geology vs proterozoic

geology is a noun but proterozoic is not a noun.

Word	Noun	Adjective	Verb	Adverb
geology	Yes	No	No	No
proterozoic	No	Yes	No	No

geology (noun)	proterozoic (noun)
a science that deals with the history of the earth as recorded in rocks

geology (adjective)	proterozoic (adjective)
	formed in the later of two divisions of the Precambrian era