CHAP. XXIX.] TIDES AND CURRENTS. 121 



one for running a vessel aground. To exaggerate rather than 

 underrate, the quantity of sediment newly deposited by the river, 

 is the bias of each witness, although their statements may in the 

 main be correct ; for in the contest annually carried on between 

 the river and the sea, there is unquestionably a vast amount of 

 destruction and renovation of mud-banks and sand bars. In 

 these changes the action of the tide, and the power of the break 

 ers during storms, and a strong marine current, all play their part. 

 There seem to be well-authenticated accounts of anchors cast 

 up from a depth of several fathoms near the mouths of the river, 

 and heavy stones sunk sixteen feet deep, and found afterward high 

 and dry on shoals. The ballast also of several wrecked vessels, 

 the submergence of which, in two or three fathoms water, had 

 been ascertained, have in like manner been thrown up, above 

 high water mark, on newly formed islands. 



All the pilots agree, that when the Mississippi is at its height, 

 it pours several streams of fresh water, tinged with yellow sedi 

 ment, twelve or more miles into the gulf, beyond its mouths. 

 These streams floating over the heavier salt water, spread out 

 into broad superficial sheets or layers, which the keels of vessels 

 plough through, turning up a furrow of clear blue water, form 

 ing a dark streak in the middle of the ship s wake. I infer, 

 therefore, that both in the summer, when the swollen river is 

 turbid and depositing mud, and in the winter, when the sea is 

 making reprisals on the delta, there is a large amount of fine sed 

 iment dispersed far and wide, and carried by currents to the deeper 

 and more distant parts of the Gulf. To this dispersing power I 

 shall recall the reader s attention in a future chapter, when dis 

 cussing the probable antiquity of the delta. 



March 2. We returned to New Orleans in the same steamer. 

 It is remarkable that for more than 150 miles above the Balize, 

 there is only one of those great bends in the course of the Missis 

 sippi, which are so general a character of its channel north of 

 New Orleans. The exception is the great sweep called the English 

 Turn. Mr. Forshey imputes this difference in the shape of the 

 bed of the river to the distinct circumstances under which a 

 stream is placed when it shapes out its course through a deposit 

 VOL. TI. F 



