4l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



DESCRIPTION OF PLATE 47 



PACK 



Baihyuriscus howclli Walcott 343 



Fig. I. (X2.) Type specimen of the species. The pleural lobes are 

 flattened a little in the shale. U. S. National Museum, 

 Catalogue No. 15457. 

 ifl. (X 2.) Cranidium partly crushed in the shale. U. S. National 



Museum, Catalogue No. 15457a. 

 lb. (X 2.) Pygidium partly crushed in the shale. U. S. National 

 Museum, Catalogue No. 15457/'- 



The specimens represented by figs, i, la-b are from the same layer 

 of very fine arenaceous shale, i and la were illustrated on plate 30, 

 figs. 2, 2a, in 1886 (Bull. U. S. Geol. Surv., No. 30). 



From locality 31, Middle Cambrian: Chisholm shales, at the 

 Chisholm Mine, southwest slope of Ely Mountains, 3 miles (4.8 km.) 

 northwest of Pioche, Lincoln County, Nevada. 



Bathyiiriscus roiuiidatus (Rominger) 34fi 



Fig. 2. (X L5-) A dorsal shield that has been elongated by lateral 

 compression in the shale. The free cheeks are restored in 

 outline U. S. National Museum, Catalogue No. 62629. 



This figure was used -on plate 4, fig. 2, in 1908 (Canadian Alpine 

 Jour., Vol. I, No. 2). 



2a. (X I-5-) A very well-preserved dorsal shield. U. S. National 



Museum, Catalogue No. 62630. 

 2b.. (Natural size.) A pencil and ink drawing of a small dorsal 



shield in which the slightly broken parts have been drawn as 



if unbroken. 



The specimens represented by figs. 2 and 2a are from locality 

 14s, Middle Cambrian: Ogygopsis zone of the Stephen formation; 

 about 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet 

 (823 m.) below the Upper Cambrian in the Ogygopsis zone of the 

 Stephen formation, at the great " fossil bed " on the northwest 

 slope of Mount Stephen, above Field on the Canadian Pacific Rail- 

 road, British Columbia, Canada. 



Bathyuriscus adcctis Walcott 334 



Fig. 3. (Natural size.) A broken dorsal shield restored in part. U. S. 

 National Museum, Catalogue No. 62631. 

 3a. (X2.) Cranidium. U. S. National Museum, Catalogue No. 



62632. 

 3&. (X I-5-) Pygidium that is of the same character as that of 

 Bathyuriscus rotundatus. U. S. National Museum, Cata- 

 logue No. 62633. 



