GEOLOGICAL FAULT AT KUERAJONG HEIGHTS. 367 



tively 400 feet and 350 feet. The fault and slight westerly 

 fold at the Out Rock displaces the strata by 523 feet 

 measured vertically from the horizontal, and about 530 

 feet below the original position of the strata due to easterly 

 dip, whereas the displacements for the westerly fold at 

 Glenbrook are about 100 feet from the horizontal, and 

 about 175 feet from the calculated original plane of the 

 strata before the folding. Thus whereas at both the Glen- 

 brook and Kurrajong areas the easterly displacements are 

 just double the westerly displacements, the total aggregate 

 displacement at the Kurrajong is a little over double the 

 aggregate displacement in the Glenbrook area. 



Mr. Card and I traced the subsidence area in a westerly 

 direction from the foot of the Out Rock for four miles, and 

 on December 13th Mr. Pittman and I followed it past 

 Norwood (Bilpin) and old Tomab to the foot of Mount 

 Tomah, where the subsidence area terminates in a mono- 

 clinal fold which effects a depression of the strata in an 

 easterly direction of about 250 feet. The Wianamatta 

 Shales are almost continuous from the foot of the Cut Rock 

 to the foot of Mount Tomah. At the latter locality they 

 have been eroded away at the base of the monocline, but 

 reappear at a higher level as shown on Plate 16. They 

 attain a thickness at Mount Tomah of from 100 to 150 feet, 

 and p^re capped by a sheet of basalt having a maximum 

 thickness of about 170 feet (see Plate 16). The total width 

 of the subsidence area from west to east, between Mount 

 Tomah and Kurrajong Heights measures about 11 miles. 

 Its northern limit has yet to be discovered, but in the 

 present state of our knowledge it may be safely stated that 

 it has a length in a north and south direction of between 

 20 and 30 miles. 



Obviously the existence of this fault at the Kurrajong 

 will have an important bearing on the laying out of coal 



