VII. — Note on the Sydney Coal Field. — ^By E. Gilpin, 

 Ll. D., F G. S., Insjiecior of Mivcs. 



(Received Xov. i^vd, 1S94- ) 



In this note it is proposed to draw attention to the presence in 

 the Sj^dney coal field of a subordinate basin. The existence of 

 the basin was indicated by the officers of the Geological Survey in 

 their reports, but its extent has been more clearly defined by 

 recent explorations. The survey of Mr. Fletcher showed that a 

 line of fault runs from Sydney to the Mira Rivei*, near the 

 mouth of Black Brook. More recent examinations have shown 

 that this fault diminishes in extent as it is followed to the south. 

 At the town of Sydney it brings up measures referred to the 

 carboniferous limestone, and the section as exposed is probably 

 directly connected with the rocks of the same horizon on the 

 west side of the Sydney River. At this point the denudation 

 of the uplifted measures has exposed these strata. As the dis- 

 tance from the point of maximum upheaval increased the lime- 

 stone series was covered l)y a gradually increasing thickness of 

 millstone grit until in the ti-ough lying against the line of fault 

 measures appear belonging probably to the top of the millstone 

 grit or the lower part of the productive measures. 



When the line of the fault reaches the MacPherson road it 

 appears to have become much reduced in extent. Beyond this 

 its passage is shown on the Morrison road by springs and rough 

 ground. It may be inferred that its line here lies a little to the 

 eastward of that marked in the geological survey plan. It is not 

 known if it is a dislocation in this vicinity or only an anticlinal. 



The Cossitt basin lies to the south-west of this fault. Along 

 the eastern side of the line of fault the measures, wherever noted, 

 have a low and regular dip to the north-east, and agree with 

 those observed in the Glace Bay district. On the west side of 

 the fault the dips are to the south-west at heavy angles, and on 

 approaching within a mile of the town of Sydney the line 

 >^of steep dip turns in a semicircle round to the west, limiting the 



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