Harrow and Hillingdon Geological Society
Fossil Insects of the Bembridge Marls
Fossil Insects of the Bembridge Marls on the Isle of Wight
Dr Andrew Ross
Natural History Museum
This talk described the work undertaken by Dr Ross and a team of 35 people to study a 19th century collection of fossilised insects from mainly the Eocene / Oligocene. The majority of these specimens were unstudied and therefore not classified. The INTAS project provided £100,000 for the research, which is in collaboration with three Russian institutes and other European scientists from France, Poland, Germany, Spain etc.
In the 1870s Joseph Smith discovered insects in the marl beds around Bembridge on the north coast of the Isle of Wight. These marls, which are from the tertiary period are limey muds found on the coast in a region extending from Gurnard Edge to Forland and including Burntwood West, Bembridge, Westcliff Bay and Burntwood East. At the base of the marls is the Bembridge limestone which is about a metre thick and 33 million years old.
The NHM collection is comprised of 500 specimens collected by Smith in 1877 and 1883. In 1898 Brodie purchased a further 2,000 and Hooley added 1,500 in 1924. Many of these specimens are incomplete and interpretation has been difficult and time consuming. There are 165 different species including a praying mantis. Today in UK there are 25 orders of insect.
We were then shown slides of the following:
The specimens are also indicative of the climate of the time which was tropical.
Hemiptera - Bugs, water boatmen, plant hoppers, cicadas, aphids
Conclusions: Everything has either been washed in or flown over and drowned in the water. It is a depositional environment, hypersaline and as a salt lake insects could not tolerate the chemistry. The terrestrial ecology was reed marsh, springs, meadows and forest and therefore suitable sites for living and breeding. Crickets, grasshoppers = dry areas – meadows, weaver ants – forests. Its age was generally early Oligocene.
These specimens were very different to those found in Baltic amber. The climate was equable subtropical and a much smaller temperature range between the seasons. A very interesting picture is emerging from this research.