Cwmnantlleucu Quarry

On my way up to SN70P yesterday evening I passed the quarry, which was quiet, so I parked in the entrance area and had a quick look at the easily accessible rock exposure. Despite everything being bone dry and caked in dust, making id challenging, species such as Amphidium mougeotii (green cushions on images below) and Racomitrium aciculare with Diplophyllum albicans (the extensive dark grey crud on the images below) could almost be described as growing luxuriantly. I still have a box of dirt-covered samples to go through over the weekend, but there appeared to be nothing particularly unusual or unexpected. One observation of interest on the dirt below the rock face was fruiting Pohlia wahlenbergii var. wahlenbergii, which is said to be rare (photo below).

The large oak on the right side of the top photo had an interesting looking pleurocarp growing on an accumulation of powdery dirt in the fork of the trunk. I was convinced this was going to be something I'd not seen before, but in the end all I could make it was odd-looking Brachythecium rutabulum [in fact Sciuro-hypnum plumosum - see comments]. Is there something I may have overlooked?