CHAP. III. DELTA OF THE MISSISSIPPI. 43 



Delta of the Mississippi. 



I have shown in my Ti'avels in North America that the 

 deposits forming the delta and alluvial plain of the Missis- 

 sippi consist of sedimentary" matter, extending over an area 

 5)f 30,000 square miles, and known in some parts to be several 

 hundred feet deep. Although we cannot estimate correctly 

 how many years it may have required for the river to bring 

 down from the upper country so large a quantity of eai'tby 

 matter — the data for such a computation being as yet 

 incomplete — w^e may still approximate to a minimum of the 

 time which such an operation must have taken, by ascertain- 

 ing experimentally the annual discharge of water by the 

 Mississippi, and the mean annual amount of solid matter 

 contained in its w^aters. The lowest estimate of the time 

 required would lead us to assign a high antiquity, amounting 

 to many tens of thousands of years (probably more than 

 100,000) to the existing delta. 



Whether all or how much of this formation may belong to 

 the recent period, as above defined, I cannot pretend to 

 decide, but in one part of the modern delta near New 

 Orleans, a large excavation has been made for gas-works, 

 where a succession of beds, almost wholly made up of 

 vegetable matter, has been passed through, such as we now 

 see forming in the cypress SAvamps of the neighborhood, 

 where the deciduous cypress (^Taxodixim distichum'), vf\ih.\i^ 

 sti'ong and spreading roots, plan's a conspicuous part. In this 

 excavation, at the depth of sixteen feet from the surface, 

 beneath four buried forests superimposed one upon the other, 

 the workmen are stated by Dr. B. Dowler to have found 

 some charcoal and a human skeleton, the cranium of which 

 is said to belong to the aboriginal type of the Red Indian 

 race. As the discovery in question had not been made 

 when I saw the excavation in progress at the gas-works in 



