“ Alluvion and diluvion are constantly taking place, especially along the seaboard, and in Noakhali district the land is said to have made rapid advance on the sea; while the islands fringing the mouth are annually being cut away and redeposited in fresh shapes. The regular rise of the tide is from 10 to 18 ft., and at springs the sea rushes up in a dangerous bore. It is greatest at the time of the biennial equinoxes, when navigation is sometimes impeded for days together. ”