REPORT OF THE DIRECTOR 1920-21 /3 



always abysmal and that these abysmal depths always existed in 

 the areas of the present oceans. 



A theory that stands in direct opposition to the view of the 

 permanence of the oceans and continents as advanced by the Ameri- 

 can authors, is that of Haug (1900) of the supremacy of the geosyn- 

 clines in the history of the face of the earth (see Gortari, 1920, p. 

 46). Haug's theory, as originally presented in 1900 and since then 

 more fully developed in his paleogeographic maps, assumes that a 

 system of relatively narrow but deep geosynclinal canals represents 

 the mobile part of the earth crust, from which the ocean waters 

 advanced in times of transgression and into which they withdrew 

 in times of emergence of the " continents." The latter comprise 

 all the immense tracts between the geosynclines. He thus con- 

 structed (see fig. 5) a North Atlantic, a Sino-Siberian, a Pacific, 

 an Africano-Brazilian and an " Australo-Indo-Malgash " continent 

 for the Mesozoic and suggests that their structure goes back to 

 Paleozoic time. Andree (1914, p. 27) points out that these geosyn- 

 clines correspond to the present intercontinental mediterranean 

 and the marginal seas, as the east-Asiatic, to which adjoins the 

 greatest depth known today; and that the assumption of a Pacific 

 continent is purely hypothetic (as Haug had himself conceded). 1 



A view which in a measure combines the hypotheses of the Ameri- 

 can authors with those held in Europe has been lately advanced 

 by Holtedahl in connection with his thorough studies of the Paleo- 

 zoics of the Atlantic- Arctic region (Holtedahl, 1920). Holtedahl 

 considers it hopeless to advocate the permanency of the oceanic 

 basins as far as the North Atlantic is concerned; for this region 

 has been the area of the greatest vertical movements in the Paleozoic 

 era and while thus through long geologic periods it had the tendency 

 to rise, it has now sunken deeply. He recognizes a geosyncline 

 of post-Ordovician folding extending through Norway, Scotland, 

 Newfoundland and the Appalachians and sees in the geosynclines 



1 Eduard Suess in a letter of March 8, 1909, to the writer has, in answer to 

 the latter's statement in " The Graptolites of New York," that the graptolite 

 shales prevailingly occur in geosynclines, expressed an interesting view on these 

 structures which it may be worth while to publish in this connection. He says 

 (not translated) " I have with great interest read what you say on shields, but 

 I do not believe in geosynclinals. No existing ocean has a synclinal structure, 

 except by superimposed sediments, and the Pacific troughs are no synclinals." 



This statement explains why Suess in his classic work never uses the expression 

 geosyncline. It appears, however, that the " Vortiefen " or " fore-depths '' 

 which he recognizes in front of the greater mountain ranges (see Suess, 191 1, 

 p. 102) correspond to the geosynclines in position and as the situs of later moun- 

 tain folding. As pointed out by Suess, they are, however, no synclines, as " they 

 are not caused by folding," as " one side is formed by the foreland while the 

 other is the front of a folded chain." 



