Input (grade 11): A build up of water in the Upper Bay allowed the river to break through to form the Narrows less than 12,000 to 13,000 years ago as it exists today (see; Waldman, 2000).
Output (grade 10): A build up of water in the Upper Bay allowed the river to break through to form the Narrows less than 12,000 to 13,000 years ago as it exists today.