322 = E.. W. Hilgard on the Quaternary of Mississippi. 
materials; which in the case of the flatwoods, is the heavy gray 
clay of the lignitic ($ 165), resisting denudation equally as much 
as the Rotten Limestone. f 
It seems to me that in this resistance to denudation is to be 
sought the cause, both of the absence of the Orange Sand depos: 
its from both tracts ($6), and of their levelness, their surface 
being, as it were, parallel to that of the strata of the underlying 
older formation. (See profile, Pl. I; fig. 2, in Miss. Report. 
y been removed ; its absence is to be accounted for. We can- 
not for a moment suppose that the waters which deposited uy 
¢ 
Cretaceous limestone is always much deeper underground. 
it is equally obvious, in passing westward from the flatwoods, 
