NO. 3 GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 5 



below the " White Zig Zags," where the upper part of the track-bear- 

 ing horizon is marked by large cleared slabs by the side of the trail 

 showing the footprints in situ, an out-of-doors exhibit was prepared 

 on a former visit to the locality. Exploration of the slope to the north 

 and south of this point disclosed track-covered surfaces wherever the 

 local conditions permitted search for them. A second locality at 

 " Dripping Springs " at the head of Hermit Gorge was not visited, 

 although I was informed that tracks were to be found there. Dr. 

 David White, accompanied by G. E. Sturdevant, visited this locality 

 during the summer of 1926, and in a personal letter says: " On the 

 Dripping Springs trail the tracks are very numerous and large ones 

 in particular are abundant." The third locality is on the new Yaki 

 Trail where it crosses the lower 150 feet of the Coconino sandstones 

 some three and one-half miles east of Grand Canyon. Conditions 

 here were not so favorable for examination of the sandstone sur- 

 faces, but numerous tracks and trails were seen ; these were so poorly 

 preserved, however, that no attempt was made to collect them. In 

 so far as one may rely on field identifications the tracks seemed to 

 pertain to the same species as those found in Hermit Basin, some 

 seven or eight miles distant in an air line. Several tracks of the 

 common Laoporus nohlei were recognized. 



That other localities yielding fossil footprints will be found in this 

 formation there seems no question, but the precipitous face of the 

 formation does not allow searching for them except at a few favored 

 localities. 



Hermit shale. — Schuchert, who was the first to discover fossil 

 tracks in the Hermit shale, makes the following comments on their 

 occurrence : ^ 



Just below the sign " Red Top " in the lower turn of the Hermit Trail and 

 immediately above the thick upper sandstones [of the Supai] are seen thin- 

 bedded red shaly sandstones alternating with deep-red zones of shale. The 

 surfaces of the glistening and smooth platy sandstones are replete with fillings 

 of the small prisms of interbedded; suncracked shales, often rain-pitted, and 

 further marked by the foot impressions of freshwater amphibians described 

 elsewhere in this number of the Journal by Professor Lull,^ as Megapezia ? 

 coloradensis and Exocampe ? delicatula. Some of the tracks are distinct 

 impressions of the feet, and others are mere strokes of the toes. In these 

 same beds also occur plant remains in very fragmentary condition which 

 were badly macerated and coated with a slime of red mud during their 

 entombment. 



No further collection of tracks was made from the Hermit shale 

 up to the time of the present expedition and consequently the known 



^Amer. Journ. Sci., Ser. 4, Vol. 45, 1918, pp. 353-354- 

 ' Lull, R. S., Ibid., pp. 337-346. 



