Bonnet?

Bonnet?

Observation - Bonnet?. Description: Clump growing on fallen birch tree. Cap dark brown, turning paler after picking. Bell-shaped in field, more umbonate later, slightly striated edge, 1.5cm across. Gills pale with darker edge, distant, different lengths. Stipe dark brown, 2cm long, 2mm wid

Clump growing on fallen birch tree. Cap dark brown, turning paler after picking. Bell-shaped in field, more umbonate later, slightly striated edge, 1.5cm across. Gills pale with darker edge, distant, different lengths. Stipe dark brown, 2cm long, 2mm wide, hollow. Smells earthy.
Any idea which species this is?