Depending on what English translation you're reading you may see this rendered as "the coasts of the earth," "the sides of the earth" or "the ends of the earth."
Brachiopods aren't an evolutionary dead-end which got wiped out in a mass extinction. Well, there was a mass extinction, but it didn't wipe out the Brachiopods. Many were buried in Noah's flood but many alive today.
If you want to believe that earth is flat no one's going to stop you. However nothing in the Bible, either in the meaning of words or in the context of passages, requires you to believe that earth is flat and has an edge.