138 



RED AND PORPHYRITIC FELSPATHIC TRAP. 



clod and coal smut, and a thin bed of coal, being all in nearly vertical positions. In 

 following this trap dyke from the Shatterford Gate to Coldridge Wood, we perceive 

 irregular alternations of coal smut, shale, and grit, with protuberances of greenstone, 

 some of which are largely quarried. An opening made in 1833, displayed the injection 

 of the trap into the strata. At the lower end of the quarry were fragments of coal and 

 greenstone confusedly mixed ; then followed in overlying succession, yellow clay and 

 clod, terminated by a thin zone of coal smut ; next a broad mass of trap, having a ten- 

 dency to prismatic structure, the prisms being chiefly pentagonal. On the other side of 

 this trap was a bed composed of irregular patches of coal, confusedly mingled with 

 layers of clod, grit, and yellow shale, folding over the irregular surface of the trap. 

 This narrow and broken band was again overlaid by basaltic greenstone, of a rude 

 prismatic form, and of concretionary structure ; and this mass threw off finally poor 

 coal seams, dipping 80° to the north-west. Future geologists examining this spot, 

 when the trap or hard road-stone has been extracted, may find the appearances very 

 different from those described ; for new phenomena are daily laid open in the quarries, 

 the pickaxe destroying today what it revealed yesterday. 



Red and Porphyritic Felspathic Trap. {Church Hill, Stagbury Hill, Warshill.) 

 By reference to the Map it will be seen that three other spots in this tract are occu- 

 pied by trap rocks. The largest of these lies at Church Hill, three miles south-east of 

 Cleobury, where the trap rising to a height of nearly 1000 feet is flanked on three sides 

 by poor coal seams, and on a fourth by Old Red Sandstone. The next in magnitude 

 is Stagbury Hill, situated on the right bank of the Severn below Bewdley, at the south- 

 eastern termination of the coal tract, and marking a point where the New and Old Red 

 Sandstones are in juxtaposition. The third is at Warshill, on the left bank of the 

 Severn, above Bewdley, where a small tongue of poor carboniferous strata stretches 

 eastward, between the New and Old Red Sandstones, which beyond it are again con- 

 terminous, as at Stagbury. These hills are all of conical forms, and the trap of which 

 they consist is of a peculiar nature, and very unlike any rock previously described. 

 This rock, in fact, is similar in composition to the trap of the Abberley Hills, which 

 bound this coal-field on the south, and to that of the Clent Hills, which skirt the 

 southern end of the Dudley field, consisting of compact felspar of dingy red and purple 

 colours, and having often a quartzose aspect, somewhat resembling the corneen of French 

 mineralogists. 



From this state of compact felspar, this rock passes into other varieties, sometimes 

 porphyritic, but more frequently of a very fine concretionary structure. Like the trap 

 hills of Abberley and Clent, these detached masses present a surface composed of only 

 shivered angular fragments, occasionally two feet square; and though excavations have 

 been made to the depth of thirty and forty feet, no solid body of the rock has ever been 

 attained. We can, however, have no hesitation in referring these hills to a trappean 



