782 E. HILL AND T. G. BONNEY ON THE 



level ridge, with a pile of stones erected by the Ordnance surveyors 

 at the south-west end, a summer-house at the middle, and a grove 

 of trees at the north-east end. The slopes of the hill are clothed 

 with trees to a considerable distance. We have passed through a 

 large part of the wood and have seen no outcrops beyond those of 

 the ridge itself. This ends with a suddeu descent, almost a cliff, at 

 the north-east end, where the dip is, as usual, uncertain ; but the 

 more probable indications denote that previously seen. £rom here, 

 across the valley, to the nearest outcrop on Green Hill is a space of 

 full three quarters of a mile. 



The rocks on the crest, with their ashy matrix and included frag- 

 ments, recall those of Ratchet Hill and Cadman*. The porphyritic 

 rock with large quartz grains of the lower quarry, closely re- 

 sembles, as we have said, the rock of Peldar Tor ; and though it 

 changes so much in the breadth of the quarry, yet its structure on 

 the south side is somewhat similar to that of the Green-Hill beds, 

 which we consider the continuation of that series, and is the point 

 of it nearest to Bardon. If so, the general structure of the hill is 

 that of a ridge cutting very obliquely across an anticlinal whose 

 axis passes between the mouth of the quarry and Hilltop. The 

 upper beds corresponding with those of High Cadman or Ratchet 

 Hill, and the middle with those of Peldar Tor, the lowest ones would 

 naturally be the equivalents of the highest visible on High Towers. 

 But that is a slate breccia, as is this lowest breccia on Bardon. 

 Lithologically, therefore, there is fair evidence in favour of the iden- 

 tification of the Bardon group with those already described. 



There are, however, one or two difficulties in these identifications. 

 On High Towers an indurated slate overlies the breccia ; and this is 

 not visible in Bardon, while the shaly beds of the latter are not 

 seen on the former. Also we have seen no indication of the " good 

 rock" of the upper quarry on Ratchet Hill, which would be its 

 natural place. We may, however, answer that the base of the 

 Peldar series is nowhere visible, that there is space enough between 

 Green Hill and High Towers for the shaly beds and others also, 

 and that between the quarry and the slate breccia near its entrance 

 there is plenty of space for the indurated slates or their equivalents. 

 It is also quite possible that the above beds may greatly change 

 their character in such a distance as that which separates the two 

 localities. The last remark may be applied to the absence of the 

 "good rock" from Ratchet Hill. Still the beds there, if a little 

 finer in texture, and sufficiently altered, would, we think, resemble 

 it. Further, the passage-bed there leading into the Peldar series is 

 a breccia, containing a purple porphyritic rock, which is apparently 

 identical with that in the breccia occupying the same position on 

 Bardon. 



Microscopic examination confirms the opinion which we have 

 formed on the spot — that there is no true igneous rock in the pit. 

 The good rock of the upper quarry is extremely like a felstone ; but 



* This is noticed also, we find, by Professor Hull, in the Memoirs of the 

 Geological Survey. 



