= 
et tmay have been for matt by gaseous emanations: from the 
54 Notice of Hayden’s Geological Essays. 
or Mammoth—horns of deer, and other animal as well as 
table remains, are found in many parts of our alluvial 
eaack, both near and remote from the sea; and evincing, 
completely, that they could never have been deposited and 
covered by any of the origi meeps of alluvion. 
ese facts, it is well known, are common to the alluvial 
regions of other continents ; re Mr. Hayden has adduced 
many examples in relation to this part of the subject. — 
The author has suggested some ingenious thoughts as’ to 
e: ‘processes of petrification. We feel and acknowledge, 
that there is a difficulty in accounting for the preservation of 
animal and ee substances, by petrifaction or other 
ot potted bodies have been invested by 
or that even our plan- 
ao Hayden ee that, from the opposite polar re- 
gions, there were currents which combined to produce the 
erase and he preciiotis that their ravages are distinctly 
Oakes Toyden' shee to sabe acsliad ideas asto “ sien 
tion of soils and loose earth, by the decomposition of rocks, 
which he believes to en much less asiesai and rapid, than 
has been generally imagined. This is probably true in a 
degree, but still we cannot but ‘bial that he has underrated 
these agencies. The d g from the un- 
 intermitted activity of galvanic electricity, evolved by the 
Juxta position of strata and fluids of different kinds, is prob- 
ably Me Hayden cause, and is not, we believe, adverted to by 
«This cance would, however, it is true, 0 My the i 
ior of he , » Operate, eines yi in the inte- 
