The Ares region on Mars photographed by Sojourners rover. Photographs of Mars raise and answer questions about the origins of the rocks and other deposits found there. Deposits are not the same everywhere. Bright, fine-grained drifts (right center) are abundant as thin (less than a few centimeters), discontinuous ridged sheets and wind tails that overlie cloddy deposits of dust, clods, and tiny (less than 1 cm) rocks.