6?6 



NORTH AMERICAN INDEX FOSSILS. 



218. T. shumardi (de Verneuil). (Turbo shumardi.) (Fig. 940.) 



Devonic. 



Large, last two whorls with strong oblique folds on shoulder 

 portion, these appear gradually and progressively increase in 

 strength ; median carina strong, blunt ; aperture subpentahedral. 



Onondaga of Ohio, Falls of Ohio, Indiana, Kentucky, and New 

 York (?). 



Family Strophostylid^: * Grabau & Shimer. 

 LXXI. Holopea Hall. 

 Spirally coiled shells with round whorls generally smooth, and 

 complete aperture. Ordovicic-Mississippic ? 



219. H. ampla U. and S. (Fig. 941.) Ordovicic. 



Fig. 941. Holopea ampla, X Z A- (After Ulrich, Pal. Minn.) 



Large, umbilicated, growth lines frequently fasciculate and coarse. 

 Stones River of Minnesota and Wisconsin. 



220. H. similis U. and S. (Fig. 942, a (left).) Ordovicic. 

 Smaller, higher spired, more slender and with smooth whorls. 

 Black River of Minnesota, Lorraine of Kentucky. 



221. H. rotunda U. and S. (Fig. 942, b (right).) Ordovicic. 

 Small, whorls higher, spire less obtuse, umbilicus smaller than 



in preceding. 



Stones River of Illinois ; Trenton of Tennessee. 



Fig. 942. Holopea similis (left); H. 

 rotunda (right). (After Ulrich and 

 Scofield, Pal. Minn.) 



Fig. 943. Holopea (.<?) textilis. 

 ( After Ulrich and Scofield, Pal. 

 Minn.) 



