35 



It will thus be seen that the Lower series of Coals, or those 

 occurring beneath the Pennant, can only be, and are only 

 worked along and aroimd the basia at their outcrops, as in the 

 following wood-cut, (Fig. 2,) the dotted oval indicatiag the 



Tortworth Court 



Line of Fracture 



Fig. 2.— Section showing the Pennant Zone ; places of rich Iron x ; position of Pits, &c., • ; to show 

 their relation to the Pennant, which in the Transverse Section shows its place, &c. 



Fig. 3.— Section across the Basin at a, showing Pennant diTiding Upper and Lower Coal Measures. 



intermediate position of the Pennant. The upper series of coals, 

 on the contrary, are worked within the zone and down to the 

 Pennant, though never through it, as no shaft has ever penetrated 

 through the Upper Coal Measures and Pennant down to the Lower 

 Coals in one continuous sinking, this Pennant Sandstone forming 

 an effectual barrier, both physically and economically, to such an 

 undertaking, (see Pigs. 3 and 4) this widely-spread surface rock 

 D 



