How many of us grew up with this image of a lost prehistoric scene? A deep, shimmering pool of oily death, looking deceptively, enticingly, like a refreshing basin of water . . . an unsuspecting creature that steps in, expecting to slake its thirst . . . only to find itself trapped in acrid, viscous tar! Its companions watch helplessly as the beast succumbs to exhaustion and sinks into the inky goo like a doomed ocean liner. The La Brea Tar Pits have claimed another victim.

That was the conception of the La Brea Tar Pits I had had all my life: deep hydrocarbon ponds into which animals wandered and then never came out. Enormous infernal death traps great enough to swallow mammoths and saber-toothed tigers whole. This is such a dramatic, cinematic image that the modern caretakers of the Tar Pits have recreated it in diorama form near the entrance to the grounds to greet incoming visitors.

The truth, as usual, is far less dramatic. It turns out that the La Brea Tar Pits were not so named because they were originally deep pits of tar into which animals sunk, but because they eventually became deep pits from which tar (or, more precisely, asphalt) was dug up — in the last century or so. In the millennia before then, when the tar was doing its paleontological dirty work, the gooey dangerous part was never more than several inches thick.

As displays in the museum on the La Brea grounds explain, starting around 40,000 years ago, subterranean pressure forced petroleum up through deep underground fissures to the surface, where it slowly oozed out and collected in shallow depressions. The most volatile components would evaporate, leaving a thin layer of thick asphalt. This doesn’t have the same ominous gravitas as “Tar Pit”, but “Tar Puddle” would have been a more accurate description.

Dust or leaves or perhaps a layer of rainwater would fall over the tar puddle, and then some hapless prehistoric horse or camel would wander atop it and find itself stuck. At some point, it might attract predators or scavengers — either through panicked cries as it tried to free itself, or by the scent of its own decomposition after it had succumbed — and maybe some of these creatures would also find themselves stuck in the tar puddle. Eventually the old tar would harden, with a stash of fossilizing bones inside, but the earth kept forcing up new goo, and that would form a new tar puddle atop the old one. The museum at La Brea estimates that 10 years could have elapsed between the formation of one puddle and the next atop it. Sounds geologically slow, but over the course of 40,000 years, such processes formed the Tar Pits that were later dug up by humans.

We are so accustomed to the idolization of the dramatic — the winning play, the reversal of fortune, the overnight success — that the old image of the La Brea Tar Pits as a overwhelming cauldron sucking pachyderms into its depths resonates. Our concept of time also plays a part: we know that the remains of thousands of animals have been unearthed at La Brea, and it is hard for us to imagine that that many animals could have died in one place unless it were happening every day in an unfathomable deep. We simply cannot relate to something happening incrementally, once every ten years over 40 millennia.

We often view our career success in the same way. Weaned on stories of Zuckerberg, Damon and Affleck, and Obama, we expect that our personal progress will come to us in a rush, with the grand scheme, the deal of a lifetime, the big speech. It is harder to imagine that we might accumulate recognition, competence, reward, and fulfillment one small bit at a time, over the course of decades. Until one day we take stock of our lives, and count out the wealth we have acquired.

And if you still think of this patient, incremental course of action as nearly unimaginable, consider this: it is still happening at La Brea. Even today, the earth forces new flows of tar onto the grounds of the site, forming new tar puddles. They look innocuous, almost silly; shimmery smudges in a green island in a concrete jungle. But each has the potential to capture giants.