The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1872-04-22
The GREAT DRIFT PROBLEM.
Professor Agassiz on His Way
to Patagonia.
From Rio to Montevideo- Quarterback Lectures
and Salt Water Experiments Northern and
Southern Drift-The Professor Quar-
anfined-Goes Ashore-Is Arrested
with Rocks in His Pockets.
UNITED STATES COAST SURVEY SrEAMER(
HASsLER, MONTEyIDEO Feb. 90 1872 I

Early on the morning of the 18th OF February we
left the harbor OF Rio Janeiro, where we had lain
for some three weeks. The weather was not very
pleasant, and our last glimpses of Rio and its
environs were through heavy mist, which soon
became drizzng rain. At nine O'Clock we took
our departure from Raj Island, distant about ten
miles, the course being fixed at southwest-half
south. The wind, at first somewhat irregular in
force, soon freshened into quite severe gale,
which at last compelled us to lay to until it abated.
Fully o-thirds Of our first forty-eight hours out
were spent in this manner the sea running very
high, and often dashng completely over us. No
material damage resulted our only losses being the
PEAK OF THE sPANKER GAFF
and one of the leadsman's platforms. On the nth
we were able to resume our course with tolerably
pleasant weather and fair winds, which continued
for several days. On the Goth cast of the dredge
was made In about fifty fathoms of water but the
bottom was found to be muddy and but few speci-
mems were secured. The following day we en-
countered another gale and were again forced to
head up to the wind, but resumed our course in q
few hours On the 22d
SEVERAL DREDGES WERE MADE
as We approached the mouth of the Rio de la Plata,
and were more successful than the last, bringing up
a number of living specimens chiefly mollusca. On
one OF the days when the weather was propitious
we had lecture from Professor Agassz on sub
ject which, as we near Patagonia, is rapidly be-
coming very prominent in our thoughts viz, that
of "Glacial Action" Some explanation may be ne
cessary to make our hopes and anticpatons upon
this subject and it's connection with our work ap
parent. Our last sight of the coast of New England
when we started on this cruise was from
TARpAUILN COVE, OFF NAusHoN,
the largest OF the Elizabeth Islands. Two rocky
rsinp the constituted
spcuous feature in this somewhat barren land
scape but were chiefly interesting from the fact
that about their origin and the origin OF similar
ones there have probably been more disputes and
controversy than upon any other scientific question.
On examining them and their surroundings more
closely it has been found that between them lies
conglomerate composed OF clay, sand or loan, and
nterspersed with rocks or bouders of various sizes,
shapes and materials These boulders are not ar
ranged With any regularity as regards their position
in the mass, but they have characteristic which
is almost uniform. Whenever their chemical or
physical constitution is such that they will bear ex
posure to atmospheric and other influences without
undergoing disintegrakon their surfaces are found
to be
MARKED IN A PECULIAR AND DISTINCTIVE MANNER.
They are polished often to as high degree Of
smoothness as could have been attained by artif
running in straight llnes never in curves. Some
of these boulders or filling up the grooves looking
as if it had been subjected to great pressure.
short distance from these rocks one might find on
the sea beach pebbles and stones consisting Of the
same mate-wals-quartz, granite, feldspar, lime
stone, &c.--but having an entirely distinct appear
ance, being rough, rounded washed clear by the
action of the water, and being neither polished nor
grooved. 1t has been found that there are
spread over the whole northern part OF our
Continent immense quantities of a loose de-
post, often two or three hundred feet in thick
ness, and containing bouldcrs the vast majority OF
which are marked in this way. The underlying
rock Is also generally found to be smoothed and
polished In similar manner, and grooved with
lines varying in size from such rs are made by an
engraver on steel or glass to burrows foot or more
in depth. These grooves have always one general
direction,
RUNNING FROM NORTH TO SOUTH,
and are found the north side of elevations of
ground and not on the others. They invariably pre-
sent the same direct continuous rectilinear series,
and may be found by u careful examination, on
every hill In our land whose composite material
has offered any resistance to dislntegrating nu-
ences. In some places long lines ridges of loose
sand, stones and rocks extend for miles nearly
parallel to each other. The same appearances have
been observed in the northern parts OF other con-
tinents, and for long while nothing definite as to
their cause was known, although number OF
theories existed.
They were for some time ascribed to floods, cata-
racts, foundations or mighty tidal waves which,
sweeping across country, were supposed to have
carried with them these various materials and to
have produced the markings described by bringing
them in contact with the surfaces over which they
passed. They were therefore called by biologists
drift the term being used to denote both the loose
unstratined gravel and the b0ulders which 1t con-
tains.
The difference already pointed out between drift
rock and those which have been waterw0rn, the
regularity in the character OF the markings, their
constant southwark direction and the immense size
OF some of the boulders, exceeding
TWENTY THOUSAND CUBIC FEET,
are evident and mighty arguments against the the
DRY of transportation by water, and 1t is not now
considered to be at all tenable. About the COM
mencement OF the present century some Swiss
shepherds conceived and promulgated the idea
that all these appearances could be accounted for
by glacial action, and subsequently Venetz and
Charpenter demonstrated that the glaciers must
formerly have been much more extensive than at
the present day.
In regions where the average annual tempera-
turc exceeds thirtytwo degrees Fahrenheit the
snow which falls Is gradually changed into ice,
which ia called glacial 1t differs from ordinary
pond river ice In not being strati6ed with lines Of
separation between the layers, marked by bubbles
OF air but it is the contrary made up OF angular
fragments formed by the compression or the snow.
When on high mountain certain level is passed
a similar state of affairs Is found to exist; but here
the attraction OF gravitaton, together with the pis
q tergo OF fresh falls Of snow, induces O gradual
downward motion OF the whole mass, so that ga-
cierS
DESCEND TWO OR THREE THOUSAND FEET
or more into regions where they could not possibly
have been formed. They carry with them during
this descent great quantities OF stone and earth,
frozen lttO tlell lOWcF suTldCeS anu iOIr lines vi
rocks and clay, which fall upon them from the sides
Of the hills, and are called "movaines." IL may
easily be imagined that the immense superincuni-
bent weight OF the glacier pressing together the
rocks which 1t carries with it, and the surface over
which IL moves, are sufficient to polish and groove
them both. When 1t finally comes TO rest, and is
melted or dissipated by heat and other agencies,
the various materials which it carried are left rest
Ing upon the subjacent ground and the 'movaines"
form the long parallel ridges already mentioned.
On account of these and multitude OF other
facts Professor Agassiz came to the conclusion,
some thirty years ago, that the whole OF the North
ern hemisphere Of our globe must at one time have
been covered by vast sheet OF Ice, which trans.
ported the bouders, rounded the hills and polished
and grooyed the rocks, and he then established the
glacial theory as IL now exists. The truth OF TINS
theory has since been so fully demonstrated that
there il probably not one living geoogist who doubts
it, and the time during which this movement took
place constitutes in geological chronology division
OF the post-tertiary period, aud is known as the
glacial epoch.
One interest in these facts at the present time is
due to the following causes:- In the whole southern
Hemisphere no one has ever described single
ledge Of rock bearing the marks which werc
shown by Professor Agassz to exist over the entire
M hoIr If Ula q