C is for the cold, in which the crystals coalesce and creep, and for the calving cliff where they recombine with the circulating deep. C is for Cirque (or Corrie or Cwm), and for the creaking, cracking crevasses and conduits where crampons really count and the climber or caver can't find much room. C is for cryoconite, for campsite, for the continuity equation and the column-averaged flow law of calibrated computer calculations. C is for the coarse-cobbled clay with characteristic clasts collected at Columbia, Cascade or Cook. C is for cores at Camp Century and Dome-C, and for the ice cap carapace of Cotopaxi, Chimborazo, Cayambe and the rest. C is for crossed polarizing filters, and C is the optic axis through Paterson's "crinkled molecular sheets".