PLATE LXXVI. 



PAGE. 

 Figs. 1 to 3 MACLURINA CUNEATA Whitfleld 1042 



(See also plate LXXXlI.j 



1 Upper side of an average cast of the interior of this common speeies. showing the 

 small umbilicus. 7 mm. less than natural size. Geological and Natural His- 

 tory Survey of Minnesota, Museum Register No. 8440. 



2 and 3 The lower side and a lateral view of another specimen. 5 mm. less than natural 

 size. Maclurea bed of the Trenton group, Stewartsville, Minnesota. Geologi- 

 cal and Natural History Survey of Minnesota, Museum Register No. 8441. 



Figs. 4 and 5 MACLURINA MANITOBKNSIS Whiteaves 1041 



(See also plate LXXXIl.) 



Two views of a cast of the interior. Trenton group, Lime City, Minnesota. 

 Geological and Natural History Survey of Minnesota. Museum Register No. 

 4105. 



Figs. 6 to 8 TROCHONEMA OBSOLETUM Dlrich 1054 



6 A finely preserved example of the natural size. Upper Trenton, near Burgin, 



Kentucky. 



7 Lateral view of same x2.5, showing surface markings and obsolescence of 



revolving ridges on the last whorl. The ridges are quite distinct on turns 

 preceding the last. 



8 Basal view of same xl.8. 



Figs. 9 and 10 TROCHONEMA ARCTATUM Ulrich 1054 



9 Outline view of the type of this species. Trenton group, near Burgin, Kentucky. 

 10 Apertural view of same x2. A few of the fine lines of growth are faintly indicated. 



The peripheral band is unusually narrow for species of this genus, and might 

 easily be mistaken for the band of a pleurotomarian shell. 



Figs. 11 to 15 TROCHONEMA ROBBINSI U. and S 1053 



11 to 14 Four views of a large cast, in part both interior and exterior, imperfect at both 



extremities. The even slope of the surface from the suture to the peripheral 



band is one of the most striking features. Fusispira bed, Wykoff, Minnesota. 



Geological and Natural History Survey of Minnesota, Museum Register No. 7516. 



15 A small cast of the interior from the same locality. 



Figs. 16 to 18 TROCHONEMA NIOTA Hall sp 1052 



Three views of the nearly entire cast of the interior upon which this species is 

 founded. Stones River group, Beloit, Wisconsin. 



