xii 



CONTENTS. 



Page. 



CHAPTER V. 



ON ROCKS DENOMIISTATED PRIMARY, ANT) THE CHANGES TO WHICH 

 THEY HAVE BEEN SUBJECTED. 



The Origin of Rocks called Primary believed by many Geologists to be ig- 

 neous. ...A Classification founded on this View... .A Classification independent 

 of Theory. ...Constituent Minerals of Gi anite.... Varieties of Granite. ...Structure 

 and Appearance of Granitic Mountains ...Mont Blanc, and the Aiguilles in its 

 Vicinity.. ..Localities of Granite. ...Granite Veins. ...Passage of Granite into Por- 

 phyry and Sienite.... Minerals found in Granite. ...On Granite as the Foundation 

 Rock on which other Rocks are laid. ...The relative Antiquity of ditFerent Gran- 

 itic Mountain Ranges.. ..Granite pierced through by Porphyry and Currents of 

 Lava, ...Granite sometimes protruded among the upper Strata, - - 54 



CHAPTER VL 



ON GNEISS AND MICA-SLATE, AND THE ROCKS WHICH ARE ASSO- 

 CIATED WITH THEM. 



On the Passage of Granite into Gneiss ...Gneiss and Granit veine... .Mica- 

 Slate. ...Formation of Gneiss and Mica-Slate.. ..Talcous Slate, and Chlorite Slate. 

 ....Crystalline Limestone denominated Piimary, occurs both in Primary and 

 Secondary Mountains. ...Formation of Limestone and Coral Islands by Animal 

 Seci'etion.. ..Dolomite, or Alpine Magnesian Limestone. ...Serpentine and Ollite, 

 or Potstone....Euphotide or Saussut ite the hardest and heaviest of rocks. ...Trap 

 Rocks changed to Serpentine.. ..Eurite or Vv hite Stone. ...Piimary Porphyry a 

 Mode of Granite. ...Recurrence of the same Rocks in Rock Formations of dif- 

 ferent Epochs, - -- -- ---71 



CHAPTER Vn. 



ON INTERMEDIATE OR TRANSITION ROCKS. 



Characters and Classification of Transition Rocks. ...Slate or Clay-Slate. ...Pe- 

 culiarities of Structure.. ..Varieties of Slate.. ..Flinty Slate. ...Greywacke and 

 Greywacke-Slate ; its Passage into Red Sandstone and Giitstone... .Errors of 

 Geologists respecting the old Red Sandstone. ...Lower Transition Limestone : 

 remarkable Position of its Beds. ...Upper Transition or Mountain Limestone.... 

 Magnesian Limestone, in Mountain Limestone. ...Peculiarities in the Stratifica- 

 tion of Clouds Hill. ...Errors respecting the Mountain ]-,imestone of Derbj'^- 

 shire... .Remarkable Structure of Crich Cliff... .Quartz Rock. ...Jasper Green- 

 stone. ...Coal Strata in England separate the Upper Transition Rocks from the 

 Secondary. ...Observations on the. Transition Rocks of distant Countries... .Errors 

 of Geologists respecting them, 82 



CHAPTER VHL 



ON THE LOWER OR GREAT COAL FORMATION. 



The Geological Position and Structure of Coal Districts, called Coal- Fields. 

 Dislocation and Disturbances of Coal Strata by Faults and Dykes. ...Mineral 

 Coal, Anthracite, Plumbago, Wood-Coal or Lignite. ...Iron-Stone accompanying 

 Coal Strata.. ..On Carbon as an original Constituent Part of the Globe. ...On the 

 Origin of Coal Strata, and their Deposition in Frccihwater Lakes or Marshes.... 

 Numerous Repetitions of the same Series of Beds in the same Coal-Field... .Pre- 

 cautions necessary in the Establlshm.ent of Iron Furnaces. ...On the Mode of 

 searching for Coal. ...Hints to landed Proprietors on the Probability of finding 

 Coal in Districts where it has not yet been discovered. ...On the Formation of 

 Coal-Beds in Freshwater Lakes. ...On the Conversion of Vegetable Matter into 

 Coal. ...Imperfect Coal Formations. ...Salt Springs in Coal Strata. ...Coal Mines 

 in France and North America. ...Observations on the Consumption of Coal in 

 England, and the Period when the Coal-Beds v^ill be exhausted, - 101 



