480 /. T. JiUson: 



Detinite conclusions on these points must await further exam- 

 ination. 



A careful examination of the country along the western 

 edge of the Dandenong Ranges has not been made ; so that the 

 nature of the junction here between the Croydon Senkungsfeld 

 and the mountains has not been determined by personal obser- 

 vation. 



I have however come to the conclusion that it is extremely 

 probable that such junction is a fault, and that from the fol- 

 lowing considerations : — 



If the eastern boundary of the Croydon Senkungsfeld along 

 the western edge of the Dandenong Ranges be continued in the 

 same (south-westerly) direction, it will be found to pass along 

 the western edge of the granodiorite at Dandenong, along the 

 eastern side of the Carrum Swamp, and along the eastern side 

 of Port Phillij) Bay to the Nepean Peninsula. This line it 

 will be noticed, is on the western edges of the granodiorite of 

 Mts. Eliza and Martha and Arthur's Seat, which are so sharply 

 defined along the coast. 



Selwyn in 1857 (9, p. 33) stated that a fault extended in a 

 direct line from Frankston to Arthur's Seat, parallel to the 

 coast. This line is included in the line above noted, stretching 

 from the Dandenong Ranges to the Nepean Peninsula. 



As already stated, the Brushy Creek Fault appears to pass 

 southward into a gentle tilting or folding, which enables the 

 western boundary of the Croydon Senkungsfeld to be traced 

 (in continuation of the Brushy Creek Fault) towards about 

 Spring'\'ale. If fi'om the latter place the line be continued in 

 the same direction, it will be found to pass through Mordialloc, 

 which is at the western end of the Carrum Swamp. 



There is no reason to doubt that Selwyn's fault line is 

 ;i true fault. It bounds, as Mr. Hart has pointed out (10, p. 

 257), the granitic areas of the district ; its continuation to the 

 north-east bounds the depression of the Carrum Swamp, and 

 also the igneous rocks of the Dandenong Ranges. West of the 

 latter a Senkungsfeld exists. There seems little doubt there- 

 fore that a strongly marked and remarkably straight fault 

 exists from the northern end of the Dandenongs to Dromana, a 

 distance of nearly 50 miles. This fault may appropriately be 



