The island can split into two islands by a shallow isthmus according to the sea level .
When islands are split the larger island on the west is known as Saint Paul 's Island while the smaller one on the east is known as Quartz Island .
The island can split into two islands by a shallow isthmus according to the sea level , and when they are split the larger island on the west is known as Saint Paul 's Island while the smaller one on the east is known as Quartz Island .