definite conclusions ought to be reached regarding their time of
existence. In his account of the cave and of the exhumation of the
animal and vegetable remains, Mercer (1899, pp. 269–286) has shown what
extreme care was taken in recording the position which each specimen
occupied in the deposits. In his figure 9 he has noted the levels which
the various species occupied. While the existence of four beds of
materials makes it evident that the deposition went on for some time, it
is noted that few or no differences exist in the character of the
species included. Possibly Mercer’s subdivision 1 is to be excepted in
this statement. Certainly no great changes went on in the fauna while
the cave was being filled; no such changes as occurred in the glaciated
region from the Aftonian interglacial stage up to the Late Wisconsin. It
appears more probable that the deposits in the cave and the animals
entombed there appertain to about a single Pleistocene stage. Is, then,
the stage the Late Wisconsin?
This cave is situated only about 55 miles south of the Wisconsin
moraine. At the time the species found in the cave existed they must
each have occupied a wide extent of territory. It is not to be doubted
that the range of nearly every species extended northward far beyond the
moraine mentioned. Why, then, in deposits overlying the Wisconsin drift
have there never been found any remains of the four Port Kennedy species
of _Megalonyx_, of _Mylodon_, of the two species of horses, of the
tapir, of the three species of peccaries, of the deer _Odocoileus
lævicornis_, of the five extinct species of cricetids, of _Ochotona_, of
the extinct species of _Blarina_, of the great bear _Arctotherium_, of
the six extinct species of skunks, of the extinct otter, of the extinct
dog, of the extinct fox, of any species of saber-tooth tiger, or of the
extinct cats _Felis inexpectata_ and _Lynx calcaratus_? The absence of
so many species of animals, most of them of large size, from deposits so
well adapted to preserve bones and teeth, render it very certain that
the animals no longer existed there.
Did the extinct species which are referred to above exist in eastern
Pennsylvania at some time during the Wisconsin glacial stage and perish
before the close?
A few of the species found in the cave and still existing are at present
inhabitants of regions somewhat more northerly than Port Kennedy. Such
are _Erethizon dorsatum_ and _Gulo luscus_; but the great majority,
living and extinct, indicate a climate at least as warm as that of the
present; many of them suggesting a still milder condition. Within
historical times both of the species just named have inhabited the
Alleghany Mountains at least as far south as Port Kennedy. Cope, in 1871
(Proc. Amer. Philos. Soc., vol. XII, p. 99), concluded that he had then
identified in the cave remains of 11 neotropical species. It appears,
therefore, wholly improbable that this assemblage of animals lived in
that region, so close to the foot of the glacier, during the Wisconsin
stage. These animals must have had their time of existence previous to
this inhospitable epoch. It seems to the writer that the proportion of
extinct species, three-fourths, and the history of many of the genera
and species, indicate a time about equivalent to the Aftonian.
Professor A. Heilprin (Proc. Phila. Acad. Nat. Sci., 1895, p. 451)
expressed himself as being inclined to refer this cave fauna to the
Pliocene. An examination of this opinion would show that it is no more
tenable than the opinion that the fauna is of the Wisconsin stage. It
will not be discussed here beyond saying that deposits containing a
similar fauna are found along the Atlantic coast from New Jersey to the
Gulf, and that at one place at least, Vero, Florida, these are underlain
by abundant Pleistocene sea-shells.
Besides the vertebrates which have been listed, a number of beetles were
found and about 10 specifically determined plants. Wheatley (1871, p.
385) presents a list of the beetles as determined by Dr. G. H. Horn, but
the names were not accompanied by descriptions. When later (Trans. Amer.
Entom. Soc., vol. V, 1876, pp. 241–245) Horn came to describe them he
reduced the number of species and, in some cases, gave them other names.
The following is a list as given in Horn’s paper just cited: _Cychrus
wheatleyi_, _C. (minor)_, _Pterostichus_ (spp. indet.) _Cymindis
aurora_, _Chlænius punctulatus_, _Dicælus alutaceus_, _Choeridium?
ebeninum_, _Phanæus antiquus_, _Aphodeus precursor_. All of these, as
the writer is informed by Dr. E. A. Schwarz, of the U. S. Department of
Agriculture, are regarded as extinct, but as closely allied to species
now living in that general region. The plants, as reported by Mercer,
are _Quercus palustris_, _Q. alba_, _Q. macrocarpa_, _Fagus ferruginea_,
_Corylus americana_, _Pinus rigida_, _Carya porcina_, _C. alba_,
_Ampelopsis quinquefolia_, _Cratægus crus-galli?_, and all still
flourish in eastern Pennsylvania.
