450 



MUD-LUMPS OF THE MISSISSIPPI. 



[Ch. XIX. 



heavy stones from a vessel which was known to have been 

 wrecked in water ten feet deep. The island of the Balize 

 originated in this manner, and five salt springs were described 

 as rising in it, by certain French surveyors, as long ago as the 

 ear 1726 * Mr. Forshey states that, in 1832, a mud-island 

 made its appearance in the middle of which a spring issued. 

 These new islands, as we learn from the subsequent survey of 

 Captain Talcott in 1839, vary from an acre to several acres 



Pig. 34. 



S. View of Carr's Lump, N.E. Pass. 

 Extreme height above low water, 8 feet. 



in extent. The gradual rise of some of them was watched 

 during the survey, from two feet below water to three teet 

 above it, and it was observed that they were always situatea 

 of some one of the mouths of the river. They have never been 

 known to make their appearance in that part of the del 



modern additions are oeing made to the 



Sometimes 



the level of the sea (see figs. 34, 35). They are composed 

 almost entirely of tenacious mud, usually homogeneous, 

 ^dAnallv miTMl with sand. This mud is chiefly pusn 



some of it consists of matter 



spring to the top of the dome 



on the surface on all sides, over 



a mass, auu "*-■ ~ ■ - 



which the muddy water 



ocq 1S59-60. 



* Thomassy, Bulletin cle la Soc. Geol. de France, tome xvn. p. M*. 





- 



is 



rather t 



