CONTENTS. 



PART I. 



CHAPTER I. 



ON THE FOUR GREAT CLASSES OF ROCKS THE AQUEOUS, VOLCANIC, 

 PLUTONIC, AND METAMORPHIC. 



Geology defined Successive formation of the earth's crust Classification of 

 rocks according to their origin and age Aqueous rocks (p. 15.) Their 

 stratification and imbedded fossils Volcanic rocks, with and without cones 

 and craters (p. 18.) Plutonic rocks, and their relation to the volcanic 

 Metamorphic rocks, and their probable origin (p. 21.) The term primitive, 

 why erroneously applied to the crystalline formations (p. 23.) Division of 

 the work into two parts ; the first descriptive of rocks without reference to 

 their age, the second treating of their chronology. 



CHAPTER II. 



AQUEOUS ROCKS THEIR COMPOSITION AND FORMS OF STRATIFICATION. 



Mineral composition of strata Arenaceous rocks Argillaceous Calcareous 

 Gypsum Forms of stratification (p. 28.) Original horizontally thin 

 ning out Diagonal arrangement (p. 31.) Ripple mark. 



CHAPTER III. 



ARRANGEMENT OF FOSSILS IN STRATA FRESHWATER AND MARINE. 



Successive deposition indicated by fossils Limestones formed of corals and 

 shells Proofs of gradual increase of strata derived from fossils Serpula 

 attached to spatangus (p. 37.) Wood bored by teredina Tripoli and semi- 

 opal formed of infusoria Chalk derived principally from organic bodies 

 (p. 41.) Distinction of freshwater from marine formations Genera of fresh- 

 water and land shells Rules for recognizing marine testacea Gyrogonite 

 and chara (p. 48.) Freshwater fishes Alternation of marine and fresh- 

 water deposits Lym-Fiord. 



A * (5) 



