Some of the most frequent questions we face as archaeologists revolve around a common theme; Why is archaeology underground? Did people live below ground in the past? Was the ground level much lower back then?
The answer is simple… well, sort of. A large chunk of the archaeological features we uncover today were always intended to be underground. Think graves, building foundations, cellars, post holes, waste pits, drains, and the headline grabbing, buried treasure; the hoard. All of these are intentional below ground features. The treasure hoard is often interpreted as the hasty burial of an individual’s or an entire communities’ wealth when danger or uncertainty loomed. Vikings spotted on the horizon? Time to hide the family jewels.
Often on a site, we won’t see the ancient ground surface or historic ‘street level’. We’re essentially still occupying the same space nowadays, though perhaps we’ll just see a pattern of historic post holes and the bottom of rubbish pits, the top of which has been disturbed by later buildings and construction. On rural greenfield sites, centuries of ploughing may have destroyed the ancient ground surface.
Nature often plays a part in burying archaeological remains. We’ve all seen a ruined shed or barn sat in a field, roof collapsed, covered in ivy. If left alone, more of the structure will fall in and a thin soil of vegetation litter will eventually form. If ruins are situated at the foot of a steep hill, they can become covered over time by soil and debris washing or falling down the slope. Similarly, remains on a floodplain may become buried under silt left behind after repeated flooding. Probably the most striking example of the destructive power of nature seen in archaeology is at Pompeii. Two days of hot pumice and ash raining down from Vesuvius buried the Roman city, and those not able to escape, under 5m of debris.
Closer to home in London, as in most intensive urban areas, many factors play a part in the burying of the past. Much of London was low lying and wet when it was first urbanised by the Romans. Soil and rubbish was intentionally dumped and new structures built over old as streams and boggy ground was filled in and raised. Most cities are dynamic, not static places, and are continually being rebuilt. Notice the ever-present cranes on the skyline and site hoarding along the pavements. This isn’t a new phenomenon. As new buildings replaced the old, parts of the former structures were often left beneath the ground, be it as demolition debris, a cellar or a footing.
Sometimes after a destructive event, such as the Iceni tribe’s razing of Londinium in AD61 or the Great Fire of 1666, it was easier in places to flatten the remains and build directly on top of them, preserving a charred snapshot of the city for future archaeologists. As centuries progress, deep and complex strata will build beneath a city’s centre.
If you would like to discuss this further or want to know the archaeological potential of your site, do get in touch.