52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



of the Stephen formation ; west slope of ridge between Mount Field 

 and Wapta Peak, one mile northwest of Burgess Pass, above Field 

 on the Canadian Pacific Railway, British Columbia, Canada. 



Collected by Mr. and Mrs. C. D. Walcott. and B. Stuart and Sidney 

 S. Walcott. 



Family HOLOTHURIIDiE 

 Genus LAGGANIA, new genus 



Of this species only one specimen and its matrix is known. This 

 indicates that the body was elongate, pear-shaped, and slightly flat- 

 tened on the ventral surface. Mouth ventral, near the anterior end, 

 and surrounded by a ring of plates. Surface marked by longitudi- 

 nally radiating lines. Traces of tube feet occur on the ventral surface. 



Genotype. — Laggania cambria, new species. 



Stratigraphic range. — Limited to a parting in a stratum of dark 

 siliceous shale ,2 feet in thickness in the lower portion of the 

 Ogygopsis zone ( = Burgess shale) of the Stephen formation as de- 

 scribed in 1908. (See the footnote on page 51 of this paper.) 



Geographic distribution.- — On the slope of the ridge between 

 Wapta Peak and Mount Field, north of Burgess Pass, and about 

 3800 feet above Field on the line of the Canadian Pacific Railway, 

 British Columbia, Canada. 



LAGGANIA CAMBRIA, new species 

 Plate 13, fig. I. 



There is not much that can be added to the brief generic descrip- 

 tion. The body of the animal is so completely flattened that the tube 

 feet are obscured, the outline of the ventral sole lost, and the con- 

 centric bands almost obliterated. It is not practicable to make out 

 the arrangement of the plate-like structure surrounding the mouth, 

 as the calcareous plates, if ever present, have disappeared. 



The surface shows indistinct concentric bands, each one of which 

 is crossed by fine longitudinal lines. 



Formation and locality. — Middle Cambrian: (35k) Burgess 

 shale of the Stephen formation ; west slope of ridge between Mount 

 Field and Wapta Peak, one mile northeast of Burgess Pass, above 

 Field on the Canadian Pacific Railway, British Columbia, Canada. 



below the massive, arenaceous limestones of the Eldon formation that cap 

 Mount Burgess, Mount Field, and Mount Stephen. 



Organic remains. — Middle Cambrian : large and varied fauna characterized 

 by crustacean remains on the slope of Mount Field and the Ogygopsis trilo- 

 bite fauna on the northwestern slope of Mount Stephen. 



