Re: Age of the Barun Goyot, Djadoktha and Nemegt Formations

[David Marjanovic <david.marjanovic@gmx.at>]

> Again, Norman considered S. angustirostris and S.
> osborni to be virtually indistinguishable.

This only (!) works as an argument if you assume a certain fixed speed of 
morphological evolution _and_ disregard stabilizing selection. In other 
words, your argument is built upon two speculations.

> Apples and oranges. Turnover among large dinosaurs
> was faster.

How do you know?

> Saurolophus is unknown from the Campanian
> or late Maastrichtian.

In North America, yes... at least so far...

> >   I think armchair geologists
>
> Was Shuvalov an armchair geologist? Or Sukhanov,
> Martinson, Russell, or Jerzykiewicz? They all
> expressed views on the age of the Nemegt simlar to
> mine, based on all the evidence.

There is so little evidence, in any direction, that the armchair is not a 
meaningful distinction in this case.