622 J. T. JiUson: 



distribution will be dealt with when treating of the geological 

 structure. Almost all the coarser-grained rocks are fossiliferous 



(c) Geological Structure. 



Folds. — The principal structural features are the anticlines 

 and synclines, into which the whole of the silurian rocks of the 

 district have been thrown. There are great folds which embrace 

 a wide area, and which can be traced along the strike of the 

 rocks considerable distances. Sometimes they give place to 

 smaller but more numerous folds. The main anticlinal lines at 

 times bear on their crests smaller folds, which in some instances 

 are not very much compressed, the legs being at moderate 

 angles ; in other cases the pressure has been so great that 

 the legs are almost vertical, but no example of inversion has 

 been observed. The minor folds seem to soon run out along 

 the strike of the rocks. Where there is a main anticlinal fold, 

 with numerous smaller ones on its crest, fracture of the rocks, 

 as would be expected, has taken place, and so channels have 

 been opened for the deposition of quartz, gold and other 

 minerals. The generally short courses of the subsidiary folds 

 probably account for the restriction of quartz reefs in a 

 meridional direction. The general strike of the rocks would 

 average about 15 deg. east of north. 



Treating the folds in more detail, a traverse from Temple- 

 stowe through Warrandyte to the north of Croydon shows that 

 at Templestowe an anticline, which, in its principal or sub- 

 sidiary folds, has been traced south to the Koonung Ivoonung 

 Creek, and north to the northern boundary of the parish of 

 Nillumbik (crossing the Diamond Creek to the south of the 

 township of that name), a distance of nine miles. At Temple- 

 stowe two sharp minor anticlines occur, which may be regarded 

 as folds in the nuiin axis. The reef containing gold and anti- 

 mony, that has been worked at Templestowe with unfortunately, 

 (in recent times at least), non-payable results, probably occurs 

 on one of the minor anticlinal folds. The western limb of the 

 anticline is much contorted in places, as may be seen on the 

 main road between the Plenty River and Eltham, and on the 

 Eltham railway line. The anticline here described may con- 

 veniently be i-ef erred to as the Templestowe Anticline. 



