﻿140 GEOLOGICAL ACTION OF 



tide is so well understood, that those persons who search for the property of stranded 

 vessels never go to the northward of the wreck when it lies to the south of the point of 

 separation, or to the southward when it lies to the north of it. And in this latter case 

 the movement is, as at Nantucket, opposite to the prevailing winds. The transportation 

 of such heavy materials as coal and hricks has been mentioned. Mr. Small, the keeper 

 of the light at Truro, from whom I have received much valuable information, communi- 

 cated another curious instance of the power of the current in moving heavy articles. 

 A briir of two hundred tons was stranded near Truro, and three weeks afterwards Mr. 

 Small picked up her anchor, which had some ten fathoms of chain cable attached to it, 

 about one and a half miles to the northward of the wreck. The anchor advanced, prob- 

 ably, by being turned over and over, the force of the water acting chiefly on the large sur- 

 face of the stock ; and the chain was dragged after. This illustrates the manner in which 

 the kelp on the rocks at Chelsea Beach may be supposed to facilitate their transportation. 

 Mr. Small also said, that, when articles float light upon the water, and offer a large body 

 to the resistance of the wind, they may, during the violence of the storm, be carried 

 against the current. During seven eighths of the time, to use the expression of Mr. 

 Small, the waves break on the shore at Truro in a direction to the northward of west, 

 the shore itself running north and south. This takes place in opposition to northerly 

 winds. If these winds are exceedingly strong, they may for a short time overcome this 

 prevailing tendency ; but as soon as the strength of the gale abates, the waves resume 

 their ordinary course. It is the same on the eastern shore of Sandy Hook and of 

 Nantucket, as I have myself observed. As the flood tide runs in a northerly direction 

 at each of these places, the idea is suggested that there is an intimate connection be- 

 tween the course of the current and the manner of approach of the waves to the beach ; 

 and if, upon further examination, this should prove to be the case, then the wave and 

 current actions combine to produce the same effect, and we shall be less surprised at 

 the transportation of heavy materials along the coast. 



The constructive process of the flood is equally exhibited in the way in which the 

 hooks, &c., are built up. They extend and increase always in the direction of the ad- 

 vancing current ; as, for example, the Great Point of Nantucket gains constantly to the 

 north, and the Point of Monomoy to the south, which are the directions of the flood cur- 

 rents at these two places respectively. And so with all the hooks, both great and small, 

 of the northeastern coast, whether formed on the borders of the sea, or in inclosed bays 

 and harbours. 



To return to geographical distribution. The shores of the United States, from Florida 

 to Maine, so far as alluvial deposits form the ocean border, exhibit similar features both 



