A. Winchell on the Prairies of the Mississippi Valley. 337 
to their growth. It can hardly be doubted that the germs ex- 
isted in the soil, ready to germinate whenever free sunlight, 
warmth and atmospheric air should be permitted to rouse their 
latent vital energy. the same nature is the recurrence of par- 
ticular forest growths upon the same soil. Not unfrequently the 
Second growth is of a very different nature from the first. In 
the “old fields” of Virginia and other southern states, the soil, 
cleared originally of deciduous trees, and then abandoned, after 
years of continuous cropping, sends up a growth of pines instead 
_ Of deciduous trees. Many similar examples will suggest them- 
Ve selves to the mind of the reader. 
4. The living germs of the diluvial deposits were buried during 
the glacial epoch. 
Whence come the germs of that vegetation which is every- 
Where springing up in situations to which recent seeds could not 
have been distributed? This question has agitated the mind of 
many an inquirer who would have shrunk from the proposition 
which we here venture to enunciate. Let us examine the acts, 
will greatly increase the number. Yet these plants, probably 
older than the Claiborne sands, show, according to Lesquereux, 
: t 
material, and we may fairly presume that further investigations 
“the greatest affinity with species of our own ime.” From 
ner beds of the middle or earlier Tertiary, we have still other 
wos, Acorus calamus.” It is true that Dr. D. D. Owen has 
assigned the deposit containing these remains to the Quaternary 
_“ This Journal, [2], xxvii, 363. ® This Journal, [2], xxvii, 364. 
AM. Jour. Sc1.—Szconp Szrres, Vor. XXXVII, No. 114—Nov., 1864. 
43 