[Illustration:
FIG. 11.—Section of Port Kennedy bone cave at time of first
exploration, 1871. Redrawn from Mercer.
M, M, Triassic shale; AL, Triassic shale; B, black clay, with leaves,
etc.
]
Mercer (1899, p. 269) has given a description of the cave found in
quarrying operations. It was located on the right bank of the Schuylkill
River, at the village of Port Kennedy and about 2 miles below Valley
Forge. Wheatley (1871, p. 236) gave a map which showed the position of
the quarries. A comparison of this with the topographical map of Folio
162 of the U. S. Geological Survey shows that they were situated about
800 feet away from the river and facing the valley of an unnamed
streamlet. None of the descriptions give the elevation of the cave above
the river or above the sea. The river at that place is apparently about
70 feet above sea-level. The 100–foot contour-line runs along near the
location of the quarries, but these may have extended back to a higher
level. Putting all of the statements together, it appears probable that
the mouth of the cave was, in Wheatley’s time, about 50 feet above the
level of the river. Originally the surface elevation may have been still
greater, but may have been reduced by erosion of the hill. The surface
rock here is red shale of the Stockton formation, belonging to the
Triassic, and is underlain by the Shenandoah limestone, a member of the
Cambro-Ordovician series. This limestone was being quarried in 1871,
when a cave was broken into, filled with incoherent materials and
exposing fossil bones in abundance. It was visited by Charles Wheatley,
who proceeded to make excavations and collect the fossils. In studying
the fossils he worked with Professor E. D. Cope and Dr. G. H. Horn. The
results were published in Wheatley’s two papers of 1871 and in two
papers by Cope in the same year (Proc. Amer. Philos. Soc., vol. XII, pp.
15, 73–102). According to Wheatley’s description and his figures, the
part of the cave seen was about 20 feet wide at the top, expanded below
to about 30 feet, and then narrowed at the bottom, as then recognized,
to about 10 feet. The depth was given as 40 feet, but Mercer thinks that
this was improbable and that Wheatley’s measurements were to some extent
guesses. Mercer (1899, p. 271) stated that this cave might be compared
to a bottle of unknown size. It had opened to the surface; and on his
page 283 Mercer spoke of it as forming a well-like hole that might have
been as much as 70 feet deep. Evidently Mercer here included that part
of it which he himself excavated. The materials filling it were,
according to Cope (1871, p. 73), the débris of the neighboring Triassic
strata. Figure 11 is taken from Mercer’s paper and is a reproduction of
a sketch made by Wheatley in 1871. After Wheatley had made his
collection the cave was covered over by débris from the quarry and
forgotten.
[Illustration:
FIG. 12.—Section of Port Kennedy bone cave at time of last
exploration, 1894. Redrawn from Mercer.
]
In the course of further quarrying operations the same cave was broken
into again in 1893. Excavations in the materials that filled the cave
were made in 1894 by Dr. Samuel Dixon, H. C. Mercer, and others,
resulting in the securing of the collection which formed the subject of
Cope’s paper of 1894 and his final report of 1899. At this time,
according to Mercer, the quarrying operations carried on from 1855 had
transformed a gently sloping hillside into an amphitheater several acres
in extent, walled with perpendicular escarpments of rock, sometimes a
hundred feet high. At this time the floor of the quarry had been lowered
and the cave was broken into at a level below that reached by Wheatley.
Figure 12, reproduced from Mercer’s figure 5, shows the relation of the
later excavations to those of 1871. As already stated, Mercer concluded
that Wheatley’s dimensions were probably results of guesses, inasmuch as
the top of Mercer’s exposure was not more than 30 or 33 feet below the
original level of the hilltop. According to Mercer’s figure 5, his own
excavation probably extended down about 16 feet below the level reached
by Wheatley; but other statements appear to make this somewhat greater.
Mercer wrote that the materials filling the cave had been stratified by
the action of water. He recognized four subdivisions, most of which
stood higher around the walls than at the center of the cave. Of these
subdivisions, the first and uppermost was supposed to mark the lowest
level attained by Wheatley. It consisted of fine clay and loam of black
color, intermingled with fine and coarse muck, in which were found some
remains of small mammals, just what species was not stated. On his
chart, his figure 9, a tapir is indicated as occurring in it.
