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area. Huntington's suggestion of collusion in these Smithville
finds and his regarding them as being really part of the Cfocke
County iron, do not seem to the writer from his knowledge of
the circumstances to be at all well taken. No object can be
seen in any one going to the trouble of securing portions of a
fall, carrying them several hundred miles across the mountains,
secreting them forty or fifty years and then making presents
of them to strangers ! The only reasonable conclusion is that
the Smithville finds fell near Smithville and not in a far dis-
tant corner of the state.

* Hontington. O. "W., Amer. Acad. Arts and Sci. Proc., vol. xxiz, pp.
251-260, 1894.

Vanderbilt University, Jan. 19, 1904.



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J. p. Smith — Periodic Migrations. 217

Akt. XX. — Periodic Migrations between the Asiatic and
the American Coasts of the Pacific Ocean; by James
Perrin Smith.

The fossil marine faunas of the western coast of the United
States, of British Columbia, Alaska, Japan, and India are
fairly well known, especially in the Mesozoic era. These
faunas are now similar, now different in the various provinces,
or in parts of them, presenting an apparently inextricable con-
fusion not capable of any rational explanation. But this con-
fusion is only apparent, for when studied in succession, a
regular scheme can be traced in the relationships and diversities
of this ancient region. And the changes that are noted point
to changes in physical geography that would be insignihcant
in themselves, compared with continental uplifts and subsi-
dences, though by no means insignificant in their effects.
Also there is abundant independent physical evidence that
these changes really took place, so they are in no sense merely
hypothetical.

Briefly stated, the facts are these. There is at present a
remarkable similarity in the living marine molluscs of the
western coast of North America and of the eastern coast of
Asia in approximately the same latitudes, and this similarity
can be traced back with certainty until the Lower Trias, and
probably even below that. But the resemblance is not con-
tinuous, there being periods in which the faunas were unlike,
and these periods of interruption recur several times, although
not regularly. It is clear that no migration is taking place
between the opposite sides of the Pacific now, and equally
clear that such migration did go on in comparatively recent
geologic time, when a large part of the present species of
marine invertebrates already existed. It remains to state the
facts in succession, and then to show how the intermigration
must have taken place, and the cause of the periodic interrup-
tions, reasoning back always from modem conditions to those
of the past.

Ancient Faunal Relations,

Paleozoic time, — We know little with certainty of the
fannal geography of the Paleozoic of the western coast of
America except that during the Carboniferous the con-
nection seems rather to have been with northern Asia than
with the interior of North America. The kinship of American
and Asiatic forms can not be charged to universality of faunas
or physical conditions, for we know that there was nearly as
much provincial differentiation in the marine Carboniferous as
there is now.

Am. Joub. Sol— Foubth Sbribs, Vol. XYII, No. 99.— Maboh, 1904.
15



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218 J. P. Smith — Periodic Migrations.

Lower Trias, — The writer* has already shown in several
papers that the Lower Trias of California and the Great Basin
shows an intimate relationship to that of Asia, and none with
that of the Mediterranean region. Many genera are repre-
sented by closely allied species on both sides of the Pacific
Ocean that are wholly unknown in Europe at that time;
such are Flemingites^ Ophiceraa^ Proptychites^ Lecanites^
AspiditeSy Clypites^ Pseudosageceraa^ TJssuria^ and many
others. Some of the species of these may even be identi-
cal, but even without this the association of the genera is
such that a paleontologist from Asia would feel himself to be
perfectly at home while collecting in eastern California or in
Idaho. In some respects the relationship of the fauna of the
western coast seems to be closer with that of northern Asia
than with that of India; for instance, Pseudosageoeras and
Vsauria^ which are not uncommon in the Meekoceras beds of
the Inyo Kange in California, and the Aspen Mountains of
Idaho, have never been found anywhere else except at Ussuri
Bay in eastern Siberia, from which place they were first
described. These genera are probably not of American origin,
and most of them are of unknown antecedents. But, fortu-
nately, the geologic history of some of these forms is known.
Ophiceras^ XetiaspiSj Xenodiscus^ and IlunaariteSy which
occur in the Trias of Asia and America, chieify in the lower
beds, have also been found in the Permian of southern Asia.
To this region, then, we must look for the source of the
Lower Triassic ammonites which appear as immigrants in the
American waters, marking the first distinct Asiatic invasion-
After the deposition oi the Meekoceras beds, a few species
with Mediterranean affinities begin to make their appearance
in western America. But it is noteworthy that, at this time,
the Indian still appears to have been cat oflf from the Mediter-
ranean region.* The geographic regions described by E. von
Mojsisovicsf for the Trias will hold good only for the Lower
Trias, and wobably not even for the whole of that period.

