What did mark twain say about the nonsense side of extrapolation in life on the mississippi?

Twain begins his indication of frustration with those who tried to use extrapolation to predict anything about the river by citing statistics that showed the lower Mississippi River had "shortened itself two hundred and forty-two miles" over a period of one hundred seventy-six years. Twain creates an average rate of change based on this distance and time ("a trifle over a mile and a third per year"), then uses extrapolation to draw the ridiculous conclusion that just a million years ago next November, the Lower Mississippi was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-pole.