263 

 ANNOTATED GUIDE. 



SYDNEY TO GEORGE RIVER STATION. 



(G. A. Young.) 



Miles and 

 kilometres. 



o m. Sydney. — Leaving Sydney station, the Inter- 



o km. colonial railway, before passing out of the city 



crosses the fault line forming the boundary 

 between the area of Carboniferous Limestone 

 series on which the city is built and the 

 wide area of Millstone Grit extending far to the 

 south and east. After leaving the city proper, 

 the railway passes close to the shores of the 

 estuary of Sydney river. Occasional outcrops 

 of Millstone Grit occur along the shore, the 

 strata dipping to the southeast at angles of 

 from 15° to 35°. Strata of the Limestone 

 series, also dipping to the southeast, are exposed 

 on the opposite side. 



Three miles (4-8 km.) from Sydney, the 

 railway crosses Sydney river. The low valley 

 of the river extends with this character for a 

 number of miles to the southwest and is floored 

 with strata of the Carboniferous Limestone 

 series, the measures dipping to the southwest. 

 At the crossing of Sydney river, the band of 

 the Limestone series is less than | mile (o • 8 km.) 

 wide and the railway in a short distance passes 

 into an area occupied by the Carboniferous 

 Conglomerate series. The strata of the Con- 

 glomerate series are arranged in anticlinal 

 form about a ridge of Pre-Cambrian strata 

 which rises several miles southwest of the 

 railway. The reddish conglomerates, sand- 

 stones and shales of the Conglomerate series 

 dip at low angles, away from the central ridge 

 of Pre-Cambrian rocks and are flanked on the 

 east, north and west by apparently conformable 

 strata of the Limestone series. 



Three miles (4-8 km.) beyond the crossing 

 of Sydney river, the railway passes over a low 

 summit situated approximately on the anticlinal 

 axis of the fold in the Carboniferous strata, 



