Found while removing lawn leaves. Can I get some ID?

I've been removing foliage from my lawn when I noticed there were mushrooms growing under it.

http://imgur.com/LJcs9bf
http://imgur.com/0e6qGGw
http://imgur.com/ngWxb4A
http://imgur.com/L9XHtGg

They were found under a chestnut tree, close (2m away) to an oak tree forest, fall foliage is mainly composed of oak leaves.

I've never seen them before, this place is known to have poisonous amanita (panterina, muscaria), different species of boletae and lactarius. I live in SW Europe.