Quoting from Grotzinger et.al. in EPSL
"To obtain true stratigraphic thicknesses, one must be able to correct for deformation of strata associated with folding, faulting, and brecciation due to impact. At Eagle, Anatolia, and Fram the bedrock is fractured and consists of rotated blocks. In general, systematic deformation patterns are absent, which precludes ordering of the stratigraphy at those locations. Exceptions to this are the El Capitan and Big Bend areas of Eagle crater, where strata can be traced laterally for several meters as mostly intact units"
Doug