CHAPTER XXXVI.
METAMORPHIC ROCKS--_continued_.
Strata near some intrusive masses of granite converted into rocks identical with different members of the metamorphic series--Arguments hence derived as to the nature of plutonic action--Time may enable this action to pervade denser masses--From what kinds of sedimentary rock each variety of the metamorphic class may be derived--Certain objections to the metamorphic theory considered--Lamination of trachyte and obsidian due to motion--Whether some kinds of gneiss have become schistose by a similar action 473