ORGANIC REMAINS IN VOLCANIC GRITS. 



271 



able, dipping to the west-north-west at angles of 40° and 45°. The junction with the amorphous 

 and massive trap of the Llanfawr and Corndon is obscured in the slope of the hills. 



If another transverse section be made across the ridges and furrows of the hilly tract to the south- 

 east of Leigh Hall, we perceive other alternations of trap and shale. We here, however, find the 

 stratified masses thrown over in great undulations both to the west-north-west and east-south-east. 

 (PI. 32. f. 2.) The first of these, lying to the east of Leigh Hall, is a very remarkable rock. It is a 

 hard grey, regularly bedded, compact felspar, in parts porphyritic, containing fragments of indurated 

 schist, and passes into a rock undistinguishable from some of the concretionary traps. Calcareous 

 matter enters largely into its composition, frequently appearing in small crystals. It contains also a 

 small Euomphalus of undescribed species and other shells. (See Euomphalus Corndensis, PI. 18. f. 16.) 



Notwithstanding the regular bedding of this rock, in layers varying from eight inches 

 to two feet thick, and the occurrence of organic remains, I am convinced that like the strata 

 at Middleton and Marrington Dingle, it is of volcanic origin and formed of matter thrown 

 down from submarine outbursts, mixed with the usual exuvise and sediments of the ocean. 

 (See section, below the large map, indicatingthe method by which such rocks were formed.) 



In the Notmoor and Lordstone Hills, on the anticlinal line of the Corndon, beds of the same 

 nature as at Leigh Hall, dip in a reversed direction. (PI. 32. f. 2.) On the summit of this 

 ridge are lines of regularly bedded concretionary trap, the upper and lower faces of the strata 

 being quite conformable to ordinary bedded masses of the shale and flagstone with which 

 they alternate. In hand specimens much of this trap might, without the aid of the lens, be 

 mistaken for a common grit, but it really consists of concretions of compact felspar, and contains 

 crystals of common felspar, hornblende, and iron pyrites, with a little disseminated lime. The 

 beds dip 25° to the east-south-east, and are from two to three feet thick, splitting into flags. At 

 Bromlow Callows, in the prolongation of these stratified masses to the south-south-west, there 

 are many other varieties, (see PI. 32. f. 2.) They consist of compact felspar with concretions of 

 felspar, some very minute, others as large as gourds, together with grey granular felspar, and finely 

 laminated volcanic sandstone. These and other trap rocks, in beds from two to ten feet thick, 

 alternate many times with shale. In parts the trap is somewhat of a breccia, enveloping fragments 

 of schist, in others it is coiled round lumps of schist in concentric folds thus, 



the laminae of the schist following the form of the nucleus; 41. 

 but in this as in all other examples the bedding is distinctly 

 preserved, the dip being 45° to the east. a. Schist and flag- 

 stone, b. Volcanic grit, enveloping fragments of schist (c). 

 In a second quarry at Bromlow Callows, some beds of the 

 volcanic breccia pass into grit, others are complete green- 

 stone slates; in a third are cream-coloured claystones, with 

 concretions of compact felspar alternating with micaceous 

 sandstone. The harder sandstone and schist are generally 

 much fractured by vertical joints ranging north to south. 

 The section being prolonged from Bromlow Callows to 

 the east-south-east, (PL 32. f. 2.) passes over another low 

 parallel ridge, called Oakage, the strata of which are re- 

 versed, dipping 40° to the west-north -west. In this ridge 

 is much porcellanite. 



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