The sun. [volume] (New York [N.Y.]) 1833-1916, 1882-12-17

Have Comet. struck the EarthS


on which we live and which are collectively
known TO scientists rs the drift. arc due not to
any OF the causes heretofore postulatcd by
biologists. but to n collision OF the oarth with
the tail Of great comet. According to the tho
"sy hore developed this catastrophe took place
Mt tho close OF mo tcI,ta~y era nboilt 80 600
years ago and itself ushered In thosu transfor-
nations OF tho earth's surface and changes of
climate which distinguish the latest geological
epoch from the preceding age. Tho author en-
dcavors to reach this conclusion by contending.
first that none of the other explanations of the
drift phenomena which have been mooted are
adequate secondly that the assumption OF coll
lison with comet offers a complete solution
OF tho problem thirdly. that such catastro-
phe is. on astronomical grounds. not merely
possible but extremely probablc and. finally.
that the myths and legends Of many nations
concur in attesting the reality Of such cata-
clysm. This theory. which, OF course must be
pronounced a paradox. since it runs counter
to the almost unanimous opinions OF mon Of
science. is set forth with tho dexterity and
earnestness with which in n previous work tho
author tried to prove the whilom existence OF
the tabled Atlantis. and 1t is equally certain to
rouse the curiosity and enchain the attention
Of large body Of readers. A glance ut some
Of tho moro serious considerations urged -
hsis,f ri t;,!s startling hypothesis will'indcatc
In the book itself.
Mr.. Donney begins by describing the drift
phenomena. which it is the aim of his theory to
account for. Tho drift. he reminds us. Is u
vast deposit of clay. gravel. and sand some
times fifty. sometimes hundred, sometimes
five hundred feet thick, and which is known to
cover the large part Of North and South
America. Europe. eastern Asia. and Of so much
Of Africa as has been explored by biologists.
Passing from the continental magnitude to the
character Of this formation. he points out the
significant circumstance that the drift is main
ly unstratined the lower portion Of the deposit
being almost wholly so. The author does not
mean to say that in limited areas there may
not be some signs Of qualification. such Us
tempests might make working in a dust heap or
such as rivers might cause In turning over the
material. But of continuous layers. stretch
ing over large tracts Of country the drift offers
no example. Another striking feature Of this
surface deposit is the fact that it contains al
most no traces of pretXstent or contempt
raneous life. 1t is uniossilifcrous. Not. indeed
that we do not sometimes find in upper
portions of the drift small isolated beds
Of loose gravel. sand. and stones mixed with
the remains of man and other animals. But
all these 1t is averred. have the appearance Of
being later in their deposition. and OF having
been worked over bv the action of water and
Ice. Another point to be noted Is that the So
called ill.," or lowest portion OF the drift ~
Ing Immediately over tho stratiiled rocks. is of
exceeding hardness. being so tough that eng
neers would prefer to deal with granite than to
attempt the removal of this tili' or hard pan"
from their path. In this lowest section of the
drift are found some strange stones. not water
worn. not rounded as by the action OF waves
and yet not angular. for every sharp projection
has been ground off. These stones are always
Btriated. that Is. cut by deep lines or grooves
usually running lengthwse. Above the till is
less tough deposit called the boulder clay"
Here the stones are larger and more angular.
and sometimes Of immense size. 1t is also to
be noted that in some cases no rocks Of the
same material have been found within two
hundred miles
From these characteristic features OF the
drift Mr.. Donnelly infcrs that it must have been
the result of sudden and violent action OF some
kind. and that this action must have taken
place upon a stupendous scale. He then pro-
ceeds to examine the several theories by which
attempts have been made to explain the drift
phenomena. These were at one time attributed
to the action OF great waves and floods Of water.
but this hypothesis has long been discredited
by the facts that not single trace Of any ma
rine organism has yet been detected in true
till. and that stones striated or scratch ed with
found in river beds or on sea shores. The
hypothesis which ascribes the drift deposits to
icebergs floating down in deep water over
sunken land seems to be disposed Of by the
want of qualification When. an iceberg
drops the debris attached to it. the heavier
blocks reach the bottom first. then the
smaller stones. and lastly the finer ingredients :;
there is no such arrangement visible in the
normal till. Again. whenever deposits are
dropped in the sea they cover the surface be-
low with a uniform sheet no thicker in one
place than another. But with the drift this is
not the case The deposit is thicker in the
valleys and thinner Oh the hills being some
times absent altogether on the higher eeva-
tons That is to say. it fell as snow storm
falls driven by high winds. Once more. if the
sriiP. or scratchngs upon the drift stones.
were made by the rocks adhering to the base of
drifting icoberg'. the situations would occur
only when tho water was Just deep enough to
float the berg but not deep enough to raise the
berg clear from the rocky bottom Of the sea-
As a matter offact. tho striated stones of the
drift are found at all elevations, at the tops Of
hills and at the base Of valleys, as we'll as at all
Intervening points they are. in short universal
within very large areas. We come now to the
glacier theory. which has had so many Gdvo-
Gates. but which is now pronounced inadequate
TO account for the origin Of the drift. The
fundamental objections are that tho glaciers do
not produce striated stones or drift clay and
that they could not have reached to the great
plains OF the continents far remote from tho
valleys to which their operations are confined
We have lastly tho hypothesis upon which the
glacierists have fallen back that. namely of
continental leo sheets. II 10 assumed that tho
whole north and south regions Of tho globe. c.-
tending from the poles to So OF north and south
latitude, woro in tho drift age covered with
enormous continuous .noets Of ice from ono
niue th'cts nc Its southern margin to three or
five miles thick at the poles. To this, which is
at present the favorie hypothesis OF scientists.
Mr.. Donnelly takes exception on several
grounds. He contends that tho present leo
sheets Of the remote north leave no such de-
posts as the drift. and make no such markings
as are found on the striated stoEes He
observes further that continental ice sheet.
II it made tho drift markings, must have scored
the rocks going up hil while it did not sc..re
them going down b., ror it Is only The north
sides OF hills and mountains that are stratcd.
He asks. moreover. how it happens If the cold
formed the ice and the ice formed the drift,
that there is no drift in some of the coolest O.