136 The Bed of the Ocean. 



rents would occupy the critical latitudes, and their direction 

 would be from east to west, or parallel with the equator. We 

 should have an equatorial plateau separated by zones of depres- 

 sion from plateaux occupying the parallels between lat. 30° and 

 50° N. and S., which again would be divided by zones of depres- 

 sion from the plateaux of the polar regions, and the surface of 

 our planet would have the appearance of being divided into 

 more or less parallel strips composed of alternate areas of eleva- 

 tion and depression. 



The elevation of ridges parallel with the axis of these 

 plateaux, and due to what at present is termed volcanic or sub- 

 terraneous agency, would at once cause a change in the system 

 of oceanic circulation, and consequently in the distribution of 

 solid matter. As they rose up from the surface of the plateaux 

 directly in the path of the currents, the latter were compelled to 

 flow along the side of the ridge opposed to them, and the result 

 was a denudation of the plateau on one side of the ridge, while 

 the accumulation of strata continued on the other side. 

 We have here a possible explanation of the fact that we 

 generally find an area of depression on one side of a mountain 

 range — i.e., that the latter forms or has formed at one time a 

 coast range with a high plateau on the opposite side. On one 

 side of the ridge we have a comparatively steep incline caused 

 by the denudation of the plateau, on the opposite side the low 

 and wide-spreading incline of the original plateau. 



The continued action of the currents would ultimately result 

 in the cutting through at right angles of the original plateaux, 

 and in the formation of new plateaux following the direction of 

 the meridian, while the ridges subsequently raised up on their 

 surface would follow the same direction, stretching from 

 north to south. The surface of our planet would now present 

 the appearance of primary areas of elevation running parallel 

 with the equator, with their ridges or mountain ranges 



