The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1842-04-11

| GeOAOxy-GlocAerS ana lceberH0.
GLACIERS. Mr. LYELL commenced this lecture
by referring 10 the enormous quantities OF bouders,
and large rounded masses of the Oldest and other
rocks that were to be found in various parts Of the
world many of them in such enormous quantities
as to form apparently distinct strata, but mostly
unstratfed, as the newer rocks always are and yet
these great beds of boulders would be found resting
on the top of some very modern formation, and
sometimes mixed up with shells similar TO those
| found now existing in some of our seas and lakes
Some of these shells are brackish though the sea
had by high winds, been forced into the fresh water
| in which they existed, and made them bracklsh.
We had only to suppose, in order TO see how this
was done, that the sea of the Northern Ocean, by
high winds should be forced down the Ca,tegat, far
into the Baltic, to dam back the vast body OF
fresh water that is constantly poured into the Baltic;
| tee shells would become bracksh; then to suppose
that in winter, when the Baltic frozen up,masses
| rocks should crack and fall down from the rocks
situated at the extremity of the Baltic, and all along
its shores when the ice began to break up and float
down toward the main ocean in the spring, many of
these large fragments of rock would be carried
down on the floating ice for miles and miles; the ice
bergs crushing and grinding against the shores, az it
went down, would rub off the edges and angles Of
these fragments; carry them all down towards the
ocean with them, and then, when the ice melted,
these large masses Of rocks would all drop to the
bottom Of the sea, and form an enormous unsiratifed
| bed of boulders. Then we have to suppose the bed
of the Baltic heaved up as high as the tops of some
of our hills, and should have precisely the
| appearances and state of things which we now find
| in many parts OF the world.
| Mr.. LYELL went on to state that in this way only
| shores and islands of the Gulf of st. Lawrence, be
accounted for particularly the curious nature OF the
beds of boulders found on the sea beach opposite
| H.. IL, -
renee Gulf. In this beach we find shells that have
| lived in much colder climate and yet this boul-
der formation is OF very recent origin. The shells
! in them are nearly all the tn ose living.
In fact there is very little doubt that the deposition
of these cratic strata commenced just before that
era which has been termed the post pliocence Pc
Rod and that it went through part of that period.
We have to account for these masses Of rocks
being brought lakes and rivers, hills
and valleys, many miles from their parent rocks,
stratlfed, as they are, and almost all OF them non
| Mr. LYELL remarked here, that in speaking of
glaciers and icebergs, it must be borne in mind that
| in the extreme north, and in many low ATTITUDES,
| above 5000 feet high, the snow never melts The
| snow forms on the summit and the sides Of the
Alps when it accumulates to great extent, it de.
scends by its own gravity, and covers fields and
day in summer, and freezes by night, and
thus gets consolidated. It is pushed down from the
| mountains TWO miles nigh, 10 plains that are only
5000 feet high above the level Of the Here i
forms those enormous glaciers, which we see all
over Switzerland. The snow will accumulate many
hundred feet in thickness. but the average thickness
the glacier is showed and driven forward by other
great descending Of frozen snow behind, and
brings along with it the large bouders and masses
| of rock that had been torn from the sides of the
mountains, and hurled down into the valley by the
| frost and falling and ice. These glaciers will
| fill valley Two or three miles wide, and several
summer by the melting caused by the heat OF the
sun, at the rate OF an inch to three inches hour.
In these valleys large ridge of these enormous
boulders and rocks will be formed, caused by the
| masses of snow descending from the mountains on
each side Of the valley, carrying before them the
| fragments of rocks, unul both masses meet in the
middle and form these great ridges which we find
IN the valley of the Aar, in the Benese Alps where
are also several smaller parallel ridges caused
! by the descent of snow several miles farther
| up the valley, and by which the whole mass is
pushed and showed along grinding oil the edges and
angles of the rocks, until they are nearly round
| [Here Mr.. Lyell pointed to map OF the great
| Glacier of the Aar in the Bernese Alps, with the
mountains of the Fainsterra and Lcutelba, on each
| sidel The masses OF snow come down literally,
| caring these immense morays, or masses Of rock,
| before them. In the hot summers days you may
see these icy rivers moving along an inch or more
| an hour and the ice cracking and rending with
| noise like thunder. These glaciers, at their termi-
nation where the valley only two three hundred
feet wide, and in beautiful arch where the water
| rushes out in magnificent cascades forming the
sources OF rivers. In very cold summers these
glaciers will move back, and sometimes 60 back
half mile in one summer; and then you can see
at the bottom of the part deserted what has taken
place the quartz pebbles has polished and scratched
the limestone underneath and ploughed deep fl r.
rows in it, In this way we can see how large pieces
OF rocks get rounded the ice possesses great grind
ing properties and grnds off the angles. To prove
that the ice does this without water, we find the
same phenomena OF rounded masses, thousands of
feet below the level OF perpetual snow, where there
isno water hut was built in 1927, in the me-
dial moray of the Great Glacier Of the Aer; nine
years afterwards in 1885, il was found TO be perfect
ly unipjured, but had moved along 22O0 feet! In
four years afterwards in 1910, ii found to have
moved 1900 feet down the valley, travelling at the
rate oiixteen inches day. And all this travelling
is done in summer. Between the eleventh and fit
teen,h centuries, the glaciers were much less ad-
vanced than they are now They retreated then
In the seventeenth and eighteenth centuries, they
advanced. In Chill in latitude 46, the same latitude
as the Bernsse Alps, these glaciers VIII come down
sea. And the Andes here are only 1000 feet high,
or half the height Of the Alps The reason of these
is that the summer heat IS less intense In Chill than
in Switzerland. In Europe we must 60 as high up
as O. north latitude before we see glacier de
scent to the sea; and yet in Chill, in latitude 49,
glaciers GO to the sea, and there form cebergs
mandatory of icebergs going on all the year
round. Mr.. Lyel then went back to the Swiss
glaciers, which, he said, after retreating for TWO
three more cold summers would leave large tracts
of land and rocks formed by their deserted morays
| these would soon be covered with huts and vegeta
: tons and trees. Then some hot summer the gla-
cler would ADVANCE again, ana snove several mo-
rays into one crush in the sides of the hus and tear
up the trees Of many years growth with very slow
motion then retreat again; and trees would again
| grow and the huts be rebuilt.
Mr. LYELL observed that these unstratified boulder
formations could not have been deposited by water
because water has an asserting power separates
small stones from large and sand and mud from
, both, and deposit the whole in a stratihed form
water carries all the smaller materials much farther
than the larger. But ice carries small and large all
along together; and these Alpine moray deposits
seen after they have been left by the retreat of
, glacier back up the valley, exactly resemble the
great boulder formations. These boulders in this
country, seen On Long Island, in the valley of the
Connecticut, and elsewhere, are rounded on three
sides and hauened at the bottom, and the limestone