Just a quick look in a fungus book will tell you Oyster fungi grow on wood and usually (but not always !) has an off centre (eccentric) stem, and will normally be growing in a big bunch (tiers)
It is possible they could be on buried wood, but in your photo we can clearly see a central stem, with decurrent gills (running down the stem) so together with cap colour (despite the flash) I would say you have
Clitocybe nebularis.
Neil.
