The San Francisco call., 1904-02-20
Great Lakes Tilting.


the land has continued to rise more
rapidly at the north than at the south
around the basin of the Great Lakes.
The lake ridges bordering Lake On
tario. Lake Erie. Lake Huron and Lake
Michigan all show this. These lake
ridges are old shore lines formed when
the ice obstructed the drainage to the
northeast. and so We're at the time of
their formation level. But now they
gradually rise, so that they are much
higher at WatertGwn, n. Y, than they
are at Syracuse, and they are higher
at the northeast end of Lake Erie than
they are at the southwest. and so as
you go north along the shores of Lake
Huron and Lake Michigan, and in the
Red River Valley along the old shore
lines Of glacial Lake AgassiZ, it is
found that there has been a warping
Of the earth's crust since their for
nation, which has left them much
much higher to the north than they
are at the south.
c. K. Gilbert of the United States
Geological Survey, after careful study
Of the facts, shows that this deforma-
ton of the earth's crust in the basin
of the Great Lakes is still going on,
and is gradually tipping up the basin,
tending to drown out the cities that
are at the southwest end of the lake,
and eventually to turn the whole drain
age over through the line of the Chi
cagO drainage canal into the Missis-
sippi Valley The rate of this change
of level at the northeast part of the
basin he finds to be such that the wa
ter level at Chicago will rise from nine
to ten inches in a century. This he
calculates from a study of the beach
marks that were established in Buffalo
and other places a hundred years ago.
He concludes, therefore, that unless a
dam is erected to prevent it, Lake
Michigan viii again begin to overflow
into the Illinois River in about 800
years; for the summit of the channel
leading into the Illinois River is only
about eight feet above the present
mean level of the lake, and only four
or five feet above the high water level.
In 500 or 500 years. therefore, unless a
dam is built. the water of the Great
Lakes will begin to spill over into the
Mississippi River during its high
stages. and in from 1000 to 1900 years
there Will be continuous flow dur
ing the mean stages of the water. while
in about 2000 years as much will run
into the Illinois River as now runs
over Niagara, and in $500 years the
rock bottom at the head of Niagara
/ River will be so high that there will
be no Niagara Falls for tourists to gaze
upon or for electric companies to util-
ize for light and transportation. The
basin of Lake Erie will then drain into
the Mississippi Valley by way of the
| Chicago sanitary canal.
Among other places where consid-
I cradle changes in land levels have
J taken place in recent times we may
mention the coast of New Jersey
which is sinking at the rate of about
two feet a century. This is evident
! from the advance of the wafer upon
the coast line and from the burial OF
/ large trees in the New Jersey swamps
which formerly grew on dry land, but
are now sunk many feet below water
/ level. DR.. Robert Bell brings evi-
dence to prove that the land about
! Hudson and James Bay is rising al
! the rate of from five to seven feet q
/ century. The southern coast of Green
! land is slowly sinking, while that OF
! Scandinavia is rising. Darwin has
! shown that the eastern coast of South
America has been rising since the gla-
/ cial period. In 1922 100000 square
miles along more than 100 miles ol
/ the western coast was permanently
raised three or four feet by a single
earthquake shock. In 1919 the BED
Of the Indus at its mouth was sunk
I -, 60 Ia
/ of Sindree permanently submerged
while a portion of the delta of the
Indus fifty miles long and sixteeT
I broad was elevated ten feet. About
1912, following numerous earthquakes
In the vicinity of New Madrid, on the
west side of the Mississippi River. Z
| little below the junction with the
Ohio. a stretch of country 300 miles
long was so affected by earthquakes
that numerous tracts were sunk dowr
and others raised, so that many new
lakes and islands were formed and
the bed of the Mississippi much
changed. All around the eastern
coasts of the Mediterranean Sea there
are recent shore lines of partially con
solidated sand and gravel containing
numerous shells such as now live il
the Mediterranean. The whole re
gion. from Cairo to Beirut must re.
Gently have been raised to the extent
of 200 feet.
In the interior of continents it /.
more difficult to find evidence o
changes in land levels. because We
have no fixed data from which to cal.
culate. But in two or three place.
in New England scientific men affirm
that there have been such relativ,
changes in the heights of mountain.
that distant peaks which were ono,
visible from certain points are nov
obscured by the elevation of interven.
| ing peaks. The engineers of some o,
the Pennsylvania railroads have be-
come. convinced that the grades are
in some places changing through
gradual variations in earth levels. Ii
due time the exact facts will be as