History
The storms and waves that followed the Drowning of Númenor almost destroyed Tolfalas and left it like a barren and lonely mountain in the water not far from the new mouths of the Anduin, because the east of the bay of Belfalas was filled with new land and the river Anduin had to carve a new path by many river mouths to the bay. Before the Drowning of Númenor the city of Pelargir had been only a few miles from the sea and was far inland afterwards.
Ships that wanted to sail up the Anduin from the Bay of Belfalas passed Tolfalas on its eastern side and then took a canal that had been made by the Númenóreans in the middle of the delta of the Anduin.
Other versions of the legendarium
The spelling Tolfalas is used in an earlier typescript version of what would later become Appendix A, in an outline that was made during the writing of The Two Towers where it is mentioned that the Men of Harad (then called the Men of Harrowland and by other names) had taken the island and on the First Map of The Lord of the Rings.
