66 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 80 



STENICHNUS YAKIENSIS, new species 

 Plate 19, fig. 2 



Type. — Catalogue number 11,533, U. S. N. M. Consists of a slab 

 on which is a trackway about 330 mm. in length. 



Type locality. — -Yaki Trail (about 2 miles down from top), east 

 side of O'Neill Butte, Grand Canyon National Park, Arizona. 



Fig. 34. — Stcnichnns yakicnsis. Type. No. 11,533, U. S. N. M. 

 Diagram of trackway. About ] natural size. 



Geological occurrence. — Supai formation (about middle), P'ennsyl- 

 vanian. 



Description. — Stride about 81 mm., width of trackway (estimated) 

 94 mm., hindfoot placed forward and partially upon forefoot. Fore- 

 foot nearly equal to hindfoot in size. Hindfoot: Length about 45 mm., 

 width across the toes 23.5 mm., across sole 18 mm. There are four 

 long, slender toes. Toes nearly equal to length of sole, and inner 

 three directed straight forward, outer toe slightly divergent. Two 



