NOTE on the OCCURRENCE of EUBYDESMA in the 



UPPER MARINE (PERMO-CARBONIFEROUS) 



of NEW SOUTH WALES. 



By W. G. WOOLNOUGH, D.Sc, F.G.S., 



Assistant Lecturer in Mineralogy and Petrology and 

 Demonstrator in Geology, University of Sydney. 



[With Plate XXXV.] 



[Read before the Royal Society of N. S. Wales, November 2, 1910.] 



Until quite recently Eunjdesma was looked upon by the 

 geologists of New South Wales as characteristic of the 

 Lower Marine Beds ; but in 1905 Siissmilch 1 discovered it 

 in rocks near Belford whose age is considered to be Upper 

 Marine. An interesting section was examined recently 

 by the author in Wattle Ponds Creek (a tributary of the 

 Hunter River) above the point where it crosses the Dyrring 

 Road, three and a half miles in a straight Hue north-east 

 of Singleton. 



An exposure of the Bolwarra Conglomerate is met with 

 in portion 34, Parish of Darlington, giving rise to the bare 

 stony outcrop so characteristic of this rock. The clip is N. 

 6CV W. at 10°. Following the creek for a distance of about 

 1,500 yards, we pass over sandy mudstones with abundant 

 glacial erratics, many of them decidedly facetted, and an 

 occasional one obscurely striated. The dip of this forma- 

 tion (Branxton Beds) is not quite constant, but varies from 

 the value given above for the Bolwarra Conglomerate to 

 N. 50° W. at 8°. This indicates a thickness of some 094 feet 

 for this part of the glacial beds. 



Next comes a zone containing very large erratics ; one, 

 of Silurian limestone (see below), has a length of nearly 



1 Proc. Linn. Soc. X. S. Wales, 1900, xxsi, pt i, p. 175. 



