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Re: Mesozoic terrain



Jeffrey Willson wrote:
> 
> I believe it was L. Sprague de Camp in _Day of the Dinosaur_ who opined
> that, since grass had not evolved during the Mesozoic, ipso facto the
> terrain must have been cut up by erosion into innumerable gullies and
> ravines of small, medium, and large size. If true, this would certainly have
> had repercussions on dino locomotion and behavior.

snipped
> 
> Comments?

I don't think Sprague de Camp has ever said anything that didn't make
sense (we engineers have gotta stick together).  Our soils here in west
Tennesse are the most highly erosive in the state, and are subject to
poor farming practice that leaves them exposed for a large fraction of
the year. As a result, we lose (from memory) about 18-19 tons per acre
per year of soil to erosion of the worst soil types.  If averaged, this
would be about 1/8" of soil surface per year.  This creates a lot of
rilling, but also a lot of deposition in local flood plains.  The
erosion process creates about as much 'geometrically suitible' sauropod
habitat as it destroys.  This is even more true of my original home in
the Mississippi delta of eastern Arkansas where I've run level lines for
several miles without ever having to go to high rod.

So yes, there would have been repercussions on habitat, but they
wouldn't have been catastrophic.  They'd just have moved the animals'
preferred range about a bit.
                Best wishes,
                        Jim Cunningham