118 LECTURES. 



undertaken in this delta, no water-work built in one of its bayous, 

 no channel can be cut, no sort of improvement proposed, but that at 

 once a question arises about the former events at that place, and tlie 

 men commissioned with the execution of the work must carefully 

 study the history of the locality where the contemplated improvement 

 is to be made. 



Nearly the same is the case with the whole extent of sea-shore on 

 the eastern side of the United States, from Cape Florida to Cape Cod, 

 a line of more than 1,500 miles. All these shores are likewise low 

 and sandy, and form a barrier very easily affected by the attacks of 

 the mighty Atlantic. There is on this coast scarcely a harbor in or 

 before which changes have not taken place at some period or other. 

 The far stretching beaches of North Carolina, of Maryland, and New 

 Jersey, have been broken through by the waves at diiferent times and 

 places; and the same waves have shut and filled up in another year 

 the gaps they had previously made. The whole coast of New Jersey 

 is believed to be in a state of subsidence. Entrances formerly navi- 

 gable have completely disappeared ; and some of these ocean doors, 

 the history of which we are somewhat acquainted with, appear to 

 have been alternately opened and shut again nearly every ten years. 

 The spit of land which forms the famous cape of Sandy Hook has 

 been in the course of 50 years four times an island, and four times 

 again a part of the mainland. 



To watch closely all these changes, and to follow them and lay 

 them down on paper with rule and compass, would have no other 

 than a historical interest for us, if they did not follow in their mo- 

 tions certain luios, if the currents, waves, and gales of the ocean, with 

 their destructive results, operated accidentally like the flashes of 

 lightning, which fall now here and now there. But from what little 

 ■we know it is quite evident that such laws exist, that the Ocean in 

 his attacks follows a certain strategic plan — directing his unwieldy 

 powers for one period constantly in a certain way, and for perhaps 

 another century in an opposite one — leaving certain points unharmed, 

 and assailing others with uniform persistency. But if the ocean thus 

 follows a certain plan, then it is obvious that this plan is worth 

 studying ; that we must try to avail ourselves of some such strategic 

 art as may enable us to countervail its action, and prevent or at 

 least avoid mischief; and that it is in many respects most essential 

 for us to know the points which have for ever remained safe, and those 

 which are the most exposed, and the manner in which they have been 

 and probably will continue to be assailed. And there is no other 

 means of acquiring this information than by constantly, from year to 

 year, daguerreotyping the physiognomy of these coasts, and in this 

 way detecting the laws of those unwieldy movements. 



On this side of the Atlantic there are only the coasts of Maine and 

 parts of New England which are so rocky, so elevated, so soundly 

 built by nature, that they may almost be called unchangeable, and 

 for which, consequently, former maps, in respect to .the observation 

 of physical changes, would be of little use. But even in the neigh- 

 borhood of these coasts there lie, on the bottom of the ocean, many 

 broad banks and shoals the soundings of which may not be always 



