Pebeuaky 1, 1907] 



SCIENCE 



163 



and west bands. That remarkably com- 

 plete development of the Paleozoic series 

 made the stratigraphy of New York a 

 standard of comparison for the subsequent 

 study of the Paleozoic strata throughout 

 the eastern United States, as the strati- 

 graphic series of England had already be- 

 come, in its broader outlines, a standard of 

 comparison for the world. But that regu- 

 lar succession of Paleozoic strata from the 

 Adirondacks to the Pennsylvania border 

 was suggestive of a dynamic idea. It sug- 

 gested a gradual emergence of the land 

 from the waters of the sea. In later years, 

 as geological investigation extended west- 

 ward, a somewhat similar succession could 

 be traced in the Mississippi basin, south- 

 ward from the Archtean mass north of the 

 Great Lakes. The doctrine of the perma- 

 nence of continent and ocean— the gradual 

 emergence of continental lands and the 

 withdrawal of the waters into the deepen- 

 ing ocean basins— was first enunciated by 

 Dana in 1846. He had just returned from 

 his voyage around the world in Wilkes's 

 exploring expedition. In that voyage he 

 had studied the phenomena of barrier reefs 

 and atolls, had adopted Darwin's theory 

 of their origin by subsidence, and had de- 

 fended and illustrated the theory by a far 

 greater wealth of observation than Dar- 

 win's route had afforded him the oppor- 

 tunity to make. It was, apparently, the 

 thought of the subsiding ocean bottom, 

 rather than the thought of the emerging 

 land, by which Dana was first led to the 

 doctrine of the permanence of continent 

 and ocean; but, in his presidential address 

 before the American Association for the 

 Advancement of Science, in 1855, Dana 

 refers to the stratigraphy of New York as 

 illustrating the idea of continental emer- 

 gence. The generation of students who 

 have learned geology from Dana's 'Man- 

 ual' and 'Text-book,' will remember how 

 prominently he brings forward the suc- 



cession of Paleozoic formations in New 

 York, as illustrating his conception of the 

 gradual emergence of the land from a 

 continental sea. 



The doctrine of the permanence of conti- 

 nents when announced by Dana was essen- 

 tially a new one. Geologists and pseudo- 

 geologists of all classes had felt at liberty 

 to redistribute continents and oceans ac- 

 cording to their own sweet will. After the 

 biblical pseudo-geologists had become con- 

 vinced of the impossibility of the deposi- 

 tion of the whole series of fossiliferous 

 strata in the Noachian deluge, their next 

 shift was the supposition that the fossilif- 

 erous strata had been deposited in the 

 ocean in the interval between the creation 

 and the deluge, and that at the time of the 

 latter event continent and ocean were re- 

 versed. Hutton believed that the debris of 

 the continents was carried far out to sea 

 by means of ocean currents, and was de- 

 posited over substantially the whole floor 

 of the ocean; and, when one continent was 

 worn away, another might be uplifted in 

 some other part of the world. Lyell elim- 

 inated the catastrophic element of Hutton 's 

 theorizing; but, like his predecessor, Lyell 

 believed in an indefinite amount of change 

 in the distribution of continent and ocean. 

 In attempting to find a geological explana- 

 tion for changes of climate, he felt at lib- 

 erty to speculate on a series of changes in 

 the distribution of continent and ocean 

 which would sometimes bunch the conti- 

 nents around the poles, and at other times 

 girdle the earth with an equatorial belt of 

 land. The readers of Darwin's 'Letters' 

 will remember his half comic, half pathetic 

 protest, in a letter to Lyell, that the dis- 

 ciples of the great geologist 'in a slow and 

 creeping manner beat all the old catastro- 

 phists who ever lived.' 



There is now little doubt that Dana was 

 right in his general conception. The great- 

 er density of the suboceanic masses in com- 



