In the southwest of England lies one of the most important early sites for the study of humans and their history. Kents Cavern is a limestone cave in northern Torbay formed in Devonian limestone (which is formally named at a nearby site in Devon). After the water table dropped following regional erosion, the caves opened up to the surface. A variety of early human artefacts and fossils of extinct animals from the last ice age have been preserved within. Together with the speleothems (cave formation), the caves contain one of the most complete cave records of climate change over the last 500,000 years in northwestern Europe.
Kents Cavern is one of the earliest sites of careful archaeological excavation. After a dig in 1824, William Buckland, who I mentioned in a previous post, sponsored further excavations. Flint tools were recovered beneath cave formation, which was rejected by the British Association as being contrary to the only recognised chronology at the time, that of Archbishop Ussher. Ussher developed the chronology from a literal reading of the Old Testament and decided that the Earth was created on October 23, 4004 BC. The “Antiquity of Man” was a major scientific debate in the middle of the 19th century. Evidence was emerging, such as primitive tools, that humans had been around on the Earth much longer than biblical accounts.
Between 1846 and 1858 William Pengelly conducted a series of excavations under the auspices of the Torquay Natural History Society to show the context of human tools with the cave formation and fossil bone. These findings, together with those of Jacques Boucher de Crèvecœur de Perthes and Pengelly’s other excavation at Brixham cave, finally convinced the Royal Society, the Society of Antiquaries, and the British Association that the biblical account was wrong. This understanding laid the foundations for the development of the sciences of geology and biology.
William Pengelly continued the excavations at Kents Cavern from 1865–1880 as Chair of a committee created by the British Association. The systematic approach he used paved the way for modern archaeological excavations. Pengelly excavated all the sediment he could get access to, basically until the sediment ran out. In order to demonstrate the stratigraphy of human artefacts, all finds had to be carefully recorded in three dimensions. The cave was professionally surveyed. A datum was established at the mouth of the caverns and each deposit was excavated in a series of planes 1 foot deep. The cave formation could not be easily removed, so Pengelly used dynamite. The unit of recording in the sediment beneath was 1′ x 3′ x 1′, which Pengelley called a “prism”. The specimens were numbered and boxed up, logged and then examined and identified. A total of 7340 boxes were accessioned. Apart from some minor errors, the data recorded is so good that the position of the fossils and artefacts can be plotted today in 3D.
Pengelley described a simple stratigraphy for the site. The oldest unit is red sand deposited by a stream shortly after the caves started to form. The caves were then filled by an unconsolidated breccia containing primitive Acheulean technology tools and cave bear fossils. Early humans were not living in the caves, but cave bears were using the caves to hibernate in. Overlying this is extensive cave formation when the caves were sealed off from the outside. The bulk of the time in the history of the caves is in this unit, marked only by the slow accumulation of stalagmites and stalactites. Next, is another sedimentary unit of cave earth when the caves were once again opened up to the outside. This unit is composed of fossils of extinct animals from the end of the last ice age and evidence of visits to the cave by people at the same time. Sealing that unit is another layer of speleothem that is still forming in parts of the cave today. In the other areas there is a recent accumulation of modern debris, including animals that have wandered into the cave and died.
The model above is of a hyaena jaw that was preserved in the youngest ice age sedimentary unit. Hyaenas would have used the cave as a lair to raise young, dragging back scavenged remains or kills from elsewhere. The level of preservation is fantastic. Although most of the excavated remains are accessible from museums, the sediments and cave formation lie under the car park at the front of Kents Cavern. Unfortunately it is now not possible to go back and learn more from those sediments with modern techniques. An important lesson here is how important it is to preserve our history. Kents Cavern preserved a long chapter of our history undisturbed for thousands of years. Museums and accessible caves are needed to preserve and teach the next generation our history. For nine years I was able to lead undergraduate field trips through the caves to teach them the history. Digital photogrammetry provides a means of sharing pieces of our history with a wide audience that don’t have access to the caves.