78 REV. EDWIN HILL AND PROF. T. G. BONNEY ON THE 



8. On the Xorth-west IIegion of Charnwood Forest, with other 

 Notes. By the Rev. Edwin Hill *, M.A., F.G.S., and Pro- 

 fessor T. G. Bonnet, D.Sc, LL.D., E.R.S., Y.P.G.S. (Ecad 

 January 7, 1891.) 



Contents. 

 I. Introduction. 

 IT. The North-west Region and Bardon Hill. 



1. Greneral Description of the North-west Region. 



2. The Porphyroid of Peldar Tor. 



3. The Porphyroid of Sharpley. 



4. Field Relations of the Peldar and Sharpley Rocks, 

 y. Bardon Quarry. 



III. Additional Notes. 



G. Stahle Quarry, Bradgate Park. 



7. The Igneous Junctions. 



8. Brazilwood. 



9. The Blackbrook Group. 



10. Fragments and Pebbles. 



11. Glacial Phenomena. 



12. Age of the Clastic Charnwood Rocks. 



13. Age of the Igneous Rocks. 



14. Corrigenda. 



I. Introduction. 



It is now more than ten years since the last of our papers on the 

 pre-Carboniferous rocks of Charnwood Forest was laid before this 

 Society f- At that time, as we stated, we had no expectation of 

 writing further upon the district. But since then, though little has 

 been changed in the Eorest, beyond the enlargement of some 

 quarries, the general progress of knowledge has affected our inter- 

 pretation of some of the facts which we had ascertained, and much 

 has been learnt in regard to the whole subject of metamorphism, 

 especially as to the effects of pressure, due to movements of the 

 earth's crust, in modifying rock-structures and initiating, if not 

 producing, mineral changes. We have, we hope, more knowledge 

 and a wider experience, so that our interpretation might be altered, 

 though the facts might be unchanged %. 



Now there was one district in the Porest, that of Peldar Tor, 



* Mr. Hill desires to state that throughout this paper all references to 

 microscopic evidence are due to Professor Bonney. He himself has taken part 

 only in the field work. 



t Quart. Journ. Geol. Soc. vol. xxxvi. (1880) p. 337. 



\ Not much has been published since the date of our last paper. There is a 

 good account of a visit of the Geologists' Association published in their ' Pro- 

 ceedings,' vol. X. (1888) p. 472, by Sir. J. D. Paid, to which is appended a 

 useful note on the microscopic structure of some of the rocks, by Major-Gen. 

 McMahon, who expresses the opinion that the rocks of Sharpley and Peldar 

 Tor are lavas. Mr. W. J. Harrison refers, in some papers on the pre-Carbo- 

 niferous floor of the Midlands, to the rock of Charnwood (' Midland Naturalist,' 

 vol. viii.), and describes the syenites of S. Leicestershire (ihid. vol. vii.), but 

 adds notiiing material to our notice, to which he does not refer. 



