304 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 49 



PAGE 



Protichniics logananus Marsh. (See pi. 48) 279 



Fig. I. (Reduced to about one-fifth natural size.) Part of the trail 

 shown in the upper part of plate 48. In the central trail, 

 crossing diagonally from the left lower to upper right 

 corner, the imprint made by the caudal furca shows that 

 the animal partly lifted its body from the sand as it moved 

 along. U. S. National Museum, Catalogue No. 58402. 

 The specimen represented is from locality (77), Upper Cambrian, 

 Potsdam sandstone in Ausable Chasm, Essex County, New York. 



