XX 



CONTENTS. 



DOMAIN XL DECOMPOSED, p. 209 



Nome I. Decomposed Basaltin 235 



II. D. Porphyry 238 



III. D. Slate 240 



IV. D. Quartz ib. 



V. D.Keralite 241 



VI. D. Felspar ib. 



VII. D. Granite 242 



VIII. D. Gneiss 247 



IX. D. Pitch- stone 148 



X. ). Sandstone ib. 



XI. D. Clay-slate 249 



XII. D. Saussurite ib. 



XIII. D. Marble 250 



XIV. D. Alabaster ib. 



XV. D. Coal ib. 



Effects of Decomposition 253 



DOMAIN XII. VOLCANIC. 268 



Nome I. Compact Lava .... 313 



II. Vesicular Lava 328 



III. Indurated Mud 373 



IV. Tufo 378 



V. Pumice 428 



VI. Obsidian 443 



VII. Volcanic Intrite 469 



VIII. Volcanic Glutenite 503 



IX. Substances ejected or changed 515 



General Remarks, and Examples of singular 



Volcanoes 519 



Fumavols ,.. 545 



Veinstones , 561 



Appendix , , 5^1 



