772 E. HILL AND T. G. BONNE Y ON THE 



(Survey Map, is a very homogeneous rather crystalline rock, without 

 signs of stratification. Further, the jointing and weathering are 

 such that one cannot be surprised at its being mistaken for an igneous 

 rock, though one would have rather expected it to be called a 

 felstone. Microscopic examination, however, shows it to be of 

 clastic origin, containing many imperfect felspar crystals, apparently 

 included fragments, and not of subsequent development. The whole 

 rock, however, has been much metamorphosed; and the difficulty of 

 studying it has been increased by the quantity of epidote that has 

 been subsequently formed *. It forms a narrow ridge about half 

 a mile in length, along which there is a series of isolated outcrops 

 in the midst of a thick plantation. 



No rock can now be seen at the point three quarters of a mile N. 

 of Copt Oak, marked with a dip arrow on the Survey Map. 



The hill of Hammercliff is entirely syenite. 



12. Hitherto the strata described have had a general likeness, and 

 the beds, though here and there faulted, can, as we have seen, be 

 arranged with little difficulty and much probability. In the region 

 on which we now enter the variety of the rocks, the contradictory 

 appearances of bedding, and the confusion resulting from faults are 

 enough to make a geologist despair. We have made many observa- 

 tions and have drawn some inductions from them, but are prepared 

 to have these disputed, and even disproved, by future and more 

 successful surveyors. It is difficult even to select the best way of 

 describing this intricate country. On the whole we think it best to 

 continue the course hitherto adopted of describing successive sections 

 up to the anticlinal axis. Eardon Hill, however, may be deferred 

 with advantage, as without a knowledge of the rest of the country 

 its structure is unintelligible. 



At Green Hill is a mass of ash-beds apparently, but obscurely, 

 dipping S.W. The matrix is a fine green gritty ash crowded with 

 imperfect crystals of felspar and with grains of quartz indicating 

 sometimes an imperfect crystal form, some as large as a pea, or even 

 a bean, projecting from the weathered surface. 



Proceeding N.E. we pass over some distance without exposures, 

 and then come to the bastion-like corner of Timberwood Hill, stand- 

 ing as an outwork to the solid masses of High Towers and Peldar 

 Tor. It consists of a series of ash beds which appear to dip W.S.W. 

 at an angle of 45, and contain rounded fragments of all sizes up to that 

 of a cricket ball. The rock itself consists of fragments of a pinkish 

 felsitic rock in a rather ash} T -looking greenish matrix, in which are 

 numerous grains of quartz. As on BensclifF, these included fragments 

 have a rather ill- defined boundary, and give the rock a mottled 

 aspect. There is a considerable area covered by these beds ; and 

 apparently their thickness is not small. They much remind us of 

 the Benscliff and Chitterman-Hill coarse ash-beds. Moreover the 

 distance of Chittcrman Hill from the Markficld slate breccias is much 

 the same as that of Timberwood Hill from the line of strike of the 



* We find that Frof. Ramsay ('Catalogue of Rock Specimens' &c, p. 20) has 

 recognized this as an altered rock. 



