Where is Stonewood?

So I'm confused. I'm at the point where I have to make the Wishful Aurosa outfit but one item is supposed to use a Scarfworm from Stonewood. I don't see Stonewood on my map so I did a little Googling and see that it's possibly part of a quest from Chapter 3. But I'm on Chapter 8. I have no recollection as to whether or not I've done this Stonewood and Flight quest so I went to see if I could restart it or something. It doesn't look like I can. So, what do I do? Thanks.