TABLE V. 



FOSSIL-SHELLS FKOM THE CAEBOKIFEROUS LIMESTONES OF IOWA AND NEBRASKA. 



). v., Fig. 1. Pruilviius rora (large variety). Missouri River, below the mouth of Little Platte River. 



Fig. 2. Pioduclus Fhmingii (Low.) ; synonyms /o/in^jfs (Ver.) ; longispiiius [Kou.) Missouri River, near the month 

 of Keg Creek. 



" Fig. .'j, Produclus Neb7-asccnsis. Missouri River, near Council Bluffs. 



Fig. 4. Spirifer fascigci' Missouri River, near the mouth of Keg Creek, and Piattshurg, Missouri. 



This species approaches in many of its characters to S.fasciger of Keyserling. It appears to differ, 

 however, in some particulars, perhaps sufficiently to constitute a distinct species. Like the fasciger, it 

 has a deep sinus, and corresponding permanent and rather sharp bonrrelet. Like it, too, the surface 

 of the shell, on either side of the bonrrelet and sinus, both on dorsal and ventral valve, is marked by 

 folds or plications, but these are not only more numerous (4 to 0) than in the description of the 

 fasciger, but much more prominent than is indicated by the figures given of that species, Table 8, figs. 

 3, and 3 a and b* The folds are subdivided with small ribs of unequal size, generally from four to 

 five on each fold. Both the sinns and bonrrelet are provided with from nine to ten ribs of unequal 

 size. The shell is therefore marked with fascicuke or bunches of ribs collected into groups, each 

 group containing from three to six ribs. 

 There is a smaller plicated Spirifer abundant in the calcareous rocks of the western and southern 

 margins of the Iowa and Missouri coal-fleld, which is probably the same as this species, described by 

 Hall under the name of S. triplicata, in Stansbury's Expedition to the Great Salt Lake, which may be 

 a smaller variety or young individual of this fossil. 



" Fig. 0. Spirifer aitcnualiis, in member e of the Lower Series of Carboniferous Limestones, on Skunk River and else- 

 where. ' 



■' Fig. 6. Spirifer ineqnicostahts .' Skunk River"? Iowa. 



Fig. 7. AnccUa crassicoUis ? Keokuk Rapids of the Mississippi River. 



'■ Fig. 8. Cast of IBeUcrophon hiidms .' Keokuk Rapids of the Mississippi. 



" Fig. 9. Tercbraiula plano-suhata. Upper Missouri, near Council Bluff's. 



" Fig. 10. Gyroceras Buiiingtonensis (N. S.) From the oolitic bed, top of member a, of the Lower Series of Carbo- 

 niferous Limestones, Burlington quarries. 



" Fig. 11. Orlkis umbracidum? 



The description given by De Koninck of Orthis umbracidum, p. 222 of his work on the fossils of the 

 Carboniferous rocks of Belgium, agrees with the characters of this siiecies, obtained on the Missouri 

 River, both near the mouth of Keg Creek, and under the marls and drift at the base of Council Bluffs, 

 except in the number of ribs or strife, which are much more numerous in the American fossil, — at least 

 sixty at the beak, and more than double that number at the border, irregularly alternating coarse and 

 fine; with three strongly-marked, concentric lines of increase, and one less distinct. 



" Fig. 12. Clioiiclcs granuHfera (N. S.) Missouri River, near the mouth of Keg Creek. 



" Fig. 13. Allorisma regularis ? 



I have not been able to discover any essential difference between this fossil, from near the base of 

 the section at Wayne City, on the Missouri River, except that the shell is rather flatter, and the trans- 

 verse folds are not so regular, some of tlie middle ones bifurcating, or becoming broad folds as 

 they curve towards the posterior border; in this latter character it approaches to A. sidcata, but 

 it is not gaping like that species, and is less gibbous and more elongated. 



" Fig. 14. Biscdcs Itibcrculatus (N. S.) Iowa Point, Missouri River. 



* Wisseiiscliariliclie Beobaclitungeii in das Fdschoro Land, p. 231. 



