[Todd L]

I'm hoping someone can help me identify this whitish almost-fuzzy looking *growth* on my rock. I noticed it in one spot some time ago, and now that spot has not only got to be larger but now I see it in a few other areas in small amounts.

I read through the Hithchikers Guide that was posted some time back (awesome articels! thanks!) and it sort of leads me to believe it may be sponge, but I'd like to make sure. I have noticed a hole in here and there in it's structure. It sort of lays flat and hugs the shape of the rock.

Anyone have any ideas?

Thanks,
Todd