NO. 9 GRAND CANYON FOSSIL FOOTPRINTS GILMORE 37 



The above fauna, taken as a whole, shows that its affinities he 

 nearest to those described from the Carboniferous Coal Measures 

 rather than to the later Mesozoic Ichnites. This is indicated by the 

 presence in the Coconino of two and possibly three genera common 

 to the Carboniferous, whereas not a single genus of the Triassic was 

 recognized. Furthermore, the facies of the fauna is Carboniferous 

 in aspect as shown by the relatively small size of the animals, all of 

 which are quadruped, as contrasted with the considerable number of 

 very large forms and the many three-toed bipedal animals of the Tri- 

 assic. The Coconino footprint fauna also seems to have closer re- 

 lationships to the Ichnite fauna from the Middle Coal Measures of 

 Kansas, described by Marsh * than to the more extensive faunas 

 from the Coal Measures of Nova Scotia described by Dawson " and 

 Matthew.^ 



The present fauna is founded upon specimens having well-marked 

 characters, and being from a single locality and well-established hori- 

 zon, have a value of their own in throwing light upon the land verte- 

 brate life during the deposition of the Coconino sandstone. If they 

 have but little value in themselves, they may eventually shed much 

 light on the habits and characteristics of the Permian animal life. 



PSEUDO-TRACK-LIKE MARKINGS 

 Plate 2, fig. 2 



Under this heading attention is called to some peculiar track-like 

 markings found on a massive sandstone of the Supai formation in 

 that part of the Grand Canyon known as " Fossil Bay." While 

 these are not regarded as having been made by animals, they are of 

 interest on account of their superficial resemblance to tracks made by 

 horses' hoofs, and since their origin is as yet unexplained, these 

 notes are published in the hope that it may lead to a fuller investi- 

 gation. 



These markings were called to my attention by Mr. Samuel Hub- 

 bard, leader of the Doheny Scientific Expedition of 1924, who had 

 long known of their existence through information obtained from 

 the Supai Indians who regarded them as tracks made by a band of 

 horses. They thickly cover an area of several hundred square feet 

 in extent and have the appearance of semi-oval rings, frequently with 

 the two posterior extremities prolonged backward, but seldom con- 



^ Marsh, O. C, Amer. Journ. Sci., Vol. 42, 1894, pp. 81-84. 



^Dawson, J. W., Geol. Mag. London, Vol. 9, 1872, p. 251. 



^ Matthew, G.' F., Canadian Rec. Sci., Vol. 9, No. 2, 1903, p. 105. 



