24 FORMATION OF THE EARTH 



the Sahara, 1 but had receded from Scandinavia and Finland, 

 which remained united to Canada, and almost the whole of 

 Russia ; while the southern ocean invaded the south of Africa 

 and a large part of Brazil. These changes were only temporary ; 2 

 the sea reconquered Russia, the north of Scandinavia and 

 Germany, almost all Europe, Siberia, China, and the greater 

 part of the two Americas, except the east of Canada, which 

 remained united to Scandinavia. Only Scandinavia, Central 

 Africa, India, western Australia, and eastern China emerged 

 from the sea. 



It is also generally admitted that after this epoch a vast 

 continent occupied the Pacific. After having worn down the 

 coasts of the Palaearctic continent and washed away from them 

 the portions which became the Old Red Devonian sandstone, 

 the sea to the south of this continent dried up ; 3 a zone of 

 lagoons was formed there which laid down deposits of gypsum 

 and salt, in which the bitumen of the White Sea, found in 

 even greater abundance in the Appalachians, and between 

 Hudson Bay and British Columbia, was produced, doubtless 

 from decomposing animal remains. 



The Hercynian folding coincides with the period during 

 which the beds of coal, so useful to industry to-day, were 

 successively laid down in the estuaries and lakes of these 

 different regions. Their formation continued during the first 

 part of the Secondary period. The uplifting of the land accom- 

 panying the gradual formation of the Hercynian chains 

 drained the sea first from Scotland, 4 then from the south of 

 England, Belgium, and the north of France, 5 and finally from 

 the Central Plateau. 6 At the beginning of this period there 

 existed three large continental masses separated by as many 

 seas ; the transversal sea of the preceding epochs, which 

 persisted in a more or less modified form, and two others of 

 which one was oriented along the meridians. The Arctic 

 continent still linked up Scandinavia, Greenland, and Canada, 

 and formed the Canadian-Scandinavian plateau ; 7 a second 

 continent corresponded to modern Siberia and a part of modern 

 China, constituting the Siberian plateau ; a third extended 



1 Coblentzian. 2 Eifelian. 



3 Frasnian. 4 Dinantian deposits. 



6 Westphalian deposits. 6 Stephanian deposits. 



7 CI. Map V. 



