14 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8o 



ICHNITES FROM TAPEATS SANDSTONE 

 Plate 5, figs. I, 2, 3, and 4 



In a previous paper ^ mention was made in a footnote of the dis- 

 covery by Mrs. G. E. Sturdevant on the Bright Angel Trail of a 

 small section of a trackway which at that time was thought to come 

 from the Bright Angel shale. More extended search of this locality 

 by Messrs. G. E. Sturdevant and Edwin D. McKee has brought to 

 light several additional specimens, and Mr. S.turdevant writes me that 

 all of these specimens, including the one previously found by Mrs. 

 Sturdevant, are from the Tapeats sandstone. 



The correctness of his observation is fully confirmed by comparison 

 of the specimens with trails figured by the late Dr. Charles D. 

 Walcott ^ from the Tapeats sandstone of other parts of the Grand 



Fig. 7. — Trilobite ? trail from Middle Cambrian; Tapeats sand- 

 stone on Bright Angel Trail. About 4 natural size. 



Canyon, several of which are identical in character. That there was 

 an extended ichnite fauna in this formation is abundantly shown by 

 the many different kinds of trails figured by Walcott, and by the 

 specimens more recently collected. 



Walcott attributes all of the various kinds of trails illustrated by 

 him as being made by trilobites. He points out that the known genera 

 and species of trilobites from the Middle Cambrian give a wide varia- 



* Smithsonian Misc. Coll., Vol. 80, No. 3, 1927, p. 9. 



° Smithsonian Misc. Coll., Vol. 67, No. 4, 1918, pis. 37 to 42. 



