Assertion: volcano's eruption | /r/AtLocation | some point
Facets:
value: in prehistory
type: TEMPORAL
Source sentences:
text: At some point in prehistory, an earlier caldera-forming eruption had occurred, leaving as remnants Verlaten (or Sertung); Lang (also known as Rakata Kecil, or Panjang); Poolsche Hoed ("Polish Hat"); and the base of Rakata.