374 Scientific Intelligence—Botany. 
the cypress timber of Louisiana and Mississippi, found that they 
measured from 95 to 120 rings of annual growth to an inch, and, 
according to the lower ratio, a tree of ten feet in diameter will yield 
5700 rings of annual growth. Though many generations of such 
trees may have grown and perished in the present cypress region, 
Dr Dowler, to avoid all ground of cavil, has assumed only two 
successive growths, including the one now standing ; this gives us 
in the age of the two generations of cypress 11,400 years. 
The maximum age of the oldest tree growing on the live oak plat- 
form is estimated at 1500 years, and only one generation is counted. 
These data yield the following table :— 
Geological Chronology of the last Emergence of the present Site of 
New Orleans. 
Era of aquatic plants, : : 1,500 years. 
,, of cypress basin, : 11,400 __,, 
», Of live oak platform, . ’ 1 BOG Ys 
Total period of elevation, 14,400 ,, 
Each of these sunken forests must have had a period of rest and 
gradual depression, estimated as equal to 1500 years, for the dura- 
tion of the live oak era, which of course occurred but once in the 
series. We shall certainly, then, be within bounds if we assume 
the period of such elevation to have been equivalent to the one 
above arrived at ; and, inasmuch as there were at least ten such 
changes, we reach the following result :— 
Last emergence as above, ‘ ; 14,400 years. 
Ten elevations and depressions, each equal 
to the last emergence, . : »  y Aa, OOO nie 
Total age of the Delta, 158,400 _,, 
In the excavation of the gas-works above referred to, burnt wood 
was found at a depth of sixteen feet, and at the same depth the 
workmen discovered the skeleton of a man. The cranium lay be- 
neath the roots of a cypress tree belonging to the fourth great level 
below the surface, and was in good preservation. The other bones 
crumbled to pieces on being handled. The type of the cranium 
was, as might have been expected, that of the aboriginal Ame- 
rican race. 
If we take, then, the present eraat . 14,400 years, 
And add three subterranean groups, each 
equal to the living (leaving out the 
fourth, in which the skeleton was found), 43,200 _,, 
We have a total of 57,600  ,, 
From these dates it appears that the human race existed in the 
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