Fossil hunt.

I got up early this morning and slipped out of the house, careful not to wake my flatmates, to join the Otago Botanical Society for a "mystery fossil hunt". All I knew was that we'd be going to somewhere near Middlemarch to dig up some interesting fossils. I rode out with three people I vaguely recognized from my classes; we had a good deal of pleasant chatter on the way out, piled comfortably into a big red pickup truck. The scenery was lovely, too: Dunedin's rounded mountains gradually gave way to Central Otago's flat-toppped ranges, spattered liberally with weather-carved schist tors. The higher, farther mountains loomed over the plain, snow-capped and brilliant in the morning light. Twice we crested a ridge to see the valley ahead of us gone, sunk in a pool of low white fog.

It was a pleasant ride out, yes. Now imagine my glee when it turned out that the site out on the working farm, dug out between grassy banks, turned out to be the Foulden Maar site. I'd heard of it before, when a guest lecturer to my Plant Ecology class gave a presentation a few weeks ago: she showed us photos and examples of Miocene fossils, leaves so exquisitely preserved in diatomite that the cuticle -- the waxy layer over the leaves -- was clearly visible under a microscope. To the naked eye, the leaves looked like they fell two years ago, if that long ago. Now our convoy of assorted cars pulled up through the gates, past cavorting lambs, next to an unassuming little quarry that turned out to be the source of the paper's material.

It was a rare chance: the site is privately owned, and only because the paper's author was leading the fossil hunt with special permission were we allowed out there at all. We got straight to work. The diatomite is finely layered and very soft, so it came apart with little effort: kitchen knives and even fingernails could pry it apart into delicate half-millimeter sheets, each representing a year's worth of fallen diatom shells. Fossils peeled out of the sheets with startling frequency. Out of my fourth block came an inch-long, leathery black leaf with smooth edges and visible veins: something from the family Lauraceae, almost complete. It looked like a mountain-laurel leaf that had spent a year at the bottom of an anoxic pond. Knowing that it had spent more like ten million down there gave me shivers.

Working all day with my pocketknife and fingers, I turned up many more like it -- and I wasn't the luckiest or best fossil-finder in the group by far. We probably found at least a hundred leaves in four hours or so. The craziest part is that we left most of them behind: with so many available, the professional paleobotanists, Daphne and Jennifer, only want to take the best-preserved and most unusual. Turns out that the lauraceous finds are common and well-documented, so I could take several of them home with me. Something like a pumpkin seed, and another leaf that was both unusually well-preserved and of a rarer species, I turned over to the paleobotanists.

The highlight of the day came after we switched to the second site, a few hundred feet away. One of the fellows I'd ridden down with chopped a block out of the quarry wall, about head height, and split it open -- and there was the outline of a tiny fish, maybe three centimeters long. Only one other fish has ever turned up in the Foulden Maar sediments. Everyone crowded round to admire the rare find, then packed it away in cling-wrap and sent it safely back with Daphne and Jennifer.

It was great fun -- I love fossil-hunting, and knowing that the day's finds might actually advance science was extra excitement. The weather was lovely -- we didn't even need coats once the mist burned off -- and the company pleasant. (Sitting at the quarry's edge, munching on my sandwich and sorting through the finds Jennifer wouldn't be taking back, I got to chatting with her; she suggested I look into paleobotany, maybe even as a career. Hee hee!)

There are six or seven blocks of cling-wrapped diatomite on my bedroom floor now, each one with one or more embedded leaves. They won't last very long this way: freed from the weight and moisture of the diatomite layers, the leaves will crumble before too long. If I can extract them completely, though, and coat them in clear PVA glue, maybe on glass -- well, I might just be able to take them home. Ten-million-year-old leaves! Extraction will probably take a fine paintbrush, some water, and several hours; but I'll take a whack at it. It may well be worth it.