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all the Cretaceous beds of Nebraska, and of the upper Missouri
in general, are very recent and correspond, as also tnose of New
Jersey, to the Senonien of d'Orbigny, and perhaps also to his
Turonien."

From his observations in Nebraska, Mr. Marcou arrives at the
following conclusions.

1. " The rules and laws of paleophytology hitherto adopted and
followed must be greatly modified, since we find here a flora,
regarded as Miocene in Europe, at the base of the Chalk period.
Oo this account I may be permitted to add that, in the geograph-
ical distribution of the existing flora, I have discovered con-
trasts much greater than those in the distribution of the exist-
ing fauna. One of these contrasts which surprised me most is
that of the elevated plateaus of New Mexico, Texas, Arizona
and California, which is certainly more difierent from the flora of
the States bordering upon the Atlantic and the basin of the
Mississippi under the same conditions of temperature and lat-
itude, while on the other hand it does not differ from the Tropi-
cal flora of Florida, the Antilles and Panama. After this dis-
covery I could see no serious objection which would have weight
in the mixture of Carboniferous plants and Belemnites at Petit-
Couer in Laventaire, since in Nebraska we have Miocene plants
underneath 500 or 600 feet of whit© chalk containing Inocera-
mus^ Ammonites, and Bacuiites,

2. '^The new red sandstone and more especially the lower por-
tion or dyas occupies a very important place in the geology of
Nebraska, as I announced it in 1855 to the Geological Society
of France, in my geological chart of the United States and in
the explanatory rdsum^ which accompanied it.



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176 F. V. Hayden on the Cretaceous rocks of the West

8. '^ The dyas of Nebraska is composed of two members, as in
Russia and Germany, one of which corresponds to the Bothlie-
gende and the other to the Zechstein."

Prof. Capellini in a short but very interesting article confines
his observations mostly to the rocks of the Dakota group and
remarks that he does not hesitate to regard the observations of
American geologists as entirely just. The following remarks
close the article of Prof. C.

"After all we have observed in relation to the environs of
Sioux City, it is easily seen that a stratigraphic series so com-

51ete throws a dear light upon the isolated facts first noticed at
^ekainah and Blackbird Hill, and indicates the exact position of
the rocks with dicotyledonous leaves, analogous to the Tertiary
leaves of Europe but belonging in reality to the Chalk.

'*It may be estimated that the thickness of these Cretaceous
strata in the environs of Sioux City is about 40 meters. They
may be divided into two distinct parts, one rich in leaves, a
fresh-water formation ; the other truly chalky with fishes and
Inoceramus, of marine origin — both are probably not older
than the chalk of Maestricht. ' This has been my opinion from
the time I admitted that the dicotyledonous leaves of the Big
Sioux and Tekamah were Cretaceous.

" Once the age of the Mollasse with leaves established by the
aid of the stratigraphy and the animal fossils, it would be inter-
esting if it were possible to arrive at the same results by the
vegetable remains. On this account, Prof. Heer came to my
aid and investigated the specimens I collected in my explora-
tions. More than a dozen species were recognized among the
leaves from Tekamah, Blackbird Hill, and Big Sioux, but it
was especially the first locality which furnished the best speci-
mens. We are convinced that when observations are exact and
determinations made from careful examination of specimens,
there is never any disagreement between stratigraphical and
paleontological laws.''

The remarks of Prof Heer which preface his descriptions of
the fossil plants collected by Prof Capellini, are so interesting
and important that we copy them entire.

"The collection of Mr. Capellini contains 16 species; 4 are
badly preserved ; 12 are determinable. Nevertheless, of the lat-
ter, several are but fragments, so that their determination is diffi-
cult and not sufiiciently ^positive. This is especially the case
with the Phyllites which 1 have referred to the genera Platanos
and Andromeda. It is certain that all the leaves found by Mr.
Capellini are dicotyledons and with great probability one may
be referred to the ^enus Ficus, one to Salix, one to Diospyros,
two to Populus ana two to Magnolia, although there are no ac-
companying fruits or other parts to confirm these determina-



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F. V. Hayden on the Cretaceous rocks of the West IT!

tioDs. These genera are yet living and they are also found in
the Tertiary formations.

