﻿NO. 7 SMITHSONIAN EXPLORATIONS, I926 45 



COLLECTING FOSSIL FOOTPRINTS IN THE 

 GRAND CANYON, ARIZONA 



In continuation of the investigation of the fossil tracks found 

 in the Grand Canyon, so well begun in 1924,* Mr. Charles W. Gil- 

 more, curator of the division of vertebrate paleontology, U. S. Na- 

 tional Museum, made a second visit to the Canyon in the early 

 spring of 1926. 



This investigation, made possible through an allotment granted 

 by the Marsh Fund Committee of the National Academy of Sciences, 

 had as its purpose the acquiring of additional specimens of fossil 

 tracks from the Coconino and Hermit formations and the extension 

 of the explorations into the older Supai formation in which the 

 discovery of fossil tracks had been reported by Mr. J. R. Eakin. 

 Superintendent of the Grand Canyon National Park. 



Arriving at the Canyon on April 20, Mr. Gilmore with one assistant 

 spent three weeks in active field-work collecting and exploring these 

 formations as exposed on the Hermit and Yaki trails. The expedition 

 was successful far beyond expectations, as the collection made con- 

 sisted of a large series of slabs of some 2,700 pounds in weight on 

 whose surfaces were preserved the foot impressions of a great vari- 

 ety of animal life. 



The old Coconino locality on the Hermit Trail was revisited and 

 a large series of beautifully preserved tracks and trails secured, 

 which included many kinds that were new to this Ichnite fauna. In 

 the Hermit shale some 1,400 feet below the level of the Canyon rim 

 a large assemblage of fossil tracks and plants was collected. The 

 presence of insect remains was made known for the first time by 

 the discovery of the wing impression of a large dragonfly-like insect ; 

 and finally in the Supai formation 1.800 feet below the rim another 

 footprint horizon, was definitely located. 



Fossil tracks were found in considerable abundance in all three 

 of these formations and at several levels in the Hermit Trail sec- 

 tion, and it was along this trail that most of the collecting was done. 

 This later investigation shows that in the perfection of their preserva- 

 tion and in the great variety of footmarks found, there are few locali- 

 ties that outrank this one. It is further unique in probably being the 

 only place in the world where fossil tracks of three successive faunas 

 may be found in one nearly vertical geological section, separated 

 by such great geological intervals. It is now known that these 

 evidences of past life range through over 800 feet of rock strata. 



* Smithsonian Misc. Coll., Vol. 78, No. i, 1926, pp. 20-23. 



