﻿20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 78 



COLLECTING FOSSIL FOOTPRINTS IN ARIZONA 



Mr. Charles W. Gilmore, curator of the division of vertebrate 

 paleontology, U. S. National INIuseum, by arrangement with the 

 National Park Service and through the generosity of some of its 

 friends, was enabled to visit the Grand Canyon for the purpose of 

 making a collection of fossil footprints, and at the same time to 

 prepare a permanent exhibit of these footprints in situ by the side 

 of the famous Hermit Trail. Both of these undertakings were suc- 

 cessfully carried out. 



A series of slabs, some 1,700 pounds in weight, carrying good 

 examples of the various kinds of imprints occurring there, were 

 collected and shipped to the Museum. The tracks occur in the 

 Coconino sandstone in Hermit Basin, on the trail down to Her- 

 mit Camp and from 900 to 1,080 feet below the rim of the Can- 

 yon. Their excellent preservation and variety of kind, coupled 

 with their great antiquity, make this collection of more than usual 

 interest. Preliminary study of the tracks has demonstrated that 

 they represent not only a new Ichnite fauna, bvit probably the best 

 preserved and most extensive series of Permian footprints known 

 anywhere in the world. 



It was found that the natural conditions were most favorable for 

 the preparation of an exhibit of fossil tracks in situ. The rather 

 steep slope of the sandstone on whose surfaces the tracks are im- 

 pressed stands at an inclination of 30° facing toward the Hermit 

 trail, over which in the course of the year hundreds of tourists 

 travel on mule back in making their pilgrimage to the bottom of 

 the Grand Canyon. The upper layers of the sandstone cleared 

 off in large sheets, thus uncovering whatever tracks and trails 

 there were to be found beneath. The work of preparing this 

 exhibit consisted, therefore, of removing the overburden of loose 

 dirt and broken rock, then quarrying off the loose upper laminae 

 until a solid and continuous face covered with footprints was reached. 

 This was done, and a smooth surface 8 feet wide and 25 feet long 

 was carefully uncovered as shown in figure 25. 



At the side of the slab leading up from the trail, a series of 

 stone steps was laid in order to facilitate examination by those 

 interested in the footprints covering its surface. Although this 

 slab constituted the main exhibit, other large surfaces were similarly 

 uncovered, so that in all there are several hundred square feet of 

 rock surface showing imprints of feet, thus forming a permanent 

 exhibit of the various tracks and trails to be found here. 



