40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 



EXPLANATION OF PLATES 



Plate i. page 



Fig. I. Slab of footprints in situ on the Hermit Trail, Grand Canyon 

 National Park. This slab is 8 by 2S feet and located gso feet 

 below the rim or 150 feet above the base of the Coconino sand- 

 stone. The mule trail may be seen in the lower left-hand 



corner 2 



2. The same, but taken from a point farther down the trail. The 

 surface of the slab in the foreground is also covered with numer- 

 ous tracks. The slab shown in plate 9 was collected from the 

 exposed layer. Continuation of the trackway may be seen in the 

 center foreground 2 



Plate 2. 



Fig. I.. Pack mules loaded with slabs of footprints starting up the trail 

 for the top of the canyon. All the specimens were transported 

 to the top of the canyon in this manner. 

 2. Unidentified track-like markings found on the sandstones of the 

 Supai formation in " Fossil Bay," Grand Canyon National Park. 

 These occur on a massive band of sandstone 1,673 feet below the 

 level of the canyon rim 37 



Plate 3. 



General view of the foot track locality on Hermit Trail looking east. 

 Photograph taken before clearing ofiF the debris from the hill- 

 side. Photograph by Robert Carson of the Doheny Scientific 

 Expedition. 



Plate 4. 



Fig. I. Dolichopodiis tctradactylus, new genus and species. Type, No. 

 11,123, U. S. N. M. Imprints of digits of the manus are dimly 

 shown behind and slightly outside those of the pes. Less than h. 



natural size 6 



2. Nanopus merriami, new species. Type, No. 11,146. U. S. N. M. 



About i natural size 9 



Plate 5. 



Fig. I. Palaeopns rcgularis, new genus and species. Type, No. 11,143, 

 U. S. N. M. Imprints of forefeet occasionally seen directly in 



front of those made by the hindfeet. About ^ natural size 25 



2. Laoporus nobeli Lull. No. 11,148, U. S. N. M. Lateral digits not 



impressing in this trackway. About j natural size 13 



