126 ORGANIC REMAINS PRESERVED 
that contains so many perfect fishes around the 
Hartz, seems to offer two other causes, either of 
which may have produced their sudden death.*' 
From what has been said respecting the ge- 
neral history of fossil organic Remains, it appears 
that not only the relics of aquatic, but also those 
of terrestrial animals and plants, are found 
almost exclusively in strata that have been accu- 
mulated by the action of water. This circum- 
stance is readily explained, when we consider 
that the bones of all dead creatures that may be 
left uncovered upon dry land, are in a few years 
entirely destroyed by various animals, and the 
decomposing influence of the atmosphere. If 
we except the few bones that may have been 
collected in caves, or buried under land slips, 
or the products of volcanic Eruptions, or in sand 
drifted by the winds,t it is only in strata formed 
* Under the turbulent conditions of our planet, whilst strati- 
fication was in progress, the activity of volcanic agents, then 
frequent and intense, was probably attended also with atmo- 
spheric disturbances affecting both the air and water, and 
producing the same fatality among the then existing Tribes of 
fishes, that is now observed to result from sudden and violent 
changes in the electric condition of the atmosphere. M. Agassiz 
has observed that rapid changes in the degree of atmospheric 
pressure upon the water, affect the air within the swimming 
bladders of fishes, sometimes causing them to be distended to a 
fatal degree, and even to burst. Multitudes of dead fishes, that 
have thus perished during tempests, are often seen floating on the 
surface, and cast on the shores of the lakes of Switzerland. 
t Captain Lyon states, that in the deserts of Africa, the 
bodies of camels are often desiccated by the heat and dryness 
