476 C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA 



vation of about 1,100 meters, or 3,609 feet. The shores of the continents, and 

 the continents themselves, consequently appear much lower to the eye than is 

 actually the case ; the attraction of the sea to the land conceals to a great ex- 

 tent the contrast which really exists between continent and ocean. Listing 

 attempted fo determine the effect of the attraction in a large number of places 

 and found: London, 118 meters; Paris, 268; Berlin, 37.7; Konigsburg. 92.6; 

 island of Maranon (Brazil coast), 567; Bonin island, — 1,309; Saint Helena. — 

 847; Spitzbergen, — 217. [See also Dana: Manual of Geology, 1895, page 346. 

 Helmert has since shown that the calculations of Listing are based on erroneous 

 formula? and objectionable postulates. His recalculations have shown that all 

 irregularities of the geoid may not exceed the total of 200 meters. See Kriini- 

 mel, Handbuch der Oceanographie, 1907, p. 53.] 



"The significance of this fact becomes apparent if we suppose the attraction 

 to cease. That portion of the ocean which is now drawn up over the margin 

 of the continents would subside, many of the bays which deeply indent the con- 

 tinents would be laid completely dry ; the continents would gain somewhat in 

 extent, and a great deal in height and continuity. But while the continents 

 would gain in prominence, the ocean would gain in depth." 



"Carpenter, as we have said, estimates the mean height of the continents at 

 1,000 feet at most, Krummel at 440 meters ; the example taken to show the 

 influence of attraction gave 1,100 meters for the rise of the ocean, that is to 

 say, more than twice, indeed nearly three times, the higher estimate for the 

 mean height of the continents. Even supposing these figures to be exceptional, 

 and the mean result of attraction to sink to less than one-half the figure 

 quoted (a point on which I lack means of forming an opinion), there still re- 

 mains ground for a comprehensive correction of prevailing views" (I: 2, 3). 



Suess then discusses dislocations, contrasting them with transgressions, 

 as follows : 



"A dislocation, whether it consists in folding or faulting, is limited to a defi- 

 nite mountain system, often even to a very small part of it; a transgression 

 extends over a large part of the earth's surface. The intensity of a disloca- 

 tion is subject to very rapid local variations ; in a transgression, difference of 

 intensity, within the limits of a single region, can hardly be distinguished, and 

 a transgression may often extend over large areas in complete concordance 

 with the underlying beds." 



"Under various forms the theory has long been maintained that along with 

 the movements of the earth's crust, changes take place in the form of the sur- 

 face of the sea. The remarkable extension of certain transgressions leads us 

 to return to this view. A close investigation of the most recent events, such 

 as are indicated by ancient shorelines situated above the existing sea-level, 

 can alone lead to definite results. But even a hasty consideration of such 

 strand-lines suffices to show their complete and absolute independence of the 

 geological structure of the coast. In Italy the lines of former sea-levels are 

 met with on the various promontories of the Apennines in undisturbed horizon- 

 tality, here on limestone, there on the ancient rocks of Calabria, here once, 

 more on the ash cone of Aetna. The complete absence of any relation between 

 the ancient shore-lines and the structure of the mountains may be proved by 

 hundreds of examples. But the supposition of a uniform elevation or depres- 



