Tides Illustrative of Geological Phenomena. 221 



when a whole country has been carefully examined from the 

 shore to its higher summits, we shall have certain and satisfac- 

 tory data for some grand deductions. We may then hope to 

 learn which terraces belong to one and the same epoch, and 

 to what extent they are measures of the elevations of a country. 

 After these points are determined, we may look for a full 

 elucidation of the former changes of level a continent has 

 undergone during the period included, or perhaps may prove 

 coincidences between distant countries, that will point to some 

 principles in geological dynamics, yet but half acknowledged. 



The writer has said nothing upon the effects of glaciers, as 

 they will be better learned from those who have made them 

 their study. The course of investigation pointed out, pre- 

 cedes the application of any theory to account for the facts. 



We do not attempt a review of the known facts relating to 

 terraces in this country, since they can establish little more 

 than the general truth of their existence, until a systematic 

 series of observations is carried out. 



On the Tides, as Illustrative of Geological Phenomena. 



Among the discoveries in science recently made on this 

 side of the ocean, is one which has excited much interest 

 among geologists and navigators ; and which seems to us 

 equally to merit the attention of scientific men in Europe. 

 We mean the tide-theory of Captain Davis, recently laid be- 

 fore the Association of American Geologists and Naturalists 

 in Philadelphia. Having had occasion to become familiar 

 with the elements of this theory during a stay of several 

 months this summer on board the vessel commanded by 

 Captain Davis, as the officer superintending one of the divi- 

 sions of the United States Coast Survey, we thought it might 

 be profitable to publish a sketch of the principal results at 

 which our learned friend has arrived after long and patient 

 investigations.* 



The eastern coast of the United States is bordered through- 



* Mr Davis is now engaged in preparing a detailed paper on this sabject, 

 which will appear in the Transactions of the American Academy. 



