162 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the geographic results of continental movements. Enough that it be 

 granted as a possibility of geology that such uplift of a land mass may 

 take place. 



The form of the land at the initiation of a new cycle of development is 

 a most important consideration, and it is one which is most frequently 

 left out of the discussions of elevation and depression. The form of the 

 land at the beginning of a cycle depends upon the stage of development 

 reached in the previous cycle, as well as upon the amount and rate of up- 

 lift. The ideal case here considered is taken where a coast of homogene- 

 ous structure had been developed to late adolescence or early maturity in 

 the previous cycle, and the uplift was supposed to have been sufficient in 

 amount to bring all the coastal and shore forms, developed in the pre- 

 vious cycle, considerably above sealevel ; and this uplift took {dace, not 

 suddenly, but steadily, so that the sea did not have time to appreciably 

 attack the land while it progressively rose. A diagrammatic represen- 

 tation of the resulting form is given in Figure 3. The forms of the 

 shoreline and of the inland and seaward areas will each be separately 

 considered. 



(1) Smooth Bottom. — The waste from the land, brought down by 

 the streams or worn off the coast by the waves, would have been spread 

 out by the currents in the previous cycle, thus causing the bottom to be 

 smooth out from the new shoreline. In the ideal case which we are here 

 considering, the bottom would consist of the finer waste of the previous 

 cycle, where the sea currents had built it up into the continental delta, at 

 a depth below the deepest wave attack. Such sedimentation in the pre- 

 vious cycle would have filled any irregularities then existing, so that the 

 bottom offshore from the initial shoreline would be monotonously level 

 or gently undulating. 



(2) Simple New Shoreline : Buenos Ayres. — Where the ocean or 

 other large body of water now intersects the land there will be initial 

 shore features. At first before the waves have had time to attack the 

 coast the outlines will be simple, the land gently sloping toward the sea 

 and ending in broad, undulating curves, probably convex where large 

 rivers enter. As the initial land surface would have but a slight dip 

 seaward, it having been formed under water, the sea would leave ex- 

 posed at low tide a wide area of flats. The most marked feature in 

 this new born shoreline is its slight crenation and long curves. It would 

 take but a faint convexity of the land surface to give a convex shoreline. 



The Ai'gentine Republic southeast of Buenos Ayres has a shoreline 

 upon a gently sloping land, very nearly flat. Before the present chan- 



