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Show PLiLTE 1. Page. FIG. 1. PRODUCTUS LATISSIMUS; cast of interior of ventral valve, reduced to a little less than one- third diameter 354 1 a. Outline profile of same. 1 ft. Surface- stri © of same, magnified. FIG. 2. ATHTRIS SUBTILITA ?, ventral view, reduced in same way 355 2 a. Dorsal view of same. FIG. 3. SPIRIFBR KEOKUK ?, ventral view, reduced in same way 355 3 a. Ventral view of a smaller individual, apparently of the Bame species, but proportionally shorter on the hinge- line*; reduced in same way. FIG. 4. An undetermined bivalve, presenting the form and external appearance of a MACTRA or TAKCREDIA ; from New Castle Island, Nanaimo group, reduced in size as above. 4 a. Outline profile of same. FIG. 5. Undetermined bivalve from same locality and position as last, reduced in same way. 5 a. Profile outline of same. FIG. 6. IXOCERAMUS ? Imperfect cast of a left valve, reduced in size as above 359 The dim shading beyond the broken posterior and basal margins represents the restored outline. NOTE.- The figures on this and the following five plates were originally, in most cases, drawn of natural size, and arranged for quarto plates; but the whole were reduced for thisjwork to octavo size by photographs, from which the lithographer made his tracing, and then finished the figures from the original drawings. |