564 RADIOLAIUA IX HAL.KOZOIC ROCKS, 



radiolariaii rock is almost certainly continuous from Bingera to 

 Tamworth. 



(4) Jenolan Caves. — This locality is aljout 200 miles south Ijy 

 west from Tamworth. The rocks developed in this neighbour- 

 hood are the Cave Limestone, thin grey argillites and dark grey 

 and reddish-purple shales and black cherts with numerous d3'kes 

 and sills of quartz-felsite, and basic dykes rendered porphyritic by 

 augite. The Cave Limestone is a somewhat massive rock from 

 380 to 420 feet in thickness. Stratification is well marked at its 

 upper surface. It dips W. 10' S. at 60° as shown b}'^ me this 

 year in my Addi-ess to the Royal Society of X.S. Wales, Plate ii. 



The following fossils have been recorded as occurring in it by 

 Mr. R. Etheridge, junr.* :— Fenfamerns Knightii, J. Sowerby; 

 Palceoniso Brazieri., Eth. fil.; Loxovema antiqua, De Kon., and a 

 large Favosites. 



Mr. Etheridge considers that the occurrence of the large 

 varieties of Pentamerus Knightii in this Cave Limestone renders 

 it not improbable that it approximates in age to the Aymestry 

 Limestone of England. At the same time he comments on the 

 fact that Pentamerus Knightii has not yet been discovered in the 

 Yass beds of N. S. Wales, the horizon of which is almost certainly 

 Upper Silurian, and Mucophyllum crateroides, a very characteristic 

 and abundant coral in the Yass beds has not yet been observed 

 in the Jenolan Cave Limestone. Stromatojwra, on the other 

 hand, is very abundant, as it is in the Tamworth Limestone. On 

 the whole, I am of opinion that the Jenolan Cave Limestones and 

 their associated radiolarian beds are somew hat newer than the 

 Yass beds, so that if the Yass beds are Upper Silurian, the 

 Jenolan Cave Limestones may be of Lower or Middle Devonian 

 Age. Immediately overlying the limestone are fine-grained dark 

 clay shales and argillites and Ijlack cherts. Mr. Yoss Wiburd, 

 the guide to the caves, informs me that these must be at least 



* Records (leol. Suiv. N.S. Wales. Vol. iii. Part ii. 1S92, p. 57, and 

 Annual Report Dep. Mines, N.S. \Yales, 189.3^ p. 128. By authority. 

 Sydney, 1894. 



