Thursday 20th May...
Sometime ago myself and Richard set to on a mission to re-find a number of caves on Portland previously explored and recorded, but since 'lost' due to paths vanishing and entrances getting grown over. We ticked off most of these which were listed in the Portland book a few years ago but a few short caves remained which we'd not visited. Yesterday, following lockdown and then some 'knee recovery time' myself and Richard met for the first time in many months and decided to go looking for Top Hole, one such cave still on our to do list. I'd previously hunted around most of the easily accessible parts of King Barrow Quarries with out success and had come to the conclusion the cave was either lost or now hidden in the undergrowth. It took a couple of hours and some 'speculative gardening' but eventually we found the entrance amongst the bushes and brambles.
Despite being only 15 m in length the cave is a reasonable size for Portland, consisting of a low entrance area and two rift chambers joined by crawls through boulders. The rift chambers contain some nice orange flowstone. It's situated in an island of freestone left behind by the former quarrymen measuring approximately 50 m x 30 m completely surrounded in quarry. The end of the cave is obviously within this 'island' and is clearly just a mud / rock choke in the continuing passage. Obviously the prospects here are small but a 50 m through trip is certainly plausible. The other side of the 'island' is equally inaccessible but will in time be searched for a potential opening. The other hope is that the cave goes down. The quarrying in this area has only removed the upper freestone with the lower cherty series intact. Elsewhere on Portland the rifts span the height of the limestone existing in both the freestone and cherty series and so this is a distinct possibility. As a result we decided to have a couple hours attacking the end and have established a reasonable draft emanating from some small gaps in the mud / rock infill. We're intending at least one more session here in the coming weeks. I'm guessing most wouldn't bother but we're mad, the digging is easy and on Portland every metre counts!
The cave had clearly in the past been used as a 'den' containing all sort of detritus. Richard did a fantastic job of clearing all this whilst I'd popped back to the car for a prodding stick.
The pre-caving gardening & the classic Richard arse shot:
The entrance at floor level:
The low entrance area:
Rift Chamber 1:
Rift Chamber 2:
The end of the cave as we found it:
OK so it's a bit claggy!!! Richard doing the hard work here:
Second Rift chamber with it's new slightly raised floor: