PLATE XXL 
Figs. 1, 
Fig. 3. 
Murchisonia desiderata. 
Page 89. 
2. Anterior and posterior views of a specimen with incomplete spire and imperfect aperture. 
An enlargement of part of a single volution, showing the character of the strife and peripheral band. 
Murchisonia Leda. 
Page 91. 
Fig. 4. An imperfect specimen of this species, showing the mouth. 
Murchisonia Maia. 
Page 91. 
Figs. 5, 7, 8. Imperfect individuals of the species. 
Figs. 6, 9. Enlargements of a single volution, showing the character of striae and peripheral band. 
Murchisonia desiderata var. 
Page 90. 
Fig. 10. A cast from a mold in silica, giving a somewhat more slender form than the typical specimen. 
Murchisonia micula. 
Page 93. 
Fig. 11. A specimen imperfect at the apex (a common condition of the species), enlarged to six diameters. 
Pleurotomaria? apicialis. 
Fig. 12. View of the spire of a specimen as obtained by a gutta-percha cast taken from the natural mold 
enlarged to two diameters. 
Fig. 13. 
Fig. 14. 
Pleurotomaria trilix. 
Page 79. 
Enlargement of a specimen of this species. 
An enlargement of a specimen to two diameters. From the soft shales of the Hamilton group, 
outlet of Crooked Lake, N. T. 
Fig. 15. Enlargement of the typical specimen to two diameters; the Upper volutions are imperfect. From 
the shales of the Hamilton group, Seneca Lake, N. Y. 
Pleurotomaria adjutor. 
Page 80. 
Fig. 16. A specimen of this species (natural size). From the limestone of the Upper Helderberg group, 
Dublin, Ohio. 
Pleurotomaria insolita. 
Page 81. 
Fig. 17. The only specimen of this species known, enlarged to three diameters, and showing the character 
of the surface. 
