94 
THE) STORY OR THE) OAK TREE 
ages, so that these finely ground particles of rock form 
the main bulk of the soil covering the earth. If all the 
soil in your garden, if all the soil in America were swept 
into the sea, the bare rocks beneath would after long 
years become covered with soil by the weathering of the 
rocks beneath. 
Dig through the soil and the sub-soil, and you will 
strike rock, as you know. But not all soil is of the same 
nature as the rocks beneath. The soil in your garden 
may have been carried there by the great ice sheets which 
swept the earth thousands of years ago. Some was laid 
by rivers long since dried, a rich dark soil which makes 
fertile the valleys in which it lies. 
I cannot stop here to tell you the story of the earth. 
Mother Earth, so the books tell us, is fifty million years 
old, and in fifty million years she has had too many ad¬ 
ventures to put into this little chapter or this little book. 
And all the time the sun looked on—what a story he 
could tell! Unwinking, the sun watched our earth, a 
whirling mass of flaming gas, cool and harden to hot 
rock, to cool rock, to sea! He saw mountains levelled, 
plains thrown up into hills; as he watched, the sea be¬ 
came land, and the land sea. That warm Mediterranean, 
on the shores of which the young Grecian priests heard 
their destiny in the whispering leaves of the sacred oak 
of Dodona—that warm sea was once a fertile valley, 
