GULLIVER. — SHORELINE TOPOGRAPHY, 159 



Professor Salisbury has given us a very pretty example of such epi- 

 cycles in' his Beacon Hill and Pensauken subdivisions of the Yellow 

 Gravel of New Jersey, and of what we may term vibrations in the 

 Jamesburg and later subdivisions.* He has found it possible to deter- 

 mine from the geographic form and position of the deposits the change 

 of level of the coast, though the changes are relatively so small that the 

 evidence of movement cannot be traced far inland. It is possil)le, on the 

 other hand, to trace the Tertiary peneplain for a considerable distance into 

 the interior, where for instance it is seen in the floor of the Great Valley ; 

 while the Cretaceous peneplain is the great surface of reference for 

 geographic features in the eastern United States. These cycle features 

 must not be regarded as the result of some sudden massive uplift, but 

 rather as the summation of minor vibrations and epicycles, during which 

 the average position of the land was such as to cause the Tertiary and 

 Cretaceous peneplains. 



Scandinavia (Atlas Univ., 29, 30) is a good example to show the 

 differences between cycle, epicycle, and vibration. Taken as a whole, 

 the peninsula is a depressed region, some portions being deeper drowned 

 than others. Two typical areas will illustrate this. The form of the 

 region around Stockholm (Swe., 67, 68, 75, 76, 77, and adj*ent sheets, 

 Swe. Geol., 50, 51, 52, 53) indicates that it was maturely dissected in 

 the previous cycle, and is now submerged to a greater and greater amount 

 out from the shore, as is shown by the large islands near shore, the 

 smaller islands off shore, and the minute islets and skerries out in the 

 Baltic. Baron de Geer makes the axis of greatest uplift in the recent 

 episodes of elevations in the central portion of Scandinavia.f This tilting, 

 at whatever time it occurred, is indicated by the increasing relief in certain 

 directions of "the topography of this area. 



The second region is in central Norway (Nor., 45, C, D ; 46, C, D ; 

 48, B; 49, A, B, C, D; 50, A, B, C, D ; 52, B, D ; 53, A, C, D; 56, 

 A, B). This area shows adolescent dissection of the upland, the land 

 being more continuous than in the first region mentioned. 



While in a large geographic way the Scandinavian peninsula is a de- 

 pressed area, there have been epicycles of elevation in which terraces 

 have been cut. | Recent vibrations are also shown by changes of water 

 level at the established water-marks (R. Seiger). 



* Ann. Rep. State Geol. N. J., 1893, 3&-328. 

 t See references. 



t See papers by Briigger, Chambers, de Geer, Hogbom, Kjerulf, Lyell, Miller, 

 Mohn, Munthe, Pettersen, Reusch, Sandler, Sexe, and Sieger. 



