within the area occupied by the Wisconsin drift lived during or after
that stage. Even within this area there may occur fossil-bearing
deposits of an older Pleistocene time. These older deposits may underlie
the Wisconsin drift or they may occur as old terraces high up on the
sides of the valleys of rivers. Cases of the latter kind are found along
Allegheny River (Leverett. Monogr. XLI, U. S. Geol. Surv., pp. 229–252;
Shaw Jour. Geol., vol. XIX, 1911, pp. 140–156; folio 178, U. S. Geol.
Surv., p. 8). On the other hand, an animal of very late Pleistocene age,
or even of the Recent, may be buried in deposits which overlie an old
Pleistocene deposit. It is necessary, if it can be done, to determine
the actual age of the deposit containing the remains; otherwise one must
depend on the geological age of the species involved, or be content to
wait for further information. Unfortunately, but few of the quadrangles
in the glaciated area have had their geological structure studied and
reported on. At present the U. S. Geological Survey has published only
Folios 92 (Gaines) and 93 (Elkland and Tioga), lying mostly in Tioga
County, partly in Potter; also Folio 172 (Warren), occupying a part of
Warren County. Information may sometimes be secured from the numerous
volumes which have been published by the Geological Survey of
Pennsylvania and from articles in the scientific journals.
[Illustration:
FIG. 10.—Glaciated areas of northern Pennsylvania. From W. C. Alden.
]
The Pleistocene deposits which lie outside of the glaciated areas have
been mostly laid down along rivers. Some of the materials were
transported by the streams which carried away the drainage from the
glaciers; in other cases the materials were brought down from the higher
lands and laid down along the lower and less sloping parts of the
streams. In the unglaciated area many of the quadrangles have been
surveyed by the U. S. Geological Survey and the folios aid in
determining the age of deposits which contain fossil vertebrates.
Important collections have been made in a few localities, and these will
now be considered:
At Pittston, in Luzerne County, on Susquehanna River, have been found
teeth of the horse _Equus complicatus_ (p. 184), remains of mastodon (p.
68), and of a musk-ox (p. 248). The presence of the horse makes it
evident that the deposit containing the fossils belongs to a stage older
than the Wisconsin, although the locality is within the area of the
Wisconsin.
We consider now the contents of a cave found near Stroudsburg, Monroe
County. The Hartman (or Crystal Hill) Cave was discovered in 1880 and
explored first by Mr. T. Dunkin Paret, of Stroudsburg. It was soon
afterward examined by Dr. Joseph Leidy, of Philadelphia, and Dr. Thomas
C. Porter, of Easton. Leidy published the first description of it in
1880 (Proc. Acad. Nat. Sci. Phila., pp. 346–348) and presented a list of
the species of animals which had been secured by Mr. Paret. In 1889
(Ann. Rep. Geol. Surv. Pennsylvania, for 1887, pp. 1–18, plates I, II),
a more detailed report was made by Leidy, including descriptions and
illustrations of some of the vertebrates and of certain artifacts which
had been discovered.
In 1894, Dr. H. C. Mercer made a re-exploration of the cave and gave a
more extended description of it (Proc. Acad. Nat. Sci. Phila., pp.
96–104).
Combining the statements of Leidy and Mercer with data obtained from the
Delaware Water Gap topographical sheet issued by the U. S. Geological
Survey, one finds that the cave is situated on Crystal Hill, about 3.5
miles in a straight line southwest of Stroudsburg and close to the
village of Stormville. Crystal Hill is a part of an anticlinal fold,
Godfrey Ridge, of the Helderberg limestone. South of the fold runs
Cherry Creek; north of it, Mt. Michaels Creek. On the northeast the hill
is cut off from the rest of the ridge by a valley about 300 feet deep.
Mercer’s account states that the cave is on the top of the hill, about
0.25 mile from Cherry Creek, but the topographical map locates the top
of the hill about 0.75 mile away from this stream. Mercer also wrote
that the cave was 800 feet above Delaware River, 5 miles away. However,
the hill has an elevation of somewhat less than 840 feet above
sea-level, while the river at the nearest point is somewhat more than
280 feet above sea-level. Inasmuch as the cave is probably somewhere on
the southern slope of the hill, it is about 500 feet above the Delaware
and about 300 feet above the bed of Cherry Creek.
