222 PROCEEDINGS OF THE AMERICAN ACADEMY 



by others, not along the coasts of Europe merely, but even in the 

 southern hemisphere, marks having been established by order of the 

 British government on the coast of Van Diemen's Land, for the same 

 purpose. Were it necessary to urge the paramount importance of 

 such examinations, both in a scientific and practical point of view, 

 your committee would simply recall the words of that illustrious natu- 

 ralist, Alexander von Humboldt, who says, ' If similar measures had 

 been taken in Cook's and Bougainville's earliest voyages, we should 

 now be in possession of the necessary data for determining whether 

 secular variation in the relative level of land and sea is a local phe- 

 nomenon, and whether any law is discoverable in the direction of the 

 points which rise and sink simultaneously.' If such a law exists, it 

 can be demonstrated only by a sufficient number of observations made 

 on the several continents. 



" Your committee deem the establishment of similar land-marks 

 on the American continent the more important, because the whole 

 eastern coast of the United States exhibits evidence of a gradual rise 

 of the land during the nrt)st recent geological periods, in the deposits 

 of recent marine shells, which are to be seen, undisturbed in their 

 natural position, many feet above the highest tides. There are, more- 

 over, direct indications of a gradual rise of the land actually in prog- 

 ress on and around the island of Newfoundland, and, according to one 

 of your committee, similar indications may be traced along the coast 

 of Maine. 



" A system of land-marks established at measured heights above 

 mean sea-level on both shores of North America, within the limits of 

 the United States, would eventually determine whether any changes 

 in the relative level of sea and land take place, and whether such 

 changes, if they do take place, are general or local, and whether there 

 is any thing like a balance movement in this continent, whereby one 

 coast rises while another sinks. 



" The preliminary step to be taken is to cause a series of careful 

 tidal observations to be made at the places where the marks are to be 

 established, in order to determine the mean sea-level at those places, 

 to serve as a fixed plane of reference. These observations might, as 

 your committee suppose, be made under the direction of the Superin- 

 tendent of the Coast Survey, whose well-known regard for science 

 warrants the belief that he would cheerfully lend his aid to accomplish 

 that important object. Your committee, therefore, propose that the 