" If we compare these plants of Nebraska with the Cretaceoas
plants of Europe, we find no identical species among them. I
sent drawing of them to Dr. Debey of Aix la Chapelle, who dis-
covered in that locality a Cretaceous flora. He has written to
xne that he has not found one species identical. Even the greater
part of the genera are different. There *is but one Gissites (C.
aceroides Debey) which recalls slightly the C. instgnis (Plate iv,
fig. 6). The Cretaceous plants of Menant, Belgium, those of
Blankenburg and Quedlinburg are also very different.

*' Prof Schenk has recently sent to me, a collection of plants
of Quedlinburg for determination. Besides conifers and ferns
characteristic of the chalk, it contains dicotyledons, but no
forms like those of Nebraska.

"The Cretaceous flora of Moletein, Moravia, which I have
lately studied, exhibits more resemblance. It contains two spe-
cies of Ficus which much resemble the Ficus of Nebraska, two su-
perb species of Magnolia, one with a fruit cone. There is a re-
lationship between the flora of Nebraska and that of the upper
Chalk of Europe, although identical species are wanting. But
to the present time no characteristic genus of the Cretaceous flora
of Europe has been found in Nebraska.

"If we compare the plants of Nebraska with the Tertiary plants
we find no identical species, but 7 genera, (Populus, Salix, Pi-
ous, Platanus, Andromeda, Diospyrus and Magnolia) are also
Miocene and likewise living. It then appears that the Nebraska
flora is related more to the Tertiary than to the Cretaceous flora
of Europe, a fact which struck me when I first saw drawings of
the former. But it should be remarked that we know but a
very small number of American species, and on the other hand,
the European Cretaceous flora has more relationship with the
Tertiary flora than I at first supposed. I have found in the Cre-
taceous flora of Moletein, Moravia, species of Ficus and Magno-
lia which resemble Tertiary species; a Myrtacea, which is a near
neighbor to the Eucalyptus rhododendroides^ Mass, of Mt. Bolca ;
a Juglans and a Laurinea, which also have their analogues in the
Tertiary flora; a Pinus and two other conifers whii^h belong to
the genus Sequoia, which was extensively distributed in Europe
and America in the Miocene epoch and which is now only found
in California. •

" As the Cretaceous fishes are more nearly related to the Terti-
ary than to the Jurassic fishes, the upper Cretaceous flora is also
entirely different from the Jurassic and more nearly allied to
the Tertiary floras, and it appears that in America the relation
between the Tertiary and Cretaceous flora is yet more intimate
than in Europe.



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178 F. V. Hat/den on the Cretaceous rocks of the West

"It is remarkable that the plants of Nebraska (as Magnolia and
Liriodendron) present relations with the existing flora of Amer-
ica, whilst the Cretaceous flora of Europe has more of an Indo-
Australian character. It thus appears that since the Cretaceous
epoch, the American flora has not undergone a change so great
as the European flora. While the Cretaceous flora of Europe is
entirely different from the existing European flora, that of Ne*
braska contains 8 genera yet found in America, and it is the
more remarkable that the greater part are yet found in a country
under the same latitude."

Prof Heer describes the following species of plants from this
group in this memoir: Populus litigtosa^ P.I Debeyana^ Salix
nervilheay Betulites derUiculata, Ficus jmmordialis^ PlcUanuaJ New^
berryana^ Proteoides gremtteoBformiSy P, daphnogenoides^ P. acuta^
AristolochtUs dentcUa^ Andromeda Parlatorii^ Diospyms primasva^
CissUea irmgnis^ Magnolia aUemanSj M. OapelUnij Liriodendron
Medcii^ PhyUUes Vanonce.

Both Mr. Marcou and Prof Capellini agree in regarding this
sandstone in which the dicotyledonous leaves are found as a
fresh-water formation. I would simply say that I have always
regarded it as marine and I am sure this has been the opinion
of my friend Mr. Meek. At any rate we have found mingled
with the leaves at Sioux City quite well preserved casts of Pha-
rellaf Dakotaensis^ Axinoea Siotucensia and Cyprina arenaeea, shells
peculiar to marine deposita

The question has arisen, whether this period had a fauna cor*
responding to its flora ? Besides the Mollusca already alluded
to, no remains of land animals have yet been discovered which
could be positively identified. On the eastern slope of the Big
Horn mountains, 1 saw in 1869, a series of beds holding a posi-
tion between No, 2 Cretaceous and the Jurassic rocks below,
which I referred without hesitation to this group. In these rocks
were beds of earthy Lignite, large quantities of petrified wood,
and numerous large uncharacteristic bones which doubtless be-
long to some Saurian. !No remains of strictly land animals have
ever been found.