Middle Trias,— In the Middle Trias a certain kinship still
persists between the marine faunas of western America and
Asia, though this may be due as much to inheritance from
similar ancestors, as to immigration. No species are any
longer common to the two regions, and many genera, even, are
different on opposite sides of the ocean. But at the same time
a kinship between the American and the Mediterranean faiinas
begins to be noticeable, especially in the nodose ceratites and
other members of the Ceratitidse. It is possible that during

*Jour. Geol., vi, 776-786, 1898; Jour. Geol., ix. 512-521, 1901.
f Arktische Trias-Faunen, pp. 147-155, 1886, and Beitr. Eennt. obertriad-
ischen Cephalopoden-Faunen des Himalaya, pp. 114-128, 1896.



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«/. p. Smith — Periodio Migrations. 219

tbe Middle Trias a connection was established between these
regions through some other way than the Indian branch of the
old central Mediterranean, or " Tethys," but we have no way
of knowing this passage. It seems possible, however, that it
may have been through the Boreal region. The writer* has
already given a suggestion of the faunal change at the end of
the Lower Trias, based on his own collections made in Nevada
during the summer of 1902. No species are thought to have
been absolutely identical with European forms, but many are
BO similar to species long known from the Alps that some sort
of connection is beyond question.

Upper Trias^ SubbtUlatus beds. — The writerf has brought
out several years ago the relationship of the Trias of California
to that of the Alps. Further study, in field and museum, has
served only to strengthen this hypothesis, and recent work in
India has given a means of comparison with that region, show-,
in^ that the same thing is true there also.

The Karnic horizon, zone of Tropites 8ubbullatu8y contains
many elements common to the Mediterranean region and west-
em America, and many of these are also found in India.
Tropites subbuUatics^ T. iorquiUxis^ Paratropiten SeUai^ Ento-
moceras sandlingense^ Sagenites Herbichi^ Polycyclus Henseli^
and Halobia svperba are common in both California and the
Tyrolean Alps, and many other species are very closely related,
Most of these are represented in India by forms that may be
identical with them, although complete publication of recent
geologic explorations in India must be awaited before a final
decision can be made.

Now it is well known that the Tropitidae appeared as immi-
grants in the Mediterranean and the western American regions
in the Upper Trias, without local ancestors. They also
appeared at the same time in India, but since we do not yet
know the faunas of the upper part of the Middle Trias in that
region, there is still a possibility that the Orient may have
b^n the source of this part of the fauna, for it is highly prob-
able that the Indian province was the connection between
Europe and America. This Karnic fauna, however, is not yet
known elsewhere in Asia, and the only proof we have of the
migration is the occurrence of similar species in the widely
separated regions. The path of this migration cannot be
traced, for fossils of the zone of Tropites subbullatns are
known io America only in California, not having been found
at any other place in either North or South America.

Upper Trxas^ Noric horizon, — Fossils of the Noric horizon,

♦Centralblatt fftr Mineral. Geol. tind Pal., pp. 689-695, 1902.
tThe Metamorphic Series of Shasta Cotinty, California, Jotur. Geol., ii,
588-612,1894.



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220 J. P, Smith — Periodic Migrations.

zone of Pseudomonotis ochotica^ are known in Alaska, British
Columbia, California, Nevada, and as far south as the coast of
Peru. Pseudonwnotia ochotica is widely distributed in Siberia
and Japan, and is probably identical with the American
Pseudomonotis sithcircularis. This ijroup is distinctly Asiatic
in origin, and never reached the Mediterranean waters. Its
appearance in America marks another Asiatic immigration,
but this time it came from the north. We see here a
reversion to the conditions of the Lower Trias, but on the
Asiatic side the immigrants do not seem to have reached any
further than to Japan. The widespread occurrence of beds
with Psexidomonotis ochotica around the northern shores of
the Pacific and around the Arctic Ocean shows a transgression
of the sea on what was formerly a continental border. These
forms were endemic in the Boreal region, and made their way
southward when the transgression of the sea opened the way,
on both sides of the Pacific. Of course, this may not have
had anything to do with climate, but at the close of the Karnie
epoch the fauna of western America sliows a sudden change
of facies from the Indian-Mediterranean character to that of
Siberia, which shows, at least a change in connections. A
passage from the Arctic to the Pacific was reopened between
Asia and America, and the Boreal, though not necessarily
cold-water, type came through, making its way southward.

