If we read [wiki]Vana Parva, Mahabharata/Book III Chapter 81[/wiki]
We find mention of Saptasaraswata (सप्त सारस्वत) (3.81.97), where the celebrated Rishi, Mankanaka (मङ्कणक), had obtained ascetic success.
This indicates there were seven Saraswatis ? But where?