GEOLOGICAL FAULT AT KUBRAJONG HEIGHTS. 365 



corner of portion 182, Parish of Kurrajong, at the upper 

 junction of the new and old roads, the dip is E. at 8°. At 

 the 11 mile mark, at little over 300 yards on the Kurrajong 

 side of the top of the ridge, the dip is from S.E. to E.S.E. 

 at a low angle, perhaps about 6°. 



The ridge forming the Kurrajong Heights is bounded on 

 the west by a steep slope of from 10° up to 34° (see Plate 17). 

 The Wianamatta Shales are truncated by erosion at the 

 top of the ridge. On descending the slope the observer 

 comes at once on massive Hawkesbury Sandstone which 

 still maintains an easterly dip of about 6°. gradually lessen- 

 ing until within about four chains of the foot of the hill 

 when they become flat. They then dip over to the west 

 at angles which extend up to 10°, and then within a few 

 yards of the fault plane suddenly steepen up to 30°. What 

 I take to be the plane of the fault is marked by a seam of 

 clay flucan, at a point two chains easterly from the peg at 

 the foot of the hill shown on the line of section {Plate 17). 

 The clay flucan is seen in the cutting of the new road now 

 in course of construction. The seam is about six inches 

 wide and is nearly vertical with apparently a slight dip to 

 the west. 



The Wianamatta Shales make their appearance again, on 

 the downthrow side of the fault at a distance of a little 

 over a chain west of the road peg shown on the section 

 {Plate 17). A restoration of the eroded strata on the up- 

 throw side of the fault as shown by the dotted area on 

 Plate 17, shows the amount of throw of the fault as well as 

 the minimum amount of erosion which has taken place 

 since the faulting. The throw is probably at least 423 feet, 

 as calculated from the survey by Mr. Halligan and myself, 

 while the displacement due to bending and 'drag' of the 

 strata on the opposite sides of the fault plane may amount 

 to a maximum of 100 feet. The total displacement due to 



