fossils

i've realized the irony of creationists constantly chiding "evolutionists" for the supposed lack of intermediate forms, while glossing over the total absence of modern species fossilized in the same formations as extinct species, such as dinosaurs. here's how AIG addresses this issue:

Further, the more mobile, intelligent animals would tend to survive the Flood longest and be buried last, so their remains would be vulnerable to erosion by the receding floodwaters at the end of the Flood and in the aftermath of the Flood. Hence their remains would tend to be destroyed. The intelligence factor could partly account for the apparent separation of dinosaurs and mammals such as cattle, for example.15

Most creationists would regard large mammal fossil deposits, such as in the John Day County of Oregon, USA, as post-Flood. Return to text.

source: http://www.answersingenesis.org/docs2/4419.asp#r15

so, the difference in intelligence between cattle & dinosaurs explains things. but the large mammals, presumably also intelligent, couldn't have been fossilized by the flood, ergo, they must have been fossilized by some unexplained mechanism. and any dinosaurs that had a brain to body ratio comparable to mammmals--and there were some--somehow weren't able to survive any longer than the mammoth, stupid, dinosaurs. and slow moving mammals like sloths all managed to find a handy raft to cling to, until succumbing to fish at the end, as in this scenario from AIG:

On the other hand, land animals, such as mammals and birds, being mobile (especially birds), could escape to higher ground and be the last to succumb. People would cling to rafts, logs etc. until the very end and then tend to bloat and float and be scavenged by fish, with the bones breaking down rather quickly, rather than being preserved. This would make human fossils from the Flood exceedingly rare.

yet somehow, not all birds survived this way, many turned into fossils. not even talking about disputed birds like archaeopteryx, there are plenty of undisputed fossilized birds.