oil leak coming from where??

I have an oil leak I just found. It looks like dirty oil. I do not believe it is trans fluid. It is leaking down from between the engine and transmission as far as I can tell. There is a cover that extends down right in front of the transmission oil pan and I believe behind the transfer case. The oil is coming through what appears to be a hole in this cover(?) and also from its edge. I call it a cover because that is what it looks like. It does not look like it should be sealed. So I think the oil is dripping down and accumulating on top of this cover and then leaking out. My trans fluid appears to be full. I did not check the oil as I just realized it might be engine oil. I was originally thinking transfer case oil which it still could be.

So any ideas what could be leaking in this area? Any idea what it will cost to have it fixed? Would this be covered under the engine warranty? Is there a way to check the level of the transfer case oil?

Thanks so much and sorry for the poor description. I did the best I could.