Background
The low cliffs and rock platforms along the coast from the mouth
of the River Ogwr south east towards Dunraven Bay (Southerndown)
provide outstanding access to some of Wales' geological heritage.
Most of the rocky outcrops around the high tide
mark are of Carboniferous Limestone (about 335 million years
old).
In the area around Grid Reference 865-746, both
on the wave-washed platform and on horizontal bedding planes
capping the low cliffs, it is possible to see large curved solitary
corals, colonial corals and large brachiopod shells.
Wales was situated close to the
Equator at the time, under a monsoonal-type of climate, with
warm, shallow tropical seas.
Within some 15 million years the seas had closed and a mountain
chain up to 4000m high (the height of the Atlas Mountains in
Morocco) was beginning to form over what is now Devon and Cornwall.
In front of this developing mountain chain a basin formed in
south Wales that became filled with the debris as the mountains
were eroded.
The river and delta deposits filling this basin became the host
for Wales' coal wealth.
Eventually the forces building the mountains to the south also
deformed and uplifted the coal basin. In places like Ogmore
the once deeply buried (several kilometres) Carboniferous Limestone
was now exposed to weathering and erosion.
By about 205 million years ago late Triassic) South Wales was
an arid region at the latitudes of today's desert belts.
Ogmore-by-Sea was located on the northern edge of a dry lake
basin similar to Death Valley today.
At times a salt lake filled the area between Ogmore and the
Mendips.
The products of limited weathering in this arid setting were
washed down by flash floods and their remains can be seen along
the rocky shoreline with masses of fragmented limestones usually
set in a white of red matrix.
There are even small valleys (wadis) cut into the Carboniferous
Limestone, filled by these deposits, clearly visible again near
865-756.
By about 200 million years ago (early Jurassic) the climate
had changed and the seas were rising.
The low hills over the present day Vale of Glamorgan were inundated
to form a small archipelago set in a tropical sea.
The hills were largely made of the exhumed Carboniferous Limestone.
The Ogmore-Ewenny area was one of those islands, and as the
seas flooded the area, the hill was surrounded by a rocky-sandy
shoreline just like it is today, only warmer, with the sea alive
with ammonites and giant marine reptiles.
At Pant-y-Slade (872-741) the Jurassic shoreline sands (shelly
sands full of broken molluscs) are banked against the highly
irregular cliffs of Carboniferous Limestone.
Telling these two limestones apart is not easy but if you look
carefully the contact is marked by large coral colonies of Jurassic
age, buried by Jurassic shelly sands with pebbles of darker
Carboniferous Limestone.
Rocky shorelines are places of erosion where delicate features
are readily destroyed; the Jurassic rocky shoreline at Pant-y-Slade
is one of the finest examples anywhere in the world.
From this location look south east towards Witches Point in
Dunraven Bay (Southerndown).
The main cliffs are of the Jurassic Blue Lias and represent
the muddy, deeper water offshore deposits around the archipelago.
Accessibility: The coastal path is probably accessible to
a wheelchair but not the actual fossil sites.
All the above are accessible at high tides - but of course anyone
visiting any part of the south Wales coast must be aware of
the dangers our local extreme tides present.
The sites are all adjacent to cliffs and at Pant-y-Slade there
can be a danger from large waves.
Facilities: There is a very large car park at Ogmore.
The National Wetlands Centre Wales
*please click the image
below to access a photo slideshow of the visit to
The National Wetlands Centre Wales
The Photographs were taken
by Dorothy Witcomb.
What a glorious day the 1st of June was as we set off from
Caldicot by coach to visit The National Wetlands Centre
at Llanelli. The trip was organized by our Science and Natural
History Convener, Dorothy Witcomb.
On our arrival we were greeted with complimentary coffee,
biscuits and lots of smiles from the staff. Then we were
off on a guided tour and those of our party that wished
to make their own way were also off. The diversity of wild
life kept us absorbed and digital cameras clicking. Attached
is a slide show of some of our member's photographs.