The opening of the cave in the rock was wide (Mercer, p. 96, fig. 1),
but had become almost wholly choked by débris. Nevertheless, a hole
large enough for adventurous boys to enter remained (Leidy, op. cit.,
1880, p. 346). After a few feet descent the cave extended nearly
horizontally more than 100 feet. It had become filled nearly to the roof
by various deposits. Excavations showed that on top was a layer, about a
foot, of “black friable earth mingled with animal and vegetal remains”
(Leidy). Mercer describes it as a “top layer of limestone roof-splinters
and down-slidden outer talus thinning inward into less stony cave
earth.” Beneath this layer was a thin stratum of stalagmite. Further
digging showed that below this stalagmite flooring the cave was filled
to a thickness of as much as 14 feet in one place. This deposit is
described by Mercer as being a continuous homogeneous bed of exquisitely
fine clay deposited in thin laminæ rarely sprinkled with sand pockets
and underlain with a thin film of sand. Neither in this deposit nor in
the stalagmite was there found a trace of any formerly living thing. All
the remains of animals and all the artifacts were discovered in the
uppermost layer.
It should be noted at this point that this cave is situated about 5 or 6
miles north of the Wisconsin moraine.
The following is a list of the species of vertebrates identified by
Leidy. When his names differ from those now in use they are inclosed in
parenthesis.
_List of species of vertebrates._
Chelydra serpentina.
Terrapene carolina (Cistudo clausa).
Meleagris gallopavo sylvestris (M. gallopavo).
Equus sp. indet. (p. 185).
Mylohyus pennsylvanicus (Dicotyles) (p. 213).
Rangifer caribou (p. 246).
Odocoileus virginianus (Cervus) (p. 237).
Cervus canadensis (p. 237).
Bison bison? (B. americanus) (p. 267).
Marmota monax (Arctomys).
Tamias striatus.
Sciurus carolinensis.
Castor canadensis (C. fiber).
Peromyscus leucopus (Hesperomys).
Neotoma magister (N. floridana).
Microtus pennsylvanicus (Arvicola riparius).
Erethizon dorsatum.
Castoroides ohioensis (p. 272).
Sylvilagus floridanus (Lepus sylvaticus)
Myotis subulatus (Vespertilio).
Eptesicus fuscus (Vespertilio).
Scalopus aquaticus (Scalops).
Procyon lotor.
Mustela noveboracensis (Putorius ermineus).
Mephitis putida (M. mephitica).
Urocyon cinereoargenteus (Canis virginianus).
Canis lycaon? (C. lupus).
Lynx canadensis (Felis).
Besides these vertebrates, there were reported by Leidy the land snails
_Helix albolabris_, _H. alternata_, and _H. tridentata_; also a pair of
valves of the river mussel _Margaratina margaritifera_ and a fragment of
another valve. Leidy regarded these as showing that this mussel formerly
lived in Delaware River; whereas in his view it no longer existed there;
but specimens of it from Philadelphia are in the U. S. National Museum.
An examination of the list shows that nearly all of the species of
vertebrates are yet in existence and most of these still living in that
general region. _Rangifer caribou_ lives now far to the north and _Lynx
canadensis_ has its range somewhat further north. The two indicate a
colder climate, especially the reindeer. Both got into the cave probably
after the glacial front had withdrawn from that vicinity. The remains of
_Castoroides_ may have been carried in there at about the same time. The
type specimen of _Mylohyus pennsylvanicus_ was found in this cave. Cope
referred specimens of a peccary found in Port Kennedy Cave to the same
species with doubt. Undetermined species of the genus were recognized by
Barnum Brown in his collection made in the Conard fissure in
northwestern Arkansas. Dr. W. J. Holland reported _Mylohyus
pennsylvanicus_ from the cave at Frankstown, Pennsylvania. The type of
the genus, _M. nasutus_, was found in Indiana. Beyond the testimony
furnished by the Crystal Hill Cave, we have no evidence that the genus
_Mylohyus_ existed after the Wisconsin stage; the possibility exists
that this species got into the cave before this stage.
