760 C. CALLAWAY ON THE QUARTZITES OF SHROPSHIRE. 



I cannot believe that the conformity is real. The following section 

 (fig. 4) will illustrate the succession which I have just described. 



Yig. 4. — Section across Little Caradoc and valley to the South-east. 

 km. S - E - 





BWggg 



j i 

 Faults. Faults. 



Length of section about half a mile. 



a. Syenite of Little Caradoc. b. Quartzite. e. Hollybush sandstone. 



d. Tremadoc (Shineton shales). e. Caradoc. 



c. Cardington subarea. — A little over a mile from Caer Caradoc 

 to the south-east is an abrupt ridge of quartzite called the Sharp 

 Stones, dipping to the north at from 40° to 50°, and striking east 

 and west for about half a mile. It rests upon the bedded volcanic 

 rocks of Cardington Hill, and is evidently tilted up by the elevation 

 of that mass. Succeeding it to the north is Caradoc Sandstone, 

 with its usual south-west strike, apparently unaffected by the 

 upthrust of the older rocks, and probably separated from the 

 quartzite by a fault. 



2. Relations of the Quartzite to the associated Rocks. 



Along the south-eastern flanks of the Wrekin range, the quartz- 

 rock rests upon the bedded tuffs and felstones of the volcanic 

 nucleus unconformably, the igneous rocks dipping north, while the 

 quartzite dips south-east. Towards its base the quartz-rock contains 

 fragments derived from the older series, consisting of small rounded 

 or unrounded pieces of felstone greatly decomposed, but in some 

 cases showing distinctly the banded structure characteristic of some 

 of the Wrekin felstones. At its base the quartzite is brecciated, 

 both the fragments and their cement being quartzose, with the 

 occasional occurrence of barium sulphate. This breccia can be 

 traced along the line of junction through the Ercal, Lawrence Hill, 

 and some distance along the south-eastern flank of the "Wrekin. 

 There are also signs of brecciation on the opposite side of the range, 

 near the ravine between the Ercal and Lawrence Hill. This 

 breccia may be a friction breccia, caused by the upthrust of the 

 rigid mass of volcanic rock which forms the backbone of the range; 

 and the fact that the breccia is not derived from the rock upon 

 which it rests favours this conclusion. There is thus reason to 

 conclude that the plane of junction between the younger and older 

 series is a fault. I have not observed the breccia in other parts of 

 the Wrekin (Church-Stretton) area, except at the quarry east of 



