306 ANNUAL OF SCIENTIFIC DISCOVERY. 



1. Quantity of water discharged by the Mississippi river, annually 5 

 14,883,360,636,880 cubic feet. 



2. Quantity of sediment discharged by the Mississippi river, annu- 

 ally, 28,188,083,892 cubic feet. 



3. Area of the Delta of the Mississippi, according to Mr. Lyell, 

 13,000 square miles. 



4. Depth of the Delta, according to Professor Riddell, 1,056 feet. 



5. The Delta, therefore, according to 3 and 4, as above, contains 

 400,378,429,440,000 cubic feet, or 2,720 cubic miles. 



6. According to 2, it would require for the formation of one cubic 

 mile of Delta, five years and eighty-one days. 



7. For the formation of one square mile, of the depth of 1,056 feet, 

 one year sixteen and one-fifth days. 



8. For the formation of the Delta, according to 2, 3, 4, time required 

 14,208 4-5 years. 



9. The valley of the Mississippi, from Cape Girardeau to the Delta, 

 is estimated to contain 16,000 square miles, of 150 feet depth ; it there- 

 fore contains 66,908,160,000,000 cubic feet, or 454J cubic miles. 



MUD LUMPS IN THE MISSISSIPPI. 



Among the many mysterious operations of nature, one of the most 

 singular, and at the same time apparently inexplicable, is the forma- 

 tion of what are termed " mud lumps," in the delta of the Mississippi 

 river. At frequent intervals, small islands composed of clay and mud 

 suddenly make their appearance on either side of the channel, above 

 the surface of the water, jetting mud and water from an orifice in the 

 centre, something like a small mud volcano. The action continues 

 until an island is formed, sometimes to the height of twelve or fifteen 

 feet above the level of the water, when its operations cease, as appa- 

 rently without cause as had been their beginning. And not always is 

 this mysterious formation confined to the still waters on either side of 

 the channel. Often when a ship grounds upon the bar, an island sud- 

 denly appears under her lee, changing the channel and puzzling the 

 pilots to their utter disgust. 



Many theories have been suggested as to the probable or possible 

 cause of this phenomenon, and much ingenious speculation thereon 

 has been brought forward, but without leading to any convincing or 

 satisfactory explanation. Professor Forshey, and Lyell, the geologist, 

 suggested a subterranean connection with the springs of more north- 

 ern latitudes ; but one of the difficulties with this theory is to account 

 for the non-appearance of the " mud lumps " any where else than in 

 the delta of this river. Mr. Sidel endeavored to find a cause for these 

 formations in the evolution of gases formed by the decomposition of 

 vegetable matter buried under the alluvial deposits of the river; Avhile 

 the pilots of the Balize have, with a semi-seriousness, ascribed them 

 to witchcraft or magic. None of these theories give a reasonable 

 cause, nor suggest any possible removal of the difficulty, Avhich has 

 so long been a serious detriment to the deepening of the bar at the 

 mouth of the Mississippi. 



