Crossword Clue:

long period of time

AnswerCrossword Clue
EONLong period
AGELong period
ERALong period
EONVery long period
ICEAGEPeriod when Long Island was formed
SPANPeriod of time
ERAPeriod of time
SPELLPeriod of time
HOURPeriod of time
WHILEPeriod of time