Deep water, cutting oil Asia from America, would have
separated the two Triassic regions just as eilectively as cold
water, but since there was free passage for the group of
Pseudomonotia ochotica down both sides of the Pacific, it is
strange that it did not reach Tropical India, and that the
Tropical Indian forms ceased temporarily to come to America.
If such changes had occurred in Tertiary time we would say
without hesitation that the Boreal invasion marked an influx
of cold water from the Arctic Ocean through the open passage
between Asia and America.

The group of Pseudomonotis ochotica has also been cited
by Suess* from New Caledonia, but this occurrence is doubt-
ful, since JRothpletzf found only Monatis salinariay a Med-
iterranean type, in that region. It may be, however, that io
the Indian Ocean the Boreal and the Mediterranean facies
were temporarily united, in which case the presence of
Pseudomonotis ochotica would not necessarily be a proof of
the southward extension of a lower temperature.

A modern instance of the same restricted dispersion is seen
in the occurrence of Purpura laj>illus in the North Pacific.

* La Face de la Terre, ii, 423.

fPerm-, Trias- and Jura-Formation anf Timor nnd Rotti im mdiBohen
Archipel, p. 90.



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J, p. Smith — Periodic Migrations. 221

This species is abundant in the North Atlantic, and has made
its way through the Boreal region into the Pacific. On the
western coast of North America, where there are no sudden
changes in the temperature of the sea water, this species has
made its way as far south as Margarita Bay, in lat. 24° N.,
mean temperature 73° F. On the Asiatic side it has made its
way through Bering Sea down the shores of Kamschatka with
the cold water, but has been stopped by the sudden change of
temperature at Hakodadi, lat. 41° N., Japan, mean tempera-
ture 52° F., where the warm Japan current meets the cold
current from Bering Sea. That this is not an accident of dis-
tribution is shown by the fact that Purpura lapillua has, in
the Atlantic, a similar distribution, and for the same reasons.
On the African side it reaches lat. 32° N., mean temperature
66° F., and on the American side it is barred back by the sud-
den change of temperature at lat. 42° N., mean temperature
52° F.* There can be no doubt that the temperature, or
rather evenness of change of temperature, controls the distri-
bution of Purpura lapillua now, and it would seem only
reasonable to suppose that similar conditions in the Trias
caused the unequal distribution of Pseudomonotis ochotica.

Lias. — It is probable that during tlie Lias the southward
migration of the Boreal type of animals was interrupted, for
the Arietites group, which was characteristic of that epoch in
Europe, is known in California and Nevada, as well as in
Mexico and South America.* It was, however, practically
universal, having been found also in the Indian region, though
not as yet from the Jurassic Arctic sea. In the Upper Lias
the genus Amaltheus was widely distributed in Europe and in
the Boi'eal region, but has not yet been found in North
America. It is known from New Grenada, associated with a
typical Mediterranean fauna. It seems probable that the Lias
of California and Nevada is merely a northward extension of
the South American type.

Middle Jura. — In California the Middle Jura, like the Lias,
appears to have been of Mediterranean type, but in the Black
Hills we have a southward • extension of a fauna characteristic
of northern Europe, and of the region around the northern
Pacific Ocean. This boreal type is extensively developed in
Alaska and in northern Siberia, and its appearance in the
Black Hills marks the beginning of another incursion from
the north.

Upper Jura.— The incursion of the Boreal fauna • into
America which began in the Middle Jura reached further
southward and westward in the Mariposa epoch of the Upper
Jura, down through California to San Luis Potosi in Mexico.

*A. H. Cooke, Cambridge Natural History, iii, p. 363, 1895.



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222 «/. P. Smith — Periodic Migrations,

Thi8 fauna is characterized by the genera Cardioceraa and
^wc^fl^, which had their home in northern Europe and northern
Siberia, and appeared in western Europe only sporadically as the
result of incursions. Pompeckj* has shown in several papers
that a Polar sea existed in the Middle and Upper Jura and Lower
Cretaceous, from which incursions were made from time to
time into the more southerly regions, when changes in physi-
cal geography made it possible. He has also shown that the
Aucella fauna had its real home in that region, where it
formed a truly genetic series, and that it appeared only spo-
radically in other regions, where the species speedily degen-
erated and the fauna becomes extinct unless replenished by
another migration.

