John Almon.

The American journal of science and arts online

. (page 6 of 102)
Online LibraryJohn AlmonThe American journal of science and arts → online text (page 6 of 102)
Font size
QR-code for this ebook


expected to reappear in Yucatan, along the foot of the Mexican
plateau, in Texas, and forming a tongue, as it were, in the di-
rection of the long cretaceous Mediterranean, and tertiary fresh-
water sea which is marked by the Great Lignite of the upper
Missouri.

In view of the slight dip of the Mississippi Tertiary, the anom-
alies mentioned may find their explanation in undulations of the
sea-bottom upon which these strata were deposited. A dip of tea
feet per mile does not differ very sensibly from the horizontal,
and a stratum deposited on such a slope would not necessarily,
on that account, vary much in thickness. If at the time of the
deposition of the Jackson group, a northward slope to that ex-
• tent existed between Jackson and Canton, a subsequent general
upheaval to the northward would render that slope a horizontal
plain, while the strata heretofore horizontal would acquire a
southward dip to the same extent Similarly, if between Baker's
bluif and the Salt Works on the Tombigby, or between Dr.
Miller's and Bed Bluff on the Chickasawhay, the sea bottom had
a slight trough-shaped undulation (such as the ocean beds of our
time frequently exhibit), the existing state of things would re-
sult Artesian borings lower down on the Tombigby river may
hereafter inform us whether or not the white limestone underlies
there, as by analogy with the Pearl river beds it might be ex-
pected.

While, however, the general features and position of the Ter-
tiary as well as of the Cretaceous strata of Alabama correspond
closely with those observed in Mississippi, it seems, contrary to
what one would expect, that the absolute amount of southward
dip is somewhat less in the former state. No numerical data re-



Digitized by



Google



of Mwissippi and Alabama. 39

^rding this point are given, bat from the great breadth of coun-
try upon which outcrops of one and the same group of the Ter-
tiary occur in Alabama, the fact is apparent enough as concerns
the latter. Whether the same is true of any part of the Creta-
ceous, is doubtful ; unless the great north and south width of the
Bipley group, as exhibited on Chunnenugga ridge in Macon and
Barbour counties (according to Tuomey's and Thornton's obser-
vations combined), should thus find its explanation. It seems
doubtful, in fact, whether the true Botten Limestone (if it exist
there) comes to the surface at all. This is the more remarkable
from the near proximity of the primary and metamorphio rocks
of that portion of the state, whose original upthrusting would
thus be proved to ante-date greatly the general Allegheny up-
heaval.

The Grand Chulf group. — I have considered the older and well-
defined eocene Tertiary apart from the two other groups de-
scribed in my Beport, whose age is doubtful and whose relation
to the former is not well recognized. A glance at the map
nevertheless shows that so far as extent is concerned, the Grand
Gulf group is perhaps the most important of the formations of
the state of Mississippi, and that, judging by the trend of its out-
lines on the Mississippi river, it must be still more so in Louis-
iana; while in Alabama it rapidly contracts, and attracts so little
attention that I find but two observers who, passim, advert to
anything resembling this formation as it exists in Mississippi.

Conrad (this Jour., [2], vol. ii, 210) states that the bluffs of
Vicksburg, Grand Gulf, Bodney and Natchez, have a similar
geologicaf origin ; that their lower portion is of marine origin,
and a member of the £ocene.

I am unable to refer to a prior publication, mentioned by Con*
rad, for the data upon which this determination is based, so far
as the bluffs below Vicksburg are concerned, I have made de-
tailed examinations of the proBles at Grand Gulf and at Fort
Adams, at the extreme limits of the formation in Mississippi,
and I may say, of all the important outcrops in the interior; but
thus far, have failed to find even a trace of a marine fossil, and
in fact, but a single specimen — a bone fragment as I take it —
likely to prove of zoogene origin. Vestiges of vegetation are
common, out only in one instance, so far, have I found any speci-
mens likely to a^mit of exact determination. I refer to the de-
posit on the Chickasawhay, already referred to, which exhibits
the trunks, stumps and roots of an ancient forest, inhabited,
among other trees, by tree palms. But even here, scarcely any-
thing beyond the most general outlines of a few leaves can be
traced. It may be th^t in proximity to the (rare) lignite beds
of this formation, better success might be had — as has been the
case in the Lower Lignitic. In the sand- and claystonea belonging



Digitized by



Google



40 E, W. Hilgard on the Tertiary formations

to this group, neither Wailes, who resided amongst them and
gave the name of **Davion rock " to one variety of the former;
nor myself who have delved in scores of exposures, have ever
found a trace of any fossil whatsoever.

