Rock (geology) arkoses (12%). Sedimentary rocks often contain fossils. Sedimentary rocks form under the influence of gravity and typically are deposited in horizontal or near horizontal layers or strata and may be referred to as stratified rocks. A small fraction of sedimentary rocks deposited on steep slopes will show cross bedding where one layer stops abruptly along an interface where another layer eroded the first as it was laid atop the first. Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was
Heat Shield Rock Heat Shield Rock Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover "Opportunity" in January 2005. The meteorite was formally named Meridiani Planum meteorite by the Meteoritical Society in October, 2005 (meteorites are always named after the place where they were found). "Opportunity" encountered the meteorite entirely by chance, in the vicinity of its own discarded heat shield (hence the name). "Opportunity" had been sent to examine the heat shield after exiting the crater Endurance. This was the first meteorite found on another planet and the third found on another Solar System body —