MEMORY is the weak link. This year I will be three hundred and ten years old, but most of my life is lost to me, buried in the years. I might as well be a creature of incarnations, moving from life to life, ignorant of my own past. Oh, I “know” that once I climbed Olympus Mons, that once I visited the Earth, and so on; I can check the record like anyone else; but to recall none of the detail, to feel nothing for this knowledge, is not to have done it.

It isn’t as simple as that, I admit. Certain events, moments scattered here and there in my life, exist in my memory like artifacts in the layers of an excavation: fragments of meaning in the debris of time, left in a pattern of deposition that I fail to understand. On occasion I will stumble on one of these artifacts — a trolley bell in the street, and I see an Alexandrian’s smile — a whiff of ammonia, and suddenly I am reacquainted with my first daughter’s birth — but the process of deposition, the process of recovery, both are mysteries to me. And each little epiphany reminds me that there are things I have forgotten forever — things that might explain me to myself, which explanation I sorely need — and I clutch at the fragment knowing I might never stumble across it again.

So I have decided to collect these artifacts, with the idea that I had better try to understand them now, while they are still within my reach — working as the archaeologists of old did so often, against rising waters in haste, while the chance yet exists: hurrying to invent a new archaeology of the self.

What we feel most, we remember best.

The Tharsis Bulge — the bulge is five thousand kilometers across and seven kilometers high, and formed early in Mars’s history. The stresses caused by this deformation in the crust were instrumental in the formation of the large volcanoes, the equatorial canyon system, and an extensive system of radial fractures. We came on the site in a hundred field cars, a caravan that lofted a plume of umber dust over the rocky plaiu. The site looked like any other youngish crater: a low rampart we could drive right up, and then a flat-topped symmetrical rim-hill, surrounded by the hummocky slope of the ejecta shield. Few craters look impressive from the outside, and this was not one of the exceptions. But my pulse quickened at the sight of it. It had been a long time coming.

I put on a thermal suit, and ordered those of my students in the car to do the same, as I needed companions for a hike to the rim. Gritting my teeth I walked up to the car containing Satarwal and Petrini, and knocked on their door window. The door popped open with a hiss and there they were, faces poking out like Tweedle-dum and Tweedle- dee: the codirectors of my dig. Blandly I told them I was going up to the rim with a few students to have a look around.

Satarwal, flexing his boss muscle: “Shouldn’t we set camp first?”

“You’ve got more than enough people for that. And someone needs to go up there and confirm that we’re at the right crater.”

Giving excuses: a mistake. “We’re at the right crater,” said Satarwal,

Petrini grinned. “Don’t you think we’re at the right crater, Hjalmar?”

“I’m sure we are. Still it wouldn’t hurt to see, would it. Before the whole camp is set.”

They glanced at each other, paused to make me stew. “Okay,” Satarwal said. “You can go.”

“Thanks,” I said, bland as ever. Petrini shot a look at Satarwal to see how the head of the Planetary Survey would take this sarcasm; but Satarwal hadn’t noticed it. Stupid policeman. With a jerk of the head I led half a dozen students and staff toward the rim. It was midafternoon, and we hiked up the gentle slope with the sun over our shoulders and the quartet of dusk mirrors almost overhead. It felt good to walk off the exchange with Satarwal and Petrini, and I left my group behind. They knew better than to catch up with me when I walked that fast. Those two clowns: I blew frost plumes as solid as cotton balls into the chill highland air at the thought of them. This was my dig. I had worked for twenty years to get the site off the Committee’s proscribed list; and I would have worked a hundred years more and never gotten their permission, too, if a friend hadn’t been put on the Committee. But it pleased him to sanction the dig for the season directly following the end of my stint as chairman of the department. So that the new chairman, Petrini, was made the codirector of the dig along with the Committee watchdog Satarwal; while I, whose work the dig would support or refute, was nearly forbidden to accompany it. I had had to grovel for the better part of a year before they allowed me to join the expedition. And my friend only laughed. “You’re lucky to be going at all, you fearsome radical!”

But here we were. I booted a rock uphill to remind me of the reality of our presence, to clear my mind of all the poison poured into it by the government. We were here. That meant that, no matter what else happened, I had won: a site had been taken off the proscribed list for the first time. And now it loomed before me — ah! — my heart leaped at the thought. I picked up my pace; the only thing that kept me from bounding up the slope was the presence of my students behind me. The ejecta shield became steeper and rougher as I approached the rim; above me blocks stuck into the dirty lavender sky, and they gave me an excuse to bound upward, to clear them. Below me the shouts of my companions sounded like the cheeps of snow finches. Between the broken blocks of compressed basalt were drifts of fine frost — crunchy sand-

And then the slope curved flat and I was on the rim. Topping it was an embankment of tan concrete; I ran to it. Concrete, with a steel coping laid in its top: a dome foundation of the early twenty-second century. So we were at the right crater. From my new vantage I could see around the circumference of the rim, and the embankment grew or shrank to level it off.

Here and there struts stuck out of the embankment over the crater below, for two meters or five or ten, until they twisted down and broke off. The supports for the dome. In several places the embankment was blasted down into the rim; one such disruption was a short distance away from me, and I went to have a look. The concrete in the break had been reduced to something like black sandstone, which crumbled into my glove when rubbed. So they had blown down the dome. I shook my head. Nasty shock for the inhabitants, no doubt.

Hana Ingtal, the least stupid of my students, popped over the rim and interrupted my survey. “Professor Nederland!” she cried, holding out between two gloved fingers a chip of blue plastic.

“What.”

“Look here — it’s a taggart.”

I took the chip from her and inspected it.

“Explosives companies put them in their products so they can determine whose explosives made any particular—”

“I know what taggarts are, Ingtal. Put this back where you found it. You know excavation procedures, don’t you? Move nothing except as part of a methodical exploration, that can be confirmed by others and recorded as authentic data. Especially on this dig. You may have destroyed this piece’s worth as data already!”

Crestfallen, she turned and walked back down the rim. But that is how students learn. “And make sure you put it where you can find it again!” I shouted after her. She was one of those students who progress in leaps, and miss things along the way — practical matters like methodology. No doubt she had developed a complete theory of the city’s end from that single chip of plastic. But she was young. A century or two of defeat would teach her what it took to build a case in Martian history.