The Coconino sun., 1926-07-02

Some 25,000,000 years or more ago
the area now set aside as the Grand
Canyon National park was inhabited
by large and varied assemblage of
animal life, none of which were like
any of the creatures living there to-
day. The evidence of the previous
existence of these animals consists or
fossil tracks and trails found pre-
served in certain rocks forming the
walls of the canyon.
At the time these tracks were made
there was no Grand Canyon and what
are now rocks were then loose sand
and mud. In the thousands upon
thousands of years that followed, af-
ter these animals left the imprintS OF
their feet, other rock-maldng mater
ials were accumulated in successive
strata above them to many hundreds
of feet in thickness. The great
weight Of this superimposed mass,
combined with cementing materials
in the sand and mud consolidated
them into sandstone and shale and IN
this hardened state the tracks re-
NAMED hidden for untold ages until
finally through the erosional action OF
the Colorado river in cutting down
through the strata in its work OF
carving out the Grand Canyon, these
track-bearing rocks were again ex-
posed to view.
The trails of extinct animals have
been found at several places in the
canyon but those most accessible and
extensive in occurrence are crossed or
lie Immediately off the Hermit Trail
as it descends into Hermit Basin and
Hermit Gorge These imprints of ex-
tinct animals were first brought TO
the attention of the scientific world
by Professor Charles Schuchert OF
Yale university, when from a study
of small collection made by him.,
Professor Lull described the new spe-
cies Laoporus schucherti and L. nobeif
delicatula from the older Hermit
shale.
No further attention was given the
tracks until ten years later large
collection was made for the U. S. Ma
tional Museum and the study of those
materials increased the list of known
kinds to nine general and twelve spe-
cies.
1t was quite apparent that there
were many other kinds yet to be
found as indicated by poorly preserv-
ed imprints in this first collection.
Consequently the discovery in 1926 by
a second expedition from the national
museum of many new kinds of tracks
did not come as a surprise to those
in charge of the work. Not only was
the fauna of the Coconino greatly in
creased but a fine series of plants and
tracks were secured from the Hermit
shale and a smaller variety of kinds
from the older Supai formation. 1t
will thus be seen that in this one geo
logical section there are three distinct
faunas occurring at three distinct lev
els. In relation to the top of the
canyon these occur in the Coconino
sandstone 900 to 1880 feet below. the
rim; the Hermit shale 1850 to 1,4OO
feet down and the Supai sandstone
1900 to 1850 feet below the top OF
the canyon wall.
This is probably the only place in
the world where fossil tracks of three
succeeding groups of animal life sep
arated by such geological intervals
can be found. They are, therefore, of
great interest scientifically, and equal
" interesting to the layman for their
great antiquity and so clearly demon
strated here that the veriest tyro in
geological phenomena cannot help but
get the lesson they teach.
What kind of animals made these
tracks? That is a question that can
only be partially answered at this
time. It is known that there are
tracks made by both vertebrate and
invertebrate animals, but as to the
kind of backboned animals only this
can be said. In Texas are rocks re-
garded by geologists as being the
same age as those bearing tracks in
the Grand Canyon. In these Texan
rocks, skeletons Of many kinds of ex-
tinct animals, some of which have the
right proportions of foot, limb and
body to have made tracks and i'm
prints similar to those found. 1t