ILLUSTRATIONS. 



Page. 

 Plate I. Figs. 1 and 2, Menophyllum ulriciianimi; figs. 3 and 4, Spiriferina aolidiroslris; fig. 5, 

 Semmula subquadrata? ; figs. 6 and 7, Oramena subelliptica; figs. 8-10, Craniena subel- 

 liptica var hardingensis; figs. 11 and 11a, Eumetria woosteri; fig. 12, Myalina heokuh; 

 fig. 13, Streblopteria media; fig. 14, Archseocidaris ourayensis; fig. 15, Prismopora trian- 

 gulata; figs. 16 and 16a, Orthotichia schucJiertensis; figs. 17-18, Chonetes flemincp; figs. 



19 and 19a, Chonetes geinitzianus; figs. 20-23, Chonetes mesolohus 484 



II. Froductus semireticulatus var hermosanus 488 



III. Figs. 1-3, Productus inflaius; figs. 4-8n, Froductus (/aUatinensu; figs. 9-11, Prodnctus 



sp. b 490 



IV. Productus cava 1 494 



V. Figs. l-2a, Productus nebraskensis; fig. 3, Productus sp. a; figs. 4 and 4a, Marginifera 



lasallensis; figs. 5-7, Marginifera maricata; figs. 8 and 8a, Marginifera wabashensis 



var.; figa. 9-lln, Marginifera haydenensis; figs. 12-136, Marginifera ingrata 496 



VI. Figs. 1-3, Spirifer hoonensisf; figs. 4-7c, Spirifer rockymontanus; figs. S-lOa, Squamu- 



laria perplexa; figa. 1 1-llc, Spiriferina kentuckyensis 500 



VII. Figs. 1-10, Seminula subtilita; figs. 11 and llo, Dielasma bovidens; figs. 12 and 13, Hustedia 



mormoni; figs. 14-14/), Pugnax utah 504 



VIII. Fig. 1, Aviculopecten. occidentalis; fig. 2, Amculopecten sp. a; fig. 3, Aviculopectenf 

 interlineatus; fig. 4, Pseudomonotis kansasensis; fig. 5, Pseudomonotis equistriata; figs. 

 6 and 7, Myalina subqiiadraia; figs. 8-13, Myalina vyyamingensis; figs. 14-17, Myalina 



cuneiformis 508 



IX. Figa. 1 and 2, Aviculopecten nebraskensis; fig. 3, Monopteria alata; figs. 4-6, Allerisma 

 terminale; figs. 7-9, Edmondia gibbosa; fig. 10, Schizodus cuneatus; figs. 11 and 12, 



Pleurophorus subcostatus 512 



X. Figs. l-2a, Platyceras parvum; figs. 3 and 3a, Strophostylus subovatusf; figs. 4-5fc, Stro- 

 phostylus remex; figs. 6-7a, Bidimorpha chrysalis; fig. 8, Loxenemaf peoriense; figa. 9 

 and 9a, Euconispira taggarti; figs. 10-106, Patellosthnn ourayense; figs. 11 and 12, 



Phillipsia irinucleata 516 



5 



