SEDIMENTARY rock
Has been formed in layers
Often found near water sources
With fossils from decayers

Then there's IGNEOUS rock
Here since Earth was born
Molten Lava, cooled and hardened
That's how it is formed

These two types of rocks
Can also be transformed
With pressure, heat and chemicals
METAMORPHIC they'll become.

( Don't forget to sing this as a "Round"; after all, it is the Rock "Cycle"! )