The suggestion of climatic influence on the dispersion of
marine animals in the Upper Jurassic is very strong, for the
AuceHa did not make its way into the Indian Ocean, although
the way was probably open. It went only where the condi-
tions of its own proper habitat existed, if only temporarily.
Even so conservative a naturalist as J. D. Danaf admits that
in Jurassic time there was a cold current to the southeast along
the western coast of North America, making possible the
migration of Aucella from the Boreal into warm temperature
or even subtropical waters.

Aucella did, however, make its way into northern India,
probably from southern Russia, during a time of extension of
the sea in that direction in the Kimmeridge and Tithonian
epochs.^

Lower Cretaceous, — After the Jurassic beds were laid down
there was in California a break in sedimentation, and the uplift
of the Sierra Nevada took place. But it was orogenic, and
although widespread, it did not aflfect the geographic relations,
for with the opening of the Cretaceous the same northern
types were still there. Aucella was still the most characteris-
tic genus, and along with it were many species of ammonites
closely related to Russian species. Aucella crassicoUis was
even identical with a characteristic Russian form. These
Knoxville species were probably in part immigrants from the
Boreal region, although some oi" them may have been modified
descendants from species that were endemic in the American

*Ueber AuceUen etc. N. J. fur Min. Geol. und Pal. xiv, 348, 1901 and
Jura Fossilien aus Alaska, Verb. k. o. Huss. Min. GeseU. (St. Petersburg),
xxxviii, 376, 1901. The Jurassic Fauna of Cape Flora, Franz Josef Land;
The Norwegian North Polar Expedition 1893-1896, Scientific Results, p, 141,
1898

t Manual of Geology, p. 794, 1895. ?

X S. Nikitin, Bemerkungen Uber die Jura-Ablagerungen des Himalayas nnd
Mittelasiens. Neues Jahrb. ftir Min., Geol. und Pal., ii, 124, 1889.



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J. p. SmAth — Periodic Migrations. 223

waters. Before the end of the Knoxville epoch, while the
Boreal forms still persisted, Lytoceras and Phylloceras^ genera
that were never found in northern Europe and Asia, appeared
in the Cretaceous beds of the western coast of America.
These forms seem to have been endemic in the warm regions
of southern Europe and Asia, and their appearance marks a
resumption of interchange between India and America, around
the shore-line formed by closing the gap between Asia and
Alaska. In proof that the gap was really closed, it may be
said that the flora of the Knoxville beds and of the equivalent
Kootanie formation appears to indicate a warm temperate
climate,* which would mean that the cold current from the
Arctic Ocean had been cut oil by a rise of the land.

During the Lower Cretaceous Ati<iella made its way into the
Tropics, around the Pacific Ocean, so that its later occurrence
gives no evidence of southward extension of Boreal climatic
eonditions.f

Upper Cretaceous, — With the opening of the Horsetown
epoch all reminiscences of the Boreal fauna are gone, and the
Tropical character of the inhabitants of the sea on the western
coast of America is marked. A close affinity and even iden-
tity of species with the Indian fauna characterizes this epoch.
And it is noteworthy that the Puget Sound Horsetown and
Chico faunas are even more closely allied to those of India
than are those of California. Migration appears to have been
free between Asia and America, but the species did not all
range so far south as California, thus indicating the direction
from which they came. Of course, not all the marine forms,
on the west coast of North America came from Asia, but the
Asiatic portion is the only one that we can trace to its source.

The lollowing species that occur in the Horsetown and
Lower Chico of western America are regarded by Kossmat:}: as
identical with species in southern India :

Lytoceraa Kayei Forbes.

X. timotheanum Mayor.

i. cola Forbes.

X. indra Forbes.

Mamiies glaber Whiteaves.
Schloenhachia inflata Sowerby.
Acanthoceras Tarneri White.
Pachydiscus otacodensia Stoliczka.

P, arialurensis Stoliczka.

Pesmoceras diphylloides Forbes.

*T. W. Stanton, Jonr. Oeol., v, 599, 1897.

f Pompeckj, Ueber AuceUen und AnceUen-fthnliche Formen, Neues Jahrb.
teMin. etc., xiv, 848, 1901.

