226 



E. HILL AND T. G. BONNEY ON THE 



It has the aspect of a porphyritie felsite rather than a truly grani- 

 toid rock, though occasionally (especially when a little decomposed) 

 it seems nearer to the latter in texture. Under the microscope, a slide 

 from one of the best-preserved specimens shows the ground-mass 

 to be microcrystalline, composed of quartz granules and brownish 



Fig. 1. — Sketch Map of Charnwood Forest, with the Narborough 



District. 



C J£ JL It WW O D 



JF O M JE 8 T 



Coalville, 



Groby 



J3a.T07 L FarA Zeicjzstek + 



/0J2Ti(Lerby 



Eatls Sltiltoni- 



jBarrcw Kill 



^Crofts 



Sboi 



&kinto7b 



Vapcote 



=£ Scale of Miles. 



Horizontal shading, slaty rocks; "cross shading, igneous rocks. 

 The arrow-head points to the position of the Enderby slate. 



decomposed felspar, in which are scattered larger crystals of felspar, 

 microliths and irregular crystalline grains of hornblende, grains 

 of magnetite, and perhaps of ilmenite, some of quartz (larger in 

 size) and small hexagonal needles of apatite. With crossed Nico Is 



