vi 



CONTENTS. 



CHAPTER IV. 



CONSOLIDATION OF STRATA AND PETRIFACTION OF FOSSILS. 



Chemical and mechanical deposits — Cementing together of particles — Hard- 

 ening by exposure to air (p. 52.) — Concretionary nodules — Consolidating 

 effects of pressure — Mineralization of organic remains (p. 55.) — Impressions 

 and casts how formed — Fossil wood — Goppert's experiments — Precipitation 

 of stony matter most rapid where putrefaction is going on — Source of lime 

 in solution (p. 59.) — Silex derived from decomposition of felspar — Proofs of 

 the lapidification of some fossils soon after burial, of others when much 

 decayed. 



CHAPTER V. 



ELEVATION OF STRATA ABOVE THE SEA — HORIZONTAL AND INCLINED 

 STRATIFICATION. 



Why the elevated position of marine strata should be referred to the rising up 

 of the land, not to the going down of the sea — Upheaval of extensive masses 

 of horizontal strata (p. 63.) — Inclined and vertical stratification — Anticlinal 

 and synclinal lines — Examples of bent strata in east of Scotland (p. 66.) — 

 Theory of folding by lateral movement — Dip and strilie (p. 69.) — Structure 

 of the Jura — Rocks broken by flexure — Inverted position of disturbed strata 

 (p. 73.) — Unconformable stratification — Fractures of strata — Polished sur- 

 faces — Faults — Appearance of repeated alternations produced by them 

 (p. 77.) — Origin of great faults. 



CHAPTER VI. 



DENUDATION, AND THE PRODUCTION OF ALLUVIUM. 



Denudation defined — Its amount equal to the entire mass of stratified deposits 

 in the earth's crust — Horizontal sandstone denuded in Ross-shire — Levelled 

 surface of countries in which great faults occur (p. 81.) — Connexion of 

 denudation and alluvial formations — Alluvium, how distinguished from rocks 

 in situ (p. 84.) — Ancient alluviums called diluvium — Origin of these — 

 Erratic blocks and accompanying gravel (p. 86.) — Theory of their transporta- 

 tion by ice. 



CHAPTER Vn. 



VOLCANIC ROCKS. 



Trap rocks — Name, whence derived — Their igneous origin at first doubted 

 — Their general appearance and character — Volcanic cones and craters, 

 how formed (p. 91.) — Mineral composition and texture of volcanic rocks — 

 Varieties of felspar — Hornblende and augite — Isomorphism (p. 94.) — Rocks, 

 how to be studied — Basalt, greenstone, trachyte, porphyry, scoria, amygda- 

 loid (p. 96.) lava, tuff — Alphabetical list, and explanation of names and 

 synonyms, of volcanic rocks (p. 99.) — Table of the analyses of minerals most 

 abundant in the volcanic and hypogene rocks. 



