STATE GEOLOGIST 107 



219 Predui ;•.>. gp ; 



\ species destitute of radiating stria- or ribs. The ventral 



valve Bhews five or six varices or iiii' - wth j the dor- 



the Bame re than this. The Bnrface 



It is allied yphoides DcKoninck, (Op. cit p. 182 



Pl. 1 \ ;. but cot to the other figui 



Uity — Grand Rapids. 



213 Pi •: 18, Bp f 



j< mbles in form a: P. muricatus, Nor-* 



1 and Pratten, from the coal measures, but the radiating 

 ribs are too fine. It is Bomewhat like DeKoninck'a fignre of 

 /'. tt Setae, (1M V1IL, Pig. 8,)%utis not sinuated. It el 



ids with P. costatus from tbe coal measures, 9 miles 

 north of St. Louis, M . except in not being Binaated, and in 

 spicuous character of the concentric rug 



Uity — Grand Rapids. 



•J 1 1 ip ? 



Has the farm of the last, but the radiating Btriae are much 

 liner and the concentric folds little conspicuous. 



Uity — Grand Eta] 



115. Orthis umbraculum (?) von Buck. 

 Allied to 0. robuMdt Ball, (Op. cit. 713.) Resembles 0. urn- 

 figured by DeKoninck, (Op. cit. p. ±2'S,) from 

 carboniferous limestone, but I igured by Owen, (Op. 



cit., Tab. V., Fig. 11.; It exceed'' mbles this B| 



- knsbury'a B • 6.) 



I Ba] 



116. 



ii.it valve with slender auriculate appendagee i \- 

 ling the hinge line to nearly the greatest width of the 



•11. ' 



Uity — Grand Rap 



■ dorsal valve m «e finely striate than the j 



•JIT. A.thyris subquadrata, HaU, (Iowa Rap., TU3.) 

 Thi- caskia limestone. 



— < rrand 

 318. a Bublamell E . (Iowa Rep., p. 702.) 



•II. luit the shell is not more than one-third 



the dim- portfonally a little thinner. 



askia limestone. 



