T. M. Reade—Denudation of the two Americas. 291 
In a GALLon (56,000 GRarns). 
Potash sulphate, Grains. 
chloride, 3°154 
Caleinm chloride 
Sages 2 SAT aE ET 2°455 
Poi . 1°753 
Cale carbonate bid alas i 6 7-307 
Magn 
Otpatiie mater pe Ou 0°818 
Total solid residue. 15-487 
? 
According to this sah ele the proportion of total solids in 
solution is by weight 5. If we take the mean annual dis- 
charge of the Mississippt a at 641, 666, 666, 666 tons* in round tig- 
ures, “there are 150 million tons of solids in solution per annum 
poured into the Gulf of Mexico by the Mississippi, a truly re- 
markable quantity, which if reduced to rock at 15 feet to the 
ton is represented in round numbers by 80 square thes, 1 foot 
thick, According to Messrs. Humphreys and Abbot the pro- 
portion of sedimentary matter to the water by weight is 
and the total discharge of matters in suspension Moyyttigen: the 
three outlet bayous is according to them 362,723,214 tons. 
The amount of matters in solution vary within certain limits 
are removed in solutiont and from the Danube basin 90 tons 
80 sar tg isa mean and probably correct. 
s been estimated that the ain of the Mississippi is 
velar at the rate of one foot in 6,000+ years, but this rate has 
been calculated from the removal of sediment alone;§ if we add 
to the matter rernoved mechanically that in solution it will 
raise the rate to one foot in 4,500 years.| What stronger evi- 
* Report of ee tag and Abbott, (1876), p. 146, 19,500,000,000,000 cubic 
feet ne 28 feet to the 
e, Text bok ‘of Geology, ¢ Chemical Denudation, p. 20. 
$ According to the figures I have Yate it would be one foot in 6. »375 years 
| This is estimated as follows: Drai inage area 1,244,000 square miles, ann 
sedimentary Gocaree he =: same area 362 723, oe tons, solids in solution 
150, 000 ,900 tons, the k estimated at 15 feet to the ton. wsge 4 
speaking , to this should | be wadded | ca cr 000 cubic feet of matter, estim. 
be pushed along the bottom and the dise harge from the bayous. For simplicity’s 
sake I omit these elemen’ 
