NO. 12 



SMITHSONIAN EXPLORATIONS, I917 



■4 



'•If "*' 



Fig. 4. — Airs. Walcott splitting out Middle Cambrian fossils from 

 slabs of shale blasted out of the fossil-bearing bed of the Burgess Pass 

 quarry. Photograph by Walcott, 1917. 



Fig. 5. ( X--) ^^'1 elongate creeping holothurian {Rcdoubtia polypodia, 

 new genus and species Walcott) with numerous tube feet and tentacles. 

 This and the forms represented by Figs. 6 and 8 belong to undescribed 

 genera and species and are here illustrated for the first time. 



