NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 23 



about 58 mm. Three toes more slender and more acutely pointed 

 than toes of hindfeet. Inner toe more widely set off from middle toe 

 than is the outer one. Toes all strongly bent inward, the second and 

 third especially so. The palm is so lightly impressed in all of the 

 imprints that its outline is not clearly indicated, so that much doubt 

 exists as to the correctness of the illustration of this portion of the 

 foot in figure 8. It has therefore been shown in a broken line. The 

 forefoot is placed in advance of the hindfoot and slightly outside. 

 That the claws were acuminate is not only clearly indicated by the 

 shape of the digits, but also by the. long, deep scratches in the rock 

 as shown on the left side of the trackway (see fig. 8). In both fore- 

 and hindfeet, distinct cross ridges indicate the presence of deep 

 creases on the bottom of the foot, at the base of the toes. The foot- 

 prints are deeply and clearly registered and there is little probability 

 of additional toes ever having been present since they did not reg- 

 ister here. 



This species is referred to the genus Barypodus largely on the 

 ground of there being three digits on both fore- and hindfeet, and 

 the presence of an elongate sole. From B. palmatus it is at once 

 distinguished by the shorter, stouter, curved toes and the absence of 

 webbing between the digits. Likewise it may be distinguished from 

 B. tridactylus by the short toes with curved claws and a shorter 

 palmar impression lacking pronounced outer hook. 



The specific name is in honor of Mr. Arthur Metszer who collected 

 the type specimen and whose efficient services contributed so largely 

 in bringing together this fine collection of footprints. 



Genus BAROPUS Marsh 



Baropus, Marsh, O. C, Amer. Journ. Sci., Vol. 43, 1894, p. 83. 



The genus Baropus was founded by Marsh on a series of tracks 

 from the Coal Measures of Kansas. With the additional material 

 collected in the Grand Canyon, it may be characterized as follows : 



Generic characters. — Large size. Quadrupedal, plantigrade. Four 

 toes on both manus and pes. Toes short, thick with rounded extremi- 

 ties, clawless. Forefoot subequal in size or smaller than hindfoot. 

 Soles of feet large. 



Genotype. — Baropus lentus Marsh. 



KEY TO SPECIES 



Imprints of fore and hindfeet subequal in size, with hindfoot placed in 

 rear of forefoot. Sole of pes elongate, subtriangular in outline, with 

 heavy protuberance on inner side. 



B. lentus 



