ere 
L, Lesquereux on the Coal Formations of North Ameria. 31 
which leaves of every kind would have been mixed, not only in 
every position, but without regard to the place of their growth. 
It is impossible to account for the successive deposits of shales 
and of sandstone by a river. When an inundation is at its 
height, it bears with it the heavier materials and these are depos- 
ited just as the current subsides. The sand would therefore be 
deposited before the mud or the sandstone formed below the 
shales and not above it. 
But the deposits of all our great rivers, the Mississippi, the 
Ganges, the Amazon, the Po, is mud only. Sand is occasionally 
transported by a river or removed from one place to another by 
some strong current, but then it constitutes a bank and is gener- 
ally a local formation of small extent. 
All the great deposits of sand in our time, which by their 
thickness and extent, may give an idea of those which have cov- 
ered the bogs of the period of the coal, are marine formations, 
The drift of North America and Northern Europe, our Pine- 
barrens of the south along the shores of the Atlantic; the 
pampas of South America, the heaths of Luneburg or sand plains 
along the southern shores of the Baltic Sea; the sand hills of 
Eastern Germany and Holland along the shores of the North 
Sea; the downs of the Gironde and of the Camargue in France; 
the sandy deserts of Syria, &c. No one of these formations can 
be referred to the direct agency of a river. : 
That the sandstone of the coal generally contains no remains 
of marine animals, does not prove that it is not of marine 
origin. The sand of our drift scarcely contains any of them. 
The hills of sand along the shores of the Baltic and the North 
Sea are almost entirely destitute of shells and animal remains. 
Sand is not only permeable to the all poem poring oxygen of the 
atmosphere, but it is a grinding agent, and as it is put in con- 
stant motion, either by the waves and currents of the sea, or by 
the wind, it is not to be supposed that even the shells would be 
long preserved in the loose 1 et in some places, the 
istone of the coal, especially when it is fine and soft, has 
