Brass starting to form at the end of the ejection port of my 10MM Rock Island. Is this normal?
Gary

Well, it happens with many of the 1911 style guns but also with others as well.
Recoil cycle and dwell time can play into this.  Things to look at:
Extractor could be holding too tight o out of tolerance.
Ejector not kicking the brass off and out, slide may not be traveling far enough to the rear.
Slide velocity can be part of the issue

I would say more normal than not.  probably 65% of my handguns do this.

Shadow and sqlbullet are both right. The only thing I have to add is if the dent is bending in the mouth of the case or just below it on the side, it's probably what Shadow has described. That would be very close to jamming and I'd check the extractor first.

If it's a slight dent about halfway down the side, that's pretty normal and can change in 10mm 1911s depending on the power level of the ammo. This sounds like what sqlbullet was describing. The slide is just moving forward and hitting the empty before it's out of the way. My Delta Elite has always done this. It usually cleans off without much trouble. It doesn't cause any issues for reloading.

If they look like this, it's not good 

My RIA 10mm does it,but as it is getting broke in it is less prevalent, I think once it settles in it may even stop doing it because it is almost not doing it now. I only have 200 rounds through it now. The loads I'm shooting are pretty spicey at 1200 FPS, and the brass is even pileing up in a nice pile about 8' behind me over to the right side a little. At first it would fling it at any random area about 30' away.

As others have said, completely normal.

If the brass discoloration bothers you, it's easily cleaned off with a little cold blue.

Jeff