It's sedimentary my dear Watson!
I rock. You Rock. We Rock. Disclaimer: This joke was made during a 6 hour road trip with the family. My only scenery was rocks.
Nothing. Because rocks don't talk and geology's not funny.
Foehn
A hawkie talkie.
said Watson. "It's a lemon tree, my dear Watson."
Watson
A-lemon-tree my dear Watson.
Elementary, my dear Watson.