I use ordinary 2 part epoxy that is easy to come by at any hardware store. They have many varieties, each with a different set time. It doesn't really matter which one you get for this kind of repair. I prefer the slow set variety. It hardens like stone. Then file it down, then sand it to the required edge contour. I have fixed gashes like that with epoxy and used my router to recut the entire bearing edge. A router won't chip it out, it is good stuff. Once I mixed wood shavings into the epoxy and used that to give it a woody appearance. But no one is going to see it anyway under a drum head, so I wouldn't bother with adding wood sandings or shavings.
Skydog75 is bang on with his suggestion because it is a two part epoxy with wood particles added. If you can afford a can, go for it. But I would just get a new package of epoxy with the 2 different tubes, one resin, one hardener and have at it.