NO. 9 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 23 



14, 15). Either of these animals would seem to fulfil all require- 

 ments in so far as the character of an animal can be visualized from 

 a study of its tracks. The absence of a tail drag would also be ac- 

 counted for by the presence of this short, stubby tail. According to 

 Williston, Cacops has a length over all of about 20 inches, whereas 

 Trematops is 36 inches long. If the above suggested correlation has 

 any merit whatsoever, these tracks are at once placed as belonging 

 to the stegocephalian branch of the Amphibia. 



The specific name of Baropesia cakini is in honor of Mr. J. R. 

 Eakin, superintendent of the Grand Canyon National Park, whose 

 generous assistance contributed so much to the success in making this 

 collection of fossil tracks. 



Genus AGOSTOPUS, new genus 



Generic characters. — Quadrupedal with five digits in the manus 

 and four in the pes ; plantigrade ; broad soled with three clawed digits 

 in the pes. Feet directed inward, hindfoot placed in front of fore- 

 foot impressions. Short limbed, wide bodied. 



AGOSTOPUS MATHERI, new species 

 Plate 10 



Type. — Catalogue number 11,135, U. S. N. M. Consists of a 

 trackway some 700 millimeters in length, showing consecutive im- 

 prints of all the four feet. 



Type locality.- — Hermit Trail, Hermit Basin, Grand Canyon Na- 

 tional Park, Arizona. 



Geological occurrence. — Coconino sandstone (150 feet above the 

 base), Permian. 



Description. — Length of stride, 134 mm. ; width of trackway, 199 

 mm. Hindfoot: Length about 67 mm., width 65 mm. Sole broad, 

 palmate, quadrately rounded, longer than digits. Four digits, median 

 two curved outward, outer three acuminate, probably terminated by 

 sharp claws. First digit short, heavy, obtusely rounded, without claw. 

 Length of digits, 1 = 4 mm., n = i8 mm.. Ill — 22 mm., IV=i8 mm. 

 Forefoot: Length (estimated) 35 mm., width about 63 mm. Sole 

 suboval, smaller than hindfoot ; apparently five short digits, fifth 

 reduced and projecting outward at a right angle to the long axis of 

 the foot. 



In addition to the slab of footprints selected as the type, the collec- 

 tion contains two slabs (Nos. 11,133 and 11,150) pertaining to this 

 species. The imprints, especially of the hind feet, are clearly pre- 