Subdivision 2 was composed of from 4 to 11 feet of sandy clay, with
fragments of sandstone and limestone, from small ones up to about 2 feet
in diameter. In this matrix there were numerous bones and teeth of large
animals, but it lacked small ones and vegetal matter. Subdivision 3 was
a sandy clay, blackened by vegetable matter and containing numerous
bones of vertebrates, large and small. The lowest subdivision, 4, was a
zone which was followed down about 10 feet and which consisted of sand,
clay, and stones, all of a yellow color. In this were found remains of
the larger mammals, better preserved than in the upper subdivisions. At
the lowest depth reached the excavation appears to have extended below
the level of the Schuylkill River and the water came in so rapidly that
further descent was not practicable.
Mercer’s theory of the filling of the cave is expressed in these words,
on his page 277:
“Enough had been seen to convince us that a fresh-water flood,
rising to a level of from 15 to 20 feet above the present level of
the hilltop, hence a general inundation of the whole surrounding
country, bearing in its current the clay, stones, and earth of
neighboring levels, had tumbled into the fissure, carrying with it
the bones of creatures previously denuded of flesh and softened by
decomposition.”
And further, on page 284:
“Not unreasonably, therefore, we may suppose, not only that the
creatures had perished together, but also that they had perished on
the spot or at the chasm—not meeting this fate during a long
interval of time, and through a long series of chance tumbles, but
suddenly and by force of a common event.”
Are we to suppose that during some summer freshet animals in such
numbers were swept away that those that were found in the cave, and
doubtless many more which decayed utterly, were only the relatively few
that happened to pass over that 20–foot hole? Where, then, were picked
up all the other animals that must have burdened the swollen Schuylkill?
Or did it possibly happen that all the animals that were swept away were
in some unaccountable manner directed into that hole? If the current was
strong enough to sweep along stones up to 2 feet in diameter, how did it
happen to deposit there fine sand and clay, leaves, cones, seeds, and
sticks? It is difficult to accept the theory that the filling of the
cave was due to a cataclysm such as has been invoked. It seems far more
probable that the mouth of the cave was open for many hundreds of years,
possibly thousands of them, so that animals, plants, stones, and fine
and coarse earth could in various ways get into it. Animals wandering
about might inadvertently fall in or be pushed in by the herd. Doubtless
at some former time the Schuylkill flowed at a higher level than now,
and during times of unusually high-water might have risen to the level
of the mouth of the cave and carried into it at each rise some mud, some
vegetation, and some animals. The filling was quite certainly a slow
process.
To the writer the part of the cavern which was worked and pictured by
Wheatley has all the marks of an enormous pot-hole, such as those which
have been discovered at Cohoes, New York. While the latter appear to
have been drilled out in late Pleistocene times, the Port Kennedy hole
must have been fashioned during the early Pleistocene or even in the
Pliocene. One may suppose that, after the pot-hole had reached the depth
where the constriction was found, the water began to find its way out at
the bottom through fissures or passages in the limestone. When this
happened, the passages may have been enlarged mechanically or by means
of solution, resulting in the formation of the various lower caverns.
When the river had been lowered enough to reach only occasionally the
mouth of the pot-hole, the latter became choked first by the coarse
materials now found in subdivision 4, and afterwards by finer sand and
mud.
Some vertebrates of the late Pleistocene or early Recent observed at
Carlisle deserve consideration.
In 1850 (Proc. Amer. Assoc. Adv. Sci., vol. II, 1849, pp. 352–355)
Professor S. F. Baird gave an account of his explorations in the caves
in the region about Carlisle, Cumberland County. One of these caves was
near Carlisle, and in it Baird found a large number of animal remains. A
second cave, the situation of which was not given, was on the top of a
hill and was a vertical shaft 30 feet deep, which opened into a large
gallery. It furnished a skeleton of a bear, but this appeared to have
only recently fallen into the cave. Another cave was on the bank of the
Susquehanna, 0.5 mile below a railroad bridge. It was, therefore,
probably near Harrisburg. The entrance was in limestone rock, nearly
vertical, and 20 feet deep. Here Baird found many bones, embedded in
mud, but of these he obtained only a few. Another cave, apparently
nearby, which Baird spoke of as “the main cave,” furnished some of his
specimens. Still another cave, probably in the same neighborhood, was
the source of his most perfect specimens. This presented a series of
galleries near the roof and these were reached by ladders. These
galleries were filled with mud, and in this mud the bones were buried.
