GEOLOGY OF THE GLOUCESTER DISTRICT, N.S.W. 



249 



formation with any degree of certainty. On the Oopeland 

 road the base was taken at a bed of conglomerate which 

 crosses the road about one mile west of the Barrington 

 Bridge. Notwithstanding this absence of direct evidence 

 there are some facts which suggest the evidence of an 

 unconformity between the two formations. This evidence 

 is as follows: 



1. The very general difference betiveen the strike of the 

 two formations, — The strike of the Devonian strata in the 

 area examined varies from due north to north 60° west, 

 the great majority of the readings, however, are in the 

 neighbourhood of north 40° west. The angle of dip is very 

 high, in many places quite vertical. The Devonian strata 

 therefore, have been strongly folded, the axis of folding 

 being about north 40° west. The Carboniferous strata are 

 also highly folded, also approaching the vertical in places, 

 but are not so steep on the average as the Devonian strata. 

 In the district under consideration they have been folded 

 into a huge syncline whose axis strikes practically north 

 and south; the axis of this syncline is opposed to the 

 Devonian lines of folding. 



2. Nature of the strata of the two formations. — The 

 nature of the Devonian sediments indicates quiet deposition 

 in moderately deep water in a locality far removed from a 

 shore line; there is an entire absence of littoral deposits, 

 and also an absence of a coastal marine fauna. It is true 

 that a terrestrial plant (Lei)idodendron australe) is fairly 

 common, but this plant is represented by relatively large 

 stems only, which might have drifted long distances from 

 land, before sinking and becoming buried in the Devonian 

 sediments. The Burindi strata on the other hand include 

 such littoral sediments as conglomerates and oolitic lime- 

 stones, while some of the mudstones and tuffs contain fossils 

 of a coastal marine fauna. It is true that there is a notable 

 absence of sandstone, although some sandy-shales occur, 



