CONTRIBUTIONS TO PAL^ONTOLOOT. 209 



The following list will illustrate the stratigraphical distribution 

 of the fossils described in the preceding pages, from the Potsdam 

 sandstone of the Mississippi valley. 



Species from the upper beds of the Sandstone, and base of the Calciferous 

 sandstone, extending not more than one hundred feet below the latter rock. 



Fossils. Page. Plate and figure. 



LlNQULA AURORA . . 126 Vl, 4 & 5. 



L. AURORA, rar 127 Vi, 6-8. 



L. MOsiA 126 Vi, 1-3 & 3 a. 



DiSCINA? INUTILIS 130 Vl, 11. 



EUOMPIIALUS? VATICINUS 136 Vl, 29. 



Serpulites murchisoni 136* Vi, 32. 



DiKELocEPHALus MiNNEsoTENsis, 138 Ix, 5-10; X, 10-12, and Xi, 1-3 & 4. 



D. ' M. rar. limbatus, 141 Ix, 12. 



D M. var 141 Ix, 11, and X, 9. 



D. PEPiNENSis 142 Ix, 1-4, and X, 13-17. 



Triarthrella auroralis 177 Ix, 13. 



Aglaspis barrandi 181 Xi, 7-16. 



Species from the beds which are here grouped together as the central portion 



of the formation, and which may hereafter be subdivided. 



Dendrograptus hallianus 124 



LiNGULA WINONA 126 Vl, 9. 



Orthis PEPiNA 134 Vi, 23-27. 



Platyceras primordialis 136 Vi, 28. 



DiKELocEPHALus MisA 144 Viii, 15. and X, 4-6 & ? 7 & 8. 



D. OSCEOLA 146 X, 18-19. 



D. SPINIGER 143 X, 1-2. 



CoNOCEPHALiTES ANATINU3 158 Vii, 34-35, and Viii, 29. 



C. BiNODOsus .. . 160 Vii, 47-48. 



C. DiADEMATus .. 167 Vii, 36-38, and Viii, 18 & 21. 



C. EOS 151 Vii, 24-25, and Viii, 8-9. 



C. ERYON 157 Vii, 10-16, and Viii, 16 & 31. 



C. HAMULUS 166 Vii. 43-44, and Viii, 25-26. 



C. NASUTUS 155 Vii, 3-9. 



C. owENi 155 Viii, 17 & 20. 



C. PATERsoNi .... 159 Vii, 45-46. 



C. PERSEUS 153 Vii, 17-23, and Viii, 33. 



C. SHUMARDi 154 Vii, 1-2, and Viii, 19 Sc 32. 



C wiscoNSENsis.. 164 Vii, 39-42, and Viii, 22-24 & 26-28. 



Arionellus bipunctatus 169 Vii, 50-51. 



PtYCHASPIS GRANULOSA 173 Vl, 33-40. 



P. MiNiscAENsis 171 Vl, 41-47, and X, 21-22. 



P. ? 174 Vi, 48. 



Chariocephalus whitfieldi . . . 175 Vi, 49-53, and X, 20. 



Ill^nurus quadratus 176 Vii, 52-57. 



Agnostus disparilis 179 X, 25-27. 



A. JOSEPHA 178 Vi, 54-55. 



A. PARiLis 179 X, 23-24. 



Species from the lower beds. 



LiNGULA ampla 125 Vi, 10. 



Lingulepis piNNAFORJiis 129 Vi, 12-16. 



Obolella? polita 133 Vi, 17-21. 



Theca primordialis 135* Vi, 30 & 31. 



Conocephalites MINOR 149 Viii, 1-4. 



C WINONA 161 Vii, 26-28. 



C. iowensis 162 Vii, 29-33, and Vm, 10-12 & 30. 



C. NACTUS 200 Vii, 58. 



[Senate, No. 115.] 27 