Although I have endeavored to give the substance of Mr.
Marcou's momoir in this article, I do not wish to be regarded as
endorsing all that he has said in regard to the existence of
"Dyas" and '* Mountain limestone." In the autumn of 1866,
while descending the Missouri river, I saw some peculiar local
beds near St Stephen's, Nebraska, from which I obtained Mya-
Una peraUeriuata^ PleurophoriLS occidentalia and I/yonsxa concava^
which were sufficient to indicate that they were either Permian
or the transition beds which we have called Permo-carboniferous.
These questions have been most ably and exhaustively discussed
by Mr. F. B. Meek in an article in this Journal, Jan., 1866, to



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Reuarches on Solar Physics. 179

which the read^ is referred. The main object of the present
article is to place before those American readers of this JourDaL
who may not have access to foreign Journals, such views and
important geological facts as Proft. Marcou and Capellini ob-
tained in their field investigations, as well as those of Prof, fieer
from the study of the fossil plants.

Univenitj of PeimsylTtBiB, Philftdelphia, J«i. 8th, 1867.



Art. XIX. — Researches on Solar Physics;* by Warbkn Db la
EuE, Esq., Pres. RA.S., Balfour Sttswart, Esq., Superin-
tendent of the Eew Observatory) and Bjenjamin Loswy,
Esq., Observer and Computer to the Kew Observatory.

First Series, — On the Nature of Sun-spots.

1. There is a marked difTerence between our luminary and
our satellite, as far as regards our knowledge of their physical
aspect and constitution. Many parts of our own globe are not
so well known, or so correctly mapped, as certaiti regions in the
moon ; and could we imagine an observer transported into the
neighborhood of Tycho or Copernicus, he would probably be
better prepared for the appearance presented to him, than he
would be if placed suddenly in equatorial Africa or central
Australia. But with regard to the sun the case is very differ-
ent ; for although the progress of science has enabled us to de-
tect the presence of certain familiar substances in the atmosphere
€3i our luminary, it has hitherto only shrouded in deeper mys-
tery than ever the origin of that wonderful outpouring of light
and heat which is the sun's most prominent characteristic, and to
this very day it has not been finally decided whether this lu-
minosity proceeds from the sun's solid body, or from an envelope
which surrounds it. Indeed so strange and so unaccountable
are many of the features presented to us, not only by our own
sun, but by many of the stars, that it has even been conjectured
that these bodies exhibit instances of the operation of some force
of the nature of which we are yet ignorant. If we accept this
view of the ease, the study of our luminary becomes one of very
great importance, but one in which we must be very careful to
be guided by observation alone. We must obtain numerous
and accurate representations of the sun's sur&ce, and study
these carefully and minutely, before we attempt to generalize.

§ I. Methods of observation,

2. There are two methods of acoomplishins; this. (1.) Eye-
obaervations of the sun's surface may be made by means of a

* From a memoir printed for primte distribntioB. *

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180 Researches on Solar Physics,

telescope, and the appearance carefully mapped by the observer.
(2.) Or we may call to our aid that art whion has already proved
of signal service in many branches of science, and, by means of
photography, obtain autographs of our luminary, which we may
measure and examine carefully at our leisure.

Each of these has its advocates, but it is not our design to
discuss the comparative merits of the two methods; on the con-
trary, as each has its own special advantages, we are willing to
adopt them both, and to avail ourselves of all those materials
which our own observations or the kindness of friends may
have put into our hands.

§ II. Historical sketch.
8. The most important knowledge which we possess regard-
ing the physical appearance and structure of our luminary is
derived from the fbilowing sources.

4. Sun^s rotatunu — We are, in the first place, indebted to Gali-
leo, if not for the first discovery of sun-spots, at least for the
first attempt to ascertain through their means the period of ro-
tation of our luminary.

5. Nature of sun-spots. — The next great advance in solar
physics is due to Alexander Wilson, Professor of Astronomy at
Glasgow, who in 1773, communicated a paper to the Royal So-
ciety, describing certain phenomena with regard to spots, which,
in his opinion and in that of many others, appear to indicate
that spots are cavities in a luminous photospnere which sur-
rounds the sun.