X Beitr. Pal. tmd Geol. Oesterreich-Ungams und des Orients, ix, Parts 3
and 4, 1895.



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224 J. P, Smith — Periodic Migrations.

Desmoceras latidorsatum Michelin.
Puzosia plaitulata Sowerby.
Haicericeras GarJeni Bailey.
FhyUoceras Whiteavesi Kossraat.

P. Velledae Michelin (cited as the probable

equivalent of P, ramosum Meek).

Besides the above, F. M. Anderson* describes the follow-
ing species from the lower Chico beds as identical with Indian
forms : Schloenhachia propinqua Stoliczka, S. hlanfordiana
Stoliczka, Desmoceras sugata Forbes. Nearly all these species
that are common to the western coast of America and India
also occur in Japan, and many of them also in eastern Africa.
They are, then, tropical or subtropical in habitat. Whether
the appearance of the AuceUa fauna of the Upper Jura and
the Lower Cretaceous in the North Pacific meant cold water
or not, the appearance of the Indian forms in the same region
can only be interpreted to mean that a warm temperature pre-
vailed there at tnat time, and that conditions were equable
around the old shore line from India as far as California.

With the closing of the passage between Asia and America,
the warm Japan current, which is now chilled by the cold
southwesterly current from Bering Sea, would warm up the
whole coast line and make the waters of western America
warmer than they are now. We also have evidence that the
temperature of the land in the northern hemisphere was
warmer than at present, for Heerf has shown that the Creta-
ceous floras of Greenland, Spitzbergen and Alaska contained
cycads and other forms indicating a mean temperature of
about 70° F. ^

Upper Chico. — In the upper Chico horizon (Senonian), of
California and Oregon the connection with India appears to
cease, and a path of migration from the interior Cretaceous
sea of America seems to have been opened.^ Several species
of pelecypods are identical with species from the upper Mis-
souri province, and some of the ammonites are closely allied.

^Eocene, — During the early Tertiary^ or Tejon epoch, in
California we have no evidence of any migration from Asia,
but it is plain that a connection existed with the Eocene sea
of the Atlantic region. Venericardia planicosta^ which is
abundant in the Claiborne beds of the states around the Gulf
of Mexico, has been found at a number of places in Oregon
and California, and it appears to be more common in southern
California than anywhere else on the western coast. Other

* Cretaceous Deposits of the Pacific Coast, Proc. CaUf. Acad. Scl., iii, Ser.
Geol., vol. 11, No. 1, 1902.
f Flora Fossilis Arctica, vi and vli, 1883-88.
t F. M. Anderson, Cretaceous Deposits of the Pacific Coast, p. 59, 1902.



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J. p. Smith — Periodic Migrations. 225

species of this fauna may be identical with Atlantic forms, at
any rate some are closely related, and it is probable that the
passage lay to the south of California.

Miocene. — In the middle Tertiary the passage to the Atlan-
tic seems to have been closed, and there is no evidence that
communication was resumed with Asia. The Miocene fauna
of California seems to have been largely endemic, for no
Atlantic species are found in it, and the only possible admix-
ture consists of forms from the south, and of circnmboreal
species tiiat made their way down from the north. But
towards the end of Miocene time the land appears to have
risen in the north, cutting off the Arctic Ocean from the
Pacific, and allowing land plants to migrate from Asia to
North America. Asa Gray* has shown that in the Miocene
northeastern Asia and northwestern America were connected,
that over those regions there existed a flora like that of warm
temperate latitudes at the present time, and that this connec-
tion persisted almost to the beginning of the Glacial epoch.

We have no evidence that a migration of marine inverte-
brates from Asia began as early as the upper Miocene, but they
would naturally be slower in their movements than land plants,
and consequently would lag behind them. The Tertiary
uplift of land in the northern hemisphere may be correlatea
with the widespread oi*ogenic uplift of the Coast Ranges on
the Pacific side of North America, which in California and
Oregon is known to have come at the end of the Miocene,
and before the Pliocene beds were laid down.

Pliocene. — There is good geologic evidence that the land-
bridge between Asia and America still existed in the Pliocene,
for there seems to have been a constant interchange of verte-
brates in that quarter,t in the Miocene, Pliocene, and early
Pleistocene. Also students of other groups find it necessary
to postulate such a connection to explain the migration of
animals. A. E. Ortmann:j: says that the identity of some of
the fresh-water crustaceans in Siberia and Alaska proves a



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