In this VIS image, taken by the NASA - Mars Odyssey Orbiter on July 1st, 2013, and during its 51.217th orbit around the Red Planet, we can see a small portion of Palos Crater (on top of the frame) and a section of the approx. 180-Km-long (such as a little less than 112-miles-long) Channel known as Tinto Vallis. In fact, Palos Crater is breached in its Southern portion by Tinto Vallis (right in the middle of the picture), and the water transported along this sinuous Channel could have collected - at some point in the Geological History of Mars - into Palos Crater itself, so to form a Lake that, later, drained to the North.
If you think about it, we can speculate that the Sediments carried by the waters flowing inside Tinto Vallis, could have reasonably been deposited within Palos Crater, so that the many Layered Units that have recently been identified (in several pictures taken by the NASA - Mars Reconnaissance Orbiter) all along the Floor of Palos, could well be representing the fossilized remnants of the aforementioned Fluvial Sediments.
Latitude (centered): 3,249° South
Longitude (centered): 110,809° East
This frame (which is an Original Mars Odyssey Orbiter b/w frame published on the NASA - Planetary Photojournal with the ID n. PIA 17439) has been additionally processed, magnified, contrast enhanced, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.