550 A STRIKING EXAMPLE OP RIVER-CAPTURE, 



cuttings on the railway line, which, between Marulan and 

 Goulburn, skirts the northern side of the Wollondilly Valley, 

 this high-level gravel can be seen covered by sandy wash, of 

 recent date, brought down from the neighbouring hills. This 

 wash completely obscures all surface indications of the under- 

 lying gravels. 



In the case of the captured river, the coarsest gravels are met 

 with on the bank of Digger's Creek. For nearly two miles along 

 the course of the old valley large boulders appear at intervals^ 

 mostly, however, redistributed in the modern stream beds. 

 Some of these are shown in the photograph (Plate xliii., fig.2). 

 The creek in which these occur heads not more than half-a-mile 

 from the place figured, and in this distance has scarcely any 

 appreciable fall. No solid rocks of any kind exist in its upper 

 valley competent to form such boulders. Another patch of 

 coarse boulders is met with just south of the railway line. In 

 the neighbourhood of Glenrock the character of the gravels is 

 distinctly different, being finer and more quartzose; but answers 

 exactly to that of the high-level gravels of .the present Wollon- 

 dilly. There can be little doubt that these represent the high- 

 level gravels of the former river. Gravels of this type are met 

 with at the Woolshed Flat, just north of the railway line, and 

 extend about a quarter of a mile north of the line, nearly to the 

 road. In the small railway cutting just west of the Barber's 

 Creek viaduct, these upper gravels are seen resting directly upon 

 decomposed granite. 



From the Woolshed Flat to the gap between Shepherd and 

 Marulan Trigs., no pebbles are met with; the country consists of 

 a sensibly level stretch of fine sandy alluvial, representing, in our 

 opinion, the recent wash from the hills, overlying the old river 

 gravels. On the north-western side of the ridge, that is in the 

 watershed of Joaramin Creek, the surface appears to consist 

 entirely of this sandy wash. 



Another very interesting comparison is afforded by the redistri- 

 bution of the " Argyle Apple " (Eucalyptus pulverulenta Sims). 

 This very local eucalypt is characterized by the light blue colour 