The accuracy of this conclusion has recently been questioned ;
but whatever may be said regarding the theory, there can be no
doubt regarding the importance of the hjct which was first re-
vealed by Wilson.

6. Their periodicity. — The next step is due to Hofrath Schwabe,
of Dessau, who has shown, as the result of nearly forty years'
laborious observations, that the number of spots which break
out on the sun's surface is not the same from year to year, but
has a maximum about every ten years — a remark which led
General Sabine to observe that the various epochs of maximum
spot-frequency were also those of maximum magnetic disturb-
ance in our own globe. »

7. Their proper motion^ &c. — Oarrington is the next observer
who has greatly extended our knowledge of this subject In a
lai^ and most remarkable work recently published, and con-
taining the result of many years' observation, he has shown that
sun-spots have a proper motion of their own, those near the
solar equator moving faster than those near the poles ; and he
has also made interesting remarks on the distribution of spots
in solar latitude for different years. In addition to these new-



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Researches an SoUtr Physics. 181

fiu^ts, he has furnished us with very aocurate data regarding the
sun's rotation.

8. OradaJtione th their luminbsity. — We ousht also to mention
the disoovery by Dawes, that what is reffarded as the umbra of
a spot consists in many cases of two well'defined and separate
parts,* the exterior part being less luminous than the interior ;
so that we have often connected with the same phenomenon not
less than five degrees of luminosity : these are— (1.) The faculao.
(2.) The ordinary photosphere. (8.) The penumbra. (4.) The
borders of the umbra. (5.) The very dark central nucleus.

Mr. Dawes's discoveries are mainly due to his employing,
with an eye-piece of his own invention, the full aperture of the
telescope ; but it is necessary to recall the fact that Sir William
Herschel, in earlier times, was fully aware of the importance of
not contracting the aperture of the objective. Moreover, we
must not forget that Sir W. Herschel contributed to solar phys-
ics a theory which still holds its ground.

9. Red flames, — But there is another phenomenon connected
with our luminary, not less curious than solar spots. We allude
to the red flames, or protuberances which are seen to surround
the sun's disk on the occasion of a total eclipse. Airy and
Arago were the first to conjecture that these belonged to the
sun. In the total eclipse of 1861, the former of these observers,
by combining his observations with those of O. Struve, showed
it to be probable that these flames do not change during the
mowCs motion. Great credit is also -due to this observer for or-

Bniziiig the Spanish expedition of 1860 ; and it was here that
r. De la Bue, by means of the Kew heliograph, set the matter
completely at rest. Mr. De la Bue, from the pictures which he
obtamed, was able to show that the flames onlv change appar-
ently, not really, by the moon's motion over them, that is, by
covering one portion and disclosing another, and do not otherwise
undergo any alteration ; so that when the clock of his instrument
was aSiusted to the sun's motion, that portion of the flames not
covered b^ the moon stood still. He also showed that the an-
gular motion of the red flames, with respect to the moon, corre-
sponds to the theory of their fixation in the sun.

These results were verified by Secchi, who also obtained pho-
tographs of the same phenomenon, which were comparea in
Bome by Mr. De la Bue and Father Secchi with Mr. De la Bue's
photographs. The forms of the red prominences were found
identical in both, so that no change occurs in their form during
an interval much longer than the duration of totality observa-
tions in a solar eclipse.

* Id tome cases, howeyer, it in fair to anume thai the appearance of lighter por-
tions of the umbra maj be caused br the floatiag across of portions of the brigmer
part of the sun's surface.

Am. Jour. Sgi.— Sbcoxd Sksom, Vol. XLUI, No. 128.^]1ibch, 18Q7.
34



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183 Researches on Solar Physics.

10. WUhw'Jeaves. — We may be allowed to mention here that
very lately Mr. James Nasmjth, during the course of his obser*
vations of the sun's surface, has come to the conclusion that,
when the circumstances of observation are very favorable, the
whole surface will be found to be composed of separate lumin-
ous bodies, of a great similarity of figure, interlacing one an-
other ; and he has given the name of unUow-leaves to these ap-
pearances. The existence of these is still disputed ; but some
of our best observers in this country have seen them under very
favorable atmospheric conditions, and they have been seen more
frequently by Secchi and other Italian obeervera

11. Other observations of the 8un*s surface, — Chacomac, the emi-
nent French observer, has noticed a behavior of those portions
of the sun's surface around a spot, which seems to imply the ex*
istence of a downward current. More recently Lockyer, in this
country, has made a very, important observation of a similar
kind. A tongue of faculous matter projecting over a spot was
observed to lose its brilliancy very rapidly, so as ultimately to
seem less brilliant than any portion of the penumbra. At the
same time it seemed to be " giving out," as it were, at its end,
and a portion of the .umbra between it itnd the penumbra ap-
peared to be veiled with a stratus cloud evolved out of it.