The Natchez bluff I have not visited; but Wailes, who resi-
ded within six miles of it, must have done so, and he is silent
on the subject of any but the Loess fossils, although be men-
tions all other fossiliferous rocks occurring in the Slate. Thus,
while I have seen mentioned in various places *^ marine strata at
the foot of Natchez bluff," I cannot trace the report to any au-
thentic source. I shall endeavor to settle the point as soon as
possible, but meanwhile observe, that according to reliable infor-
mation given me, the Rodney bluff is essentiallv a counterpart
of that at Grand Gulf; a detailed profile of which, obtained at a
medium stage of the river, is given in my Report (p. 148).

The extreme scarcity of fossils in this formation is the more
remarkable, as from the regularity of its stratification it is man-
ifest that it has been formed in quiet water, and it contains a great
variety of materials suitable for the preservation of either fauna
or flora. Even the stratacontaining carbonate of lime, however,
seem to have had nothing to fossilize, save in the solitary in-
stance of a doubtful fragment of cellular bone already mentioned.
In some portions of it, we might imagine that the abundance of
soluble salts (which pervade more or less the entire dejxwit) indi-
cated the former existence of bitter lakes, incapable of harboring
life ; but this could by no means apply to tne formation as a
whole.

The only probable presumption in favor of referring it to the
Eocene, so fur as I know, arises from the lithological resem-
blance and transition of its strata, at its northern limit, to those
of the Vicksburff group. The upper division of the latter group
in the neighborhood of Brandon is undistinguishable from the
materials of the Grand Gulf group at many points, and I so
referred them until I found them overlaid by a string of lime-
stone nodules containing Orbitoides^ about forty-five feet above
the uppermost sands of the Vicksburg group; (See section. Miss.
Rep., p. 140.) At a level about forty feet higher, the character-
istic soft white sandstone of the Grand Gulf group crops out.

This, however, amounts to mere conjecture; and, per contra^
toward the sea-coast the lithological transition into the mate-
rials of the "Coast pliocene" seems about equally cogent. The
mere fact that tree palms are found in the formation, amounts to
nothing, inasmuch as these grow at the present time in the same
latitude in South Carolina.

The existence of this formation in Alabama appears from Mr.
Thornton's notes (2d Rep. Ala., Appendix), in which he men-
tions similar materials as overlying tne (Vicksburg) marine Ter-



Digitized by



Google



df Missisiippi and Alabama. 4 1

tiary at its southern limits. Moreoyer, Bigelow (this Jour., ii, 419)
describes a sandstone formation in Baldwin county, Ala., which
impresses me as though it mi^ht be Grand Gulf sandstone over-
laid by the ferruginous sandstone with tubes, of the Orange
Sand group (Miss. Bep., p, 9), '^filled with variously colored
sand." Bigelow states that in the lowest portion of this rock he
has seen obscure impressions of shells ; which, if my conjecture
be correct, might offer an opportunity of detei^mining the age of
tiie group. The same rock is said to occur at Pensacola.

The ''blue clay bottom'^ of the Ooast— ''Coast PlewceneJ'—'ei'
nallv, as regards the imperfectly known black clay formation
of the coast (Miss. Bep., p. 154, ffl), a comparison of specimens
of shells and borings obtained from the New Orleans artesian
well,* in 1854, seems to show that it underlies the whole of the
delta, perhaps as high up as Port Hudson, whose subterranean
Cypress swamps, observed by Carpenter and by Lyell, may be-
long to this formation. No Eocene fossils have been brought
np by the augur, even from the lowest shell-bed found, at the
depth of 670 feet, (the greatest depth was 680) ; while from
among the shells of the first bed struck, at 41 feet, I have thus
far determined eighteen marine species, all now living in the Gulf.
At 163 feet a trunk of cypress, with bark, was found. At 256
feet, some extinct, or if living, undescribed shells seem to occur;
and at 480 a Gnathodon bed. I hope to be able to determine
by microscopic comparison whether or not the Grand Gulf group
has been passed through or reached in this bore, which from
present appearances has penetrated both Post-pleiocene and Plei*
ocene marine deposits. This would parallelize more closely the
Tertiary of the Atlantic coast and of the Gulf ; though so far
as I know, nothing apparently corresponding to the Grand Gulf
era has been observed in the former series. Should the chain
of the Antilles, after the close of the Eocene epoch have for some
time cut off* the Gulf of Mexico from the Atlantic, it seems pos-
sible that the deposits of the former might have changed tneir
character to the extent required by the facts observed. A strong
influx of fresh water — perhaps that pertaining to the Great
Lignite era — ^from the continent might for the time being have
extinguished the Eocene marine fauna without replacing it by
another sufficiently numerous to be readily detected in the de-
posits of the period, which might thus correspond to the Atlan-
tic Miocene. Upon the subsequent irruption of the Gulf stream
through the Antilles chain, the formation of normal marine de*
posits along the margin of the Gulf would be resumed.

