Hi all -

Sorry, but the lower Columbia Hills appears to be an oblique impact, where the low velocity asteroid impactor just tunneled in, with the center section of the tunnel collapsing later. If anyone happened to watch the oblique impact simulation on television last night (Discovery Channel) one could see the process in action: the impactor buries in, and then the crater forms. In this case the impactor velocity was lower, and the matter hit (Mars) not very solid - but then of course the upper lithosphere of Mars is for the most part mainly compacted impact debris -

Given this, it would seem that the Upper Columbia Hills might be of interest, but they appear to be the remains of an eroded crater wall -

If one were looking for fossils it strikes me that one would look for old impact debris - if one headed toward the mouth (asteroid entry point) of Lower Columbia Hills, after examining the debris from that impact one could then head toward Upper Columbia Hills - perhaps that other impact may have released some water -

ep