Ogof Cynnes

Location
Grid Ref - SO 1409 1539 approx. Altitude - 515m approx.

Right in the middle of Mynydd Llangynidr. At this location there are two parallel, elongated shake holes. The entrance is at the Southern end of the larger, Western shake hole and is a slot dropping down through millstone grit.

Access
Open access

Description
Length 1.3km approx.

ENTRANCE SERIES

Dropping through the entrance slot, a small chamber in millstone grit is entered. Across the chamber, a small climb down leads, past the head of the First Pot on the right, to a narrow rift passage. At the bottom of the First Pot (5m, belay ladder to boulders) is a dig which comes very close to connecting with the Easter Series. The rift passage eventually closes down but before this there are two separate ways on towards the Main Chamber.

The first is via Talk Back, a body sized tube at floor level on the left that descends at 30 degrees. This is not passable to persons of larger than average size and should be avoided in winter as the route goes through the main bat roosting area of the cave. There is a narrow trench in the floor, which must be avoided to prevent becoming wedged. Climbing down boulders on the far side a walking passage with a flat mud floor is entered. To the left is a chamber and gritstone choke, while the way on is to the right. Easy going leads to a cross junction. A descent on the left leads to a short series of passages and a chamber which end in grit chokes. To the right a very muddy chamber is entered with the way on to the left, to a boulder choke and the Main Chamber. Straight on at the cross junction is a narrow passage which also leads to the choke.

The second route towards the Main Chamber is a few metres beyond Talk Back in the rift passage near the entrance. A slightly larger tube, at floor level on the right, descends gently to the head of the Second Pot (5m, belay ladder to boulders in the rift). Care should be taken here as the tube ends directly over the pot. At the bottom is a slippery climb up a mud bank to a crawl floored with very sticky mud. This leads to the head of the infamous Muddy Slot, difficult to ascend on the return. Straight on at the bottom of the slot is a very narrow rift leading to the boulder choke before the Main Chamber. An easier option is to duck under a low arch in the left hand wall to enter the very muddy chamber mentioned above. An immediate right turn leads to the choke.

A squeeze up through the choke into a flat-out crawl leads to a steeply descending passage and an awkward 2m climb down into the lofty Main Chamber. At the far end of the chamber are two ascending passages. The one on the left leads to the Left-Hand Series and the one on the right leads, logically, to the Right-Hand Series.

LEFT-HAND SERIES

Climbing up, the passage immediately turns right to enter a tall, straight rift. Beyond another right turn, a bouldery chamber is soon reached. A number of narrow rifts leave the chamber straight on and to the left. Those straight on interconnect and lead to the 11ft Pot, a muddy climb down which drops into a short, phreatic passage. Those to the left are very narrow and end in boulders. At the base of one of the left hand rifts is the very tight route into the Black Hole Series.

RIGHT-HAND SERIES

The floor of the tall passage gradually ascends, passing two short side passages, to a crawl leading to a T-junction. To the right soon ends, while to the left is the Peat Bog, a narrow, muddy crawl to a sharp right-hand turn. Beyond is a tall, narrow rift, the floor of which drops away to reveal Square Passage going off to the left.

''Square Passage leads to a T-junction. To the left soon ends. To the right the passage leads to a right-hand turn to enter a deep rift, while straight on is a small boulder chamber. Descending the rift a junction is met. To the right the descent continues a short distance. To the left and in the right-hand wall is Snake Passage, a small, wet, muddy tube with tortuous bends which connects to a deep rift in the Boulder Chambers area of the cave. '' Back at the entry to Square Passage, staying high in the rift and traversing on wedged rocks leads to a squeeze to the right into a narrow crawl. This soon enlarges and a junction is met. To the right leads to a pool of deep, glutinous mud and a 3m mud bank, at the top of which a crawl only goes a short distance. Straight ahead the passage descends to the base of another 3m high mud bank. Climbing this and dropping down the other side another high mud bank is soon reached, on the other side of which is a complex junction. Behind boulders straight ahead is the way down into Tich Pot, a deep narrow rift, requiring a ladder, which becomes too tight. To the right at floor level ends in mud fill. To the left, a passage leads to the Boulder Chambers area of the cave.

