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Williams |
These and such-like
revelations have come to light in our own time - are, indeed, still being
disclosed. Needless to say, no index of any sort now attempts to conceal
them; yet something has been accomplished towards the same end by the publication
of the discoveries in Smithsonian bulletins and in technical memoirs of
government surveys. Fortunately, however, the results have been rescued
from that partial oblivion by such interpreters as Professors Huxley and
Cope, so the unscientific public has been allowed to gain at least an inkling
of the wonderful progress of paleontology in our generation.
The writings of Huxley in particular epitomize
the record. In 1862 he admitted candidly that the paleontological record
as then known, so far as it bears on the doctrine of progressive development,
negatives that doctrine. In 1870 he was able to "soften somewhat the Brutus-like
severity" of his former verdict, and to assert that the results of recent
researches seem "to leave a clear balance in favor of the doctrine of the
evolution of living forms one from another." Six years later, when reviewing
the work of Marsh in America and of Gaudry in Pikermi, he declared that,
"on the evidence of paleontology, the evolution of many existing forms
of animal life from their predecessors is no longer an hypothesis, but
an historical fact." In 1881 he asserted that the evidence gathered in
the previous decade had been so unequivocal that, had the transmutation
hypothesis not existed, "the paleontologist would have had to invent it."
Since then the delvers after fossils have
piled proof on proof in bewildering profusion. The fossil-beds in the "bad
lands" of western America seem inexhaustible. And in the Connecticut River
Valley near relatives of the great reptiles which Professor Marsh and others
have found in such profusion in the West left their tracks on the mud-flats
- since turned to sandstone; and a few skeletons also have been found.
The bodies of a race of great reptiles that were the lords of creation
of their day have been dissipated to their elements, while the chance indentations
of their feet as they raced along the shores, mere footprints on the sands,
have been preserved among the most imperishable of the memory-tablets of
the world.
Of the other vertebrate fossils that have
been found in the eastern portions of America, among the most abundant
and interesting are the skeletons of mastodons. Of these one of the largest
and most complete is that which was unearthed in the bed of a drained lake
near Newburg, New York, in 1845. This specimen was larger than the existing
elephants, and had tusks eleven feet in length. It was mounted and described
by Dr. John C. Warren, of Boston, and has been famous for half a century
as the "Warren mastodon."
But to the student of racial development
as recorded by the fossils all these sporadic finds have but incidental
interest as compared with the rich Western fossil- beds to which we have
already referred. From records here unearthed, the racial evolution of
many mammals has in the past few years been made out in greater or less
detail. Professor Cope has traced the ancestry of the camels (which, like
the rhinoceroses ,
hippopotami ,
and sundry other forms now spoken of as "Old World," seem to have had their
origin here) with much completeness.
A lemuroid form of mammal, believed to
be of the type from which man has descended, has also been found in these
beds. It is thought that the descendants of this creature, and of the other
"Old-World" forms above referred to, found their way to Asia, probably,
as suggested by Professor Marsh, across a bridge at Bering Strait, to continue
their evolution on the other hemisphere, becoming extinct in the land of
their nativity. The ape-man fossil found in the tertiary strata of the
island of Java in 1891 by the Dutch surgeon Dr. Eugene Dubois, and named
Pithecanthropus erectus, may have been a direct descendant of the American
tribe of primitive lemurs, though this is only a conjecture.
Not all the strange beasts which have left
their remains in our "bad lands" are represented by living descendants.
The titanotheres, or brontotheridae, for example, a gigantic tribe, offshoots
of the same stock which produced the horse and rhinoceros ,
represented the culmination of a line of descent. They developed rapidly
in a geological sense, and flourished about the middle of the tertiary
period; then, to use Agassiz's phrase," time fought against them." The
story of their evolution has been worked out by Professors Leidy, Marsh,
Cope, and H. F. Osborne.
A recent bit of paleontological evidence
bearing on the question of the introduction of species is that presented
by Dr. J. L. Wortman in connection with the fossil lineage of the edentates.
It was suggested by Marsh, in 1877, that these creatures, whose modern
representatives are all South American, originated in North America long
before the two continents had any land connection. The stages of degeneration
by which these animals gradually lost the enamel from their teeth, coming
finally to the unique condition of their modern descendants of the sloth
tribe, are illustrated by strikingly graded specimens now preserved in
the American Museum of Natural History, as shown by Dr. Wortman.
All these and a multitude of other recent
observations that cannot be even outlined here tell the same story. With
one accord paleontologists of our time regard the question of the introduction
of new species as solved. As Professor Marsh has said, "to doubt evolution
today is to doubt science; and science is only another name for truth."
Thus the third great battle over the meaning
of the fossil records has come to a conclusion. Again there is a truce
to controversy, and it may seem to the casual observer that the present
stand of the science of fossils is final and impregnable. But does this
really mean that a full synopsis of the story of paleontology has been
told? Or do we only await the coming of the twentieth-century Lamarck or
Darwin, who shall attack the fortified knowledge of to-day with the batteries
of a new generalization?. |
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