Index Fossils 
Geologists date rocks by index fossils and they date fossils by the layer of rocks they are
 in (circular reasoning). What if the index fossil are wrong? In 1974, Burdick found a set of 
fossilized footprints of a barefoot child in a wheeler formation at 2000 feet altitude in the
 Swasey Mountains (west central Utah). In the middle of a track laid the compressed remains of a 
Trilobite. Obviously the Trilobite was not fossilized when the child steeped on it. It must have 
been alive to be squashed. But we know that Trilobites became extinct 300 million years ago 
and certainly man came no earlier than 3 million years ago????? 

Fossils and rock layers are cross checked.  There are more techniques (mostly radiation decay) used to date the layers than just the fossils or just the rocks.  I don't know what footprint is being mentioned here, but I am familiar with the Glen Rose footprints in Texas, where one print out of an otherwise unbroken set of reptilian prints looked vaguely human.  It looked more so when a fundamentalist preacher was caught with a hammer and chisel prettying up the resemblence.
TP