Figs. 
Figs. 
Figs. 
Fig. 
Fig. 
Figs. 
Figs. 
Figs. 
Figs. 
31 and 32, 
31. 
32. 
33 and 34. 
35 to 37. 
35 and 36. 
37. 
38. 
39. 
40 and 41. 
42 and 43. 
42. 
43. 
44 and 45. 
46 and 47. 
PLATE XXXVI.—Continued. 
PSMOCONCHA) MINNESOTENSIS,) Win SP) cteiete)sisjeleta ce eve nile cieinie’ om ale etaare| sleim ehieioia elele eiciefoteletels 
The right side of a cast of thelinterior, which has been shortened by pressure no 
less than is indicated by the outline restorations. 
Dorsal outlines of same. Middle Galena, near Pleasant Grove, Minnesota. 
HN DODESMA. (CUNE AUG, ip SPrictere reiclelslais eieia'a of ielote ane ote aie tal ofeleyntecinietate ete sletetetet a) <a aiets 
Dorsal and lateral views of an excellent cast of the interior. Middle Galena, 
near Wykoff, Minnesota. 
EENDODESWA" COMPRESSUM? (1: SP ixtatals =. Lilo le oieiels eieieleisuareteie stole inte ibs et otainiole Sleteiotale 
Dorsal and lateral views of a cast of a left valve. Middle Galena, near Wykoff, 
Minnesota. | 
Sectional view across the shell a short distance behind the beaks, showing the 
inbending of the hinge plate. 
ENDODESMA’ UNDOSUM, Th SDis <0. fo 5 cee one et wcia'e alaiels|mis/ole/biaisivisiele e's © sis/alalets Asotes 
Cast of the interior of both valves. ‘‘Upper Buff” beds of the Trenton formation, 
near;Beloit, Wisconsin. Geol. Sur. Mus. Reg. No. 8344. 
CUNEASLYAT TRUNCATAS SI SD oe ore cite .eiets cinch tosotern tela iol tet ejall= atoll alendiaeiatoteinletaleistele stalls 
Cast of the interior of a right valve. Middle Galena, near Wykoff, Minnesota. 
GUINHAM YA OBLONGAG ae: SPs ie cre wietelals sisteletetarstereteta abe olotererstcinal eteiha ley pualalsyaleiotelemnteicinisieteaaie 
Lateral and dorsal views of the specimen described. The imperfect posterior 
end is restored in the figure. Upper Galena, Dixon, Illinois. 
SPHEN OFMUM Ale Ads Tir UM eIRce SP stseletetetes ciele olelere Suet atale) ehclaiehd afelage emote late ainieiellatereis nie 
Cast of the interior of a right valve, imperfect at the anterior end, but otherwise 
in an excellent state of preservation. 
Cardinal view of the same, with the left valve restored in outline. ‘‘ Lower 
Blue” beds of the Trenton formation, Mineral Point, Wisconsin. Geol. Sur. 
Mus. Reg. No. 8346. 
SPHENOLIUM STRIATUM, D. SP.....- ccccen cece nc cece creer stces cceseteceeestecccnse 
Lateral and dorsal views of a nearly complete cast of the interior. Middle 
Galena, Goodhue county, Minnesota. 
RHYTIMYA SINUATA, D. SP. ccc cece cece ence ese ee ee cece penneeee sens cece eeee reas 
Lateral and dorsal views of an internal cast of a left valve. Middle Galena near 
Wykoff, Minnesota. 
529 
529 
622 
623 
624 
624 
619 
