104 



ALTERED SLATES, GRITS, AND 



Gaxleby ?l tered slate > q uar *£_ r ock, granite, &c, and resembles rock 



Wall-case 45. 



No. 190 and 191, Case 4, 



Specimens illustrative of the igneous and altered Cambrian 



rocks of Charnwood Forest, Leicestershire. 



N.E. and N. W. 



Maps 63, 



21. — Greenish grey slaty rock, Greenhill, Charnwood 



Markfi 



Hill. Pi 



Forest. Very little altered. 



22. — Greenish purple coarse 



More hardened than 21. 



23. 

 by heat. 



24. 



altered than 23. 



25.— Greenish grey and purple banded argillaceous 



and gritty rock. Tin Meado 



More 



Hi 



Very much indu- 



Hill 



rated and porcelainised. 

 26. 



Slightly porphyritic, with a few small imperfect crystals of 

 felspar and hornblende. 

 27. 



28. 



felspathic, Green Hill. 



Old John Hill. Stratification 

 in this specimen nearly obliterated. Rock chiefly composed 

 of imperfectly crystallised felspar with indications of a few 

 imperfect crystals of hornblende. 



The rock here appears to have been so far softened by 

 heat that its constituents were partly at liberty to re- 

 arrange themselves according to their chemical affinities. 



29. — Grit, similar to 28, 



Hi 



Alteration a 



little further advanced, contains more hornblende. 



30. 



High 



Very much altered 



by heat. Composed chiefly of felspathic matter, sometimes 



imperfectly crystalline, containing numer 



.blende. 



31. — Altered grit, 



spathic base, containing crystals of ft 



Hill. Composed of a fel 



and a little 



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I, 



r, 





l-A: 

 lifters' 





In 3 



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