Arctodus
Jedi
One saying of the C's I can't wrap my mind around is the concept of "saber-toothed tigers[cats], mastodons[or was it mammoths?] and ground sloths killing off and replacing the dinosaurs.
I'm only a layman, but I've seen many fossil sites both personally, once in real time, through books and through basic internet/flickerphotos showing loads of Cenozoic deposits. Aside from *neornithine birds, no dinosaurs are present in any convincing numbers.
*the Lithornithiformes may have been a surviving sister group to modern neornithines. They died out by the late Eocene.
It is certainly possible that dinosaurs survived into the Paleocene, a lot of fossil teeth and some bones are fairly common in Paleocene deposits up until 60 mya, then they become much rarer, finally disappearing by 55 mya. However, they are usually regarded as "re-worked" fossils since there is only one case of a possible "associated" fossil of some 36 bones some one million years after the K/Pa extinction event. It is certainly possible that non-avian dinosaurs made it past 65** mya but they don't seem to have made it past 55 mya.
**I know, the C's say 27 mya, okay, that is just...odd.
Anyways, by 60 mya (or roughly 25-23mya according to the C's) the first proboscidean *Eritherium* a rabbit sized critter appears. The first sloths and the first felines....well, who knows, they don't really appear until well into the Eocene, around 45 to 40 myas. Like the proboscideans, sloths and felids were rather small critters for a large portion of their history. Proboscideans became fairly large animals around 35 myas, sloths around 20 myas and felids around 10 myas.
This is rather hard to wrap my mind around. The Cenozoic is just chock full of strange mammals, reptiles and other critters that simply do not have modern descendants.
I'm only a layman, but I've seen many fossil sites both personally, once in real time, through books and through basic internet/flickerphotos showing loads of Cenozoic deposits. Aside from *neornithine birds, no dinosaurs are present in any convincing numbers.
*the Lithornithiformes may have been a surviving sister group to modern neornithines. They died out by the late Eocene.
It is certainly possible that dinosaurs survived into the Paleocene, a lot of fossil teeth and some bones are fairly common in Paleocene deposits up until 60 mya, then they become much rarer, finally disappearing by 55 mya. However, they are usually regarded as "re-worked" fossils since there is only one case of a possible "associated" fossil of some 36 bones some one million years after the K/Pa extinction event. It is certainly possible that non-avian dinosaurs made it past 65** mya but they don't seem to have made it past 55 mya.
**I know, the C's say 27 mya, okay, that is just...odd.
Anyways, by 60 mya (or roughly 25-23mya according to the C's) the first proboscidean *Eritherium* a rabbit sized critter appears. The first sloths and the first felines....well, who knows, they don't really appear until well into the Eocene, around 45 to 40 myas. Like the proboscideans, sloths and felids were rather small critters for a large portion of their history. Proboscideans became fairly large animals around 35 myas, sloths around 20 myas and felids around 10 myas.
This is rather hard to wrap my mind around. The Cenozoic is just chock full of strange mammals, reptiles and other critters that simply do not have modern descendants.
This is not what I remember reading. I think you are mixing things together. Could you reference the above to a link so that I may read what you are interpreting? I did a quick search through the forum, and a site search on Cass.org but can't find anything relating to mastodons or mammoths etc. wiping out dinosaurs. 
