Well, Human beings are not going to be found in the proper geological layer either.
Those not killed by the first strike might take a while to die. It could have taken hundreds of years to kill them all.
I think there was more than one reason why the giant reptiles and giant mammals died out. Of course, the asteroid/comet ? could have caused several effects.
It’s a good thing they are all dead. Can you imagine having to pick up the POOP?
“Just below” the KT Boundary can mean it died days before or thousands of years before depending on any number of variables. Things like how far below the KT boundary, the type of sediment, how densely packed it is, etc.
>> “I think there was more than one reason why the giant reptiles and giant mammals died out.” <<
.
Must have been, since a bunch of them were still very much alive when the temple at Ankor Wat was built, otherwise how would they have gotten those carvings so perfect?
.