Plant fossils are abundant in the Ward Point Member rocks at Cape Enrage in New Brunswick. You do not need to be an expert to find them in beach stones beneath the cliffs. You do need to be an expert to identify all the fragments accurately. I am not an expert. However, as far as I can make out, most of the fossils that I saw were the strap-like leaves of Cordaites, a primitive conifer from upland regions which according to the guide books resemble Amaryllis leaves or corn husks. There were also fragments of Calamites stems; this was a tree-like plant that could grow up to 10 m tall and is related to the much smaller present day horsetails or Equisetum plants (see images below). The stem is ribbed and jointed like bamboo with a diameter of about 10 cm and it would have had narrow whorled leaves at intervals along the stem. It formed dense thick undergrowth in lowland wetter areas. The diverse fossil flora at Cape Enrage represents dead vegetation washed downstream by rivers and stacked up in piles on the banks of many river channels about 320 million years ago in the late Carboniferous Period. The plant debris would become covered in successive layers of sediment brought down by the rivers as they wandered across the flood plain to the sea, and eventually preserved in sandstones and mudstones.
The Cape Enrage Visitor Centre has some excellent examples of fossils on display, and education officers are available to give advice and help with identifications. They are very helpful and friendly. I am sure that, time permitting, a professional guided tour would reveal many more in situ fossils of different types than those illustrated here.
Cape Enrage is one of the many spectacular stop-off points as you travel along the north shore of the Bay of Fundy on the east coast of Canada. The cliffs are composed of thick and thin layers of sandstones, mudstones, and conglomerates that built up along river beds and valleys about 320 million years ago. The ancient river channels can be seen in cross-section in the exposed and weathering strata. The way that the rocks are fracturing and splitting up into their component layers makes many intriguing natural abstract patterns. Plant debris that piled up on the river banks as it was washed downstream in the Carboniferous period has been preserved as fossils.
Cape Enrage in New Brunswick, on the north shore of the Bay of Fundy, is a popular site for visitors because of its fantastic geology. The rocks are composed of Carboniferous Period Ward Point Member sandstones and mudstones of the Enrage Formation and the Cumberland Group. The almost vertically inclined rock layers in the cliff fracture and weather to create wonderful abstract patterns. The sediments that make up the rocks are fluvial in origin, originally deposited by rivers, and the exposed cliff-section shows many in-filled river channels. Large areas of rippled surface can be seen where channels are exposed; this together with chunks of rock with cross-bedding is interpreted as point bars in which the channels were constantly migrating laterally (as in present day braided river channels before they enter the sea). Localities with conglomerate composed of sandstone with rounded pebbles represent the the centre of river channels where the flow was fastest, or where flash floods have deposited heavier loads.
West of the promontory bearing the famous Cape Enrage lighthouse in New Brunswick, across a wide wetland valley blocked by a shingle bank, is another spectacular promontory with pine topped cliffs. The rocks here belong to the Mabou Group of The Enrage Formation, part of the Cumberland Group from the Late Carboniferous Period. My visit was a brief one and I wished I had known at the time that this is a site where fossils may well be found. Unfortunately, I didn’t know what to look for and simply marvelled at the natural rock textures and fracture patterns without discovering their hidden secrets. Further east on the shore beneath Cape Enrage itself I was much luckier and found some plant fossils – but more of that later!
These rocks are seen on the west side of The Island or St Ives Head in Cornwall, England. They form outcrops on the west side of Porthmeor Beach. I was fascinated by the sheer complexity of the colours, patterns and textures. As far as I can make out they belong to an un-named igneous intrusion (matagabbro or metamicrogabbro) composed of silica-poor magma which was later altered by low-grade metamorphism in the Devonian period between 359 and 416 million years ago.
The rock looks very different from that nearby which was featured in an earlier post. I was particularly drawn some outcrops which had an almost dark navy blue smooth surface but the majority of the rock surfaces were blue-grey and dirty yellow shades – some with smoother almost layered textures and others textured like lumpy porridge. The patterns were complex but included ancient splits and cracks that had been infilled with other materials of contrasting colours, giving paler or darker straight lines and angled cross lines – not to mention all the complicated later fracture patterns. There seemed to be large inclusions of other rock types too; this often occurs in granites. It is incredible that rocks of the same basic type can vary so much in their appearance within a few metres.
Porth Kidney Sands in Cornwall is well known for its beautiful golden beach but it also has some very interesting rocks. The natural textures, colours, and patterns of cliff strata on the west side are quite different from those previous photographed in a rock outcrop at Porthmeor near St Ives. At Porth Kidney there are two types of rock, both dating from the Devonian Period about 359 to 385 million years ago, Many parts of the bedrock show layers that have been folded in complex ways by pressures and forces in ancient times and some of these strata have been metamorphosed by heat from a major igneous lava intrusion at a later date – but still retain evidence of their sedimentary origin in the layering effects.
Slates and siltstones of the Mylor Slate Formation are found in one area and are followed further west by Hornfelsed Slate and Hornfelsed Siltone (the metamorphosed version of the rocks) nearer to Carbis Bay. There are even some spectacularly bright blue-green patches between the layers which are likely to be some derivative of copper; and an iron-bearing stream that cascades down the cliff has converted the adjacent rocks to a striking orange colour that clashes with the green algae adjacent. The upper reaches of the shore are covered with irregular beach stones and also large boulders.
A compilation of images of native Cornish rocks, igneous and metamorphic, granites and slates, with interesting natural patterns and textures, found in various stone walls of buildings in St Ives, Cornwall in England.