HOCK TEMPERATURES AT SYDNEY HARBOUR COLLIERY. 



219 



Strata. 



Thickness 



Depth from 

 Surface. 



Bluish-grey micaceous sandy shale 







6 



1,481 



5 



Very hard line grained bluish-grey micace- 











ous sandstone ... 



1 



n 



1,482 



n 



Greenish-grey micaceous sandy shale 



3 







1,485 



n 



Hard fine grained dark bluish-grey micace- 











ous sandy shale 







H 



1,486 



4 



Bluish-grey micaceous sandy shale 







n" 



1,489 



3 



Hard tine grained light grey micaceous 











sandstone 



1 



H 



1,490 



n 



Bluish-grey micaceous sandy shale with 











light streaks ... 



1 



H 



1,492 







Hard fine grained light grey micaceous 











sandstone 



2 



8 



1,494 



8 



Bluish-grey micaceous sandy shale 







*i 



1,495 



0J 



Hard fine grained light grey micaceous 











sandstone 







[1,500] 





It may be mentioned that the Birthday Shaft bears S. 67° 15' W. 

 from the No. 2 Oemorne Bore, and is 260 chains distant. The 

 original rock level at the Birthday Shaft was 73 feet above mean 

 low tide level in Sydney Harbour, but the top of the brick wall- 

 ing in the shaft is now 80 feet above mean low tide, this being 

 the finished level of the pit mouth. The distance from the shaft 

 to the shore of the harbour at the nearest point is 70 yards. 



With regard to features, connected with the geological section, 

 which may have some modifying influence on rock temperature, 

 it may be mentioned that very little gas has, as yet, been met 

 with in the shaft, with the exception of a small blower at the 607 

 feet level. A bed of clay shale, having a thickness of 7 feet, was 

 met with three feet below this level. For some distance above 

 this, and for a considerably greater depth, the sandstone showed 

 a tendency to burst off, in large flakes, from two sides of the shaft 

 as though it were under considerable pressure. This necessitated 

 the walls of the shaft being temporarily secured by close timbering, 

 pending the putting in of the permanent brick walling. 



As regards water circulating in the strata penetrated by the 

 shaft, the following may be recorded : — The amount of water met 



