The Evolution of Wales Gallery

The Exhibition

History of the Exhibition
Geology has played an important part of the displays in Cardiff since the National Museum opened in 1907. These displays have always centred on the geological history of Wales and its relation to the rest of the world. When the major phase of rebuilding took place in the Museum in the early 1990�s, the opportunity was taken to design and construct the Evolution of Wales exhibition incorporating state of the art display cases and audio-visual effects. Her Majesty the Queen opened the exhibition.

The Exhibition
Your journey through time commences with the spectacular Big Bang video, with its own carpet and walls of �twinkling stars�. After watching the birth of our planet you emerge onto the primitive Earth, of nearly 4,000 million years ago, to see the oldest of our rocks, meteorites and even a piece of moon rock. Here there are minerals, rocks and fossils showing the range of life in the oceans that covered Wales during the early Palaeozoic. Nearby, a diorama of a Silurian coral reef brings this next period to life. Throughout the early Palaeozoic there were periods of intense volcanic activity in the area. During the Ordovician this, coupled with hydrothermal activity, resulted in the formation of many metalliferous veins of gold, silver, lead and copper. The early Palaeozoic large-scale movements of the earth�s crust that brought Wales above the level of the sea were heralded by more volcanic activity, vividly portrayed in a volcano video show.

The late Palaeozoic started with the retreat of the sea, with much of Britain covered by rivers and deltas. The resultant Old Red Sandstone deposits contains evidence of both early land plants and freshwater relatives of living lungfish that could survive by breathing through their primitive lungs. Then the temperature climbed and tropical marine conditions resulted in the deposition of the Carboniferous Limestone with its range of corals, crinoids, brachiopods and bivalved molluscs. Swimming in these seas were distant relatives of modern squids.

Land elevation once more brought the land to the surface, but this time the tropical wet conditions encouraged the growth of giant clubmosses and horsetails in enormous swamps that covered thousands of square kilometres. Ferns and seed-ferns grew on the delta levees while the ancestors of the conifers formed forests on the surrounding drier land. The accumulation of peat in these swamps produced the coal seams that made Wales once the most important coal producing area in the world. Fossils, coal and a video of coal formations back up a diorama of such a coal swamp. All these luxuriant tropical swamp forests disappeared at the end of the Carboniferous, leaving a much-reduced flora in the drier conditions of the following Permian.

Next on your tour comes the step over the divide between the Palaeozoic and the Mesozoic when a major catastrophe swept the Earth with more than 90% of living species dying out. Wales was low-lying, covered by deserts and subjected to flash floods and violent storms. Now the giant reptiles that came to dominate much of the world confront you. Skeletons and reconstructions of some of these dinosaurs are there together with remains of the new range of conifers, maidenhair trees, cycads, cycadeiodes and ferns that made up the worlds vegetation. The super continent, that we call Pangea, was now starting to break up into the land masses that form today�s continents so your route now �drops down� into the warm shallow Jurassic sea that covered most of Wales and much of Britain. Fossils and images vividly illustrate the life in these seas. Among the most common fossils found in rocks of this age are the ammonites that are distant relations of the octopus, squids and cuttlefish. There were also marine reptiles such as the Ichthyosaurs, Pleisosurs, Pliosaurs and the giant Mosasaurs that were up to 10 metres long. On the sea bed were many shelled molluscs, being distant relatives of modern cockles, oysters, winkles and whelks.

The transition to the succeeding Cenozoic Era takes you over the so-called K/T boundary when a giant asteroid is thought to have collided with the earth and wiped out the dinosaurs. Very little Cenozoic deposition occurred in Wales so we have little direct evidence of the enormous changes that took place around the world. Shoals of modern-looking fishes swam in lakes and rivers, while birds and crocodiles lived on the water margins. On land it was the turn of the mammals with their rapid evolutionary change from small shrew-like creatures into the new giants of the age. Here you can look at the way today�s horses descended from a cat-sized ancestor that lived 55 million years ago. Plants were similarly diversifying and the flowering plants came to dominate much of the world�s vegetation. Indeed by 1.6 million years ago modern patterns of vegetation were firmly established. The main features of the modern Welsh landscape were established and elsewhere early humans were evolving.

Coming ever closer to the modern day you then step into a cave system to the Ice Age to be confronted by moving mammoths. A video explains the causes of extreme changes in climate and the glaciations that resulted before you pass by the imposing remains of the animals that lived on the open tundra. There is a skeleton of the giant deer, the �Irish Elk�, with its 4m spanning antlers, mammoth remains and a reconstruction of a woolly rhinoceros. The advancing and retreating ice sheets carved out the U-shaped valleys and upland corries that in Wales are called cwms. The ice caused havoc with the vegetation, with the cold weather forcing out all except the hardiest of the smaller plants that we now know as artic/alpines. Many species were forced out of Britain, never to return.

With the Ice Age finally over - as far as we know - the forests came back to Wales. But, then with the melting of the glaciers, great stretches of the low-lying coasts were drowned. Evidence of drowned forest can be seen along many parts of the Welsh coast, especially when spring tides scour the beaches and uncover the stumps of oaks and pines embedded in fossilised peaty soils.

The final changes in the Welsh landscape came with forest clearance, started 10,000 years ago by the Mesolithic settlers. These were followed by the latter settlers who mined welsh copper 4,500 years ago and mixed it with Cornish tin to make the alloy bronze. This was the most important metal for nearly 2,000 years until the appearance of iron.