DESCRIPTION OF SPECIES 321 



Two imperfect specimens of this species were collected from the 

 Amsden, and the reference to T. suhcuneata Hall is provisional. 



8CHIZ0PH0RIA 8WALL0VI ? (Hall) 



Plate 19, figures 12-13 



1858. Orthis swallowvi Hall, Geological Survey of Iowa, volume 1, part 2, 

 page 597, plate 12, figures 5a- 6. 



1914. Schizophoria swallovif Weller, Illinois State Geological Survey, mono- 



graph 1, pages 167-168, plate 22, figures 1-6. 



This is one of the rare fossils in the association. A single immature 

 specimen, with conjoined valves, is illustrated. Fragmentary specimens 

 in the collection show that the species reached the following dimensions : 

 Length, 36 millimeters; breadth, 34 millimeters; thickness, 26 milli- 

 meters. This species has not hitherto been recorded from above the Bur- 

 lington, but specimens from the Saint Louis of Knox County, Missouri, 

 are in Mr. Greger's collection. 



CHONETJES GHESTEBENSIS (Weller) 



Plate 18, figure 19 



1915. Chonetes chesterensis Weller, Illinois Geological Survey, monograph 1, 



page 83, plate 8, figures 31-34. 



Only one specimen was collected from the Amsden. It is referred to 

 C. chesterensis, though it seems to agree as well with C. cheroJceensis 

 Snider.^ 



ORTONIA cf. BLATCWLEYI (Cumings and Beede) 



Plate 18, figure 15 



1905. Ortonia Matchleyi Cumings and Beede, Indiana Department of Geology 

 and Natural Resources, thirtieth annual report, page 1273, plate 19, 

 figure 8. 



Only one specimen of this species was collected. It is approximately 5 

 millimeters long and II/2 millimeters wide at the open end. Attached 

 for the entire length; trumpet-shaped; the small end bent; strong annu- 

 lations, but overlapping not determinable. Agrees in most respects with 

 Ortonia hlatchleyi. 



MIC ROD ON cf. OBLONGUS (Hall) 



Plate 19, figures 25 and 11 



1856. Cypricardella oMonga Hall, Transactions of the Albany Institute, volume 

 4, page 18. 



8' Oklahoma Geological Survey, Bulletin 24, p. 77, pi. ill, figs. 16-18. 