UotTtriiity of Missiatippi, July 26, 1866.

* The«e specimens were furnished by Drs. Copes and S. S. RiddeH, of New Or-
leans, to Haj. Gen. A. A. Humphreys, and by him referred to me for examination ;
which, however, ia not yet completed.

Am, Joua. Sol— Sbcoitd Sxrhs, Vol. XUn, No. 127.— Jav., 1867.
6

Digitized by VjOOQIC



49 A. S. Packard an Glaciers in the White Mountain Valleys.



Art. YI. — Evidences of the existence of ancient Local Glaciers in the
White Mountain VaUeys; by A. S. Packard, Jr., M.D.

The following obseryatioDS were made duriDg the past au-
tumn in the yallejs of the tributaries of the Saco, and Andros-
coggin rivers. At Jackson, N. H., on Thorn mountain, which lies
just south of Tin mountain, there are some well marked glacial
scratches which point directly toward Mt. Washington, which
stands at the head of the valley of the Ellis river; their course
being N, 26® W. These were first noticed on quartz veins run-
ning over the ledges which have been polished smooth as porce-
lain and finely grooved. At other places on the same mountain
part way up, and also upon the summit, upon removing the soil,
similar striae occurred running in the same direction. On this
mountain and the neighboring hills occurred occasional boul-
ders of a peculiar mica slate, enclosing crystals of staurotide,
which had evidently been transported from near the summit of
Mount Washington. The summit of Mt. Kearsage we found
moulded by ice. Dr. C. T. Jackson in his report on the Geology
of New Hampshire states that the drift scratches one half way
up Mount Kearsage run N. 30° W. He also states that on
Mount Chicorua they run N. 35"* W. (S. 85° E.), which is the
course of the Ossipee valley just below it

On a hill just east of Goodrich's falls on the Ellis river are
very distinct ice-marks, on polished surfaces, with strm running
N. 30° W., and lunoid furrows with their horns pointing up the
valley in the same general direction as the grooves.

Crossing over the mountains into Chatham, and Stowe, Maine,
into the valley of the Cold river, another tributary of the Saco,
we find another set of strisd. The broad summit of Speckled
mountain, opposite Mt. Boyce, which two mountains guard the
southern entrance of Evans' Notch, is glaciated both on the N.W.
and N.E. flanks. Here also is a "col, down which the ice must
have moved in both directions. Near the summit the grooves and
lunoid furrows run N. 15° E., following the course of the valley
at this place, and aiming at a higher peak to the north and east.
On Mt. Baldface, 3600 feet high, three or four miles southward,
the grooves are very clearly indicated both below and directly
upon the summit Here they run N. 10° W., and it might be
mentioned that the Cold river valley turns more to the southeast
at this point. On a shoulder of the ^mountain, perhaps 300 feet
below the summit, the lunoid furrows are especially abundant.

On the summit of this mountain, which is made up of a li^ht
colored 6ne syenite, were a few boulders of a peculiar porphyntic
syenite, with oblong crystals of albite. Following the N. 10°
w . course, less than a quarter of a mile, we traced them to the



Digitized by



Google



H. Haug on the Electro-motive Force, etc. 43

{laretit rock composing Peaked moantain, which is somewhat
ower than Baldface, at least 100 feet

Again, crossing the high range of mountains over into G-ilead
in the Androscoggin valley, glacial marks directed N.W. oc-
curred on a high ledge near the river, indicating that the ice
moved from the northwest, pursuing the general course of tho
valley at this point

Here, then, are good proo& of distinct systems of glaciers
radiating from a central mer de glace which capped the White
mountains. This dome of ice must, so far as our slight observa*
tions show, have been soon subdivided into local glaciers which

S)ur8ued their route down the different valleys to the sea. Thus
bllowing down the Androscoggin river, at Lewiston, the ice-
marks run nearly north and south, the course of the valley at
that place, as we are informed by Mr. G. J. Yarney of that town ;
and at Brunswick, on the seashore, there are deep furrows run-
ning in a N.W. direction, being the ancient course of the river
where it undoubtedly entered the sea, up to a late period of the
Terrace epoch.