The specimen of _Equus_ is still more doubtful. It consisted of two
isolated first and second milk molars of a very young colt. Leidy was in
doubt whether the colt belonged to the domestic horse or to an
indigenous species. The specimen had been collected with no record as to
the part of the cave or of the depth in the upper layer of soil where it
was buried. A fragment of a jaw of a colt might easily have been carried
into the cave by some carnivorous animal since the coming of the whites.
A fragment of the lower jaw of a bison also was found which had in it
the last molar; and this was referred by Leidy to the existing buffalo.
It can hardly be doubted that this cave was hollowed out before the
Wisconsin ice period. It may have been formed during the early
Pleistocene. The fact that it was filled to a depth of 14 feet, in some
places, with a fine laminated clay devoid of all traces of organic
beings seems to indicate that for ages it had been shut off from the
outer world, and that streams charged with fine sediment were permitted
to pass through it. During possibly some glacial stage preceding the
Wisconsin, erosion may have opened the cave so that the horse remains,
those of a bison, and of _Castoroides_ were dragged into it. The
evidence for these suppositions is slender, but so too is that for a
late Wisconsin indigenous species of horse in Pennsylvania. It is
probable that most of the species found in the cave belong to the late
Pleistocene or even to the Recent.
Fossil vertebrates found in a cave in Bucks County require our
attention.
In 1880 (Proc. Acad. Nat. Sci. Phila., 1880, p. 349), Leidy presented a
list of vertebrate remains which had been lying unstudied for 40 years
in the collection of the Academy. These had been found in Durham Cave,
somewhere near Riegelsville, in Bucks County. It is not improbable that
the cave took its name from the village of Durham, about 2 miles
southwest of Riegelsville. Leidy stated that the cave appeared to have
been obliterated in the quarrying of limestone. In 1889 (Ann. Rep. Geol.
Surv. Pennsylvania, for 1887, pp. 18–19) Leidy published a list of the
species which he had identified.
_List of fossil vertebrates from Durham Cave._
Acipenser sturio.
Ameiurus nebulosus (Amiurus atrarius).
Thamnophis sirtalis (Eutænia).
Chelydra serpentina.
Terrapene carolina (Cistudo clausa).
Meleagris gallopavo sylvestris (M. gallopavo).
Rangifer caribou (p. 246).
Cervus canadensis (p. 237).
Alces americanus (Alce).
Odocoileus virginianus (Cervus) (p. 227).
Erethizon dorsatum.
Marmota monax (Arctomys).
Sciurus carolinensis.
Castor canadensis (C. fiber).
Neotoma pennsylvanica (N. floridana).
Ondatra zibethica (Fiber).
Sylvilagus floridanus (Lepus sylvaticus).
Ursus americanus.
Procyon lotor.
Mephitis putida (M. mephitica).
Urocyon cinereoargenteus (Vulpes virginianus).
This list differs in its species from Leidy’s list of 1880 only in the
exclusion of the bison and the inclusion of the elk, _Cervus
canadensis_. All the species are still in existence, most of them in
that region. The presence of the reindeer, the moose, and the porcupine
suggests a cooler climate than now prevails there. These animals may all
have become buried in that cave during the latest times of the Wisconsin
stage or even during the Recent.
We are now to study a case which furnishes us with a store of knowledge
regarding the life of the Pleistocene. In 1871 there was found at Port
Kennedy, Montgomery County, a cave which was worked for its fossils by
Charles Wheatley and later by Dixon, Mercer, and Cope, the latter having
devoted himself to the description of the vertebrates. First of all will
be given a list of the species of vertebrates, mostly mammals which have
been recognized in the materials found in the cave. When Cope’s names
differ from those employed here they are put in parenthesis.
_List of species of vertebrates found in Port Kennedy Cave._
Ranidæ:
Rana sp. indet.
Emydidæ:
Clemmys insculpta.
C. percrassa.
Terrapene eurypygia (Toxaspis anguillulatus).
Colubridæ:
Coluber acuminatus (Zamenis).
Meleagridæ:
Meleagris superbus (M. altus).
Megatheriidæ:
Megalonyx (p. 31).
M. scalper (p. 31).
M. tortulus (p. 31).
M. wheatleyi (p. 31).
Mylodon harlani? (p. 31).
