290 COSMOS. 



between the already dried land and the ocean in which these 

 rocks were forming. An ingenious attempt has been made to 

 draw maps of this physical portion of primitive geography, 

 and we may consicler such diagrams as more correct than 

 those of the wanderings of lo or the Homeric geography, 

 since the latter are merely graphic representations of mythical 

 images, whilst the former are based upon positive facts 

 deduced from the science of geology. 



The results of the investigations made regarding the area! 

 relations of the solid portions of our planet are as follows : 

 in the most ancient times during the silurian and devonian 

 transition epochs, and in the secondary formations including 

 the trias, the continental portions of the earth were limited 

 to insular groups, covered with vegetation; these islands 

 at a subsequent period became united, giving rise to numer- 

 ous lakes and deeply indented bays ; and finally, when the 

 chains of the Pyrenees, Apennines, and Carpathian moun- 

 tains were elevated about the period of the more ancient 

 tertiary formations, large continents appeared, having almost 

 their present size.* In the silurian epoch, as well as in that 

 in which the cycadea3 flourished in such abundance, and 

 gigantic saurians were living, the dry land, from pole to pole, 

 was probably less than it now is in the South Pacific and the 

 Indian Ocean. We shall see, in a subsequent part of this 

 work, how this preponderating quantity of water combined 

 with other causes must have contributed to raise the tempe- 

 rature and induce a greater uniformity of climate. Here we 

 would only remark, in considering the gradual extension of 

 the dry land, that shortly before the disturbances which at 

 longer or shorter intervals caused the sudden destruction of 

 so great a number of colossal vertebrata in the diluvial period ', 

 some parts of the present continental masses must have been 



* [These movements, described in so few words, were doubtless going 

 on ; for many thousands and tens of thousands of revolutions of our 

 planet. They were accompanied also by vast but slow changes of other 

 kinds. The expansive force employed in lifting up by mighty move- 

 ments the northern portion of the continent of Asia, found partial vent; 

 and from partial subaqueous fissures there were poured out the tabular 

 masses of basalt occurring in Central India, while an extensive area of 

 depression in the Indian Ocean, marked by the coral islands of the 

 Laccadives, the Maldives, the great Chagos bank, and some others, were 

 in the course of depression by a counteracting movement. Ansted's 

 Ancient World, p. 346, &c.] Tr. 