Abt. VII. — Experiinents on the Electro-motive Force and the B^
eisiance of a Oalvanic Circuit; by HsRKANN Haug.

[Oondnded from roL xlU, p. 889.]

Nattjkallt I first inquired whether or not the experiments
of other observers would exhibit peculiarities of a similar char-
acter. I am not fortunate enougn now to have a great choice
of material at hand. But the experiments of J. MiilTer, cited on
page 384, with six cells of Daniell's, if every possible combina-
tion of two diflferent intensities is calculated, show decidedly a
similar great increase of the internal resistance with the decrease
of the combined intensities, viz :

For cell No. 1, from 2*85 to 5*10
44 44 2 « 3-41 « 4-76
44 u 3 a 3.Q2 «« 4-07

44 44 4 44 3.19 41 4.07

« " 5 « 3-08 " 4-73
«« «* 6 ** 3-68 " 4-19

As I have every reason to believe that in these experiments
the circuit was really opened every time a greater resistance was
to be introduced, I considered this circumstance, or the reverse^
as not of any great account, and tried to determine at least the
general character of its influence upon the results of all the other
circumstances which may be regarded as important



Digitized by



Google



44



JET. Haug on the JSlectro-tnoHve Force



With this object in view, I preferred to exchange the nitric
acid for a properly acidulated solution of bichromate of potash,
since a battery with this liquid, after having been used for some
time, possesses much less reliability as regards constancy than
the Bunsen battery. The results of this series of experiments
are recorded in table VL They are very irregular, from errors
of observation, and from what are called the fluctuations of the
electromotive force. For every external resistance two mean
values of the internal resistance are calculated, one from the first
half, the other from the second half of the single observations.
These mean values are:



For centlm. of


Firsl


Second


For centlm. of


Firat


Seeooc


platlaum la


mean


mean


platinum la


mean


mean


Uf circuit


value.


value.


tbe rirculL


value.


value.


8


26-69


3600


80


87-88


84-87


4


S6-6


2848


40


84-72


8609


6


S8-8i


81-08


60


4187


89-76


%


88-4i


8169


120


41-86


8967


10


8136


81-76


200


41-64


4009


20


86-27


8466









In nine out of eleven cases the mean values of the first ob-
servations are greater than the mean values of the last observa-
tions. From this fact I thought myself warranted to believe
that all those circumstances together which may be considered
as influential upon the results, generally tend to diminish the
ratio of increase, or at least, that m my experiments they would
not increase this ratio. I therefore considered the results of my
experiments reliable enough, as far as the fact of the great in-
crease of internal resistance was concerned, and I changed only
the manner of determining the intensity by observing the de-
flections of the swinging needle, both ways, and taking the mean,
instead of waiting for the resting of the needle. In this way I
made two series of observations, the results of which are given
in tables vri and viii. The battery was Bunsen's, the acids hav-
ing been used once before.

Since tbe heating of the thin platinum wire of the reochord
prevented me from observing higher intensities (those above
tan. = 0*6), and calculating upon them, and since I was aware
that the influence of temperature upon the resistance of con-
ductors would probably oe, and has been, con.sidered as suffi-
cient to explain the inerease of internal resistance, as proceeding
from the common method of calculation, I preparea myself a
rather imperfect reochord with copper wire, because this metal
becomes heated but very little, and would afford me to compare
the results of very different intensities. Table vii contains the
results of experiments with this copper wire rheochord. All
i^istances are expressed in centimeters of this copper wire.
Experiments of table vui are made with the platinum wire rheo*



Digitized by



Google



and ReHstance of a Galvanic Circuit 45

cboidi besides which the circuit conskantlj contained 200 centi-
meters of thin copper wire. As to the calculation of the internal
resistance I have to make the following statements.

The vertical columns (a) of both tables exhibit this resistance
when calculated after the common rule, viz: combining the
direct intensity with every lower intensity.

