PLATE LXXIX. 



PAGE. 



F igs. 1 to 5 HOLOPEA INSIGNIS U. and S 1065 



1 and 2 Opposite views of the interior cast of a young shell. The bight is relatively 

 greater than in fully grown individuals. Stones Eiver group, Minneapolis, 

 Minnesota. 



3 to 5 Three views of a large cast. This specimen is so sharp and clean that it may be 

 a cast of the exterior rather than of the interior. Stones River group, Cannon 

 Falls, Minnesota. 



Fig. 6 HOLOPEA CONCINNULA D. and S 1066 



A cast of the interior, the last whorl with obscure lines of growth. Stones 

 River group, Beloit, Wisconsin. 



Figs. 7 to 10 HOLOPEA APPRESSA U. and S 1065 



7 to 9 Three views of a small but entire cast of the interior, giving a good idea of 

 the peculiarities of the species. Clitambonites bed, Goodhue county, 

 Minnesota. 



10 Under side of a larger cast. Geological and Natural History Survey of Minnesota, 



Museum Register No. 6765. 



Figs. 11 and 12 HOLOPEA EXCELSA U. and S 1067 



11 Apertural view of an incomplete cast of the interior. Fusispira bed, Wykoff, 



Minnesota. 



12 Dorsal view of a nearly complete cast from the same locality. 



Figs. 13 to 18 HOLOPEA PYRENE Billings 1067 



13 and 14 Two views of a cast of the interior, the inner whorls restored. Trenton group, 



near Cannon Falls, Minnesota. 



15 to 18 Four views of a cast of the interior of a young specimen. Fusispira bed, near 

 Cannon Falls, Minnesota. 



Fig. 19 HOLOPEA var. PARVULA Dlrich 



Dorsal view of the largest of three specimens. Upper Trenton, near Burgin, 

 Kentucky. 



Figs. 20 and 21 HOLOPEA ROTUNDA U. and S 1066 



20 Perfect silicifled shell, showing the aperture, minute umbilicus, and general 



form of the, shell. Trenton group, Hartsville, Tennessee. 



21 A much larger specimen, presumably of this species, from the Stones River 



group at Dixon, Illinois. 



Figs. 22 to 25 HOLOPEA AMPLA U. and S 1065 



22 An average example of this species. The specimen is a cast of the interior 



and shows broad varices of growth and rather obscure traces of revolving 

 lines. Stones River group, Cannon Falls, Minnesota. 



23 to 25 Body whorl of a large specimen, strongly marked with wrinkles and lines of 

 growth. The specimen appears to be a cast of the exterior and is from 

 Cannon Falls, Minnesota. Geological and Natural History Survey of 

 Minnesota, Museum Register No. 5836. 



Fig. 26 HOLOPEA SIMILIS U. and S 1066 



Dorsal view of an average example of the form which we have separated 

 provisionally from H. ampla and H. obliqua under this name. Shales of the 

 Black River group, Flllmore county, Minnesota. Geological and Natural 

 History Survey of Minnesota, Museum Register No. 7381. 



Figs. 27 and 23 HOLOPEA SUPRAPLANA U. and S '0*58 



27 Dorsal view of a cast of the interior. Lower part of Fusispira bed, Kenyon, 



Minnesota. 



28 Apertural view of the largest specimen seen. Though a cast of the interior, 



it gives a good idea of the strongly inrolled thin inner lip. Kenyon, 

 Minnesota. 



