1010, Zoic Maxima, or Periods of Numerical, etc. { December, 
LV. Phenomenal influences, as cataclysms, poisoned or heated 
waters, storms, shocks, destruction by enemies —It is enough to 
mention these to suggest their frequent occurrence. But the 
effect of these in geological time has been, doubtless in some 
case, to produce deposits of animal forms in sudden abundance, 
as when a fauna by their action has almost simultaneously dis- 
appeared. Thus Dr. Newberry has suggested that the fish beds 
of Illinois afford evidence of a wholesale destruction of fish life, 
possibly through submarine explosion, diffusion of poisoned 
vapors, etc., while the phenomenal disappearance of animal life 
from the Atlantic, as shown by the observations of the Fish 
Commission in 1881, is a modern instance of a widely extended 
‘catastrophic obliteration of animal forms. 
Zoic Maxima.—lt is evident that if all the above conditions 
were favorably conjoined for some reasons, in accordance with 
the needs of any special organism or any group of organisms, | 
that these would attain probably an unusual fertility, and that 
if passing such a climax as this the succeeding years would de- 
velop conditions in the same way, as strikingly unfavorable, we 
would have in the marine deposits, accumulated during these 
years, two contrasted beds of respectively rich and barren con- 
tents connected or graded into each other by intervening beds o 
diminishing productivity in shell remains. But if after a period 
of phenomenal activity and success in the production of" forms 
. such as instanced, a disaster, such as those we have suggested 
under the fourth heading, took place, then we would have a bed 
gradually reached through lower beds of increasing numer ical 
strength until it crowned the series as a climacteric to be suc- 
ceeded by later layers quite devoid of animal remains. _ 
These periods, when all the conditions are most favorable for 
animal multiplication, we designate as Zoic Maxima; and as 
_ they are in accordance with the requirements of the greatest 
, number of specific forms we call them Pan-zoic Maxima ; he 
oe they are so combined as to exert a selective influence, permitting 
: __ the preponderance of one or a few species, or directly contribu- 
_ ting to the propagation of this one species both in numbers an 
in size, we call them Sol-zoic Maxima. 
_It is certainly true and known that such Zoic Maxima, both 
in their general and restricted manifestations, are known in our 
ntemporaneous faunas. It is probable that the varying ge s 
A fossil remains in the beds of fossil-bearing rocks are @U 
P 
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