In the hermit shale, spores, plants, and insects were found in the hollows or troughs that had eroded into the top of the underlying soil. The hermit shale fauna as it is currently known consists of the following forms.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 9
The ichnite fauna of the Supai Sandstone as known at this time consists of the genera and species described below.
LIST OF DESCRIBED TRACKS FROM THE CARBONIFEROUS OF NORTH AMERICA
12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80
SYSTEMATIC DESCRIPTION OF GENERA AND SPECIES In the systematic description the genera and species are divided
FAUNA OF THE COCONINO SANDSTONE
In the type, the hindfoot was placed in front of the forefoot, but in this specimen the impression of the forefoot is usually slightly in front of or to one side of the hindfoot. Marsh's conception of this genus, as presented in his description of the type species, may now, with the discovery of two new species, be greatly modified, as follows.
14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE I 5
Judging by the depth of the prints, the weight of the animal was largely carried by the hind legs. The large size of Nanopus maxiinus distinguishes it at once from the other species of the genus, all of which are small.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE I9
20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80 BARYPODUS TRIDACTYLUS, new species
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 21
That the claws were sharp is clearly shown not only by the shape of the digits, but also by the long and deep scratches in the rock, as shown on the left side of the track (see fig. 8). On both the forefoot and hindquarters, distinct criss-cross ridges indicate the presence of deep creases on the bottom of the foot, at the base of the toes.
24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL
In this specimen the hind foot is placed in front of and outside the impression of the fore foot, whereas in B. Hind foot: I. length about 75 mm, the hind foot is placed in front of the fore foot, the sole usually obliterates the toes of the manus.
28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80 ness from all others, but in the expectation of again visiting the
The front part of the impressions gives the impression that they were made by a single broad toe, . which had a broadly rounded ungual. Forefoot: The ])lacing of the hindfoot in whole or in part after the impression of the forefoot has obliterated most of the details of its structure.
30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 3
The feet appear to have been unidactylus, and made single depressions like marks that lie diagonally to the axis of the line of motion. The impressions forming the two rows on either side of the tail drag are regularly alternated. The abrupt termination of a path in the center of the plate, as shown in plate 1 1, suggests that it was made by an animal that was able.
The type is the only specimen of this species observed in all hundreds of square meters of sandstone surface examined. This question can be satisfactorily resolved only by a re-study and comparison of the type specimens, which is beyond the scope of the present study.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 37
A specimen was found a quarter of a mile west of the "Red Peak" sign on the HermitTrail, at the top of Hermit Gorge, by Mr. Sturdevant of the Park Service, who found it lying on a slope about 30 feet above the Hermit-Supai junction, where it had been exposed to the weather, which explains to some extent the distinctness of the fine marks impressed on the upper surface. There are five digits and the drawing of the plan of the foot when placed on Lull's figure of a dog, although slightly larger, matches the placement and arrangement of the toes exactly.
The forefoot has a length of 7 mm., a greatest width from tip to tip of first and fourth digits of 10 mm. There are four widely radiating digits that are apparently without claws, although Lull thought he detected "clear impressions of terminal claws". Manus turned strongly inward to the axis of the direction of air movement.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 39 and fourth toes usually in line across the palm of the foot, the former
The salamandroid characteristic of the feet is seen in the inward-facing toes of the front feet and the more outward-facing toes of the hind feet. The specific name is indicated by the obscure state of most of the tracks. These are long and slender, regularly increasing in length towards the outside of the foot, the third is the longest, the fourth is much shorter.
The sole is well impressed and the full rounded outline of the heel is shown in figure 19, whereas the sole in the Joggins species is. A description of the other details of the foot must await the discovery of better preserved specimens.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 45
He also concludes (p. 85) "that five toe marks on the hind foot and four on the fore foot are the typical number of Hylopus." This conclusion is fully supported by the semi-])lantigrade character of impression of the specimen to be described. If a claw- bluntly rounded end and was apparently clawless. was present on the first digit, it must have been blunt tipped. all the numbers the sole is rather faintly impressed as far as its. the exact rear outline is concerned.