We ought likewise to mention the excellent and numerous
observations of Pastorff, preserved in the library of the Boyal
Astronomical Society, also those of Captain Shea, both of which
the Council of that Society have placed at our disposal. Pro-
fessor Wolf, of Zurich, has collected data for establishing the
periodicity of sun-spots before the commencement of Schwabe's
observations. Also, the Bev. J. Howlett, in this country, has

Eroduced a large series of drawings of the sun's surface on a
irge scale, and of exquisite delicacy of delineation^ which will
no doubt prove of much value; and, finally, this field of re-
search is one that has been occupied by many observers in all
parts of the world, so that we may hope with some confidence
for a speedy increase of our knowledge in this very important
branch of physical astronomy.

12. Composition oj solar atmosphere. — Before concluding this
very brief historical sketch, we ought to allude to the discovery
of Kirchhoff and Bunsen, who, by means of the spectroscope,
have proved that many familiar substances, such as sodium,
iron, magnesium, &c., exist in the atmosphere of our luminary
in the state of yapor.

§ III. Materials at the author's disposal.

18. We now proceed to describe what materials we have at
our disposal for the purpose of these investigations.
In the first place, Mr. Carrington has very kindly put into



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Be$earches on Solar Physics. 183

our hands all his original drawings of sun-spots. These extend
finom^November, 1858, to March, 1861 ; and in them the sun's
disk is represented on the scale of one foot in diameter, while,
for each spot, the apparent position on the disk, as well as the
pro portion in size to the whole surface, is accarately delineated.
We hope, in our investigations (as far as spots are concerned),
•to make much use of these pictures by Oamngton ; they do not,
however, aflford us any information with regard to faculea.

More recently we have received into our hands the magnifi-
cent collection of drawings of the sun made by Hofrath Schwabe,
of Dessau, during the course of about forty vears, — this distin-
guished observer having generously placed these in the posses-
sion of the Royal Astronomical Society, for the use in the mean*
time of the Kew Observatory.

Our materials are, moreover, derived firom the pictures taken
by the Kew heliograph. This instrument, with its various ad-
justments, has already been described by Mr. De la Rue in the
Bakerian Lecture for 1862 ; and it is therefore unnecessary to

five a further description of it here. A few pictures were taken
y this instrument at the Kew Observatory in the years 1858
and 1859. In July, 1860, it was in Spain, doing service at the
total eclipse. In 1861, a few pictures were taken at Kew ; while,
from Feoruary, 1862, to February, 1868, the instrument was in
continuous operation at Mr. De la Rue's private observatory at
Oranford ; and from May, 1863 until the present date, it has been
in continuous operation at Kew, under Mr. De la Rue's superin-
tendence. It is right to mention that for the perfection of these
pictares much crrait is due to the late Mr. Welsh and to Mr,
Beckley, under whose immediate sapervision the pictures at
Kew have been taken by a qualified assistant, Miss Beckley.

§ IV. Method of reduction.

14. These are the materials at our disposal ; and it may here
be desirable to state in a few words the principle by which we
shall be guided in our reduction of these materials. In the pro-
gress of this branch of knowledge, observers have been lea to
recognize certain laws, which represent the average behavior of
sun-spots; but to each of these laws there are individual excep-
tions. In this state of things it is probable that our knowledge
of the subject will ultimately be aavanced, not only by a study
of those groups which behave in a normal manner, but also by
a study of those which are exceptions in their behavior to the
general rule ; and on this account it has been thought desirable
to publish the results in such a way that any one may be able
as far as possible to study the appearance and behavior, in fact,
the whole history of any one group. Setting aside, in the mean-
time, Schwabe's drawings for future consicTeration, we propose



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184 Researchei an Solar Physics.

to adopt the following plan of publication for Carrington's pic-
tures and for those of toe Kew heliograph. In discussing Gar^
rington's observations, we shall of course adhere to the number-
ing of his different groups, which he has given ; and as he has



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