Equidæ:
Equus complicatus (E. fraternus) (p. 185).
E. pectinatus (E. f. pectinatus) (p. 185).
Tapiridæ:
Tapirus haysii (p. 203).
Tagassuidæ:
Mylohyus nasutus (p. 213).
M. pennsylvanicus? (p. 213).
Tagassu tetragonus (Mylohyus) (p. 213).
Camelidæ?:
Teleopternus orientalis (p. 224).
Cervidæ:
Odocoileus lævicornis.
O. virginianus?
Bovidæ:
Bison sp. indet. (Bos) (p. 256).
Elephantidæ:
Mammut americanum (Mastodon) (p. 69).
Sciuridæ:
Sciurus calycinus.
Castoridæ:
Castor canadensis (C. fiber).
Cricetidæ:
Peromyscus leucopus? (Hesperomys).
Anaptogonia hiatidens.
Sycium cloacinum.
Microtus dideltus.
M. diluvianus.
M. involutus.
M. speothen.
Zapodidæ:
Zapus hudsonius?
Erethizontidæ:
Erethizon dorsatum?
Ochotonidæ:
Ochotona palatina (Lagomys).
Leporidæ:
Sylvilagus floridanus (Lepus sylvaticus).
Talpidæ:
Scalopus sp. indet. (Scalops).
Soricidæ:
Blarina simplicidens.
Vespertilionidæ:
Myotis? sp. indet. (Vespertilio).
Ursidæ:
Ursus americanus.
Arctotherium haplodon.
Mustelidæ:
Taxidea taxus (T. americana).
Mephitis fossidens.
M. leptops.
M. obtusata.
M. orthostica.
M. putida.
Osmotherium spelæum.
Pelycictis lobulatus.
Mustela diluviana.
Gulo luscus.
Lutra rhoadsii.
Canidæ:
Canis priscolatrans.
C. dirus? (C. indianensis).
Urocyon cinereoargenteus.
U. latidentatus.
Felidæ:
Machairodus gracilis.
Smilodontopsis mercerii (Smilodon).
Felis eyra.
F. inexpectata (Uncia).
Lynx calcaratus.
Into this list there are admitted 60 species, of which 54 are mammals.
Of these, 41 are extinct, not counting the doubtful species unless there
is good reason for it. There are, therefore, 68 per cent of the species
extinct.
No remains of _Rana_ were mentioned by Cope in his list of 1899. One
species unnamed was recorded by Wheatley in his lists of 1871 and by
Mercer in his paper of 1899. The turkey (_Meleagris superbus_) was not
included by Cope in 1899, but it was included by Wheatley and Mercer and
Cope in their papers of 1871 and in that of Cope in 1896 (p. 378).
Mercer (1899, p. 280) mentions a leg-bone of a turkey, with spur, found
by Wheatley. Remains of _Megalonyx_ were abundant, but of _M. loxodon_
only a single tooth was met with. _Mylodon_, believed to be _M.
harlani_, was found only by Wheatley and was represented, as stated by
Cope, by only a claw phalanx. The horse remains were originally (Cope,
1895, p. 447) referred to _Equus major_ (=_E. complicatus_). Mercer, in
1899, in his figure 9, following Cope’s nomenclature, uses the name _E.
complicatus_. In 1899, Cope concluded that the equine remains
represented two races of _Equus fraternus_, _E. f. fraternus_ and _E. f.
pectinatus_. The present writer believes that the teeth referred to the
subspecies _fraternus_ are too large to belong to the species which was
called _E. fraternus_, but which is now called _E. leidyi_. Only a
single species of tapir, _Tapirus haysii_, was recognized. Cope (1895,
p. 447) stated that it was the most abundant of the larger mammals. Cope
(1899, p. 257) reported that 18 individual peccaries were represented by
teeth, while bones were numerous. He recognized the presence of three
species. The identifications of _Mylohyus nasutus_ and _M.
pennsylvanicus_ were uncertain. A new species, _M. tetragonus_, was
based on a ramus of a lower jaw. Milk molars were yet present and the
third molar had not appeared. Cope spoke of the long diastema; but, to
judge from his figure, the diastema equals only about the length of the
milk molars and the first molar.