''The route to Boulder Chambers starts with a 3m climb up a mud bank. A larger passage with a boulder floor is reached which goes to the right. Beyond another right-hand turn, a long rift is entered which eventually reduces to a crawl and ends where it becomes too narrow. Halfway along, a descending rift in the left-hand wall leads to the Boulder Chambers. To the right is the lower chamber and up and to the left is the upper chamber - another bat roosting area. Before the chambers the rift continues to descend and the other end of Snake Passage is encountered. '' Back at the complex junction, climbing the boulders straight ahead and traversing to the right across a high ledge leads into Roof Passage, which is mostly hands and knees crawling for 40m on a dry mud floor. There are three side passages, one on the left and two on the right, ending at boulder chokes. Roof Passage ends at a 9m sand dig which is the route into the Easter Series.

EASTER SERIES

At the end of the sand dig is a flat out crawl to an awkward U-bend into a slightly larger section of passage. A low arch under the right-hand wall enters Lourdes Passage, a walking sized passage leading off to the left. To the right is smaller and ends after 12m. Lourdes Passage lowers to hands and knees just before a junction. To the left a wet, muddy dig leads to a very tight squeeze into a short passage which soon chokes but contains a few small formations. To the right a short, flat-out crawl leads to the low Five Ways Chamber. Most of the small passages radiating off the chamber only go a very short distance. The way on is straight across, through a squeeze, passed a constant drip of water and up through grit boulders into a large, square-cut passage. Most of the passages from this point on are in millstone grit, formed by collapses into the older passages in the limestone below. To the right the large passage ends at a choke and to the left it continues, under a loose roof, as a bedding crawl which becomes too-tight. Straight across the passage, a short slope is ascended into another passage which turns left, leading to the further reaches of the Easter Series. There are a couple of short passages to the right and straight across a climb down behind boulders leads to a tube containing a 4m pitch (thread belay).

''At the base of the pitch a rift leads into a pleasant, mud floored chamber containing a few straws. To the right is a crawl over mud which eventually ends very close to the base of the First Pot near the entrance. To the left is a mud bank. Ascending this, the floor drops away again and the enlarged passage quickly ends at a vertical mud cliff which comes to within a few centimetres of the roof. Back at the top of the mud bank, an ascent through boulders on the right enters another chamber. Care should be taken here as the ascent is through the boulders forming the floor of the chamber. Any movement of the boulders could block the way out. There are short passages at either end of the chamber, while at the base of a rift directly opposite the point of entry, is a too-tight bedding plane which can be seen to enlarge at the far side.''

Following the main Easter Series passage to the left, a 90 deg. turn to the right is met after 24m. A short descent and re-ascent enters a chamber, with the passage continuing straight ahead. To the left of the chamber, a very tight crawl over bedding leads to a low, bouldery chamber with no way on. Continuing along the passage, it reduces in size and after 11m boulders almost block the way on. Over the boulders straight ahead, a steep slope drops into a tall, loose chamber with no way on. A low crawl, to the left of the boulders, leads into the continuation of the passage. Soon a smaller passage on the right leads to Glimpse Into Hell, a 4m deep pot in loose grit boulders. Continuing along the passage a constriction is met before it opens out once more. A descent can be made through boulders on the right, while ahead the passage chokes.

History
The entrance was discovered by Martyn Farr in 1967. He noticed a frost-free area of grass on the side of a shakehole while everything around was frozen. The entrance was opened and the cave explored and surveyed by Martyn and friends from Hereford Caving Club.

The Easter Series was dug into, explored and surveyed by members of Morgannwg Caving Club at Easter 1993. The discoverers (Andy Deeley, Karen Sinyard, Ben Lovett, Dave Glover and Huw Jones) were also all either current or ex members of the Polytechnic of Wales/University of Glamorgan Caving Club.