346 EEV. E. HILL AND PROF. T. G. BONNET ON THE 



some resemblance to members of the above series. "We had feared 

 that its decomposed condition would unfit it for microscopic ex- 

 amination ; but Mr. Cuttell has succeeded in preparing us a good slide 

 from a specimen rather of the Sharpley type. Except for the entire 

 or almost entire absence of quartz, and the larger amount of viridite 

 and ferrite present, it is remarkably like that rock. The ground-mass 

 is similar ; the included felspar crystals, often sharp-edged as though 

 broken, are in all respects identical. Part of the green mineral is 

 rather fibrous, dichroic, and probably a chlorite. The ferrite has 

 infiltrated into cracks. This rock, then, is probably about on the 

 horizon of the Sharpley series. 



(4) Bardon Hill, 



The quarry here has been much enlarged since the date of Part II. 

 A considerable mass of the purple schistose rock in the upper quarry 

 has now been excavated. As already stated, it much resembles that 

 on High Sharpley, except that it has fewer quartz grains. It appears 

 to pass up irregular^ into a greenish rock; and at one place there 

 seemed to be a parting of this between two bands of the purplish 

 rock. Its thickness also seemed variable. The dip was not very 

 clearly marked, but appeared to be about 48° JST.W., the strike of 

 the cleavage being W. 10° S. This rock seems to end abruptly ; as the 

 foreman said," it dies out at a slither." The approximate N.E. to S.W. 

 strike differs much from that of the "shaly band" in the lower pit, which 

 is "W.N.W. to E.S.E. It is, then, very probable that a fault runs near 

 the northern flank of the pit. On reexamination of the " shaly band" 

 we were struck with a resemblance between the less decomposed 

 portions of it, the ashy bands of High Sharpley, and parts of the 

 purplish rock in the upper pit. Microscopic examination has not, 

 however, strengthened the evidence for this resemblance ; for our 

 slide of the first appears to consist of broken felspar crystals, often 

 much decomposed, a few grains of quartz, and a large quantity of 

 viridite so arranged as to give a rather schistose aspect to the rock, 

 no part preserving the peculiar cryptocrystalline structure noted in 

 the others. Still, in our slide from the purplish rock in the upper pit, 

 there is a small lenticular band consisting wholly of broken felspars 

 (with epidote) ; so that the identity is yet possible. If this were the 

 case, and the shaly band an attenuated representative of the Sharpley 

 rock, then that already described * as so curiously like the Peldar- 

 Tor rock would be in its right place, and the typical compact green 

 rock t of the pit would belong to some part of the Peldar- Ratchet 



* Quart. Journ. Geol. Soc. vol. xxxiii. p. 781 ; vol xxxiv. p. 205. 



t As this rock, perhaps more than any other of its kind in the Forest, re- 

 sembles a true felsite, we have had additional slides prepared. We retain, how- 

 ever, our former opinion that it is not an igneous rock. We need only refer to 

 our descriptions given at p. 206, vol. xxxiv., and repeat that our study of all 

 these peculiar rocks in the northern district confirms us in the opinion that they 

 are not only clastic, but also have been tuffs, and that the amount of alteration 

 which they have undergone is not sufficient to account for their porphyritic 

 character. 



