METAMOBPHISM, OK THE TKANSFOKMATIOKS 

 OF KOCK-MATTEK. 



METAMORPHISM, DEFINITION OF THE TEEM ALL ROCK-MATTER 

 INCESSANTLY UNDERGOING INTERNAL CHANGE THROUGH PRES- 

 SURE, ATTRACTION OF COHESION, CHEMICAL ACTION, HEAT, MAG- 

 NETISM, 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 GRADUAL DETECTION OF THESE IN 

 PECULIAR LOCALITIES RESOLUTION OF THE SYSTEM INTO MINOR 

 SECTIONS AND CHRONOLOGICAL ORDER INCONCEIVABLE AMOUNT 

 OF TIME IMPLIED IN THE DEPOSITION AND SUBSEQUENT TRANS- 

 FORMATIONS OF THE METAMORPHIC SYSTEM HOW TO DEAL 

 WITH IT AS A PART OF WORLD-HISTORY ITS CONVENIENCE AS 

 A PROVISIONAL DESIGNATION. 



IT has been already explained that all the substances com- 

 posing the earth's crust, from the most recent and super- 

 ficial soils, sands, muds, and gravels, down to the oldest and 

 deepest slates and schists, are known as rocks and rock-forma- 

 tions. It has also been shown that all these rock-matters 

 are undergoing incessant changes, being weathered and worn 

 from the old hills, borne onwards by streams and rivers, 

 laid down as sediments in lakes and seas and estuaries, and 

 again upheaved by vulcanic agency as the solid strata of 

 newer continents. In this long and ceaseless round they are 

 disintegrated and dissolved, reconstructed and consolidated, 

 and it is to the varied processes of reconstruction and consoli- 

 dation that we would here direct attention. Every substance > 



