146 STUART WELLER 



10. ScJiizophoria swallovi Hall. Specimens of this species identical 

 with those in the Burlington limestone are present in this fauna. 



11. Rhipidomella bnrlingtonensis Hall. Individuals of this species 

 from the Pierson limestone resemble those from the Northview 

 sandstone, and are more nearly like typical representatives of the 

 species from the Burlington limestone than are the Sac limestone 

 specimens. 



12. Camarophoria sp. undet. This species is of the general form of 

 C. caput-testudinis White, the types of which are from the base of the 

 Burlington limestone, and bed No 7 of the Kinderhook at Burling- 

 ton. The Pierson limestone species, however, differs from C. captit- 

 testudinis in being a much smaller and flatter shell. 



13. Rhynchonella cooperensis Shum. This species was originally 

 described from the Chouteau limestone of Cooper county, Missouri. 



14. Athyris lamellosa Lev. This is one of the commonest species of 

 the fauna, and specimens from the Pierson limestone are indistin- 

 guishable from those in the Burlington limestone. 



15. Spirifer marionensis Shum. This is the same species that occurs in 

 the Northview sandstone. It is one of the commonest members of 

 the Pierson limestone fauna and also of the oolitic limestone fauna 

 at Burlington. 



16. Spirifer latior Swall.? The specimens identified as this species 

 are not different from those in the fauna of the Sac limestone. 



17. Spirifer peculiaris Shum. The Pierson limestone representatives 

 of this species are not unlike those from the Sac limestone. 



18. Spirifer grimesi Hall. This Burlington limestone species is repre- 

 sented by typical individuals in the Pierson limestone. 



19. Spirifer sp. undet. This species has the high area of Syringothyris, 

 but lacks the syrinx, and is apparently not punctate. 



20. Reticularia cooperensis Swall. This species rarely occurs in the 

 fauna. It is a common form in the typical Chouteau limestone and 

 also occurs in the upper "yellow sandstone" at Burlington. 



21. Dielasma sp. undet. These specimens have the general form and 

 size of those recorded from the Sac limestone, but usually have 

 more conspicuous lines of growth. 



22. Macrodon sp. undet. A single imperfect specimen of this genus is 

 the only pelecypod recognized in the fauna. 



23. Orthoceras sp. undet. Fragmentary specimens of a species of 

 Orthoceras are not uncommon in the fauna. 



In the Pierson limestone fauna we find a disappearance of 

 the pelecypod element which is so characteristic of the North- 

 view sandstone, and a return of the brachiopods. Some of these 



