96 REV. EDWIX HILL AND PROF. T. G. BONNET ON THE 



We have also paid some attention to the pebbles in the con- 

 glomerates which occur elsewhere in the Forest. Felstones and 

 slates are commonest, but true quartzites are found at Forest Gate 

 and Hanging Stones (Woodhouse). 



Under the microscope the felstones at the latter place bear a 

 general resemblance to the " purple porphyritic " fragments of the 

 North-west region. The groundmass of one exhibits, in parts, an 

 imperfectly-developed spherulitic structure. A small fairly-rounded 

 pebble of compact quartzite from this locality consists of grains of 

 quartz, commonly more or less subangular, set in a finely granular 

 matrix. For the general aspect of the rock, see Fifth Annual 

 Report of U.S. Geol. Survey, pi. xxxi. fig. 4, lower half. But in 

 the Charnwood pebble the matrix consists of a pale filmy micaceous 

 mineral (abundant) mingled with minute chalcedonic quartz. The 

 rather " ragged'^ outline of the quartz grains indicates enlargement 

 in situ. The rock reminds us more of some Huronian quartzites 

 than of those of later age. 



Another fairly rounded pebble from the same locality is generally 

 similar, but the quartz grains are more numerous and slightly 

 larger, one or two containing very thin colourless belonites. The 

 micaceous constituent also is slightly larger. A grain of plagioclas- 

 tic felspar can be recognized, and there are two or three small 

 grains of a honey-yellow mineral, giving fairly bright tints with the 

 crossed nicols. A well-rounded pebble from the ashy rock at 

 Forest Gate consists of quartz grains, as above, one or two con- 

 taining belonites, with some secondary enlargements, but there is 

 little " matrix." A few grains suggest decomposed felspar, and the 

 rock is more ferrite-stained than in the other case. All these 

 pebbles may very well have been derived from different parts of 

 the same rock-mass. 



11. Glacial Phenome7ia. — During our work in Charnwood Forest 

 Ave did not attempt any precise record of the distribution of erratics 

 or other glacial phenomena ; but as we were not unmindful of the 

 question, the general results of our impressions may be of interest. 

 The ordinary signs of the action of glaciers, so far as we have seen, 

 are wanting in the Forest, while the forms of the crags on Cademan, 

 Peldar, Eatchet Hill, and Sharpley, or indeed in any other part of 

 the Forest, are such as to prove that they either have never been 

 moulded by the action of ice, or have now lost all traces of it. The 

 northern part, indeed, of the Sharpley ridge might be called a 

 model, on a small scale, of a group of Alpine aiguilles. Again, we 

 have frequently seen old surfaces of very hard rock, as at Bardon 

 Hill, or near the Groby syenite-quarries, or at Mount Sorrel, 

 exposed by removal of the protecting soil. In no case have we 

 seen a characteristic ice- worn surface*. Now and then a few inches 



* We cannot agree with the opinion expressed by Mr. H. E. Quilter (Mid. 

 Nat. vol, vi. p. 237) that the diorite near Brazil Wood gives indications of the 

 action of land-ice. He states that he saw a junction between the diorite and 

 the granite ; this we have not noticed. 



