E.W. Hilgard on the Quaternary of Mississippi, 328 
boniferous rocks being analogous, apparently, rather to the Yel- 
Alabama. 
The former possess a dense growth of gnarled, tattered trees, the 
latter had the appearance of artificial parks—now marred by the 
The “ Hummocks,” or Second Bottoms.—W hile the period mark- 
ed by the Yellow Loam and its equivalents must have presented 
features not now exemplified, called forth by causes which have 
ceased to act, the formation next in upward order differs from 
those now in progress only in the quantity or intensity of the 
action which produced them. ) 
The Second Bottoms form part of the valleys of all the larger 
Streams of the state, and in some districts even of the “ creeks.” 
hey are in general most extensive where the material of the 
adjoining uplands was most easily denuded (without being too 
Pervious, as in the Pine Hills of the south ($$ 32, 77), and has 
therefore permitted the excavation of wide valleys; while, where 
that material resisted denudation, the contraction of the valley 
and consequent greater swiftness of the stream have either pre- 
Vented the formation of these deposits, or caused their subsequent 
Temoval, 
There are two points of difference between these “second bot- 
toms” and the “ first bottoms” of the present era, which enable 
the observer to distinguish them even when either is entirely ab- 
Sent. In the first place, the “ hummock” is always out of reach 
of the highest water within the memory of the “oldest inhabit- 
ant,” and in many cases the first bottom is as distinctly cut into 
the second bottom deposits, as the water channel is into the first 
