(FWIW, & AFAIK, no one has ever claimed that souls leave an imprint in the fossil record.)
Where we may differ considerably is that I also have no problem accepting the likelihood (borne out by the fossil and archaeological record) that during His forming (devlopment, optimization ) of humanity's physical and mental structure, God had populated the earth such that Adam & Eve found themselves surrounded by a diverse populace fully their mental and physical equals. (Thus explaining the availability of compatible wives for Cain & Abel.)
Otherwise, how did a single man and his (cloned, genetically identical) wife generate the astounding genetic diversity found in today's human race -- in just 6,000 years?
Evidence for fully (physically and mentally, if not spiritually) developed humans (even on this continent) at least twice 6,000 years ago is absurdly easy to come by:
FYI, I have personally found one of these (Clovis Point) in situ...
And as a lithic technologist, I can attest to the exceptionally high visuo-motor and mental skills required to produce one of these masterpieces of craftsmanship...