In table vn, the column (a) gives an increase of internal resist-
anccy if only the mean values of the first, and last, five obser-
vations are taken, from 108*95 to 128*51, or from 1 to 124.
In table vin, the corresponding column (a) gives, from the first
and last, three values, an increase fix>m 6*6 to 10*65, or from 1 to
1*61. For the whole range of intensities, between the limits
1*982 and 0*7844, the increase of resistance therefore is as 1 to
1^24x1*61, or as 1 to 1*996. The two centimeters of platinum
wire were far from being red hot, yet it is difficult to decide,
whether or not, this increase can be explained simply by the
influence of temperature, the latter not being determined. I
thus failed to get a direct proof that the increase of internal
resistance, as visible after this way of calculation, is decidedly
greater than the temperature of the measuring wire could ac-
4K>unt for.

But thinking the matter over I found why this way of calcu-
lation is wrong. The first direct observation belongs to a cir-
cuity with high intensity, and where there is no part of it heated
considerably. With this observation there are to be combined,
first, the observation of an intensity somewhat lower, but the
measuring part of the circuit heated very much ; second, the
observation of a low intensity within a circuit heated but very
little. It seems evident both as regards the influence of temper-
ature, and as regards the supposed influence of the intensity of
the current, upon the internal resistance, that in this way mat-
ters become rather mixed up, and mean results are arrived at,
instead of the extreme values sought aflier. To study the influ-
ence of temperature, of intensity of the current, upon the inter-
nal resistance, requires therefore to combine with each other,
first, two observations of high intensities in circuits, with the
measuring unit of resistance heated considerably ; and second,
two observations of low intensities at which this unit of resist-
ance is heated but very little. Estimating then the ratio of
increase, due to the difference of temperature of the unit of
resistance, the quotient of it into the actual ratio of increase will
ffive the ratio of increase of the internal resistance, due to the
difference of intensity of the current Of course, it would be
much better to provide means for keeping the unit of resistance
at constimt temperature, but I refer to the method of determin-
ing the constants of the battery as commonly practiced.

In order to eliminate as much as possible, the errors of obser-



Digitized by



Google



46 H. Haug on the Electro'tnoiive Force

vation I preferred to calculate upon the combination of every two
intensities. The results are contained in the vertical columns
to the right of columns (a), of tables vu and Vlll. In table Vli,
I further calculated the mean of the last five values of each
vertical column from (a) to (b) ; and the mean value of all the
other figures. The table shows unmistakably a general and great
increase of the internal resistance with decrease of observed in-
tensities. Comparing now the mean of the first five values of
oolumn (a), not with the mean of column (b) which may be too
high, but with the mean of all the last figures, which is still less
than the mean of 171*6 and 198*9 ; we get a ratio of increase
of from 108*91 to 188*6 ; or 1 to 1*77 ; and this for a reduction
of intensity from 1*982 to 7844, or from 2-53 to 1 ; and for a
reduction of temperature of the unit of copper wire which I
should not think at all sufficient to explain that ratio.

In table viii, calculated in the same way, the mean values at
the foot of it embrace only the last three figures of each col-
umn. Comparing here the mean of the first three figures of
column (a) with the mean of the last two mean values, viz :

~ ^=17*08, in order to avoid any overrating, we get an

increase of from 6*5 to 17*08, or from 1 to 2*68, which again can-
not be accounted for solely by the difference of temperature of the
unit of resistance. This ratio is therefore partly due to the ratio

•7844
of decrease of intensity of the current which amounts to -7:^,

equal 8*62 to 1. "^^^

In table vn, with the copper wire rheochord, a reduction of

intensity to t-^ , and of temperature of the rheochord wire to
2*00

an unknown extent, are attended with an increase of internal re-
sistance from 1 to 1*77. In table viii, with the platinum wire

rheochord, a reduction of intensity to -— , and of temperature

-of the rheochord wire to an extent much greater, I have no doubt,
than in case of the copper wire, is followed by an increase of
internal resistance not more than from 1 to 2*68, being less, in
pro^rtion, than in case of table vil. It therefore seems that
the increase of internal resistance, as proceeding from difference
x)f intensities, is greater at high intensities than at low intensi-
ties of the current. And combining now the results of both
tables, we find an increase of internal resistance from 1 to 1*77 X
2*68, or from 1 to 4*655, this increase being due first to the re*
duction of intensity from 1*982 to -091, and second to the dif-
ference of temperature of the unit of resistance, which however
oould not produce half that ratio, I should think*



Digitized by



Online LibraryJohn AlmonThe American journal of science and arts → online text (page 6 of 102)