It makes me think of Mossy Maple Polypore - Oxyporus populinus.
Unknown Polypore
12/14/06 in Pisgah Woods, Northboro
It is about 4" wide. Growing on a dead tree that I think
was an oak but could be a maple. The black top of the bracket attracted my
attention. It pealed off the tree quite easily. It is light in
weight. It did not yield a spore print, overnight, so it might be dormant
or dead. The pores are very small and can not be seen with the naked eye.
It makes me think of Mossy Maple Polypore - Oxyporus populinus.
Underside
Pores photographed next day in micro mode.
Note the cracks formed due to drying overnight.