For people interested in the subject generally I highly recommend John McPhee's anthology "Annals of the Former World." Actually I highly recommend everything John McPhee has written but this is a good start :).
Second for John McPhee! Also Rising From the Plains.
References to his books should carry a warning - something to the effect of:
"may inspire circuitous road trips involving many stops dangerously examining road-cuts on busy interstate highways"
I can also recommend: "The Earth: An Intimate History" by Richard Fortey