CONTENTS. 



xiii 



Page. 



CHAPTER IX. 



ON UNCONFORMABLE TRAP ROCKS AND BASALTIC DYKES. 



Different Positions of Trap Rocks, as overlying, imbedded, or intersecting 

 other Rocks... .Varieties of Trap Rocks.. ..Porphyry, Porphyritic Trap, Sienite, 

 Greenstone, Clinkstone, Basalt, Amygdaloid, and Wacke.... Passage by Grada- 

 tion into each other, and into Volcanic and Granitic Rocks. ...Remarkable In- 

 stance of this Passage at Christiania in Norway. ...Mountains of Porphyritic 

 Trap and Clinkstone w ith deep Craters. ...High Stile, Cumberland ; Caderldris, 

 Monmouthshire.. ..Basaltic Dykes: Extent of the Cleveland Basalt Dyke....lso- 

 lated Caps of Basalt. ...On interstratified Basalt... .Remarks of Professor Sedg- 

 wick on the Protrusion of Basalt between regular Strata. ...On columnar Ranges 

 of Basalt.. ..Organic Remains enveloped in Basalt.. ..Remarkable Basaltic Dis- 

 tricts in Europe and America.. . Experiments on Basalt.. ..Theory of Werner.... 

 On the relative Age of Trap Rocks, ----- 127 



CHAPTER X. 



A RETROSPECTIVE VIEW OF CERTAIN GEOLOGICAL FACTS AND IN- 

 FERENCES. RELATIVE AGES OF. MOUNTAIN RANGES. — PRELIMINARY 



OBSERVATIONS ON THE SECONDARY STRATA, - 150 



CHAPTER XI. 



TABULAR ARRANGEMENT OF SECONDARY STRATA. RED SANDSTONE. 



MAGNESIAN LIMESTONE. — ROCK SALT AND GYPSUM. 



Relative Geological Position of the Secondary Class of Rocks. ...Their Mine- 

 ral and Zoological Characters. ...Tabular Arrangement.. ..New Red Sandstone 

 and Red Marl. ...Upper, Middle, and Lower Beds, chiefly formed of the Frag- 

 ments of more ancient Rocks, broken by some great Convulsion.. ..Lowest Red 

 Sandr^tone, oi Rothe-todte Liegende of the German Geologists. ...Separated from 

 the Middle Beds, by Beds of Magnesian Limestone.. ..Middle and Upper Beds 

 of Red Sandstone and Marl ; their Accordance with those of France and Ger- 

 many. ...Muschel Kalk wanting in England, but probably exists in Ireland, as 

 the Lily Encrinite has recently been discovered there. ...Magnesian limestone 

 of the Northern Counties. ...English Red Marl and Sandstone formed of more 

 ancient Rocks, paiticularly of Porphj'ry and Trap. ...Gypsum accompanying 

 Rock Salt originally Anhydrous. ...Rock Salt Deposits, in diiferent Formations, 157 



CHAPTER XII. 



ON THE LIAS AND OOLITIC SERIES. 



Geological Position of Lias Clay and Limestone. ...Their Mineral Characters. 

 ....Alum-Slate in Lias. ...Remarkable Organic Remains and Characteristic Fos- 

 sils. ...Extent of the Lias Formation in England. ...Interesting Junctions of Lias 

 and Red Marl. ...Lias of France and the Alps... .Oolite or Roestone, the Jura 

 Limestone of Foreign Geologists. ...Mineral Characters, and remarkable Or- 

 ganic Remains. ...Lower Oolite. ...Oxford or Clunch Clay.. ..Middle Oolites.... 

 Kimmeridge Clay. ...Upper or Portland Oolites.. ..Stonesfield Slate with Organic 

 Remains of Insects, Bnds, Flying Reptiles, and small Land Quadrupeds ...Ex- 

 tent of the Oolite Formation in England, and its abrupt Termination... .Sections 

 of the Oolitic Series of Beds in Yorkshire and the West of England, compared 

 with a Section of the Secondary Strata in Germany, - 178 



CHAPTER XIII. 



ON THE SUSSEX BEDS, OR WEALDEN, CONTAINING REMAINS OF LAND 

 PLANTS, AND AMPHIBIOUS AND FRESH-WATER ANIMALS. 



Extent of the Sussex Beds.. ..Their Geological Position and Mineral Charac- 

 ters.... Remarkable Organic Remains of enormous Lizards and Plants, analogous 



