NO. 3 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 65 



hillside about one-fourth mile west of the sign " Red Top " on the 

 Hermit Trail, in Hermit Basin, and from 30 to 40 feet above the 

 Hermit-Supai contact. The single track is deeply impressed on the 

 sun-baked surface of a slab of reddish sandy shale. There are five 

 toes and a tapering heel of moderate length. If correct in regarding 

 it as being the imprint of a right foot (probably the hind), the fifth 

 toe is somewhat set ofif from the others and subequal in length with 

 the fourth. The fourth is the longest digit, the others progressively 

 reducing in length toward the inside of the foot. The toes give the 

 impression of all being acuminate. The track has a greatest length 

 of 128 mm. ; a greatest spread of toes of 130 mm. Length of digits 

 as follows: I = 20 ? mm.; H = 30 mm.; HI = 40 mm.; IV = 

 52 mm. ; A" = 50 mm. On the lower left hand corner of this slab, 

 about 165 mm. posterior to the above described tracks are three toe 

 marks, but whether made by the same foot cannot be determined. In 

 size, narrowing of the heel, presence of five digits, toes reducing in 

 length inward with a divergent fifth digit, this track .'suggests affinities 

 with ChirotJicriuin hctcrodactyhitn (King)' from the Carboniferous 

 of Pennsylvania. The much shorter digits with other minor dififer- 

 ences would separate it from that species if more perfect specimens 

 should show its affinities to lie within that genus. 



A second specimen (No. 11,530. U. S. N. M.) from this same 

 locality and geological horizon, and likewise consisting of a single 

 track made by a much smaller animal, also seems to represent an 

 undescribed member of this Ichnite fauna. Its principal characteris- 

 tics are well shown in plate 17. figure 3. It has four long, tapering, 

 acuminate toes, two of which are curved. A short spur extending 

 outward from the base of the larger toe on the left hand side of the 

 specimen may represent a very short fifth digit. The heel is largely 

 missing. Greatest spread of toes 46 mm. Length of digits taken 

 from left to right is as follows; 1 = 5 mm.; II = 15 mm.; Ill = 

 26 mm. ; lY = 34 mm. ; V = 31.5 mm. 



FAUNA OF THE SUFAI FORMATION 



Genus STENICHNUS, new genus 



Generic characters. — Quadrupedal, plantigrade. Four toes on both 

 fore- and hindfeet. Toes long, slender, and acuminate. Hindfoot 

 placed upon the impression made by the forefoot. 



Genotype. — Stenichnus yakicnsis, new species. 



^Amer. Journ. Sci., Vol. 48, 1845, pp. 349-351. 



