PLATE XIII. 



PAGE. 



Fig. 1. Platyceras (Okthonychia) LoDiENsis 313 



la. A lateral Tiew. • 



16. View from above. 



Figs. 2 and 3. Melockinus (Ctenocrtnus) Bainbridgensis 158 



2. Lateral view of the specimen, looking upon the right antTo-lateral ray. 

 iirt. Ba.sal view of the specimen, the anal ari-a being on the lower side. J'i-oni the Huron shale 

 (Devonian). 



Fig. 4. PlATYCRINUS BEDFOKnENSIS 161 



View of a portion of the block upon the siufiico of which the specimens are inil)e(l(lcil and 

 partly covered by a pyritiferous shale. 



AlLORISMA (SeDGWICKIA?) PLEUROPLSTHA 309 



4a. A left view of a specimen somewhat distorted l)y oblique pr- ssuie. 



4b. Another tspecimen, apparently of ttiia spt-cies, with the posterior end broken away, and the 



costae ranging mnch more obliquely than in the last, the ditference being proliably due 



to oblique pressure in one or both. 

 4c. Anterior view of same, the inequivalve appearance probably accidental. 



Fig. 5. Grammysia ventricosa , 303 



5a. Left view of a specimen, probably, to some extent, a littld more- than naturally depiessp<l. 

 56. An anterior view of same. 



Fig. 6.. Edmondia ? tapesiformis 304 



Right side view. 



Fig. 7. Pleurotomahia textiligera 314 



7«. View ot a specimen that is mainly an internal cast, but shows indistinctly remains of sur- 

 face markings. 



76. A guttapercha cast of the upper part of the spire taken in a natural mould, showing the 

 sharply defined marks of growth. 



