Seems like these should be something easy like a Galerina autumnalis but the spores did not cooperate. Growing on a large old log, very hygrophanous, a thin veil, but spores that look smooth and with a small apical pore. The spores averaged ~ 8.0 X 5.0 microns. Hopefully, Doug The LBM Specialist, can shed some light. While my spore measurements seem a little larger for either K. mutabilis or K. vernalis, everything else does fit and the mutabilis is said to be a Fall mushroom.