As the settlers depart on their voyage, their friends & family sing "Auld Lang Syne" to them. This scene takes place in 1777 and "Auld Lang Syne" wasn't written until 1788.
Patriarch Thomas Hall reads from a 1777 newspaper and refers to George Washington as 'that young Washington.' In 1777 George Washington was already 45 years old, having been born back in 1732.