Paleo-Environments

["Dino Rampage" <dino_rampage@hotmail.com>]

1) Just wondering... I've been told that the Two Medicine & Judith River 
Formations are actually the same formation, except that the two are now 
separated by a modern erosional arch. Does this mean that in those days in 
the Late Cretaceous, the fauna of both formations could have intermngled 
together?? I've always had this image that while the Judith River was 
predominantly low-lying floodplain, the Two Medicine was more of like a 
series of plateaus that effectively separated dinosaurs such as Maiasaura, 
Hypacrosaurus stebingeri, Einiosaurus & Achelousaurus from their Judith 
River cousins like Gryposaurus, Corythosaurus, Centrosaurus & Styracosaurus? 
So is it true that the fauna & flora of both formations were not so 
isolated?

I understand that different taxa would have different habitat preferences, 
with some keeping to the uplands, and others to the lowlands, but is it 
accurate to speculate that the fauna & flora of both areas would have 
constituted what amounted to an entire Great North American Ecosystem? (Just 
like the Africa in prehistoric times- the mopane woodlands of south-central 
Africa connected to the semi-deserts & veldt of southern Africa & the 
savannas of eastern Africa)

What I'm just implying is that while the fauna of both formations had 
different ranges, habitat preference etc etc, some taxa would be more 
generalised and inhabit virtualy every habitat in this ecosystem (think 
wolves in North America & Eurasia, & buffalo, leopard & olive baboons in 
Africa) Thus, some fauna would have been common to both formations.

Any comments? Would the fauna of both the Two Medicine & Judith River 
formations have intermingled with one another?


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