DIY History | Transcribe | Scholarship at Iowa | Coal Measures and Coal Mining in Iowa, including paleontology and a discussion on the coal formation; also the methods of mining by Russell T. Hartman, 1898 | Coal Measures and Coal Mining in Iowa by Russell T. Hartman, 1898, Page 104

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Coal Measures and Coal Mining in Iowa, including paleontology and a discussion on the coal formation; also the methods of mining by Russell T. Hartman, 1898

Coal Measures and Coal Mining in Iowa by Russell T. Hartman, 1898, Page 104

[page]103.[/page]

ly continuous with the primary lamellae which are placed between  the laterally directed spiral cones of the brachia. The jugum is simple, may be complete or may be incomplete.

[underlined]Spirifer plano-convexus[/underlined], Shumard,
Plate VIII. figure 7.
Shumard, 1855, Rept. Missouri Geol. Survey, p.202. Ambocoelia gemmula, McChesney, 1860, Descr. Pal. Foss., p.41. Martina plano-convexa, McChesney, 1869, Trans. Chic. Acad. Science, vol. I., page 34.
     Shell very small, sub-ovate in anthis, varying from concavo-convex to slightly bi-convex, the dorsal valve being the variable one; the usual form, however, is nearly plano-convex; relation of length to width variable, greatest dimension not more than one third of an inch, hinge line, shorter than greatest width of shell.

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[page]103.[/page] ly continuous with the primary lamellae which are placed between the laterally directed spiral cones of the brachia. The jugum is simple, may be complete or may be incomplete. [underlined]Spirifer plano-convexus[/underlined], Shumard, Plate VIII. figure 7. Shumard, 1855, Rept. Missouri Geol. Survey, p.202. Ambocoelia gemmula, McChesney, 1860, Descr. Pal. Foss., p.41. Martina plano-convexa, McChesney, 1869, Trans. Chic. Acad. Science, vol. I., page 34. Shell very small, sub-ovate in anthis, varying from concavo-convex to slightly bi-convex, the dorsal valve being the variable one; the usual form, however, is nearly plano-convex; relation of length to width variable, greatest dimension not more than one third of an inch, hinge line, shorter than greatest width of shell.