>I had always been under the impression that Creationists mainly believed in Bishop Usher's notion that 

>the Earth was created in 4004 BC, as stated in the Bible.



Actually, as has been stated in earlier posts, there are a number of creationist philosophies. The good Bishop's version is one of the "young earth" flavors. There are various "old earth" flavors, re-creationist, intelligent design, space aliens, and I'm sure I'm missing a couple. The common thread is that "someone/something else" created us rather than us evolving over time from common ancestors. In fact, many of them are happy to allow for adaptation within a species. They just reject speciation.



Most of the "new earth" version are incompatible with paleo simply because they would reject the concept of a Paleolithic era. For them we can call it the "Eden diet".



I think the variety of creation theories stems from someone wanting to believe in creationism, but not being able to reconcile it with what they know of science. So, they tweak both sides of the argument to fit their needs. And, of course, endeavor to discredit evolutionary theory as much as possible.