UNDER THE APPLE-TREES 
makes a sheer leap the whole distance, — twenty, 
thirty, or fifty feet, as the case may be, — the harder 
rock at the top always holding out while the softer 
layers retreat beneath it, forming in this respect min- 
iature Niagaras. When near one of these falls I 
seldom miss the opportunity to climb the side of the 
gorge under the overhanging rock and inspect its 
under surface, and feel it with my hand. The ele- 
ments have here separated the leaves of the great 
stone book and one may read some of the history 
written there. When I pass my hand over the bot- 
tom side of the superincumbent rock, I know I am 
passing it over the contours, the little depressions 
and unevennesses of surface, of the mud of the old 
lake or inland sea bottom, upon which the material 
of the harder rock was laid down more than fifty 
millions of years ago. There are here and there little 
protuberances, the size of peas and beans, which 
probably mark where little gas bubbles were in the 
old mud bottom. 
One thing that arrests attention in such a place 
is the abruptness of the change from one species 
of rock to another, as marked and sudden as a 
change in a piece of masonry from brick to stone, or 
from stone to iron. The two meet but do not min- 
gle. Nature seems suddenly to have turned over a 
new leaf, and to have begun a new chapter in her 
great stone book. What happened? There is no 
evidence in this region of crustal disturbance since 
46 
