Landscape
Cumnor Fossils
"Everyone nowadays knows that fossils are the remains of once living things..."
OGG President, Phil Powell, writes about the fossils of the Cumnor area.
Everyone nowadays knows that fossils are the remains of once-living animals or plants but three centuries ago the nature of fossils was puzzling and a matter of hot debate. One common idea was that fossils could have originated in vapours over the sea which were impregnated by the semen of animals and the seeds of plants. These were blown over the land and fell with rain, sinking deep underground where they germinated and grew. This seems far-fetched today but it fitted a number of features of fossils and fossilisation; for example, the presence in England of nautiluses and other exotic sea shells and the variation in preservation from perfect replica to vague or partial representation.
Plate 7
Plate 12
In 1686 a young man at Oxford began to study fossils and their origins. He was Edward Lhuyd (or Lloyd or Llwyd ), assistant to Dr. Robert Plot, the keeper of the Ashmolean Museum on Broad Street (the building now houses the Museum of the History of Science). His first task was to catalogue the collection of fossils and minerals, or 'formed stones' as they were called.He also set about enlarging the collection by acquiring more specimens from correspondents and collectors and by visiting the numerous small quarries in the Oxford district.
His work was published in 1699 in a pocket-sized book snappily entitled Lithophylacii Britannici Ichnographia which translated means Map of the British Stone Cabinet It was the first systematic descriptive catalogue of British fossils, containing 1, 766 entries and 25 plates and illustrations. There was also an appendix comprising letters to other savants explaining Lhuyd's ideas and inviting discussion.
Lhuyd must have walked out of the city's West Gate, across the Botley marshes and up Cumnor Hill to visit the local quarries. Finds at Cumnor are mentioned seven times in the catalogue while Chawley has 14 entries and Bessels Leigh 16. Plate 7, shown here, figures two fossils snails from Bessels Leigh. These will have come from the brown sands and sandstone which underlie the Coral Rag limestone sequence. Lhuyd's name for figure 322 means 'a kind of whelk' and for figure 341 'a kind of spinning top shell'. Indeed this is more or less right though the modern scientific names are Ampullina argot and Psudomelania heddingtonensis
Jaw apparatus
Plate 12 illustrates sea urchins (echinoids)from various localities. Number 928, from Chawley, appears to be a fragment of a shell. Another Chawley specimen, number 1002, is one of the stubby spines that articulate with the knobs on the shell as seen in 916 and 910. Figure 1078, also from Chawley is an uncommon fossil. It is a tooth, one of the five which form part of the so-calledAristotle's Lantern, or jaw apparatus of a sea urchin.
Aristotle's Lantern
Aristotle's Lantern, the jaw apparatus of Sea Urchins, as in the common English species (Echinus esculentus); it is of five sections, each of which consists of four pieces, a triangular pyramid (alveolus), perforated by a long keeled tooth. Above is a curved piece (compass/radius), and along the upper junction of two pyramids is the rotula/ brace.
Although there are no small working quarries to visit these days, fossils like these can be spotted by careful observers in the stones of old walls and in the field in the local area.
Lhuyd made no further mention of Cumnor or fossils as he turned his attention to the study of Celtic languages. Sadly he died in 1709 aged 49 from the effects of asthma and pleurisy, probably exacerbated by sleeping in a damp basement at the Ashmolean. He was buried in the church of St Michael in the Northgate where a plaque in the south aisle commemorates his life.
Psedomelania heddingtonensis
Commerative plaque St Michael in the Northgate Church, Oxford