No Major Disagreement
I personally think impacts probably have played a major part in mass extinctions so I don't have any major quible with your comments. We just don't have conclusive evidence that is the case and we do have some good reasons to doubt it. My issue was that mass extinctions are not the major source of extinction as Peiser and some paleontological illiterates here seem to think. Climate change certainly impacted many if not most of the pachyderm extinctions you mentioned not to mention pressure from a new form of predator. The surviving pachyderms may benefit from a shortage of cliffs in their area.
Regards,
Mark