"The Hand Sculpted House" - Ianto Evans. It's been awhile since I've read it, but I remember there being a good section on earthen floors. It's also just a fantastic book all around, great and thorough info and philosophy on all things natural building.
Check out Sukita who runs Claylin. She's probably the best to consult these days for floors. She doesn't have a book as far as I know but she would probably respond to an email. Try a quick google search. Otherwise, there is some good advice and a handful of good recipes in Carol Crews' new book "Clay Culture"
I guess everyone has an angle. Fine, what do you want? Just know that you cannot have this tiny ad:
Contemplate spending the next 20 years building a better world in montana