New cave in Ystradfellte - Ogof Sarn bell

Hi all,

Late in 2025 while walking the Pant Mawr catchment for known and unknown caves a small slot was chanced upon in the moors by Matt Cocke and I. After some gentle inspection and removal of boulders, a new cave was discovered, leading to about 5m of crawling passage. Following another day digging - navigating through a short boulder choke, we popped into a chamber, which led to over 100m of passage! This cave is super exciting, and presents itself as a single, large, fossilised phreatic tube with a very wide lens, filled nearly to the top with sediment.

Typical passage in the cave:

I believe the trench here was dissolved out by reactivation, or a fossilised inlet which made its way in deeper in the cave, beyond the dig face.

Matt in the breakthrough chamber. Main passage to the left at head level:

I was lying - actual typical passage in the cave:

We have since surveyed the cave, and gained landowner permission. We are digging at the extent of the cave, where the sediment leaves about 8 inches of airspace between floor and ceiling with another 10m of visibility until it (presumably) turns towards caverns measurless to man. The cave has some fantastic stal, and distant rumbling can be heard in the boulder choke near the entrance in times of flood, and for the area, the limestone is uncharacteristically stable and well-formed. My personal theory is that this new find a very old resurgence broken into by an invasive, much younger cave.

Weird stals:

Just a teaser for now... We will be reporting on this further in the May WSG bulletin and hope to make an article for the next Descent.

We have since discovered another cave, and found an open lead in a known cave we have yet to dig (due to a lack of permission). This lead has a person-sized passage with streamway winding off into the distance and definite draft (and very scary ceiling at first held together by hopes and dreams). Once landowner permission has been gained we will hope to say more.

I would also like to thank all of those who have helped with this project so far, in digging and assisting me in learning to survey and scaffold. We will continue to report as we keep digging.


More to come!
Joe

 

[Long Drop]

Congratulations! About time some new cave was found up there! Will look forward to reading more. M

 

[drmwc]

Hello.

I'm Matt, the chap in the photos.

 

[Lankyman]

This looks great. Some of the best times I had caving was looking forward to getting back somewhere that looked like it was 'going'. Better than Christmas!

 

[mrodoc]

Congratulations!

 

[Rhys]

Da iawn. We'll done team. That's looking good!

 

[JBarty]

We went back on Sunday to take some photos. Here are some more pictures to make up for the sideway-osity of the first batch including yours truly.

Photo of "The witches finger" (Thanks James)

And look at this eroding curtain!!

 

[JBarty]

The cave is also covered in these "burrow" lined sediment-banks. They are about 2 inches in diameter and are at least a feet deep. Fascinated to know if anyone can identify how these form. Is it a glacial thing, or just the act of very-early dissolution from water?

More photos of the formation under lower lighting

 

[drmwc]

We spent a day looking at small caves in the valley. I had a pin in Google maps when we were looking for Cwm Huw Bwub (which I may have mis-spelled). Neither of us had been to it before.

My navigation is a bit duff, so we ended up at a different hole in the ground. And that is how we found Ogof Sarn Bell.

 

[andybrooks]

Well done! If still interested, you should find Cwm Huw Bwub on the west side of the river, just a little upstream from the bridge below Dyffryn Nedd farm. It's west of the bridge trail, near a ruined cottage, and it was fenced off the last time I looked, which was probably some 20 years ago.

 

[Andy Farrant]

Looks like a great find. As for those burrows, hard to judge from a photo, but some may be deep drip pits, formed by water dripping off the ceiling and washing away the sediment, easy to do if it's glacial sand and silt. You can also get soil piping by the same water, especially if its a rapid wet weather drip. Unlikely to be animal burrows unless you are close to the entrance. Irrespective of how they formed, it would be great if the sediments could be taped off and preserved. Mud formations often don't get as well protected as the more pretty stals.

 

[Huge]

Well done on your finds and fingers crossed they keep going! Thanks for sharing.

Cwm Huw Bwb (no relation) is a very interesting place. It seems to me that it could be an abandoned resurgence. A bit like Pwll Ddu but left high and dry by valley down cutting. It's a large feature and an dig there is likely to be a major undertaking.

 

[Goydenman]

well done looks to be a great find with hopefully way more to dig into. Thanks for sharing

 

[JBarty]

Looks like a great find. As for those burrows, hard to judge from a photo, but some may be deep drip pits, formed by water dripping off the ceiling and washing away the sediment, easy to do if it's glacial sand and silt. You can also get soil piping by the same water, especially if its a rapid wet weather drip. Unlikely to be animal burrows unless you are close to the entrance. Irrespective of how they formed, it would be great if the sediments could be taped off and preserved. Mud formations often don't get as well protected as the more pretty stals.

I'll try to get a few more photos of the burrows when we next visit (and has given me a nice name for one of the passages). I am relatively convinced some of the piping seems to go upwards, with no exit hole on the top of the sediment. I'm pretty sure it has nothing to do with animals as the mud is very fluffy. Some of the cave is extremely close to the surface - with roots poking into the passage, but these holes only occur in the phreatic tube which is deeper in the cave.

We'll make sure to tape off the mud banks when we next visit!

 

[JBarty]

For all those interested, here is the current dig-face.

You're seeing about 6-8 inches of airspace, and it appears to wind off to the right after 5-7 meters. I've artificially lit the photo to help with visibility. It's the easiest digging I've ever done. There's clear evidence of a brecciated fault in another passage at roof level with a small pebble strewn hole in the floor which looks like a good secondary dig, but I'm not much of an expert.

If anyone more geologically minded wants to come and take a look, pop me a message.

 

[Pegasus]

Hello.

I'm Matt, the chap in the photos.

Hello Matt