Daily globe. [volume] (St. Paul, Minn.) 1878-1884, 1883-08-21
Section E.-Geology and GeaJrapty.

AGAINST TIE DRIFT THEORY.
The paper On evidences from southern
New England against the iceberg theory
of the drift by j. D. Dana was the first
paper read yesterday il this section. The
following is the full text:
In presenting to the association evidence
from southern New England with regard
to the insuficiency OF the iceberg theory
of the drift, Ishall have to say some things
that have often been said before and by
various investigators. But I may claim
for what is here brought forward that il is
in my own mind, the fortified conclusion
OF long continued investigation.
The arguments on the subject are de-
rived from three sources
I. The scratches and groovings over
the rocks.
II. The transported boulders and other
material.
III. The facts as to the relative level
of the land and sea.
Under the first head there is first, the
old argument on the universal distribution
of the scratches over the region Of all New
England. These effects of abrasion are to
be found everywhere beneath the soil,
each fresh exposure of the rocks bringing
them to light. This was said years ago.
and the conyi3tion of its truth has been
gaining force With every year educational
observation. It view of this fact it Is urged
rightly that only an abrading agent that
pressed heavily against the broad rocky
| surface could have produced the effects,
and such is not an occasionally grounding
iceberg, or a succession OF them. Neither
| is it the still more locally acting shore ice.
Secondly, floating ice would have found
| little bare rock over the sea bottom to be
| abraded. Like the bottom of existing
! seas, and eminentiy those of the CONT
mental borders, the submerged region
| would have had for the most part q bottom
of detritus-its former detritus and addi-
| tional detritus from later dispositions; the
| removals would have been local and rela-
| lively of small area. Consequently the
drifting ice would rarely have reached
down 20 the rocks. Shore ice carried
along by the currents would have had a
better chance, and yet poor one for the
work to be done.
| Thirdly-The character OF the groovings
and plowings is to great extent such as
over the metamorphic rocks in many
places.
Boulders of trap, from fifty to 1,00C
tons, are numerous in the New Haven re-
gion. especially along its western border
All are Connecticut valley travellers; fol
the trap ridges of the valley are the only
possible source. They were gathered up
by the ice from these trap ridges and car
ried fifteen to sixty miles down the valley
It is mechanically impossible that the lar
ger boulders should have been taken up OIL
gathered in any way by floating
ice, either shore ice, where the
water was but 1000 feet deey
and less; or by that of icebergs, where tn,
depth was greater. 1t is we'll known tina
the distance of drift transportation is il
general less than twenty miles. Hills o
but 100 feet often have their long trails
A moving glacier would easily gather ant
carry along the material from hills, high
or low, wherever loose or detached masse
of rock or gravel existed to be gathered
while floating ice would be very poor a
gathering and hence inefficient in dis
tributing.
I have examined carefully along south
ern New England for proofs of the quater
nary submergence which the iceberg thee
ry assumes to have existed and the glacla
era. I thought at one time that l saw evi
l dence about New Haven Of a submergenc
: of forty-five to fifty feet. But the terrac
that afforded the evidence was situated 81
miles back from Long Island Sound &C
=, joining the rivers and on further exam
nation found thai the deposits had pre-
L cisely the structure of those along th
= river valleys farther north and that in fac
o they were nothing but fiuvial formation;
It The highest terraces On or nea
d the shores of the sound, in the vicinity {
Q New Haven, have height above mean tic
: of twenty three to twenty-six feet; and 0
Il Milford bay, nine miles west. similarl
q. situated terrace has height of thirty I
4 thirty-fve feet. Along tie hills facin
II the waters and the southern extremity o
l. the valleys no traces OF any higher lev
/ exist, twenty-five to thirty-hve feet is II
It greatest amount of submergence the fac
5 sustain. Sea border deposits exist at
II higher level on the $coast OF Maine and c
! the shores of the St. Lawrence and sho
d what was the position of the shore line
ir those regions. But the level along soutl
n ern New England is not proven by IL
= facts there gathered; neither is it esta
3 Iished by the demands Of the iceberg the
" ry. In conclusion, if icebergs,
IS floating masses of ICE, were not capable
ie covering with scratches great continuo1
1T areas, and would have had chance f
10 little rock abrasion on account of Il
IS covering of detritus; if they could n
le have made, in their hitching and swiDgi1
/ way OF action, when touching botto1
1T scratches over the great areas that had Il
q even course OF parallelism characterize
e those Of drift regions, or could not ha
ct ploughed out the deep burrows: if tn
Re could not have gathered the great bowlde
Or for transformation; and if the sea alol
D the sound did not cover the la
Dr. in any part of the e
y of ice to greater depth than thirty
ly thirty five feet, the iceberg theory of I
lg drift may be reasonably pronounced U
bit satisfactory for southern New Englar
DO And similar facts show that it is equal
N unsatisfactory for the rest of New En-
3. land.
1e ANIMAL REMAINS.
a The second paper was by VIM. McAdal
10 on the animal Remains from the Lo'
~, and Glacial Clays."
III After considering this paper the sect
adjourned uTtj5 thiS II crDiDp.