Would it be some weathered Horsehoof fungus by any chance? But I thought they would have appeared singily rather than in a group as in your pic.
ps don't take my word for it, I'm still learning too
I thought that to begin with Pandabean, but like you say I'm not certain considering how many there are all in one place. Having had a little look in a book borrowed off my mum I think it might be old beefsteak fungus?
Still not sure though!
Sorry for the double post but I still cannot edit my posts.
Another possibility.... what about shaggy bracket? Inonotus hispidus.
Im not too sure on the dead polypore idea....see below a photo from a nearby tree which is quite abundant with polypore. They just seem to shrivel up and don't as far as I am aware occur in a similar fashion to your ones.
IMG_9195 by pandabean2010, on Flickr
Yeh there is a problem with the board, already posted in the bugs forum about it.
My book says the Giant Polypore usually grows near the base of the tree or close to the ground on roots. The original photo looks like it is a few feet off the ground.
Is it growing on Elm or Poplar? Difficult to tell from the pic...might just give a clue that's all...