352 GREAT SERPKNTINE BELT OF NEW SOUTH WALES, vii., 



Summary op Devonian Sthatigraphical Succession. 



Before attempting to draw up an amended columnar section 



(Text-fig. 1 ; see also 6, p. 549), we must point out the uncertainty 



of some of the data upon which it is based. Owing to the rarity 



of exposures showing the angle of dip, reliance must be based 



TufF Qnd 

 MudsJ'one 



wil'h Radiolar'ia 



OcruD Mounlri 

 Conclome''ahe t 



"inl'o C\uv)b^o•^e 



Loornberoli 

 Uini«rsl"one 



Cfierr^ Radio- i 



larian flay^rooe ) 

 Dolenfe ■ 



I anon C/ayslron 



KeratoV>h:<re — > 



Cher/y Radio 

 I a nan Clays Tone 



Text-fig. 1. 

 Generalised cokunnar section of the Devonian rocks of the Loomberah 



District. 



upon the correlation of certain leading zones with other zones, 

 the horizons of which have been determined in the Tamworth 

 District. This correlation is often lithologieal only, and the 

 zones compared are sometimes pyroclastic accumulations, which 

 may vary greatly when traced in a lateral direction, or may 



