Assertion: cave | /r/MadeOf | lake
Facets:
Source sentences:
text: Composed mainly of two types of limestone (Coeymans and Manlius) from different periods in the Earth's early history, deposited hundreds of millions of years ago when the Atlantic Ocean stretched far inland, the cave contains a lake, called the Lake of Venus, as well as many speleothems.
text: Many caves contain unique life forms, underground streams and lakes, and have unusual mineral formations called speleothems.