Geology of Wamindf/fe Goldfield. 539 



Whether the dyke occupies a p-reat fault, or merely a frac- 

 ture, or a fault with little displacement, is an important ques- 

 tion to decide. There is little evidence of a great fault. 



In i>laces the western wall appears somewhat smooth, but no 

 striations or slickensides have been noticed. The rocks on 

 opposite sides are slightly different lithologically, but a little 

 sli]) could produce this. The dip of the strata on the western 

 wall is not easily determined, but it appears to be the same as 

 thi-t on the eastern wall — i.e., to the east. The dyke meets 

 the Main South Anticline near its northern termination, and 

 this is rather peculiar, but on the other hand, if the dyke 

 proceeds north-westerly to Kangaroo Ground, as shown by Mr. 

 Whitelaw, it does not disturb the Main North Anticline, and 

 the syncline to the east. 



This fact and the structure generally support the contention 

 as to the non-importance of the dyke structurally. The minor 

 folds certainly tend towards a common point, and do not run 

 parallel to one another towards the dyke. The strike of the 

 eastern limb of the Warrandyte Anticline swings round from 

 north-east to north-west, just as would be expected if the pres- 

 sure on the eastern limb were very great at one point, and it 

 was not nmch relieved by crumpling. In the least disturbed 

 part of the eastern limb — i.e., south of Warrandyte — the dips 

 regularly continue from west to east across the line of dyke. No 

 appearance of faulting is here. As already remarked when dis- 

 cussing the quartz reefs, there seems to be a direct connection 

 between the lengths of the minor folds and the reef occur- 

 rences. 



On the whole therefore I think that the dyke in either of 

 the two possibilities above suggested has had no influence in 

 the general geological structure of the country, and hence none 

 on the reefs so far as their distribution is concerned. The 

 minor folds, with fractui'es as the result of great pressure, 

 offer a solution of the distribution of the reefs. In no other 

 parts of the area have well defined and numerous reefs been 

 found, and it is only at Warrandyte that such intense contor- 

 tion has taken place. It is interesting to note that where some 

 anticlinal folds are pressed closely together, as at Ringwood and 

 Templestowe, isolated reefs occur. 