National Wetlands Centre Wales -
Llanelli
Stretching over 450 acres on the Burry Inlet, this magnificent
mosaic of lakes, pools and lagoons is home to countless
wild species as diverse as dragonflies and Little Egrets.
Plus over 650 of some of the world’s most spectacular
ducks, geese, swans and flamingos, many so tame they feed
from the hand.
Website link: www.wwt.org.uk
Thank you Dorothy for a wonderful day out.
DOLAUCOTHI GOLD MINES
On 11th
May 2009 members of the History and Science Groups visited
the Dolaucothi Gold mines in Carmarthenshire where gold
has been mined since Celtic times.
*please click the image
below to access a photo slideshow of the visit
to Dolaucothi Gold mines in Carmarthenshire
photo: Rosa finds Gold
The Photographs were
taken by Dorothy Witcomb, Glenice and Adrian Dallow
We were given a warm welcome by members
of the National Trust and divided into to groups. One
group went on a short walk along a Victorian adit (tunnel),
the second climbed up the hill for an extensive tour
of Roman and Victorian mines.
We then tried panning for gold and learnt
to distinguish between fool's and red welsh gold. There
was also time to see the exhibits, buy gold, and sample
Irene's delicious home made deserts.
These unique gold mines are set amid wooded
hillsides overlooking the beautiful Cothi Valley. The
Romans who exploited the site almost 2,000 years ago
left behind a complex of pits, channels, adits and tanks.
Mining resumed in the 19th century and continued through
the 20th century, reaching a peak in 1938.
Guided tours take visitors through the
Roman and the more recent underground workings. The
main mine yard contains a collection of 1930s mining
machinery, an exhibition about the history of gold and
gold mining, video and interpretation.
Gold panning gives visitors the opportunity
to experience the frustrations of the search for gold.
Other attractions include waymarked walks and picnic
areas. There is fishing and accommodation on the estate,
including a 35-pitch touring caravan site.
Gold mines in use from Roman times
to the 20th century
-
Unique Roman gold mine set amid
wooded hillsides
-
Guided tours of the underground
workings and exhibition on gold
-
Opportunities to experience the
frustration of gold panning
-
Splendid views of the beautiful
Cothi Valley and three estate walks
-
New exhibition on mining history
Wacky Scientific Experiments
Dorothy Witcomb our science convenor brought
a different approach to our meeting this month (November)
and it made for an enjoyable morning.
Firstly Dorothy showed a
DVD borrowed from our head office which kept us sitting
on the edge of our seats while the demonstrator was demonstrating
different types of explosions within a safe laboratory
set-up.
We then moved on to the practical
part of our meeting “hands on” where we were
asked to use our mobile phones in a way that made popcorn
jump. Four mobile phones were placed on the table all
pointing towards the popcorn, then four other phones were
meant to ring at the those on the table at same time,
the problem was that only one or two of our members knew
their own phone numbers so we never got to see the popcorn
jump.
Dorothy then told us it had
been seen working on UTUBE website but she informed us
it had turned out to be a hoax.
We then tested our reaction
to catching a plastic ruler when it was dropped by another
member; the measurement was taken when the catcher caught
the ruler. The idea was to then measure the effect on
our reaction to catching the ruler again when someone
called us on our mobile phone.
It was to see what effect
it could have on our concentration when the phone went
while driving a vehicle.
After this excitement we
were asked to try and get a boiled egg that was larger
than the bottle top into the bottle, even I couldn’t
have faced eating one of these eggs after seeing some
of the final results.
At the end of the class a
comment was heard from one of the two grandchildren who
were present due to a teachers training day at their school
“this is better than school!”
Now view a few photo’s of our members
trying these Wacky Scientific Experiments
Thank you Dorothy.
Atomic Energy
Richard Blount, a member
of our U3A, gave a very interesting talk on atomic energy
at our
science and natural history class.
He first showed a short
film entitled "Our friend the atom" which is
a Walt Disney production and first shown in 1957 but is
still very relevant.
