PLATE LXXX. 



PAGE. 



Fig. 1 FUSISPIRA SCHUCHKRTI U. and S 107(i 



View of the type and only known specimen of this species. Part of the shell 

 is preserved. Its great thickness is the most important, of the peculiarities 

 of the species. Black River group, Beloit, Wisconsin. Geological and Natural 

 History Survey of Minnesota, Museum Register No. 7322. 



Figs. 2 to 4 FUSISPIRA NOBILIS U. and S 1078 



2 and 3 Opposite views of a sharply defined but incomplete and small cast of the 

 interior, showing, besides the usual characters of the species, seven obscure 

 revolving lines on two of the whorls. Trenton group, Fusispira bed, Wykoff, 

 Minnesota. 



4 A larger specimen from the same locality. This slightly exceeds in size the 



average for the species. The whole surface is covered with a thin layer of 

 crystalline calcite and exhibits not a trace of revolving bands. 



Figs. 5 to 7 FUSISPIRA SULCATA Ulrich 1077 



5 Dorsal view of a specimen that, excepting the patch of shell shown, is a 



sharply defined cast of the interior. The shell is rather thick, and, as shown 

 in the figure, the external suture line is situated considerably higher than 

 * it is in the cast. The latter shows, especially on the upper whorls, rather 

 distinct revolving sulci. Base of Utica or top of Trenton, Scott county, 

 Kentucky. 



6 Apertural view of same. 



7 Small portion of the surface of the shell xlO, showing punctae of two sizes 



arranged in series parallel with the suture line. 



Figs. 8 to 10 FUSISPIBA CONVEXA U. and S 1077 



8 Dorsal view of an incomplete but clean cast of the interior, from the Trenton 



limestone at Trenton Falls, New York. Has obscure revolving bands like 

 the preceding species but differs in its more convex and more depressed 

 whorls. 



9 The last two whorls of a larger cast, apparently of this species. Clitambonites 



bed of the Trenton group, Goodhue county, Minnesota. 

 10 Outline of the lower and outer parts of the lip of same as seen from beneath. 



Figs. 11 to 16 FUSISPIRA SUBBREVIS U. and S 1076 



11 and 12 Opposite views of a small cast of the interior, Fusispira bed, Goodhue county, 

 Minnesota. 



13 Apertural view of a much larger cast. This specimen has the mouth entire 



but has suffered some from pressure and may not really belong to this species. 

 Maclurea bed of the Trenton group, Stewartsville, Minnesota. Geological 

 and Natural History Survey of Minnesota, Museum Register No. 8728. 



14 Dorsal view of lower two whorls of same. 



15 Dorsal view of a specimen from the Fusisptra bed at Decorah, Iowa. This 



agrees, so far as we can see, exactly with the original of fig. 11. Geological 

 and Natural History Survey of Minnesota, Museum Register No. 7362. 



16 Outline, as seen from below, of lower and outer portions of the lip of the 



specimen represented by figs. 13 and 14. 



Figs 17 and 18 FUSISPIRA INFLATA Meek and Worthen 1075 



17 Apertural view of a cast of the interior of a young specimen. Lower part of 



Fusispira bed, Kenyon, Minnesota. 



18 Apertural view of a large and nearly perfect cast of the interior, showing the 



adult appearance of the species. Fusispira bed, Goodhue county, (Hader 

 P. O.), Minnesota. In the variety which occurs in the Maclurea bed the 

 under side of the whorls is more ventricose, causing the bend in" the Inner 

 outline of the aperture to be more abrupt. 



Figs. 19 to 21 FUSISPIRA INTERMEDIA U. and 8 1076 



19 Dorsal view of a specimen showing the slender spire and relatively rapid 



expansion of the last whorl. Maclurea bed, Stewartsville, Minnesota. Geolog- 

 ical and Natural History Survey of Minnesota, Museum No. 7451. 



20 and 21 Opposite views of another specimen from this locality, showing, as far as it goes, 

 the same features. 



