100 B. K. EMEKSQN — TETRAHEDRAL EARTH: INTERCONTINENTAL SEAS 



lias remained the same in its principal features throughout the northern 

 hemisphere since the Cambrian time — that is, since the existence of the 

 oldest known traces of organic life to the present day. A similar degree 

 of permanence, however, does not belong to the oceans. During this 

 time new oceans have been formed by sinking, whose succession in time 

 expresses itself in the transgressions. Other oceans have disappeared, 

 partly as a result of the new depressions themselves and partly by the 

 heaping up of new folded chains according to the old plan. 



So do the boundaries of the continents and the seas change, despite 

 the constancy of the plan of the axial lines. 



