Prqfesaor Sc/iirarz — Earth-move?nenh, S. Africa. 549 



Ganitoos, reached the sea ; the others, which now have separate 

 mouths, then formed tributaries of these two large rivers. 



Tlie movement seems a gigantic one, but the data we have to rely 

 upon are sound; onlj' the time taken for these changes of sea-level 

 is open to some doubt. There has been rising of the land from 

 the 4,000 feet peneplane to sea-level, and from here to the 

 400 fathom line, 6,400 feet, then a sinking of the land 2,400 feet to 

 present sea-level. All this was accomplished in pre-Pleistocene 

 times, because the rock-channels of tlie rivers which cut through this 

 stepped plain, such as the Keurboom, Pisang, Zwartkops, Kowie, and 

 Buffalo, are filled in now at sea-level with Pleistocene beds. Hence 

 the whole oscillation took place within the Miocene and Pliocene 

 times, 6,400 feet vertical rise and 2,400 feet vertical sinking, or 

 8,800 feet of total movement. If the evidence below sea-level is 

 objected to, the undoubted movement is still 4,000 feet. 



Certainly the portion from sea-level to the 90 fathom contour is 

 cut into ledges such as one sees in Uitenhage or Pondoland ; below 

 this the descent to 500 fathoms is steep, and there is so much 

 glauconite sand that the surface contours are obscured. Further 

 out, the sea-floor rises again to 200 fathoms, and in one place 

 opposite the Gamtoos River to 100 fathoms; this is the remnant of 

 the old Madaga^;car ridge. 



This stepped or terraced plain, covered with Alexandria Beds, 

 which are the same when examined from either the top or inter- 

 mediate levels or even from the lowermost at sea-level, belongs 

 therefore to one and the same period. I have called such a stepped 

 plain a klimakotopedim. Lyell describes a similar stepped plain in 

 miniature in his Travels in North America, London, 1845, vol. ii, 

 p. 39 : "In proportion as the Ohio falls gradually in level after its 

 inundations, it leaves a great succession of steps cut in its mud banks, 

 each from 4 to 10 inches above the other. It appears to me an exact 

 miniature representation of the form in whicli the waves have denuded 

 the land on the sides of some valleys in the limestone districts of 

 Sicily and other countries bordering the Mediterranean." The last 

 fact is important, and one which I have not seen mentioned elsewhere, 

 because this African stepped plain is covered with a deposit in whicli are 

 found species identical with the Mediterranean Mio-Pliocene forms. 



Since the land stood exposed down to the 400 fathom line it has sunk 

 and the ends of the rivers of South Africa show deeply excavated 

 rock channels now filled in with Pleistocene sand and clay. The 

 present movement apparently is an elevatory one ; recent sea-beaches 

 are seen along the shore elevated 10 feet above sea-level, but no 

 direct proof is forthcoming. 



The movements I have been discussing are direct elevatory ones, or 

 the reverse, of the solid crust and were caused by folding and 

 faulting. The alteration of sea-level due to tlie attraction of the 

 outstanding portion of the land on the water must also have been 

 intense; when the folded coast mountains were first formed a great 

 pull would have been exerted on the sea by these towering ranges, 

 and, as they became denuded and surrounded with debris and 

 eventually swamped by the sea, their attraction became reduced 



