stem joints) of Crinoids and Echinoid plates. 

 A four-rayed sponge-spicule is also present. 



Comparisons. — In 1900 ^\v. G. W. Card, A.K.S.l\r., gave an account of 

 "Oolitic Limestones from Lion Creek, Stanwell, near Rockhainpton."* In this 

 paper Mr. Card describes an oolite very sinnlar in character to the i>resent, 

 formed of &irvaneUa tubules enwrapping \arious nuclei, as coral traginents, 

 < rinoid ossicles and other organic particles. The age of this rock is either Car- 

 bopenniaii or Carboniferous. From the occurrence of .'Lithtistrotion and some 

 Cither older-ranging corals, one would judge Iho balance of evidence as supi>ort- 

 ing a CarlionifeiTOus age. 



Mr. Card also recordsf oolitic linicstniu's Irnui New Soutli Wales and 

 Queensland i\s follows : — 



'Queensland Geol. Surv., Bull. 12, 1900, pp.25-32, PI. iii. ~ 



iOp. cU. p..Sl. 



