He began by using a clockface to explain the extent of earth’s geological time which at 4.6 billion years (Ga) is almost impossible to visualise. The first land vertebrates only evolved around 10pm on this clock and mankind occupied a tiny gap before midnight.
The coast between Berwick and Newcastle is of Carboniferous age lasting about 73 million years (Ma) between 363 and 290 Ma (9.40pm on the clock). The Carboniferous System was named after its numerous coal bearing strata which were laid down while this area was astride the equator and huge rivers produced swamps and deltas that supported luxuriant vegetation that formed the future coal seams.
These rivers brought down sand from higher grounds which formed future Millstone grits whilst limestone was laid down in the shallow, tropical waters supporting many marine creatures: fish, corals, crinoids and numerous molluscs.
Derek’s talk described some of the likely places to find fossils but he warned against indiscriminate collecting and misuse of geological hammers. Only loose material on the beach should be subjected to hammering – and cliff faces are a definite NO.
Photos of fossils should include a scale such as a coin, ruler or hammer. One coastal region rich in fossils is between Craster and Boulmer.
The oldest deposit, Sandbanks Limestone occurs below the impressive Whin Sill of Cullernose Point.
Derek showed us a photo of fragments of trilobites found here and there were also fossil crinoids (sea lilies), brachiopods and corals.
Further south towards Howick Haven similar fossils can be seen below black shales in the cliff face within Iron Scars Limestone. The crinoids have been separated into individual ossicles (nicknamed St Cuthbert’s beads) and there are fragments of corals and brachiopods (extinct shelly molluscs).
Even further south is the aptly named Sugar Sands Bay (try feeling the sand between your fingers). The limestone here contains huge gigantoproductid brachiopods up to 15 cm across (rather like modern day oysters) and trace fossils looking like brush marks 1530 cm across (these are thought to be feeding traces of unknown worm-like creatures).
Derek then described the Permian coastline south of Newcastle which is about 290 to 245 Ma in age.
In early Permian times Britain endured a very dry climate with desert sand dunes but in late Permian the sea levels rose to establish the shallow Zechstein Sea over parts of the North Sea and northern Europe.
Here were shoals of fish which were of mackerel size (Palaeoniscids) but also larger predator species which probably ate the smaller fish.
Derek brought along some museum specimens for us to examine and recommended a few well illustrated fossil books. These included the series from the British Museum (Natural History) in three volumes covering Palaeozoic, Mesozoic and Cenozoic Systems.
He also suggested scouring local museums to see specimens that have been expertly cleaned up. Obviously the Hancock Museum has some beautiful examples and he also recommended the Dorman Museum in Middlesborough and the Sunderland Museum and Winter Gardens. If you wish to buy fossils I suggest that a browse around Mr Woods Amazing Fossils Shop in ‘The Grassmarket,’ Edinburgh is rewarding.