[Image: A cave entrance in France, via Wikipedia].
I recently finished reading Last Words by Michael Koryta, a detective novel largely centered on an unmapped fictional cave system in southern Indiana, part of the great karst belt near the border with Kentucky.
One interesting thing about the novel is that this cave, known in the book as “Trapdoor,” operates on many different narrative levels. Most obviously, of course, there’s the unreliable memory of a major character suspected—yet never officially accused—of committing a murder there, where the darkness of Trapdoor’s linked subterranean spaces becomes a kind of mental model for his own inability to recall what really happened, when a woman was (apparently) murdered in the cave’s depths.
There is also a subplot, though, revealed quite late in the book, in which disguised real estate deals and obscure land trust deeds have been premised on the subterranean potential of this land snaking along the region’s old creeks and rivers, transactions inked with the belief that Trapdoor’s passages might continue beneath distant parcels; in this way, the cave comes to represent the conspiratorial intentions of people otherwise unwilling to state their true goals.
Finding the true outer limits of the cave—that is, finding the land parcels that the cave secretly connects from below—becomes coextensive with discovering the truth about what occurred underground there so many years earlier.
It was these latter parts of the novel—including a handful of plot points I won’t get into—that reminded me of notes I’d taken from a book called the Encyclopedia of Caves several years ago. That book includes a short entry written by Nevin W. Davis, called “Entranceless Caves, Discovery of.”
As Davis describes them, “entranceless caves” are like speleological versions of Schrödinger’s cat: they exist, but they have not been verified. They are real—but perhaps not. They are both in the ground and nowhere.
At times, Davis’s text is almost like a koan: “Suppose the cave is totally unknown and has no entrance,” he writes. What exactly is such a thing, and how can we account for its presence (or absence) in the landscape? After all, these are caves that have not been—and perhaps cannot ever be—located.
He goes on to describe mathematical models used to generate a probability of subterranean connection: the calculated likelihood that physically inaccessible voids might exist beneath the surface of things, linking one part of the world to another.
“Another consideration in searching for caves,” Davis continues, “is entrance lifetime. Caves are long-term features under the landscape with lifetimes measured in millions of years, whereas entrances to them are fleeting features with lifetimes measured in millennia.”
Cave entrances come and go, in other words, while the caves they once led to remain. They can be covered over, woven shut by tree roots, erased.
As Davis describes it, “leaves and twigs will soon cover and block small vertical entrances. Pits less than a meter in diameter”—tiny holes that can nonetheless lead to huge systems, such as the real-life Mammoth Cave or the fictional Trapdoor—“can be totally blocked in one season. Leaves blocking a small entrance are soon followed by roots and more leaves and it is not long before all traces of an entrance are gone.”
This leads to an activity he calls “stalking the elusive entranceless cave”—which, for what it’s worth, seems like a perfect metaphor for part of Koryta’s novel, in which the book’s amnesia-stricken potential murderer undergoes hypnosis. His memory is a cave with no entrance.
In any case, there can also be “false positives,” Davis warns. These would be caves that appear to have been detected but that are not, in fact, real. A “stalker” of previously unknown caves might find herself misled by patches of melted snow, for example, or by other signs that wrongly give the impression of warm air rising from empty passages below.
“The best condition to search for snow melt,” Davis suggests, instead, “is with a new snowfall in midwinter with an overcast sky, since sunlight can also give false positives by shining through snow cover onto rocks and melting the snow. This is a tried-and-true method that has led to countless new caves.” It’s cave-discovery weather.
In essence, this is a process of reading the landscape: interpreting its surface features in order to gain knowledge of these other, deeper dimensions.
The next entry in the Encyclopedia is also worth reading; it is simply called “Entrances,” by William B. White. “Some caves,” White writes, continuing the strangely existential thread of Davis’s work, “may have no entrances at all.”
White adds a new category here, what he calls the “concealed entrance.”
At least from an architectural point of view, what’s interesting is that this allows White and other speleologists to challenge the idea of there being a clean dividing line between inside and outside, between a cave and the Earth’s surface.
Instead, he suggests, a cave’s entrance should actually be thought of as a transition: the “cave entrance zone,” White writes, “is, in effect, a continuous sequence of microclimates,” one that eventually leads to a point at which there is no direct access to sunlight or to rainfall.
It is only at that point that you are truly “inside” the Earth. You have transitioned to the great interior.
[Image: Photographer unknown; image via Discovery Communications].
Briefly, White also points out that cave entrances are not only unstable in the temporal sense—as Davis mentioned, cave entrances can completely disappear over time.
However, they are also unstable spatially: that is, they can physically migrate through the landscape over thousands, or even tens, of years.
Due to continual rockfall, for example, a cave entrance “not only migrates deeper into the hill but also migrates upward as rocks break away,” Davis writes. This can potentially push a cave entrance dozens and dozens of feet from its original location, while the cave itself remains stationary. Imagine a mouth migrating across your body while your stomach stands still.
Of course, this also means that an entrance to a given cave system can abruptly migrate onto someone else’s property, or that it can even pop open, suddenly and dramatically changing the value of a particular piece of land.
The next thing you know, following an unusually intense summer rainstorm, you own the entrance to a cave.
[Image: A salt cave in Israel; image via Wikipedia].
Which brings us back to Michael Koryta’s novel. There, an unexpected opening into the unstable depths of Indiana’s fictional Trapdoor complex changes the lives of many characters not just for the worse, but for the tragic.
The cave, as Koryta depicts it, is a relentless and unsympathetic thing, a space always shifting, growing organically but not alive, invisible yet ubiquitous, moving beneath the surface of the landscape, connecting parcels of land, as well as the lives—and deaths—of the characters who thought they were just idly passing time above.
(Vaguely related: Life on the Subsurface: An Interview with Penelope Boston).