Viii CONTENTS. 



forms of outcrop — Rocks broken by flexure — Inverted position of disturbed 

 strata — Unconformable stratification — Hutton and Playfair on the same — Frac- 

 tures of strata— -Polished surfaces — Faults — Appearance of repeated alternations 

 produced by them — Origin of great faults, - - - page 44 



Chapter VI. — Denudation. 



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 — Coalbrook Dale — Denuding power of 

 the ocean during the emergence of land — Origin of valleys — Obliteration of sea- 

 cliffs — Inland sea-cliffs and terraces in the Morea and Sicily — Limestone pillars at 

 St. Mihiel, in France — in Canada — in the Bermudas, - - - 66 



Chapter VII. — Alluvium. 



Alluvium described — Due to complicated causes— Of various ages, as shown in Au- 

 vergne — How distinguished from rocks in situ — Sandpipes in Chalk — Alluvial 

 terraces caused by oscillation in the level of land, - - - *79 



Chapter VIII — Chronological Classification of Rocks. 



Aqueous, plutonic, volcanic, and metamorphic rocks, considered chronologically — 

 Lehman's division into primitive and secondary — Werner's addition of a tran- 

 sition class — Neptunian theory — Hutton on igneous origin of granite — How the 

 name of primary was still retained for granite — The term " transition," why 

 faulty — The adherence to the old chronological nomenclature retarded the 

 progress of geology — New hypothesis intended to reconcile the igneous origin 

 of granite to the notion of its high antiquity — Explanation of the chronological 

 nomenclature adopted in this work, so far as regards primary, secondary, and 

 tertiary periods, - - ■ - - - - - 85 



Chapter IX. — On the Different Ages of the Aqueous Rocks. 



On the three principal tests of relative age — Superposition, mineral character, and 

 fossils — .Change of mineral character and fossils in the same continuous forma- 

 tion — Proofs that distinct species of animals and plants have lived at successive 

 periods — Distinct provinces of indigenous species — Great extent of single prov- 

 inces — Similar laws prevailed at successive geological periods — Relative import- 

 ance of mineral and palseontological characters — Tests of age by included frag- 

 ments — Frequent absence of strata of intervening periods — Principal groups of 

 strata in western Europe — Tabular views of fossiliferous strata, - - 92 



Chapter X. — Recent and Post-Pliocene Periods. 



Recent and Post-pliocene periods — Terms defined — Formations of the Recent 

 period — Modern littoral deposits containing works of art near Naples — Danish 

 peat and shell mounds — Swiss lake-dwellings — Periods of stone, bronze, and 

 iron — Form of human skulls of the Recent period — Post-pliocene formations — 

 Coexistence of man with extinct mammalia — Higher and Lower-level Valley- 

 gravels — Loess or inundation mud of the Nile, Rhine, &c. — Antiquity of Post- 

 pliocene Lake-terraces in Switzerland — Upraised marine strata in Sardinia — 

 Origin of caverns — Remains of man and extinct quadrupeds, in cavern deposits 

 — Cave of Kirkdale — Reindeer period of south of France — Australian cave- 

 breccias — Geographical relationship of the provinces of living vertebrata and 

 •those of extinct Post-pliocene species — Extinct struthious birds of New Zealand 



