The layered terrain seemed transformed in pearly moonlight.

"Our borings show that the cap actually extends many degrees of latitude farther south than we see, buried under the layered terrain."

In both places, Dr. Schultz said, layered terrain bears a "striking resemblance" to the current polar regions.

Mission scientists liken their strategy for exploring the layered polar terrain to the reading of tree rings or ice cores in learning about Earth.

Expeditions were planned to numerous locations across the Martian north polar cap, including the Chasma Boreale and the polar layered terrains.

It's just more layered terrain, really.

"Sweet," one of the women commented, and then boom, they were down and running over the layered terrain.

"We believe this layered terrain is a record of climate change on Mars," Dr. Zurek said.

They felt for promising layered terrain by snaking the probe, a 10-foot metal rod, into the ground.

Named mountains, plateaus, layered terrain, and shield volcanoes use the terms mons, mensa, planum, tholus, respectively.