124 SMITHSOXIAX MISCEr.LAXEOUS COI.LECTIOXS VOL. 5^ 



DESCRIPTION OF PLATE :o 



Page 

 a. = cardinal area. 

 a'. = cast of umbonal cavity. 



Billingsella major, new species loi 



Fig. I. Cast of the interior of a broken ventral valve. U. S. Na- 

 tional Museum Catalogue No. 52256(/. 

 la. Cast of a dorsal valve. U. S. National Museum Catalogue 

 No. 522566. 



The specimens represented by Figs, i and i(/ are from 

 Upper Cambrian sandstones 2 miles {^.22 km.) west of 

 Baraboo, Sauk County, Wisconsin. 



Wimaiiclla simplex, new species loi 



Fig. 2. Type specimen showing exterior of ventral valve from Lower 

 Cambrian shales, 6 miles (9.66 km.) up Gordon Creek 

 from South Fork of Flathead River, Lewis and Clark 

 Forest Reserve, Montana. U. S. National Museum Cata- 

 logue No. 52278a. 



Wimanella shelbycnsis, new species 100 



Fig. 3. Type specimen showing exterior of compressed ventral valve 

 from Lower Cambrian Montevallo shale, 4 miles (6.44 

 km.) south of Helena, Shelby County, Alabama. U. S. 

 National Museum Catalogue No. 52272a. 



Wimanella / iiiyocnsis, new species 102 



Fig. 4. Type specimen showing cast of the interior of ventral valve 

 from Lower Cambrian limestone in Toll Gate Canyon, 

 White Mountain Range, Inyo County, California. U. S. 

 National Museum Catalogue No. 52255a. 



Billingsella inarion, new species 99 



Fig. 5. Type specimen showing cast of the interior of ventral valve 

 from Aliddle Cambrian limestones of Stephen formation 

 on Mount Stephen, British Columbia. U. S. National Mu- 

 seum Catalogue No. 536760. 



lioorthis nczvbcrryi, new species 105 



P'iG. 6. Exterior of ventral valve. U. S. National Museum Catalogue 

 No. 52350a. 

 6a. Exterior of dorsal valve. U. S. National Museum Catalogue 

 No. 52350^?. 



The specimens represented by Figs. 6 and 6a are from 

 Upper Cambrian limestcnes of the St. Charles formation, 

 in Blacksmith Fork Canyon, east of Hyrum, Cache 

 County, Utah. 



lioorthis thyoiic. new species 105 



Figs. 7 and 7a. Exterior of dorsal valves. U. S. National Museum 

 Catalogue Nos. 52377a and 523770. 



The specimens represented by Figs. 7 and 7a are from 

 Middle Cambrian limestones of the Marjum formation, 

 east of .Antelope Springs, House Range, Millard Countv, 

 Utah. 



