8 



INTRODUCTION. 



that they alter the physiognomy of the superficial structure of the 

 globe, the study of which constitutes geognosy." 



" By this," says Parkinson, " we are taught that innumerable 

 beings have lived, of which not one of the same kind does any 

 longer exist — that immense beds composed of the spoils of these 

 animals, extending for many miles under ground, are met with 

 in many parts of the globe — that enormous chains of mountains, 

 which seem to load the surface of the earth, are vast monuments, 

 in which these remains of former ages are entombed — that, though 

 lying thus crushed together, in a rude and confused mass, they 

 are hourly suffering these changes, by which, after thousands of 

 years, they become the chief constituent parts of gems, the lime- 

 stone which forms the humble cottage of the peasant, or the mar- 

 ble which adorns the splendid palace of the prince." Fossil, 

 wood, coral, and shells, are, indeed, as Bergman has very forcibly 

 remarked, the only true remaining " medals of Creation." 



