Beside Fern Pit, on the Gannel shore, the rock contains a collection of hollows which the National Trust compares in size to dinner plates.

That is an inconveniently recognisable shape. A small irregular mark might be allowed to remain a bit of weathering. Several large circles immediately look as though somebody intended something.

What they intended, if anybody made them at all, is where the agreement ends.

The National Trust’s account of Crantock locates the holes near the Fern Pit slip and treats their origin as unresolved. Suggestions have included natural processes and human activity. The South West Coast Path Association favours an unidentified manufacturing process over prehistoric carving.

An unknown manufacturing process is a splendidly unsatisfying explanation. It also has the merit of admitting the important missing part.

A mystery with a paper trail

The markings were attracting antiquarian attention in the late nineteenth century. Volume ten of the Journal of the Royal Institution of Cornwall, covering 1890–91, contains W. Iago’s paper on recent archaeological discoveries. A reproduced illustration of the Gannel hollows is attributed to its page 190. The index separately lists “Rock Markings on the River Gannel” at page 297.

Those references establish a useful route back into the discussion. The original pages still need to be inspected together before the later note can be described as a reply or an explanation. An index entry tells us that something was written; it does not tell us the conclusion.

Even with that limit, the history changes the question. This is not a mystery created by a recent photograph on the internet. The rock was interesting enough to draw and discuss in the Victorian period.

The river makes several explanations tempting

The Gannel was a working estuary. Ships, cargo handling and shore-side industry belong to its history, as When Ships Sailed Up the Gannel explains. That context makes practical human activity a reasonable possibility.

It does not identify a tool or a process. A convincing industrial explanation would need to account for the hollows’ size, shape, pattern and position, preferably alongside comparable features with a known purpose.

Natural explanations need evidence too. Weathering and abrasion can produce forms that look surprisingly deliberate, but saying that water can make hollows does not establish how these particular hollows formed. The rock type and surface detail matter.

Nor does the prehistoric landscape across the river give us permission to label the marks ancient rock art. Nearby barrows and settlements have their own dates. They cannot lend those dates to an unexplained feature merely by being close to it.

The useful next comparison

The Victorian illustration could be particularly valuable. A securely matched drawing and modern photograph might show which groups survive, how they were measured and whether the surface has changed.

That is a much better next step than choosing whichever explanation sounds most Cornish. The shoreline context makes maritime work conceivable; the wider archaeology makes an ancient interpretation tempting; the rock makes geology unavoidable. Each possibility has a different test.

Any modern recording needs lawful, safe access and advice appropriate to a tidal, cliff-side site. This is a documentation problem, not an invitation to chip samples from the surface.

Divided notebook pages sit beside a rock fragment.
Separate observations from the theories built around them. Editorial image.

Leaving the question open

An article about a mystery can feel obliged to solve it in the final paragraph. Fern Pit does not currently offer that service.

What it offers is a real feature, a nineteenth-century research trail and a set of explanations which have not yet been made to fit all the evidence. The uncertainty is part of the history of the place.

Elsewhere on the Gannel, The Gannel Crake: The Ghost That Was Supposed to Save Your Life turns an unsettling sound into a warning ghost. Here, an unsettlingly regular shape keeps attracting purposes. Both stories show how readily an unfamiliar feature asks us for an explanation.

The holes are worth looking at because they remain unexplained. Giving them a confident answer too soon would remove the most interesting thing about them.

Sources and further reading

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