id	keyword
gc-224	rudist
gc-224	coral
gc-224	reefs
gc-224	cardenas
gc-224	fig
gc-224	cretaceous
gc-224	formation
gc-224	units
gc-224	section
gc-224	rudist reefs
gc-224	mexico
gc-224	carbonate
gc-224	fauna
gc-224	marls
gc-224	upward
gc-224	sandstones
gc-224	sediments
gc-224	radiolitid