Geology rocks! New photos from Mars (pictures)

The Gale Crate wall north of the landing site shows a network of valleys that may be formed by erosion from water flowing into the Gale Crater. These fluvial systems are believed to be millions or even billions of years old -- from a time of Mars when water flowed freely across the surface. The main channel deposit seen here resembles a dirt road ascending into the mountains, which are actually the north wall and rim of Gale Crater.

Rockets from the descent stage of the rover's landing last week blew away fine dust on the surface, uncovering the bedrock below. Of particular note, NASA says, is a well-defined, topmost layer that contains fragments of rock embedded in a matrix of finer material, Seen here in the inset of the image are pebbles up to 1.25 inches across (the upper two arrows) and a larger clast 4 inches long protruding up by about 2 inches from the layer in which it is embedded. Clast-rich sedimentary layers can form in a number of ways. Their mechanisms of formation can be distinguished by the size, shape, surface textures and positioning with respect to each other of the fragments in the layers.