The morning call., 1891-09-06
TEE AGE OF THE WORLD.
Mr.. Wallace Talks Of 2OO,OOO,OOO and Even
5OO,OOOOOO Of Years.

Assuming that the average rate of denuda-
tiCA in past geological ages did not mate
rally differ from what it is at present and
that the total quantity Of stratified rock
would, if uniformly spread over the whole
globe, form a layer 1000 feet in thickness,
we have total period Of 1000 multiplied by
GOO multiplied by 4, OF p, 600, COO years.
This, however, only represents the time
necessary to deposit the rocks which have
been formed by denudatiOn from older rocks
and these again from rocks OF still greater
antiquity. Assuming that the existing strait
fed rocks have thus passed three times
through denudation and deposition we have
a period of 1900, 900 years.
DR.. HaughtOn, calculating from the OBJ
served thickness of the rocks down to the
miocene tertiary, and assuming period of
SOLO years for each foot deposited on the
ocean bed, finds, for the age of the strait
tied rocks, a period of J, 526. 80, 900 years.
Assuming the rate OF denudatlOn, how
ever, As ten times greater in ancient times
than at present, and adding Ore-third for
the period since the miOcene tertiary, he ar
rives at final result of 200,000,000 years.
DR.. Croll doubts the validity OF Professor
Haughton's assumptions, especially the
total thickness he assumes, namely, 177,2OO
feet, or over 80 miles.
Mr. A. r. Wallace, adopting DR.. Haugh-
toms thickness, but assuming the sediment
to be deposited along a belt Of thirty miles
wide round the whole coast line of the
globe, finds, with an assumed denndatl0n
of one foot in 5000 years, period Of %, 900, =
600 years. This, however, on Dr. CrolPs
assumption of reformation and denudatlon
repeated several times. would be merely a
fraction of the time required.
Dr. CroIl further shows from the evidence
of remarkable faults" in various parts Of
the world with ''dOwnthrOws' ranging from
5000 to &C, 600 feet the enormous amount of
solid rock which must have denuded off the
surface of the earth during the progress OF
geological history. He estimates that three
miles of rock have been removed since the
beginning OF the old red sandstone.
This would indicate period of 45, 900, 900
years Assuming that the period before the
old red sandstone was equally long we have
$4,000. 600 years as the minimum duration
of geological time"
These enormous periods of time do not,
however, seem to satisfy the demands of
the biologists and the supporters Of the
Darwinian theory.
Judging ''from the fact that almost the
whole of the tertiary period has been re-
quired to convert the ancestral orohippus
into the true horse" Professor Huxley be-
lieves that in order to have time for the
much greater change of the ancestral un-
gulatta into the two great Odd-toed and even
tOed divisions (Of which change there Is no
trace, even among the earliest EOcene ami
q
not the whole, Of the Mesozoic or secondary
PERIOD" and still longer periods are de-
manded for the evolution of other animals,
$50 that, on the lowest estimate, we must
place the origin Of the mammalia very far
back in PaleOZOic times.
Mr.. Wallace speaks of possible periods
of 900, COO, 010 and even 500, 100000 Of years.
Genteman's Magazine.
A Boys Questionable Accomplishment emit.
An office-boy employed in the vicinity Of
Tenth and Chestnut streets has learned an
art that is well calculated to make him the
envy of any expert forger. During his
spare moments he takes his crafty pen in
his aTtful fingers, and with few dett
strokes initiates perfectly any signature he
may find among his employers papers. He
makes specially of copying the scrawling
signatures on bank-notes. The other day
he wrote letter to himself closely Initial
ing the handwriting of his employer, whose
name he signed to the document. The pur-
port of the letter was that owing to the
boys good services, the siSner had con-
cluded to increase his wages 81. Taking
the letter into his employers private Office
in a spirit OF fun, he showed il to him. The
latter scanned the document hemmed and
hawed for a few minutes, and, without
looking at the boy, said finally: OF
course. Eddie, shall keep my word. This
goes into effect this week" The boy was
dazed for minute but thanked his boss"
and retired. II subsequently transpired
that the letter had been dated August 18th,
on which date the business man had been
"off on little bender" and was not sure
whether he had or had not written the
Philadelphia Record.