I'm merely guessing these are Ganoderma lucidum bracket fungus, but
they're not as shiny on top as G lucidum would usually be, & I can't see
that they are particularly stemmed underneath but are more purely
shelf-like. So I am probably guessing in entirely the wrong direction,
having very little knowledge of fungi. Anyhoo, here are two pictures of
them growing on the side of a rotting fireplace round:

http://www.paghat.com/images/bracketfungus1_feb.jpg

http://www.paghat.com/images/bracketfungus2_feb.jpg

They're only about two inches or two & a half inches wide, quite thin, &
strongly striped. They growing native here on west side of Puget Sound
geographically near the rain forest. The decaying round they're growing on
is fir. I'd settle for being sure of the genus, but if anyone can judge
the species from just photos, great.

I'm going to preserve this spot as-is so that the brackets continue to
grow. I think they're gorgeous.

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/