FOSSIL FOOTPRINTS FROM THE GRAND CANYON : 

 SECOND CONTRIBUTION 



By CHARLES W. GILMORE 

 curator of vertebrate paleontology, united states national museum 



(With 21 Plates) 



INTRODUCTION 



In continuation of an investigation of the fossil footprints of the 

 Grand Canyon, so successfully begun in 1924,* I was enabled, through 

 an allotment granted by the Marsh Fund committee of the National 

 Academy of Sciences, to visit the Canyon again in the early spring 

 of 1926, This expedition had as its purpose the acquisition of addi- 

 tional fossil tracks from the Coconino and Hermit formations, and 

 the extension of the investigation 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. The 

 expedition was successful far beyond expectations, the collection 

 made for the United States National Museum comprising a series 

 of slabs some 2,700 pounds in weight, on which are animal tracks 

 from three distinct and successive geological formations. 



The old locality in the Coconino sandstone on the Hermit Trail 

 was explored laterally and a large series of beautifully preserved 

 tracks and trails secured, including many forms new to this ichnite 

 fauna, and the Hermit shale, some 1,400 feet below the level of the 

 Canyon rim, yielded both fossil tracks and plants. The discovery of 

 a wing impression of a large dragonfly-like insect records for the 

 first time the presence of such forms in the latter formation. Finally 

 in the Supai formation at a level about 1,800 feet below the rim, 

 another footprint horizon was located and a few poorly preserved 

 tracks were collected from this level on both the Hermit and Yaki 

 trails. It is upon these collections that the systematic ])art of the 

 present paper is based. Even with the diversity of forms now 

 available, it is still quite evident that further collecting will add many 

 more varieties to the known ichnite faunas of these three formations. 



I am under especial obligations to Dr. John C. Merriam and his 

 associates on the Marsh Fund committee of the National Academy of 



^ Gilmore, Charles W., Fossil footprints from the Grand Canyon. Smith- 

 sonian Misc. Coll., Vol. T], No. 9, 1926, pp. 1-39, 12 plates and 2}, text figures. 



Smithsonian Miscellaneous Collections, Vol. 80, No. 3 



