330 



FAULTS 



coals as shown in the area No. 4. Such a slip occasionally brings into play scams 

 seated under those marked a, b, c, as seen at 4, 5, 6 ; and it may happen that tho coal 

 marked 4 lies in the prolongation of a well-known seam, as c, in tho compartment 

 No. 3, when the case becomes puzzling to tho minor. In addition to tho above varieties, 

 ft number of slips or hitches are often seen near one another, as in tho area niarkod 



No. 5, whore tho individual displace- 

 ments are inconsiderable, but tho 

 aggregate dislocation may bo great, 

 in reference to the seams of the 6th 

 compartment. 



The results of dykes and slips on a 

 horizontal portion of a field arc ex- 

 emplified in fig. 851 . Whore tho coal- 

 measures are horizontal, and tho faults 

 run at a greater angle than 45 to 

 the line of bearing, they are termed 

 * dip ' and ' rise ' faults, as A B, c D, E F. 

 Tho following fig. 852, which is an 

 accurate section of the Mostyn coal-field, Flintshire, will show the amount to which 

 those disturbances are experienced. The letters mark with sufficient distinctness the 

 beds on either side of the faults. 



852 



a. Worked out. 



b. Ditto. 



c. 6 yd. coal worked out. 



d. 8 yd. ditto. 



e. Inferior coal. 



/. Ditto. 



(/. Yard coal worked out. 



h. 4 ft. coal (tolerable). 



i. Main ooal, 6 ft. (very good). 

 '. 5 ft. coal. 

 *. Stone coal. 

 /. 8 ft. ooal. 



Fig. 853 gives a true section of a portion of tho North Staffordshire Coal-field, 

 Knowing tho dislocations which have been produced, and tho mechanical force < 

 by the movements which have taken place, 



