= AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[SECOND SERIES.] - 
Arr, XXX.—On the Origin of Prairies; by James D. Dana, 
In the articles on the Origin of Prairies recently communi- 
cated to this Journal by Prof. Winchell and Mr. Lesquereux,’ 
presenting independent theories, the view that this origin is in 
* See for Prof. Winchell’s ah a xxxviii, p. 332, and for Mr. Lesquereux’s, xxxix, 
317, ai af) 23, ‘Prof. Winche IL abner that the soil of the prairies is of lneus- 
a vast in fresh-water sea following 
a sea all pre-existing 
vegetation that would spring up over the recov- 
eeds transported from distant regions W would 
be herbaceous than ar’ pine? 
likely to r’ 
‘airie land was rec recovered from the borders of 
grow 
- Next, as a matter of course, covered with sedges and grass. mould, 
he observes on p- 318, partakes “as mu uch of the nature of esp as ot ca of true 
- sca it is “impregnated with a large peat of st acid, pr the 
soil, by its particula rly antisep’ ; 
pl: while nigh vg: access of 0 oxygen is unfavor- 
ma He adds, “of P all the trees, Pes ac is api only species igre 
Our northern climate, d.” 
This ar aa is stated to cover ptt t all cases of natural 
“ between the base of the Rocky Mountains and the Mississi 
XL, No. 120. 
—Nov., 1865. soe 
