New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-07-08
FINISHING A WORLD.
THE FORCES THAT HAVE SHAPED OUR
GLOBE.

scarcely more than twenty million years nave
elapsed since the globe which Is our hahltaton
cooled off enough TO sustain the earliest known
forms Of life. Professor Shaler and the geolo-
gi.ts. a class. TO say nothing or the eVoiu-
tionary biologists, require from two hundred
million to five hundred million years in order
10 account-at least to their own satisfaction
for the operations which have taken place here
since life first made Its advent. Whichever OF
these estimates one accepts, he must recognize
that the history Of this terrestrial ball even
though sketched in outline. must he wonder
fully fascinating Fortunate. indeed. then. is
the reader to whom such a story Is presented
as that written by the professor of geology
in Harvard University. AS a master both or his
subject and Of clear. popular style. he is
enabled to offer not merely to the student OF
geology in particular. but also TO the reading
public in general an excellent account Of the
processes by which this and other celestial
spheres have been brought 10 their present con-
dition.
The notion that the earth Is a sphere was held
by the Greeks and Professor Shaler regards
this as the first large discovery made by our
race" That they would also have found out
that the planets revove about the sun. had not
the Roman invasion interrupted their thought,
u not improbable AS II was, that further ser
vice 10 civilization remained for Coperncus and
Calico to perform. When man had once learned
that the earth was not the centre or the uni
verse; or even Of the solar system. he was pre-
pared for two other stupendous revelations:
Frauenhofer, by means of the spectroscope'
shoved that the sun and stars contained pretty
nearly the same substances as our own globe.
and Newton discovered the far-reaching law
In accordance with which the particles Of
single body and all the bodies In the universe
no matter how far apart-are drawn toward
each other. Finally. the material and method
Of world making were revealed by Kant and
Laplace in their nebular hypothesis
That the great mountain chains which CORFU
gate the earths crust are the product or shrink
age has long been believed. and it is almost
as well understood that the continents have been
developed by the same process. But Professor
shaler observes that until thirty years ago 1t
was common TO suppose that the alterations
OF level which continental areas have under
gone had been extreme, whereas now It is
deemed probable that they comparatively
slight and that the general outlines Of great
land areas have changed very little for mill
ions Of years.
OF the two LIQUID envelopes that enwrap the
globe the atmosphere is the thicker and IL has
had more to do with shaping the surface or
the earth than one might suppose without CIV
ing the matter due consideration. Not only
does the wind carry clouds Of dust and
sand from place TO place. but 1t bears inland
the vapor which rises from the ocean. and which
comes back TO us condensed into rain All the
erosion Of the soil that is accomplished by rivers,
all the transportation Of solid material that
these streams and the ocean currents are re-
sponsible for. would he impossible were there
no air The waves. too. are raised by this
agency and their havoc must also be charged In
part to the account Of the atmospheric sea.
Between them, the air and the surface water
have v orn down mountain ranges secured on
plains and deposited enormous quantities OF
debris at the bottom Of the ocean-there to
form new layers Of rock. Then, again. the
wind-provoked ocean currents effect a wonder
ful distribution Of tropical heat rendering
ha bitable regions In Northern Europe that would
otherwise be wildernesses. The vegetable ana
animal life Of Arctic North America was also
similarly Influenced at some remote period Of
history Still another force which has operated
In carving the face Of the earth's surface into
its present shape is glacial action. AS com
pared with the work of the air. the rivers and
the sea- this was somewhat local in character.
II does not appear that the icesheet which
overlap Northwestern Europe was ever so ex-
tensive as the one that spread down into North
America And II Is a singular fact that Siberia
does not show evidences OF any such continuous
covering The glaciers there were large but
detached from one another Regarding the
boundaries Of the American ice Professor Shaler
says:
Imagining seafarer to have approached by
the North Atlantic. as did the Scandinavians.
and that his voyage came perhaps hundred
h4fn ~ al
he would have found ice front long before
he attained the present shores Of the land This
front may have extended from south OF Green
land off the shores of the present Grand Banks
of Newfoundland thence westward 10 Central
or Southern New-Jersey. This cliff Of ice (hun-
drcds OF feet thicO was formed by sheet
which lay on the bottom Of the sea. On the
New-Jersey coast the ice wall left the sea and
entered the body Of the continent We VIII
now suppose that the explorer. animated with
the valiant scientific spirit which leads the
men Of our day to seek the poles. undertook
land journey across the continent along the
ice front. The traveller would have passed
through Central Pennsylvania, whence, although
there were probably detached outlying gla-
ciers lying 10 the south far as Central Nir-
ginia. the main front extended westward into
the Ohio Valley In Southern Ohio tongue or
the ice projected southwardly until II crossed
the river where Cincinnati now lies. extending
a few miles to the southwark of the stream
Thence IL DETECTED northwardly. crossing the
Mississippi and again the Missouri, with
tongue or lobe that went far southwark In that
State. Then, again. turning 10 the northwest.
II followed In general the northern part or the
Missouri Basin until II came within sight Of the
Rocky Mountains. There the fee front Of the
main glacier followed the trend of the noun
tains at some distance from their face. for an
unknown extent to the northward In the Cor
d,lIerss as far south as Southern Colorado. and
probably in the Sierra Nevada to south OF San
Francisco the mountain centres developed To-
cal glaciers. which in some cases were OF very
great size. perhaps exceeding any of those which
now exist In Switzerland. II will thus be seen
that nearly one-half Of the present land area or
North America was beneath a glacial covering.
though, as before noted. the region about the
Gulf Of Mexico NAV have swayed upv ard when
the northern portion Of the land was borne down
by the vast load Of ice which rested upon ii.
Notwithstanding this addition TO the land, our
imaginary explorer would have found the por-
~ he I'll for the of