= 
es 
eg 
EL. W. Hilgard— Geological History of the Gulf of Mexico. 401 
the Western, South Atlantic and Gulf States. It will then 
become possible, by a comparison of the really cognate pheno- 
mena, to trace more definitely the history, both general and, 
local, of that turbulent period, without the confusion attending 
the use of a word to which each observer attaches, more or 
Having discussed this formation somewhat in detail in 
papers recently published, I will merely state that it embraces 
& group of ly littoral and estuarian, partly swamp, lagoon 
and Tevisate daponte whose thickness and location is mani- 
estly dependent upon the topographical features of the con- 
tinent, then (during the ‘Champlain ” period) in progress of 
low depression; as shown by the nature of the deposits, and 
the numerous superimposed generations of large cypress stumps, 
imbedded in laminated clays exhibiting the yearly fall of leaves. 
These beds overlie those of the Orange Sand or Stratified t, 
while themselves overlaid by, not only the river alluvium, but 
by the Loess or Bluff silt or its equivalents; a as well as 
‘face. 
where this is absent, by the Yellow Loam of the 
___ * See Miss. Rep., 1860, p. 153. The reference of the outcrop at Powe’s to the 
Grand Gulf group, I thin, undoubtedly erroneous, and be true of 
part or whole of the Dwyer’s Ferry section, p. 154. 
