Good Friday on the South Wales coast

A field trip reccy is a good excuse for a day at the seaside!

Hoping to do a repeat of last summer's field skills day, but in South Wales rather than North Cornwall, I'd been looking at some potential locations and thought the strip of coast south of Cardiff between Lavernock Point and St Mary's Well Bay  might just fit the bill. There's a cliff section which could be good for field sketching, and a faulted syncline which would give mapping practice, strike and dip measurements etc plus an opportunity to test a hypothesis about fault movement. So, having done the homework, off we went.

Finding St Mary's Well Bay

My plan was to find somewhere to park at St Mary's Well Bay, walk eastwards along the cliff to Lavernock Point (Wales has a complete coastal path, right?) descend to the beach and work back to the start point. Following signs to ST MWB (can't keep typing it out in full!) took us past a holiday park, and down to the coast.... double yellow lines both sides all the way ... then onwards past the headland to Swanbridge, opposite Sully Island. Here the road ended abruptly! It looks as though there has been some erosion here in the past - though whether natural or anthropogenic isn't clear! 

Anyway we took the opportunity to take a look across at Sully Island: I'd only seen this, and it's famous unconformity, from the sea before on the way to Flatholm.

Sully Island from Swanbridge - we could actually have walked across as the
tide was far enough out, and going down, but it is extremely slippery so a "No"!

The unconformity is between dipping Carboniferous limestone, which has been
eroded before Triassic breccia was deposited on top

The unconformity isn't as clear at the eastern end of Sully Island

There were good views from here up the Channel to Flatholm and Steepholm, as well as similar rock exposures at the eastern end of Swanbridge foreshore. However, not a lot of point exploring them as nowhere to park!

Flatholm and Steepholm (the thing in between is a container ship, not a
new island!)

Back to Lavernock

Since SMWB was obviously no use as a parking/start point, we headed back round to Lavernock Point - there's a bit of parking here, maybe enough for 8 cars if we pack in - can't count on using the church CP as the trip will be on a Sunday! They might want it themselves....

Two paths start from here, one heads north up the coast towards Penarth and the other, currently appropriated by a small stream, down a gully to the beach. Jan went on down while I slipped and slid my way, ending up on my seat for safety, onto the foreshore. 

The wrong size cobbles :(

This is the problem here - they are deuced uncomfortable to walk on and I'm afraid that I just couldn't see myself prancing around from one group to another checking their field sketching etc. Jan clambered over an algae covered concreted pipe (sewer?) to look round the headland and reported more of the same, loose, wobbly cobbles with ridges of rock to clamber over in between. It just isn't a place where you could potter comfortably learning how to use a clino, draw exposures etc so, what with that and the lack of parking and loos, we decided it was no go.

Had a good view of Coltsfoot on the way down to the beach!

Where next?

Sifting through what places were nearby, we thought we might take a look at Ogmore by Sea and headed round there - lunchtime by now so we parked up, (at least there's plenty of parking here) and ate our sandwiches before taking a look.

As the tide was well out (low springs) we were able to make our way down onto
the sand and walk along there. 

I'd not appreciated before just how much of the rock exposed below the car park and for quite a way to the east, is Triassic breccia! The tide has always been at least halfway up, and covered the sand, on my previous visits. We had to walk quite a way before we came to the Carboniferous limestone and in the end we went up a slipway to the cliff path and walked along there instead.

Triassic breccia on the left, plastered over the eroded surface of Carboniferous
limestone - the horizontal beds on the right

This entire area is covered with breccia

View across to Porthcawl

However, interesting as Ogmore has been for a field trip looking at the rocks exposed here, the lack of structure means that it has less potential for a mapping/field skills/graphic logging type exercise. Its strengths are the beautiful coral fossils, and the unconformity and that is just not enough to build a day around. 

Walking back to the car park we were treated to some beautiful skies as we looked across the Channel towards the North Somerset coast, and we had had a good day out at the seaside even if we didn't achieve the object of finding a field skills locality.

Skies look threatening but we were lucky and the rain held off all day!

It looks as though it could be a bit damp and misty on Exmoor though!