Caves of South Wales Dragon

Ogof Marros

↓ Further information

Ogof Marros is located at the site of a significant sink where a stream runs down off the Old Red Sandstone of the Marros mountain and sinks over a wide area as it meets the lower limestone beds at Coggan's Cliff. The water sinks at the base of the 15 m high limestone cliffs and then follows and underground course for over two kilometers until it resurges at the Morfa Brychan rising at the coast.
Length 300 m +
Altitude 105 m
Grid SN 21402 09516
This potential of this site was recognised by local caver Phil Knight and digging commenced. A team of ten people mostly from South Wales Caving Club, including Phil Knight, Fred Cook, Emily Ivens, Storm Morris, Ashley Pursglove, Antonia Freem, Andy Freem, Claire Vivian, Duncan Hornby and Michael Perryman then formed to pursue this great lead. Over a summer of digging in 2015 they eventually broke through into over 300 metres of fine cave passage. The exploration can be viewed in the video on the embedded link below. The exploration of this site continues by the team.
Ogof Marros is located by a large sink at Coggan's Cliff in the Greenbridge valley. From the Pendine to Amroth Road just uphill from Greenbridge, the cave is approached via a bridleway that passes through a livestock farm and then follows a small stream that once fed Greenbridge Cave. Crossing a field to the wooded area in the bottom of the valley brings you to this massive wooded depression where the cave is located. An obvious ramp of digging spoil above the main sink near the centre of the massive cliff marks the entrance.
Carmarthenshire Google map showing the location of Ogof Marros and other caves in the area.
Location map - click marker to show entrance photo
The cave is located on private land and is a site of current exploration by the original discoverers. The cave is currently gated and bona fide cavers who wish to visit the cave should contact the team on the following e-mail address to make arrangements
A low entrance crawl enters a small descending chamber after a couple of metres, where a short shaft is found in the floor. A four metre climb down leads immediately to a constriction named "Fred's Despair" where a flat out "letterbox" squeeze leads to a drop down into roomier passage beyond. A largely stooping passage is then followed for about 20 m until low crawls on the right lead into the well decorated but low "Antonia's Grotto". The grotto is formed over the top of a settled boulder choke and has no ways on and being taped to prevent damage to the formations it contains. To the left of the grotto is "Claire's Chamber", a 3 m climb down the edge of the choke where the rumble of the stream can be heard rushing through the boulders below. At the base of this climb down, the route follows the left side of the choke and enters "Three Man Chamber". From here the original route was once a low wet crawl under the boulders to reach the streamway, but now a climb on the left through boulders has been engineered to give drier and all weather access. The route through the boulders emerges in the "Wildest Dreams" streamway, where a well formed passage with many delicate formations requires slow and thoughtful progress, there is much to enjoy on this section of low decorated passage. After 25 m the passage lowers to form "Shrimp Crawl" a still decorated passage that passes through a small decorated chamber to reach the first boulder chamber a central point leading via several routes into the Master Cave. To the left a route leads to "Crystal Carpet Chamber" this is very delicately decorated on the walls, roof and the crystal carpet formation on the floor. This oxbow passage is taped off at a viewing point to protect it. To the right is another passage taped off to protect the formations. A short climb up leads to a taped viewpoint into the passage, that can also be viewed later from the other end in the upstream Master Cave. The central two routes lead via climbs down boulders to meet the Main Streamway. This is now joined by several other inlets and flows quite strongly in wet weather. Heading upstream are 20 m of passage over 8 m in diameter adorned with short stal formations in the roof. To the right you can see the other end of the passage mentioned earlier. The passage then splits into three, with the main route ahead, where in a pool lives "Jimmy The Trout", please take care where you place your feet as you pass the pool. The passage progresses to a low wide area where an inlet can be followed upstream, heading towards surface sinks. The low area can be followed to the left down an oxbow taking some of the water back down to the main stream passage. A further inlet stream is passed just before the start of the large Master Cave. From the first boulder chamber a 5 m climb down the boulders on the left leads to the lower main streamway which starts lofty and boulder floored but quickly reduces to a low gravel floor as a downstream blockage "Long in the Tooth Choke" is reached. Just before the choke are a couple of low crawls on the left, which lead into a multi-level set of passages the "Three Tier Rifts" these are well decorated in parts and also lead to chokes.
No tackle required.
Ogof Marros Video
Cambrian Cave Registry for Ogof Marros
Cambrian Cave Registry for Ogof Marros Sink
Cambrian Caving Council Newsletter 48
Descent | No.248 p22-24 (2016)
South Wales Caving Club Newsletter | No.132 p10-25 (2016)
There are low wet sections in this cave that flood to the roof in wet weather - only visit in dry settled weather.
As with many recently discovered caves, rocks are loose and are liable to move or fall, particularly ones in the chokes.
The photographs and information of this page has been provided to help cavers planning trips. Caving can be a dangerous activity, if you are interested in exploring caves please join a caving club so you can enjoy a safe introduction to this sport. Local caving clubs are listed on the links page or you can visit the 'New To Caving' website for more options.
If you feel that any of the information is incorrect or should be updated please contact us.