The number of species which he obtained, he reported, was nearly twice
the number living there at the present time. Of these fossil species he
estimated that about 5 per cent were extinct. Baird appears never to
have completed his study of his collection. His list designates the
animals only by their vernacular names. The mammals consisted of
panthers, lynxes, wolves, foxes, otters, bears, muskrats, deer, beavers,
and rabbits. There were bird remains in great quantities, and these
included wild turkeys, some of great size, swans, wild ducks, and
pelicans. There appeared to be 8 or 10 species of tortoises. Bones of
snakes were quite common; also scales and vertebræ of fishes, and a
lower jaw of a salamander. In the uppermost 2 or 3 inches of mud were
many relics of Indians.
Baird supposed that these bones had in most cases been washed in from
above through sink holes. This collection, or some of it, was brought by
Baird to the Smithsonian Institution; and they, or some of them, are in
the collection of mammals; but the bulk of the collection has apparently
been lost. All of these animals belong evidently to either the very late
Pleistocene or to the Recent period.
A cave at Frankstown has furnished fossils of about Middle Pleistocene
time. In 1908 (Ann. Carnegie Mus., vol. iv, pp. 228–233) and again in
1912 (Proc. Internat. Zool. Congr., Boston, 1907, pp. 748–752), Dr. W.
J. Holland gave an account of the discovery of vertebrate fossils in a
fissure in limestone rock at Frankstown, Blair County. This village is
situated on the Frankstown Branch of Juniata River, a little more than 2
miles north of east of Hollidaysburg. The fissure was excavated in a
Devonian rock known as the Lewistown limestone. The quarries are
reported to be in the village and on the top of a hill that rises about
400 feet above the banks of the Juniata. According to the Hollidaysburg
topographical sheet, the 920–foot line crosses the river just above the
village. The highest hill, 1,260 feet above sea-level, is 0.3 mile away
toward the northwest. In this hill, as Dr. Holland stated, there are
several small caves. The one which furnished the fossils appeared to be
about 40 feet in length, averaging from 6 to 8 feet in width, and at the
most was not more than 10 or 12 feet high. The floor was about 30 feet
below the top of the hill. The fissure appeared to have once continued
up to the surface, but the opening had been filled with fallen blocks of
limestone. The floor of the cave is described as being occupied by about
2 feet of red soil, everywhere traversed by bands and layers of dark
materials charged with organic matter. With the finer deposits were
mingled fragments of rock, some being large blocks. The fossil remains
appear to have been carefully collected, but were mostly fragmentary.
They were only cursorily studied at the time of Holland’s writing and
nothing has since been published on them. The number of species obtained
was estimated to be from 30 to 40. The following genera and species are
mentioned:
Meleagris sp. indet.
Megalonyx sp. indet. (p. 31).
Tapirus sp. indet. (p. 203).
Mylohyus pennsylvanicus (p. 214).
Odocoileus virginianus (p. 227).
Cervalces? sp. indet.
Bison sp. indet.
Mammut americanum (p. 69).
Sciurus sp. indet.
Ondatra sp. indet.
Erethizon sp. indet.
Lepus sp. indet.
Ursus americanus.
Arctotherium haplodon.
Mephitis sp. indet.
Canis sp. indet.
Felis? sp. indet.
After the foregoing had been put in type Mr. O. A. Peterson, of the
Carnegie Museum, sent the writer a revised list in which additions are
made. The following are the most important:
Cryptobranchus sp. indet.
Rana catesbiana?
Clemmys insculpta.
Blarina sp. indet.
Ænocyon dirus.
Canis priscolatrans?
Spilogale putorius.
Brachyprotoma putorius.
Boötherium bombifrons.
Equus sp. indet.
