The beds of white rocks are limestones which have formed from the precipitation of chemicals in a lake or ocean--an indicator of the presence of water.
(The beds of white rocks; are; limestones which have formed from the precipitation of chemicals in a lake or ocean--an indicator of the presence of water) (limestones; have formed; from the precipitation of chemicals in a lake or ocean)
The beds of white rocks limestones
are have formed
limestones which have formed from the precipitation of chemicals in a lake or ocean--an indicator of the presence of water
from the precipitation of chemicals in a lake or ocean