1889.] Origin of the Loess. 789 
Then the roots of the trees cut a great figure in this work. 
Think of the millions, yea, billions of roots and rootlets that have 
occupied the upper part of the gravel. I feel confident that there 
is not a cubic inch of ground in the forests as they exist here, 
that has not been occupied by a root or rootlet, from the sur- 
face to three feet down, in the last thousand years. What has 
become of them? In twenty years at most after cutting down 
a forest, no trace of the roots or rootlets can be found here. 
They do not leave their cast, or even a trace of brown mould. 
About two years ago I was riding homeward over the gravel 
road south-east of here (Rockville, Indiana), noticing the ex- 
posures along the road gutters. In many exposures the line 
between the " upper yellow clay " (as it is called here) and the 
under glacial clay (mixed with gravel) was as distinct and marked 
as the crack in a floor. When near the hill top on the east 
side of Raccoon creek, the surface clay suddenly changed to 
yellow sand. Away went my theory in a minute, which I had 
been years building. There was a small locality where the 
surface was .sand instead of clay. Trees had grown, shed their 
leaves, died and rotted there, and been succeeded by others as 
abundantly as where clay existed. Do trees turn to sand also ? 
I queried. Scarcely probable. But what has become of the 
trees, their leaves and rootlets, that have been growing on and in 
this sand for thousands and thousands of years ? A little brown 
surface mould about six inches thick is all I can see to represent 
Last May, while locating a bridge site across said Raccoon 
creek, I noticed in the .steep bank the ends of the roots and 
rootlets of stumps and dead trees, and in some of them all had 
decayed and been consumed except the bark, which was filled 
^^•ith a sandy loam the same as the surrounding earth. Been 
carried into the hollow bank by the floods, I thought. But I dug 
into the bank after them, and found them thus filled in the bank 
a distance of over three feet ; and in following these into the bank 
I ran across still others filled in in like manner, and lying parallel 
to the lines of the bank, where the flood never had touched them. 
Some of the roots were simply rotten wood inside of the bark, 