Cope, in 1899, described _Teleopternus orientalis_, basing it on a few
teeth which belonged to three individuals. He was doubtful about the
family position of the animal, but put it provisionally in the Camelidæ.
In many respects the teeth resembled those of the Cervidæ. Matthew
(Osborn, Age of Mammals, p. 469) has suggested its affinity to _Ovibos_.
Two species of deer were found in the cave, of which one was not
distinguishable from _Odocoileus virginianus_. In Wheatley’s second list
of 1871 and that of Cope of the same year there was recorded an
undetermined species of _Bos_ (_Bison_). Mercer (1899, p. 280) recorded
from the Wheatley collection remains of three individuals of one species
of the same genus. In Cope’s paper on the remains of this cave nothing
is said about the genus; but in 1872 (Proc. Amer. Philos. Soc., XII, p.
96) he stated that _Bos_ was represented by a part of a femur and some
other bones. Hence in the list given above an undetermined species of
_Bison_ is included.
Abundant remains of the mastodon occurred in the cave, but none of any
of the elephants. One need not, however, on that account conclude that
elephants were not living in that region at that time.
It will be observed that a considerable number of rodents is included in
the list. One species of porcupine is recognized. This was at first
regarded by Cope as an extinct form and called _Erethizon cloacinum_;
but in 1899 he referred all the remains, with some doubt, to the
existing species, _E. dorsatum_. Cope found remains of about 50
individuals of a species of rabbit which he determined as _Lepus
sylvaticus_, but this is now called _Sylvilagus floridanus_. In the
Wheatley collection a species of bat was recognized and put in
_Vespertilio_. Probably it belonged to _Myotis_.
Bears were abundantly present in the cave. One species, _Arctotherium
haplodon_, was larger than the grizzly bear and represented by parts of
about 25 individuals. A smaller bear, indicated by 8 individuals,
appeared to be in no way different from the existing black bear, _Ursus
americanus_. Of skunks there are listed 7 species, belonging to 3
genera, all the species being extinct except a supposed _Mephitis
putida_. Besides these mustelids, there have been identified remains of
the existing badger, the existing glutton, an extinct weasel, _Mustela
diluviana_, and an extinct otter, _Lutra rhoadsii_. Remains of true dogs
were not abundant in the collection. Cope recognized, however, 2 species
of the genus _Canis_, one of about the size of the more common form of
the existing wolf; the other exceeding in size the largest wolf known to
him. This he thought might belong to Leidy’s _Canis indianensis_ (=_C.
dirus_ Leidy). There were present 2 foxes, the existing gray fox
(_Urocyon cinereoargenteus_) and an extinct species, _U. latidentatus_.
Of the cat family a species, thought at first to be a hyæna (_Crocuta_),
received the name _Felis inexpectata_. It had the size of the jaguar,
and was represented by teeth and various bones. An extinct lynx, much
like _Lynx ruffus_, was present. Another cat was identified as _Felis
eyra_. Of this species G. S. Miller (Bull. 79, U. S. Nat. Mus., p. 116)
remarks that its type locality is Paraguay and that it is supposed to
range north to Central America. It appears somewhat doubtful, therefore,
that the fossil remains belong to this species. Nevertheless, the
progenitors of the species, in their wandering from Asia or Alaska to
Central America and Paraguay, might have sent a colony into
Pennsylvania, later to become extinct. Cope stated (1899, p. 250) that
there was an isolated calcaneum in the collection which was of the
proper size for _Felis eyra_, but which differed from that of this
species. Two species of saber-tooth cats were found, _Smilodontopsis
gracilis_ and _S. mercerii_. The former is represented by various bones
and teeth, especially by a damaged skull which presents the dentition.
The crown of the great canine is 113 mm. long.
