There are no naturally occurring rocks in New Orleans and the surrounding region. If you'd made me think about it, I might have guessed that, but no one ever made me think about it. The entire area was formed by sediment carried by downstream by the Mississippi, and all of the big stuff dropped out way upriver. By the time you get this far south, it's almost all fine silt and clay. So:
"Any particle in southeastern Louisiana coarser than a few millimeters in diameter was imported by humans."There you have it. No rocks.
And yet, somehow, we will rock you.
* Though "reading" might imply a roughly linear path through the content. In truth, it's a meandering, semi-random hopscotch, landing on choice bits of text, graphs, and deliriously delicious maps (yes, I'm finally getting my map fix).