New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1874-01-31
SCIENCE.
SCIENTIFIC PROCEEDINGS.

SCIENTIFIC PROCEEDINGS
ymrApE1PniA: AMERICAN PHILosoPmCAL Socr-
xry Jan 2-The death of the distinguished geoo-
grit Prof. Naumann, at Leipsic, was announced by
letter. Prof Cope stated that the species of pacby
derm from the miocene of the Rocky Mountains hg-
sred and described by Prof o. c. Marsh In paper
received for the library that night under the name Oh
Broatcthsriam iaeens is the described by himself
under the name of Symborodon higonocerds III the
synopsis of Extinct Vertebrate OF Colorado, Issued
IN October, 1873 by the Geological Survey OF the
Territories. Prof. Frazer said: few meetings ago
Ireferred to the fact that the white color OF the
moon by day due TO the fact that the dispersed
blue light of the sun just supplied the dispersed blue
hight Of the moon and suggested that the solar
origin of these otherwise missing rays might he
demonstrated by choosing the time OF the first or
shird quarterng of the moon when lines joining the
Sun and the earth aud the moon meet at nearly
right angles for regarding the moon through the
Nichols prism. Seeing that under these cITcum-
stances the solar light would be polarzed, change
Between white and yellow ought to be perceived
Experiment has borne out this hypothesis, although,
ewing TO the perfect reflection from suspended par
t.les of greater size than those which reflect the
blue light the color was not perfect yellow.
Prof Lesley exhibited a recently executed manu-
script Map of hundred square miles of the surface
of Centre Huntingdon, and Blair Counties, in
Middle PENNSYLVANIA with three vertical sections
crossing the district at right angles; one along the
little Junsta River, another two miles further east,
along Warrior Run, and a third five miles still
further east, along Half Moon Run. These sections
extend across the Lower Silurian Valley OF Lime
stone and it's beds of brown hematite iron ore; and
across the bounding mountains Of Middle Siiurian
Sandstone Bald Eagle Mountain on the west anu
Tnssey Mountain on the east the great antlciina
oil
tons near the eastern foot of Bald Eagle Mountain;
the Lmestones dipping east away from the fault al
pretty uniform angle Of 81 degrees
He then explained the theoretical difficulties
which beset the dynamic questions raised by
phenomenon of this kind VIZ. an overthrown and
faulted anticlinal. especially the question, why a
dip of lust about "a degrees should follow one side
Of the fault for many miles, when the rocks ON the
ether side stand vertical
This question he thought he had succeeded in set
Ting by discovery made after constructing a
fourth section. extending westward from the Bald
Eagle Mountain TO the summit of the Allegheny
Mountain, taking in the vertice Middle Silurlan
rocks, the steoply inclined Upper Surian. and the
Devonian dipping regularly less and less from p
degrees to degrees. as observed ut different points
along the sectionl. and the almost horizontal Lower
Coal measures on the summit OF the Aleghany
Mountain. ~.
Using the observed dips along the line of section
~ elements of construction, and by system OF Co
nrtln1tPs.
western side of the Great Fault displayed The
sountrv west of the dip of II degrees was taken to
be IN its original condition. East of this hypOthet
ral limit Of stability the seeply upturned strata
were supposed TO slide upon each other with shear
iug motion The basset edges OF the vertical strata
must he considered rising in Steps above each
other along the plane of fault. The slope thus oh,
tanned faces eastward at an elevation OF several
thousand feet ia the air above the crest OF the Bald
Eagle Mountain.
On calculating the angle of this slope, which is
moi perfect plane, but slightly curved surface ~
TUNED out 10 have an angle Of 81 degrees at 1000
degrees lower down; of 50 degrees Just over the
mountain. aud still sleeper where IT descended
20 the present surface of the country that IS along
the line where the vertical rocks are covered by the
buestones dipping uniformly about 81 degrees.
fl seems impossible TO resist the conclusion that
the din Of 81 degrees the limestOnes shows that
the whole mass of PaeOZOic formations, about 1000
feet thick upon the east side OF the faut ana
rode up the plane formed by the basset edges of
snass upturned vertically the western side of the
fault and that II there rested at an angle due TO
the beyc of that slOpe-a beve geOmetucally deter
mined by the sbearing movement among the MEM
bers of the upcurved mass. .
Mr. Lesley considered the discovery of much i'm
portance for structural geology and expressed a
hope that IL might prove 10 be the hrst real step
toward a satisfactory determination of the angle OF
slope of our great anticlinal faults under ground
III seems also TO prove the negative against com
mon belief that the great antlclnals OF disturbed
regions must he reconstructed IN ar sections as
gaping Ii lends support also 10 the doctrine OF vast
rrdsions doctrine taught bv Fennsylvanian geOlO-
rists many wears ago, and now cOntended for by
Jnkoe Ramsey, Geke, and other adYanced BIOLOGISTS
abroad.