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 sufiering those changes, by which, after thousands of 
years, they become the chief constituent parts of gems, the Jime- 
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 very forcibly — 
observes, the only true remaining “medals of Creation.” 
