42 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



placement is generally about the centre, and it dies out into 

 nothing at the ends ; or if the fault cuts across folded country, 

 there may be neutral points along its strike where there is no 

 displacement. (See Fig. 23). 



Where a seam is tilted up at an angle, and a fault cuts 

 across its strike the broken portions of the seam on the same 

 horizon may appear to have a lateral displacement. The seam 

 may really have been heaved to one side, or the difference in 

 position may be due to a throw. The effect of variations in 

 the dip and direction of a seam that is thrown, on the lateral 

 position of the displaced parts when worn down to the same 

 level, may be seen by referring to Figs. 24, 25, and 26. The 

 probability is that pure throws and pure heaves seldom occur, 

 but that most faults are a combination of the two, in which 

 the effect of one may te more pronounced than the other. 



