excavation vs stone pit

excavation and stone pit both are nouns.

Word	Noun	Adjective	Verb	Adverb
excavation	Yes	No	No	No
stone pit	Yes	No	No	No

As nouns, stone pit is a hyponym of excavation; that is, stone pit is a word with a more specific, narrower meaning than excavation:

excavation (noun)	stone pit (noun)
the act of extracting ores or coal etc from the earth	a surface excavation for extracting stone or slate
the act of digging
a hole in the ground made by excavating
the site of an archeological exploration