"THE PASSES" OF THE MISSISSIPPI. 551 



out to sea. The formation of the Mississippi delta at 

 its most southern or seaward part, is of the most curi- 

 ous and remarkable character, consisting here of 



" a long narrow tongue of land protruding nearly 50 miles 

 into the Gulf of Mexico, and terminating in several arms or 

 ' passes, ' which have a fan-shaped arrangement, the S.W. 

 pass (at the time of Sir Chas. Lyell's visit) being that through 

 which all the water was poured out, while each of the others 

 has by turns at some former period been the principal channel 

 of discharge. This tongue of land consists simply of two 

 low banks, covered with reeds, young poplars and willows, 

 and in appearance answers precisely to those of the river 

 in the alluvial plain." * 



The principal mouths by which the water finds exit 

 to the sea are the South West pass (spoken of above), 

 the South pass, the North East pass, and the Pass a 

 Loutre ; of these the South West pass is that by which 

 sea-going ships enter the Mississippi at present. 



An examination of a good atlas will show the ex- 

 ceedingly remarkable character of the formation at 

 the terminal arms of this delta, and will quite repay 

 the reader for a few moments' careful examination. 

 Lake Pontchartrain, the large and curious lake formed 

 to the eastward of New Orleans, is evidently a " cut 

 off," formed by the river out of the bed of the sea. 



An enormous area of swamp land extends up along 

 the alluvial plain of the Mississippi for nearly 500 miles 

 from its mouth. These bottom lands have an average 

 width of some 40 miles, and their total area is estimated 

 at about 32,000 square miles, of which comparatively 

 little has as yet been reclaimed. A narrow strip 



* Principles of Geology, by Sir Chas. Lyell, 1867, Vol. i., p. 447. 



