208 EF. W. Milgard—Lignite Beds and their Under-clays. 
Art XXIV.—WNote on Lignite Beds and their Under-clays ; by 
EK. W. Hitearp, University of Michigan. 
In the January number of this Journal, Mr. Lesquereux de- 
fends his view of the origin of the lignite beds of the Rocky 
Mountain region, against supposed objections thus formulated 
by him: 
1. That the lignite beds are of too small extent, or cover 
too limited areas, to have been formed otherwise than by the 
heaping of materials carried into small basins. 
2. That the under-clays of the lignite beds contain no roots. 
Having had extensive opportunities of observing lignite beds, 
from the Cretaceous to the Quaternary strata, in the States of 
Mississippi and Louisiana, I would add a few remarks to those 
of Mr. Lesquereux. : 
As regards the first point, I am altogether unable to see 1ts 
force. Were the bays and marshes of the Louisiana coast re- 
gion, or some portions of the Mississippi bottom, so depressed 
as to be covered over with deposit, and their peaty content: 
compressed. into lignite, there would result just such a multi- 
tude of basin-shaped masses, from a few yards to many square 
miles in extent, and of variable thickness, as we now find in the 
Kocene lignitic formations on the Gulf border. The analogy 
they may readily be swayed sideways in the soft mass, in every 
direction; but are difficult to pull up, although, under such 
circumstances, their size rarely exceeds a few feet. 
These facts, as well as the well-known ability of the Cypress 
and Tupelo to exist and flourish in water maintaining some 
depth throughout the year, led me to consider the possible 
causes of the apparent absence of vestiges of roots from the 
under-clays of lignite beds, which early attracted my attention. 
the extensive marsh at the mouth of Pearl River, a solid 
clay, resembling very much the under-clays of lignite beds, or 
the bottom clays of Cypress swamps, is deposited for some dis- 
‘ance on both sides of the river channel. The whole surface is 
covered by a dense growth of tall “round rush” (Scirpus lacus- 
o 