It is smaller than type (see measurement chart), but otherwise .. conforms closely to the size and order of the figures. In any case, all of the tracks discussed here seem to match those made by amphibians more than those of any known reptile.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 5I
Type locality.— Hermit Trail, one-quarter mile west of "Red Top" sign head of HermitGorge, Grand Canyon National Park, Arizona. The fourth digit is more than twice the length of the sole and extends directly forward as in Hylopiis.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 53
This series, which is in relief, has been cast and thus provides all the evidence of the original prints. The manus is shown to be smaller than pesi, and the digits of the former resemble those of the latter in being relatively short with rounded edges without claws. Comparison of the manus track of the newly discovered track (see fig. 27) with the P type.
These tracks are almost the same size, as can be seen in the table of comparative measurements, and further similarities are found in the short, radiating digits, with rounded corners. This specimen was found locally in the Hermit Shale about a quarter mile west of the "Red Top" signpost on the Hermit Trail.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 59
Nova Scotia (see Fig. 31), also appears to have its affinities in this genus, and were it not for the uncertainty of the digital formula of the fore-foot, I should have no hesitation in assigning it to the present genus. Matthew has doubted whether there were three or four toes in the themanus of Droiiiopusvclox, but in view of the above great similarities in the hind legs it does not seem improbable that there are five. Footprints from the Hermit shale, which have a similar digital formula, with slender sharp pointed toes, are tentatively attributed to CoUettosaurus.
Hindfoot: Five toes, third and fourth long, slender, less equal in length and usually pointing straight forward in direction. Sole Apparently long, but none of the last impressions are clear enough to show the exact shape of the sole.
62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80 about 50 miiL The length of the digits may tentatively be recorded
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 63 Unfortunately Butts neglected to state whether the imprint figured
Considerable variation in the length of the toesis noted in the many impressions available; the length of the toes as indicated below are measurements taken from the two most. The digital formula of five in the pes and three in the manus at once distinguishes this orbit from all others found in the hermit fauna, but in Joggins, Nova Scotia, the fauna is found in two genera, Aspcripes and Cursipcs, with a similar number of digits. The elongated nature of the toes, especially in the manus, and the comparatively small soles seem to show that its affinities lie in the genus Cursipcs, to which it is tentatively referred.
The much larger size of the spurs, and differences in the plane of the feet, especially in the relatively shorter and stronger toes of the pes, are characters which may serve to distinguish it from the described species, C. It is sufficient at present to call attention to the occurrence of Cursipcs in this fauna in anticipation that better specimens can.
INCERTE SEDIS
Second and third toes are less long in length, others become progressively shorter towards the outside of the foot. Icvis Matthew, but owing to the unsatisfactory nature of the evidence to be obtained from this single specimen, its designation as a distinct species is postponed for the present.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 65
FAUNA OF THE SUFAI FORMATION
66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 80 STENICHNUS YAKIENSIS, new species
In most of the prints, three toes are recorded, but the hindfoot, in the greatest number of cases, was partially placed on the front, obliterating the impression of the shortened inner toe. In slender toes and narrow sole these tracks bear a striking resemblance to Ornithoides. Scotia, but the greater number of toes and larger size of the present specimen serve to distinguish the two genera.
The outer manus and fifth toes are robust with a rounded clawless extremity directed outwards and forwards; the other fingers are pointed. The fourth digit on the left hind foot has a more pointed end and projects more directly outward than the fourth on the right side.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 69
The footprints are deeply impressed and clearly defined, except that parts of the front footprint have been destroyed by the hind feet partially stepping on it. Sturdevant, wandering naturalist of the Grand Canyon National Park, who discovered and collected the specimen and through whose efforts it was presented by the Park Service to the United States National Museum. Hind leg: Length about 68 mm., breadth about 70 mm., five toes, three medium ones subequal in length and directed forward;.
The sole is imperfectly impressed, and this fact may explain the weakness of the evidence regarding the lateral digits. The illustration shows the three-toed forefoot in its proper position in front of the hindfoot, which, apart from the lack of a fifth digit, agrees in all essentials with the type of the present genus and species.
SUMMARY
A second occurrence of this genus and species seems to be indicated by a comparison of Fig. 2, Plate 2, with the track described above.
NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 73
No information of interest resulted, as so many unknown factors enter into such a comparison that any Hkenesse found is of little consequence. The main importance of these footprints, it now appears, is the establishment of sufficient faunas for each of these three formations, which in the absence of other fossil criteria may be of future use in correlating these deposits with other trace-bearing formations from distant localities.
LITERATURE
EXPLANATION OF PLATES
