CONTEXTS. IX 



III. VULCANISM ITS NATURE AND FUNCTION. 



DEFINITION OF THE TERM MODES OF MANIFESTATION VOL- 

 CANOES, THEIR VARIOUS ASPECTS, CHARACTERS, PRODUCTS, 

 AND FUNCTIONS EARTHQUAKES, THEIR MODES OF ACTION 

 AXD EFFECTS CONNECTION WITH VOLCANOES CRUST- 

 MOTIONS, THEIR CHARACTER AND RESULTS RECENT EX- 

 AMPLES THEORIES OF VULCANISM OR INTERNAL FIRE- 

 ACTION ITS SHIFTINGS FROM AREA TO AREA APPARENT 

 FUNCTIONS OF POWER AND PERMANENCE OF, AS A NAT- 

 URAL FORCE LAV BY WHICH REGULATED NECESSARY 

 PORTION OF WORLD-MECHANISM, . .51 



IV. METAMORPHISM, OR THE TRANSFORMATIONS 

 OF ROCK-MATTER. 



METAMORPHISM, DEFINITION OF THE TERM ALL ROCK-MAT- 

 TER INCESSANTLY UNDERGOING INTERNAL CHANGE THROUGH 

 PRESSURE, ATTRACTION OF COHESION, CHEMICAL ACTION, 

 HEAT, MAGNETISM, CRYSTALLISATION, AND OTHER SIMILAR 

 FORCES ILLUSTRATIONS OF THESE RESPECTIVE FORCES AND 

 THEIR MODES OF ACTION THEIR EFFECTS MOST PERCEPTIBLE 

 IN THE OLDER ROCKS THE SO-CALLED METAMORPHIC ROCK- 

 SYSTEMAPPARENT OBLITERATION OF ITS FOSSILS GRA- / 

 DUAL DETECTION OF THESE IN PECULIAR LOCALITIES RE- j 

 SOLUTION OF THE SYSTEM INTO MINOR SECTIONS AND CHRO- 

 NOLOGICAL ORDER INCONCEIVABLE AMOUNT OF TIME IM- 

 PLIED IN THE DEPOSITION AND SUBSEQUENT TRANSFOR- 

 MATIONS OF THE METAMORPHIC SYSTEM HOW TO DEAL 

 WITH IT AS A PART OF WORLD-HISTORY, . . 69 



V. THE PRIMARY PERIODS. 



OLDER AND YOUNGER PORTIONS OF THE EARTH'S CRUST 

 THESE REPRESENTED BY PERIODS OF TIME OR SYSTEMS 

 OF STRATA TECHNICAL ARRANGEMENT OF THESE PERIODS 

 AND SYSTEMS THE PRIMARY OR EARLIEST YET KNOWN, 

 EMBRACING THE LAURENTIAN, CAMBUIAN, AND SILURIAN 

 COMPOSITION AND DISTRIBUTION OF THESE RESPECTIVE 

 SYSTEMS THEIR CHARACTERISTIC ROCKS AND FOSSILS 

 GENERAL PAUCITY OF LIFE ADVANCE DURING THE SILU- 

 RIAN CYCLE OF CRYPTOGAMIC PLANTS AND INVERTEBRATE 

 ANIMALS GEOGRAPHICAL ASPECTS OF THE PRIMARY PE- 

 RIODSINTEREST ATTACHED TO THEM AS THE DAWN OF 

 WORLD-HISTORY, . .... 83 



