This patch of windblown sand and dust downward from a bunch of dark rocks is the "Rock nest" site, which has been chosen as the likely location for first use of the scoop on the arm of NASA's Mars rover Curiosity.
The projection characteristics are reliable with a sedimentary conglomerate, or a rock that was formed by the deposition of water and is composed of many smaller rounded rocks cemented together.
The Bathurst Inlet rock is dark gray and appears to be so fine-grained that MAHLI cannot resolve grains or crystals in it. This means that the grains or crystals, if there are any at all, are smaller than about 80 microns in size.
