EXPLANATION.
Project Gutenberg EPUB3 edition
Ovid and Riley, Henry T. (Henry Thomas)
This story is simply based upon physical grounds. The river Acheloüs, running between Acarnania and Ætolia, and flowing into the Ionian Sea, carried with it a great quantity of sand and mud, which probably formed the islands at its mouth, called the Echinades. The same solution probably applies to the narrative of the fate of the Nymph Perimele.