A CENTURY OF GEOLOGY. 433 



of dispute — viz., the recognition of tlie fact that there was truth 

 on both sides, and they must be combined into a more comprehen- 

 sive view. The chief difference of opinion still remaining was as to 

 the relative importance of the two agencies, aqueous and igneous. 

 Two great advances took place about the beginning of this century: 

 William Smith, by patient, painstaking field observation and map- 

 ping, laid the foundation of stratigraphy; and Cuvier, by his pro- 

 found and brilliant studies of the wonderful discoveries of extinct 

 mammals in the Eocene basin of Paris, laid the foundations of pa- 

 leontology. These researches placed in clearer light than ever 

 before the existence of other time-worlds before the present one. 

 William Smith published his tabular view of the British Strata in 

 1790, but his map was not completed and published until 1815. 

 Cuvier's great work on the Organic Remains of the Paris Basin 

 was published in 1808. 



Thus, early in the century the two bases of our science were 

 laid by Smith and Cuvier. We now proceed to touch lightly only 

 the main steps of subsequent growth through the century. 



As, in the previous century and the early part of this, the dis- 

 cussion was between the opposite schools of l^eptunists and Pluton- 

 ists, with the final result of reconciliation in a more scientific view 

 which combined these two surface views into a stereoscopic reality, 

 so now the discussions began between catastrophism and uniformi- 

 tarianism, and ended with a similar final result. Geologists, in 

 the early part of the century, before the study of causes and pro- 

 cesses now in operation was generally acknowledged as the only 

 rational basis of a true scientific geology, seeing the frequent un- 

 conformities in the geological series and the apparently sudden 

 changes of life forms associated with these unconformities, were 

 naturally led to the conclusion that the whole history of the earth 

 consisted of a series of sudden and violent catastrophes by which 

 the bed of the ocean was suddenly raised and its waters precipi- 

 tated on the land as a great wave of translation, carrying universal 

 ruin and extermination of all life in its course. Such catastrophes 

 were supposed to be followed by periods of quiet, during which the 

 new earth was repeopled, by direct act of creation, with new forms 

 of life adapted to the new conditions. 



This view was in perfect accord with the then accepted doctrine 

 of the supernatural origin and the permanence of species. Species 

 were supposed to have been created at once, out of hand, without 

 natural process, in some place (center of specific origin), spread in 

 all directions as far as physical conditions would allow, but re- 

 mained unchanged and unchangfeable as long as they continued to 

 live or until another universal exterminating catastrophe. Species 