Besides these forms, remains belonging to bats, various birds, snakes,
and batrachians have been recognized. Of the fossils identified
generically or specifically those belonging to _Megalonyx_, _Tapirus_,
_Mylohyus_, _Cervalces_, _Mammut_, and _Arctotherium_ are certainly
extinct. Probably, too, the bison and the species of _Felis_ are
extinct. There are, therefore, pretty certainly close to 50 per cent of
the species which are no longer living. This percentage and the history
of some of the genera make it improbable that the assemblage belongs to
the Late Wisconsin stage. Some of them could hardly have been living
during the Wisconsin, when the foot of the glacier was within 100 miles
toward the northeast and northwest. On the other hand, there are no
species or genera present which make it necessary to refer the
collection to the first interglacial. The assemblage probably belongs to
the middle Pleistocene.
Coming now to the very southwestern corner of the State, we find that.
_Elephas columbi_ has been met with in the bed of Hargus Creek, 3 miles
above Rogersville, in Greene County (p. 150), and _E. primigenius_ on
Gray’s Fork of Ten Mile Creek, near Graysville (p. 133). In the
Rogersville Folio (No. 146, U. S. Geol. Surv.), Dr. F. G. Clapp
described the geology of this quadrangle. On his page 10 he briefly
discussed the meager Quaternary deposits of the area. These he referred
to the Carmichaels formation, and indicated his opinion that it belonged
to very early Pleistocene. On the geological map it is represented as
occurring along Ten Mile Creek at and just below Rogersville. The
occurrence of a tooth of _Elephas columbi_ just above this town and of
_E. primigenius_ just above Harveys (p. 133) renders it probable that
other patches of the formation exist further up the stream and along
some of its branches, and that the fossils were derived from that
formation. It is, of course, possible that small patches of a later
deposit exist there.
Reference has been made to the Carmichaels formation. The type locality
is found at Carmichaels, on Muddy Creek in Washington County. The
geological description of the locality has been presented by Marius R.
Campbell in the Masontown-Uniontown Folio (No. 82, U. S. Geological
Survey). The formation occurs extensively along Monongahela River and
other streams of western Pennsylvania. For information the reader should
consult the Geological Survey Folios Nos. 144, 146, 121, 82, and 177.
The deposits occur at levels considerably above the present streams and
are regarded as having been laid down in old and now abandoned river
channels and in tributaries of these. The time when this occurred is
believed by many, if not most geologists to belong to the early
Pleistocene, the Kansas stage, or possibly the Nebraskan. In the opinion
of some geologists the glacial ice dammed the streams and caused their
valleys to be filled with detritus. More recent Pleistocene deposits,
possibly of Wisconsin age, occur at lower levels in some places south of
the Wisconsin moraine; and perhaps the age of some of them has not yet
been recognized. When remains of vertebrate animals are discovered, it
is of great importance to determine, if possible, the exact levels of
their origin.
On another page mention is made of the finding of a tooth of _Elephas
primigenius_ at Lone Pine (p. 133), 7.25 miles south of southeast of
Washington. This village is on Little Ten Mile Creek. No details of the
discovery have been received. From Folio 144 of the U. S. Geological
Survey it is learned that patches of the Carmichaels formation are found
for several miles along Ten Mile Creek, near the southern boundary of
the quadrangle. It seems probable that there may be patches of the same
deposit along Little Ten Mile Creek, in the neighborhood of Lone Pine.
As detailed on page 70, a mastodon tooth was found many years ago about
1.5 miles south of the village of Hickory, Washington County, about
twenty miles southwest of Pittsburgh. Westland Run empties into
Chartiers Creek, and this into the Ohio at Pittsburgh. The geology of
Burgettstown and Carnegie Quadrangles has been described by E. W. Shaw
and M. J. Munn (Folio 177, U. S. Geol. Surv. 1911). No Pleistocene
deposits are mapped on the stream mentioned; but just a little lower
down, on Chartiers Creek, is a patch of the Carmichaels formation. Below
Hickory somewhere there must be a Pleistocene deposit of some kind, and
it is more probably early than late Pleistocene.
From the vicinity of Pittsburgh there have been reported remains of the
mastodon (p. 69), of _Elephas columbi_ (p. 150), and of an undetermined
species of elephant (p. 168). Neither of the elephants is certainly
determinable. The mastodon, represented by fragments of bones and teeth,
is said to have been found in the river bank, at the junction of
Monongahela and Allegheny Rivers. It is impossible to determine the
Pleistocene stage to which any of these proboscidean remains belong. As
shown on the geological map of the Carnegie Quadrangle (Folio 177, U. S.
Geol. Surv.) there are indicated here Pleistocene deposits of early,
intermediate, and late stages.