Alma record. (Alma, Mich.) 1878-1928, 1894-05-11

huge reptiles among the animals. IL
was the time when the whole surface of
the earth was still torrid in climate
due, most probably, to the internal
heat of the planct-and the luxuriance
IF vegetation of lower forms surpassed
by far anything known in recent time.
The atmosphere. too, was heavy with
carbonic anhydride generally called
carbonic acid), and SO untitled for any
form of animal life higher than the
reptilan.
Cenozoie Time.
The cenozoic (recent life) is the time
Of predominance of higher forms of
life-mammals, or warm blooded ami
mails, and Towering plants in the vege-
table kingdom. This time is divided
into two ages-the Tertiary Age, or
age of mammals, and the Quaternary
Age, or age of man. 1t is with the last
that we are principally concerned.
Length of Geologic Time
Before taking up the age of man it
will be interesting to take note, in this
connection, of the relative and absolute
lengths of these ''times" of geology.
Dana, high authority on geology,
reaches the conclusion, as to the rela-
lon nth hat 40
zoic and cenozoic are to each other as
70: - l. That is, il As millions of
years be taken as the whole time since
life appeared, the paleozoic would be
represented by SO millions, the meso-
zoic 10y 9 million, and the cenoZoic by
3 millions. As TO the absolute time,
only in one respect are biologists
agreed-that the time was long. Vari-
Gus methods of estimating lead to
widely different results. and the whole
time has been variously estimated from
10 millions to 100 millions of years.
But the lowest estimate which has been
made show the immensely of geologic
time. Sir William Thomson, by eX-
periments rs to the rapidity of cooling
of heated bodies makes the greatest
age of the earth, since sedimentary
rocks began to form, 100, 900, 900 years.
Professor Newcomb, by similar cal
culation, thinks the time not greater
10 200, 900 years. Accepting the theory
of the cause of elaciation in the change
of eccentricity of the earth's orbit, and
the coincidence of the northern winter
with time of the earth's greatest dis
lance from the sun (and there is no
other theory of glaciation worthy of
consideration the glacial period began
about $50 900 b. G. and closed $4,000
b. G. This time is susceptible Of exact
mathematical computation, and is cor
rect, if the theory of glaciation is cor
rect. These computations would cor
respond to 100000 to 15,000,0 900
years for the whole period of incrusta-
ton, or the time since sedimentary
rocks began 10 form.
Tertiary and ouate rnary Ages.
Though some remains have been
found which point to the existence of
man in the tertiary age, that point is
not yet definitely settled, and will not
be till more evidence is found. But.
accepting the theory mentioned in the
preceding paragraph as to the cause OF
glaciation, and that man has existed
during the whole of the quaternary
age, the time of mans appearance on
earth would be placed back at least
100000 years. This length of time
since the advent of man must be taken
as minimum in the present state of
science, or we must reject the only
theory of glacial action which will in
any degree account for the facts of
geology. And, further, there is evil
dence which points TO mans existence
on the earth for million years or
more.
Diluvial and AIluvial Epochs.
Daniel G.. Brinton, in treating the
subject of ethnography divides the
quaternary age into the diluvial or
pleistocene epoch and the alluvial or
present epoch; and these are again sub
divided in accordance with the scheme
presented below.
Preglacial
Diluvial or
PleistoceneI Glacial
Epoch
II Il. I'll