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> What kind of ground cover was around in the Mesozoic? Most dinosaur
> drawings I've seen show a lot of bare earth. Seems unlikely to me.
I have seen many places in western states where sage brush completely
covers the surface, with a maze of intergrown roots that would
effectively retard soil erosion. I think at least some of this was
ungrazed land, so that would be the natural state. I don't know if sage
existed in the Late Cretaceous.
I have also seen sparse conifer forests in northern California with very
little grass--mainly just pine needles, scattered sage and manzanita, and
ground-hugging herbaceous plants.
The hardwood forest floors around southern Indiana are covered with years
worth of broad leaves (oak, maple, etc.), with scattered vines (poison
ivy, blackberries) and herbaceous plants (wildflowers) poking
through--but no real ground cover. Perhaps much of the Late Cretaceous
terrain was like this.
I've seen places in Florida that are so thick with cycads that nothing
else can grow, so that's the ground cover there. How about cycadeoids
during the Triassic and Jurassic?
Also, lichens (I think they're lichens--puffy little mats of fuzzy
greenish-gray vegetation) cover much of the soil in more arid settings
today, such as Utah and Colorado, and may have done so in the drier
portions of the Morrison terrain. These are effective in preventing
erosion. In addition to lichens, ferns and mosses would have helped
cover the ground in wetter locations. I'm speculating.
Norman R. King tel: (812) 464-1794
Department of Geosciences fax: (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712 e-mail: email@example.com