Free Moving Mars by Greg Bear Page A

was not inclined to physical science, but no Martian can escape the past; we are told tales in our infant beds.
    Mars was dead; once, it had been alive. On the lowland plains, beneath the ubiquitous flopsands and viscous smear lay a thick layer of calcareous rock, limestone, the death litter of unaccounted tiny living things on the floor of an ancient sea that had once covered this entire region and, indeed, sixty percent of northern Mars.
    The seas, half a billion Martian years before, had fallen victim to Marss aging and cooling. The interior flows of Mars slowed and stabilized just as Mars began to develop and push asideits continents, thus cutting short the migration of its four young crustal plates, ending the lives of chains of gas-belching volcanoes. The atmosphere began its long flight into space. Within six hundred million Martian years, life itself retreated, evolving to more hardy forms, leaving behind fossil sea beds and karsts and, last of all, the Mother Ecos and the magnificent aqueduct bridges. (Ecos is singular; ecoi plural.)
    All around us, ridges of yellow-white limestone poked from the red-ochre flopsand. Rusted, broken boulders scattered from impact craters topped this mix like chocolate sprinkles on rhubarb sauce over vanilla ice cream. Against the pink sky, the effect was severe and heart-achingly beautiful, a chastening reminder that even planets are mortal.
    Like it? Charles asked. We hadnt talked much since leaving Durrey in the borrowed Klein tractor.
    Its magnificent, I said.
    Wait till we get to the open karstslike prairie dog holes. Sure signs of aquifers, but it takes an expert to know how deep, and whether theyre whited. Whited aquifers carried high concentrations of arsenic, which made the water a little more expensive to mine. Whited seas had entirely different life forms. Thats probably where the mothers came from.
    I knew little about the mother cysts single-organism repositories of the post-Tharsis Omega Ecos, a worlds life in a patient nutshell, parents of the aqueduct bridges. Their fossils had been discovered only in the past few years, and I hadnt paid much attention to news about them. Have you ever seen a mother? Charles asked.
    Only in pictures.
    Theyre magnificent. Bigger than a tractor, heavy shells a foot thick buried in the sands, waiting for one of the ancient wet cycles to come around again The last of their kind. His eyes shone and his mouth curved up in an awed half-smile. His enthusiasm distanced me for a moment. Some might have lasted tens of millions of years. But eventually the wets never came. He shook his head and his lips turned down sadly, as if he were talking about family tragedy. Some hunters think well find a live one someday. The holy grail of fossil hunters.
    Is that possible?
    I dont think so.
    Are there any fossil mothers where were going?
    He shook his head. Theyre very rare. And theyre not found in karsts. Most have been found in the sulci.
    Oh.
    But we can look. He smiled a lovely little boys smile, open and trusting.
    The Klein BM winery, a noble experiment that hadnt panned out, lay buried in the lee of a desiccated frost-heave plateau twenty kilometers west of Durrey Station. Now it was maintained by arbeiters, and fitfully at that, judging from the buildup of static flopsands on the exposed entrance. A gate carried a bright green sign, TrHaut Mc. Charles urged the tractor beneath the sign. The garage opened slowly and balkily, gears jammed with dust, and Charles parked the tractor in its dark enclosure.
    We sealed our suits and climbed down from the cabin. Charles palmed the lock port and turned to face me. I havent been here since the codes were changed. Hope Ive been logged on the old general Klein net.
    You didnt check? I asked, alarmed.
    Joking, he said. The lock opened, and we stepped in.
    Over the years, the arbeiters had repaired themselves into ugly lumps. They reminded me of dutiful little hunchbacks, moving obsequiously out of our way as we