262 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1928 



From this table we see thai about all that is strikingly harmoni- 

 ous in the two continents is the orogeny at the close of the Protero- 

 zoic, the Lower Devonian (Bokkeveld) faunas, the Lower Permian 

 tillites, and the Glossopteris floras; in Permian time, Mesosaui'us 

 and Noteosaums; in late Triassic time, Erythrosuchus and Scaph- 

 oiiyx-like reptiles; and finally, in latest Triassic time, the plateau 

 lavas. We gladly admit that these are striking similarities or iden- 

 tities, but after all they furnish slender evidence on which to ba,se 

 so important a conclusion as that Africa and Argentina were 

 united to one another until Cretaceous time. Against this view are 

 many more and greater dissimilarities, none of which is more strik- 

 ing than the almost total absence of the horde of African Permian 

 reptiles and amphibia and the African Triassic dinosaurs in all of 

 South America.^ Furthermore, the writer's plasteline method of 

 bringing South America against Africa leaves the Sierras 350 miles 

 northwest of their supposed connections with the Cape Mountains 

 (pL4). 



On the other hand, it must be plain to anyone looking at western 

 Pangaea that Wegener has greatly distorted and elongated the 

 Americas, and chiefly in the Central American region (fig. 1). In 

 this connection. Lake also says (1922) that when one moves the 

 Americas rigidly and without distortion again,st Euro-Africa, then 

 the Sierras of Argentina fail to meet the Cape Mountains by 1,200 

 miles. 



Krenkel in his book on African geology lias likewise studied 

 Wegener's hypothesis in relation to the supposedly connecting 

 geology and structures of eastern South America and western 

 Africa, following out five lines of evidence. These are (1) the pre- 

 Paleozoic grain of Brazil and West Africa, (2) the connections of 

 the Cape Mountains with the Sierras of Buenos Aires, (3) the con- 

 tinental rocks thrown out by the volcanoes of Ascension, St. Helena, 

 and Tristan d'Acunha, (4) the bathymetric nature of the ocean oft* 

 West Africa, (5) the comagmatic relation of the igneous rocks on 

 both sides of the Atlantic. In each instance he finds dissimilarities 

 striking enough to cause him to decide against the displacement 

 hypotliesis. On the other hand, Du Toit (1926), because of the 

 enumerations given on an earlier page, believes in a Pangaea, but 

 in his book of 1927 he holds that South America at no time was 

 united with Africa, but that the}' were always separated by some- 

 thing like 400 to 800 kilometers. This admission of the existence 

 of a wide gap is, to the writer, of the greatest significance, and with 



" This point iind t'.ic more important of the known faunal and floral assemblages are 

 discussed at length in a memoir prepared after this paper was written. It Is entitled 

 "A Review of the Late Paleozoic Formations and Faunas with Special Reference to the 

 Ice Age of Middle Permian Time," Bull. Geol. Soc. Amcr., vol. 38 (1928). 



