AMERICAN GEOLOGY EATONIAN ERA, 1820-1829. 287 



of the surface water rushing forward with inconceivable velocity, 

 until overcome by opposing obstacles or exhausted by continual fric- 

 tion and the counterbalancing power of gravitation. The Pacific 

 Ocean would thus rush over the Andes and the Alleghenies into the 

 Atlantic, which would in the meantime be sweeping over Europe, 

 Asia, and Africa. "A few hours would cover the entire surface of 

 the earth, excepting, perhaps, the vicinity of the poles, with one 

 rushing torrent, in which the fragments of disintegrated rock, earth, 

 and sand would be carried along with the wreck of animal and vege- 

 table life in one all but liquid mass." 



The period that may with propriety be called the dark age of geol- 

 ogy was that prior to the discovery and general recognition of the 

 value of fossils in stratigraphy — the fact that the relative age or 

 stratigraphic sequence of sedimentary rocks could be 

 Qeoio* 31 * Ages °' determined by means of the plant and animal remains 

 they may contain. 



According to Dr. Archibald Geikie, in his Founders of Geology, 

 credit must be given to the Abbe Giraud-Soulavie for having first 

 planted the seeds of stratigraphic geology. In a paper read before 

 the Royal Academy of Scientists in Paris in August, 1779, Soulavie 

 described the calcareous mountains Vivarais as made up of limestones 

 belonging to five different epochs, the strata in each being marked by 

 its own peculiar assemblage of fossils. 



These views, though undoubtedly correct in the main, were not 

 generally accepted even in France, a fact thought by Doctor Geikie 

 to be due mainly to the wretched style in which they were set forth, 

 and the Abbe's fame has been eclipsed by more brilliant successors, 

 among whom may be mentioned Desmarest, Kouelle, Lamanon. 

 Cuvier, and Brongniart. 



Cuvier, it will be recalled, was primarily a biologist, and may well 

 be considered the first vertebrate paleontologist — the first to announce 

 that the globe was once peopled by vertebrate animals of a type which 

 have long since disappeared. In connection with Brongniart, Cuvier 

 published in lNOS a memoir containing the results of their joint studies 

 in the basin of the Seine. Thev showed that the formations there 

 existing were arranged in a definite order and could be recognized by 

 their lithological and paleontological characteristics. Although sub- 

 sequent research has naturally tended to show that the observations 

 and deductions of these early workers were not in all cases correct, it 

 mav, nevertheless, be said that they established on a basis of accurate 

 observation the principles of paleontological stratigraphy, demon- 

 strated the use of fossils for the determination of geological chronol- 

 ogy, and paved the way for the enormous advances which have since 

 been made. 



