Poisonous Mushrooms.. .or just Mushrooms?

Today I was wondering around my apartment complex and noticed some fairly large mushrooms growing in a small group of about 6-9 mushrooms and thought I would photograph them and make a post about them on steemit.

I'm not a mushroom guru or anything, but my neighbor says she thinks these particular mushrooms are probably poisonous. She speculates this because of the large size and also the growths on the heads of them, not sure what they're called.

I'd say the average width of the mushroom heads are about 4-6 inches in diameter, and the height is probably about 3-5 inches tall. The color is obviously white, sort of c chalky white with a bit of peeling on the outer tops of the heads, kind of looks like dead skin or maybe some kind of growth like fungus or algae. I'm not sure. As I said, I don't really know much about mushrooms. However, I though that maybe you all could give me your opinions on what you think they might be as far as category of mushrooms and whether or not this kind of mushroom is poisonous or not.