dently, and more recently by numerous younger
paleontologists.

The profusion of vertebrate remains thus brought to light quite beggars
all previous exhibits in point of mere numbers. Professor Marsh, for
example, who was first in the field, found three hundred new tertiary
species between the years 1870 and 1876. Meanwhile, in cretaceous
strata, he unearthed remains of about two hundred birds with teeth, six
hundred pterodactyls, or flying dragons, some with a spread of wings
of twenty-five feet, and one thousand five hundred mosasaurs of the
sea-serpent type, some of them sixty feet or more in length. In a single
bed of Jurassic rock, not larger than a good-sized lecture-room, he
found the remains of one hundred and sixty individuals of mammals,
representing twenty species and nine genera; while beds of the same age
have yielded three hundred reptiles, varying from the size of a rabbit
to sixty or eighty feet in length.

But the chief interest of these fossils from the West is not their
number but their nature; for among them are numerous illustrations of
just such intermediate types of organisms as must have existed in the
past if the succession of life on the globe has been an unbroken lineal
succession. Here are reptiles with bat-like wings, and others with
bird-like pelves and legs adapted for bipedal locomotion. Here are
birds with teeth, and other reptilian characters. In short, what with
reptilian birds and birdlike reptiles, the gap between modern reptiles
and birds is quite bridged over. In a similar way, various diverse
mammalian forms, as the tapir, the rhinoceros, and the horse, are linked
together by fossil progenitors. And, most important of all, Professor
Marsh has discovered a series of mammalian remains, occurring in
successive geological epochs, which are held to represent beyond cavil
the actual line of descent of the modern horse; tracing the lineage
of our one-toed species back through two and three toed forms, to an
ancestor in the eocene or early tertiary that had four functional toes
and the rudiment of a fifth. This discovery is too interesting and too
important not to be detailed at length in the words of the discoverer.

Marsh Describes the Fossil Horse

"It is a well-known fact," says Professor Marsh, "that the Spanish
discoverers of America discovered no horses on this continent, and that
the modern horse (Equus caballus, Linn.) was subsequently introduced
from the Old World. It is,