118 A CENTURY OF SCIENCE 



in 1818 described the Ordovician gastropod Maclurites 

 magna. All of the paleontologists of this time were sat- 

 isfied to describe species and genera and to ascertain in a 

 broad way the stratigraphic significance of the fossil 

 faunas and floras. James Hall in 1854 (17, 312) knew of 

 1588 species, described and undescribed, in the New York 

 system, while in England Morris listed in that year 8300 

 Paleozoic forms. In 1856 Dana recites the known fossil 

 species as follows (22, 333) : The whole number of 

 known American species of animals of the Permian to 

 Recent is about 2000 ; while in Britain and Europe, there 

 were over 20,000 species. In the Permian we have none, 

 while Europe has over 200 species. In the Triassic we 

 have none, Europe 1000 species; Jurassic 60, Europe 

 over 4000; Cretaceous 350 to 400, Europe about 6000; 

 Tertiary hardly 1500, Europe about 8000. Since that 

 time nearly all of the larger American Paleozoic faunas 

 have been developed, but there are thousands of species 

 yet to be described. Who the more prominent American 

 paleontologists of this period were has been told in the 

 section on the development of the geological column. 



The grander paleontologic results of the Catastrophic 

 period have been so well stated by Marsh that it is worth 

 our while to repeat them here : 



"It had now been proved beyond question that portions at 

 least of the earth's surface had been covered many times by the 

 sea, with alternations of fresh water and of land ; that the strata 

 thus deposited were formed in succession, the lowest of the series 

 being the oldest ; that a distinct succession of animals and 

 plants had inhabited the earth during the different geological 

 periods; and that the order of succession found in one part of 

 the earth was essentially the same in all. More than 30,000 new 

 species of extinct animals and plants had now been described. 

 It had been found, too, that from the oldest formations to the 

 most recent, there had been an advance in the grade of life, both 

 animal and vegetable, the oldest forms being among the simplest, 

 and the higher forms successively making their appearance. 



It had now become clearly evident, moreover, that the fossils 

 from the older formations were all extinct species, and that only 

 in the most recent deposits were there remains of forms still 

 living . . . Another important conclusion reached, mainly 

 through the labors of Lyell, was, that the earth had not been 

 subjected in the past to sudden and violent revolutions ; but the 



