CARBONIFEROUS AND PERMO-CARBONIFEROUS ROCKS, N.S.W. 255 



extend northwards from there along the valley of the Allyn 

 River to beyond Eccleston; further good sections occur 

 along the road from Wallarobba to Clarence Town, and 

 from the latter township to Glen William. That part of 

 the Burindi Series exposed in this district will be referred 

 to as the Hilldale-Dungog Beds. 



The lower part of the Hilldale-Dungog Beds consists 

 mainly of interstratified mudstone and tuff with some few 

 beds of limestone and occasional beds of conglomerate: 

 towards the top of the series the tuffs increase in relative 

 proportion and several lava flows also occur. 



The Hilldale Mudstones. — These are thiu bedded strata 

 of greenish-grey colour and quite similar to the Burindi 

 Mudstones described by Prof. W. N. Benson 1 from the 

 Tamworth-Barraba District. Thin beds of tuff are usually 

 interstratified with these mudstones. Marine fossils are 

 fairly plentiful in some of the beds and are listed further on. 

 Fragments of drift wood and small stems of plants also 

 occur in these beds, it being not uncommon to find speci- 

 mens of Lepidodendron and other fossil plants on the same 

 slab of shale as marine fossils. 



The Dungog Limestones, — These appear to be limited to 

 the lower part of the Dungog Beds; they are usually built 

 up of crinoid stems, but oolitic limestones also occur. The 

 individual beds range up to twenty feet or even more in 

 thickness, but do not maintain such thicknesses for any 

 distance, rapidly thinning when followed in the direction 

 of the strike and frequently pinching out entirely, so that 

 they can rarely be traced along the surface for any great 

 distance. These limestones have been described in some 



detail by J. B. Jaquet and by J. E. Oarne, 2 particularly 



• — 



1 Geology of the Great Serpentine Belt. 



2 The Limestone Deposits of N.S. Wales, by J. E. Carne, f.g.p., and 

 L. J. Jones, a.s.t.c, Mineral Eesources No. 25, Department of Mines, 

 New South Wales, 1919. 