Besides the species included in the list given above, there are a few
whose presence for one reason or another is doubtful. In both of his
lists of 1871 Wheatley reported the presence of _Crotalus_, _Coluber_,
and _Tropidonotus (Natrix)_. Cope (1871, p. 98) said that the reptiles
included three or four serpents, but in 1895 (p. 447) he wrote that two
species of _Ophidia_ were recognized. In his final paper he mentioned
only his _Zamenis acuminatus_, here referred to _Coluber_. Wheatley
(1871, p. 255) recorded an unidentified snipe as belonging to
_Scolopax_. Cope (1871, p. 98) wrote that a snipe was one of two species
of birds present. Mercer (1889, p. 280) recognized the same remains as
belonging to a species of _Gallinago_. Wheatley in his last list (1871,
p. 384) and Cope (1871, p. 98) reported _Scalopus (Scalopus)_ as being
represented by an undetermined species. It is catalogued by Mercer in
the same way. Cope (1895, p. 447) stated that the raccoon was very rare;
but it was not mentioned in any of his later papers. On the same page he
wrote that there were fragments of teeth closely similar to those of
_Bassariscus astutus_; but the species was not mentioned afterward.
As already said, there are admitted into the list given above, as
identified in a reasonably good manner, 60 species, of which 54 belong
to the Mammalia. It is a matter of interest to compare these with the
species of mammals which were living in that general region before the
fauna was disturbed by the arrival of the whites. The number of species
of the existing mammals, as shown in the second column, is obtained from
Rhoads’s “Mammals of Pennsylvania and New Jersey.” The subspecies are
not included.
_Families of land mammals represented in Port Kennedy Cave and those
that have lived in that region within Recent times, together with the
number of known species in each family at each of the two epochs._
┌──────────────────────┬──────────────────────┬──────────────────────┐
│ Families. │ No. of species, Port │ │
│ │ Kennedy. │No. of recent species.│
├──────────────────────┼──────────────────────┼──────────────────────┤
│Megatheriidæ │ 5│ │
│Didelphidæ │ │ 1│
│Equidæ │ 2│ │
│Tapiridæ │ 1│ │
│Tagassuidæ │ 3│ │
│Camelidæ? │ 1│ │
│Cervidæ │ 2│ 2│
│Bovidæ │ 1│ 1│
│Elephantidæ │ 1│ │
│Sciuridæ │ 1│ 6│
│Castoridæ │ 1│ 1│
│Cricetidæ │ 7│ 9│
│Zapodidæ │ 1│ 2│
│Erethizontidæ │ 1│ 1│
│Ochotonidæ │ 1│ │
│Leporidæ │ 1│ 2│
│Soricidæ │ 1│ 5│
│Talpidæ │ 1│ 3│
│Vespertilionidæ │ 1│ 8│
│Procyonidæ │ ?│ 1│
│Ursidæ │ 2│ 1│
│Mustelidæ │ 11│ 9│
│Canidæ │ 4│ 3│
│Felidæ │ 5│ 3│
└──────────────────────┴──────────────────────┴──────────────────────┘
In the column of fossils there are 54 species; in that of the Recent
there are 58 species. Of two families represented at present in the
region, but not included in the Pleistocene column, Didelphidæ and
Procyonidæ, the latter named has had remains referred to it with doubt.
Without doubt members of both families existed there at that time.
Of the families of the Pleistocene column two no longer live anywhere
near the region; four nowhere on the continent; one nowhere on the
earth. Even of such families as the Ursidæ and the Felidæ important
elements, as _Arctotherium_ and the saber-tooths, are extinct. Of the 54
species admitted in the Pleistocene column 40 are extinct; that is, 74
per cent.
If we consider the sizes of the animals in question we gain this result:
Only 15 of the existing species are of any considerable size, ranging
from that of a raccoon to that of a bison, about 26 per cent. Of the 54
fossil species of mammals, about 30 vary in size as indicated, about 57
per cent. It is hardly to be doubted that this preponderance is due to
the poorer chances which the smaller skeletons had of preservation and
of rescue from the matrix. Had the smaller fossil species been preserved
and collected in the same proportion that the smaller existing ones have
to the larger, the cave ought to have furnished twice as many species of
mammals as it did. It is, of course, possible that the larger species
are more liable than the smaller ones to become extinct as time passes
on. We can hardly doubt, in any case, that when the Port Kennedy animals
were being buried in that cave there lived in that region a considerably
larger number of species than within Recent times. There must have
existed in that region more moles, more rabbits, more cricetids, more
squirrels, and many more bats. Certainly there is no adequate record of
the number of birds, snakes, turtles, and amphibians that must have
existed about Port Kennedy and have perished in that cave.