what is this layer on top of my secondary?

Hi everyone, this is my first post!

I've been brewing for about a year, and recently started all-grain batches. I haven't had any snags with a batch up until now, so I'm very curious as to what's happening with my latest batch. This is my second all-grain batch, and I did a pretty traditional style Kölsch. After 5 days in primary at 64 F and 9 days in secondary at 60 F, I moved it to my new fridge for a month of cold conditioning at 42-44 F. I'm two weeks into that month, and this thin, lighter-colored layer has settled on top. It doesn't look like there is anything growing on top, so I'm a bit flumoxed as to what it really is. Some of my guesses are a thin layer of the healthier Kölsch ale yeast floating along doing their thing (since it is top-fermenting, after all), or maybe alcohol settling out (this doesn't make as much sense to me, but like I said, I'm guessing). I've included a profile photo to help with the diagnosis -- can anyone help me figure out what this is?

Thanks a bunch!
Wade

Yeast, proteins, hops, other particulates, it will clear and settle.

A much delayed thanks! to you COLObrewer. That eased my mind enough to wait the month or so that it took to indeed settle out.

I guess I was just surprised at how sharp the gradient shift was between the two layers, but like you said, it all settled out and the beer was fantastic tasting, if I do say so myself. Here's a photo of the finished product, the first recipe of mine that I will absolutely have to brew again soon:

Good on you sir!