Please see the thread in the "Is it Science" forum:
"Historical science"
Yes, It would be foolish to suggest the same atmospheric and environmental conditions existed the same at any given point in the unwritten historical record. This is the problem with uniformitarainism.
Especially since the geoligic record shows without doubt that ancient paleo-environments have varied considerably from the present. We know this with as much certainty as we know matter is composed of atoms.
Edited by bdfoster, : No reason given.
Brent