. A dictionary of the fossils of Pennsylvania and neighboring states named in the reports and catalogues of the survey ... Paleontology. 789 In \^ H^i /' Psammodus ? semicylindricus, Newberry and Worthen, .Geo. Sur. 111., Vol. 2, 1866, page, 109, plate 11, figs. 4,4(?, upper surface of profile of a fish tooth somewhat like McCoy's Irish sub-carboniferous P. canalicuLatus^ Brit. Pal. Foss. p. 643, plate 3 g, fig. 12, but without its characteristic plications and its rounded crown. The shagreen-like roughness of the triturating surface is com- mon to several species of this and allied gen
. A dictionary of the fossils of Pennsylvania and neighboring states named in the reports and catalogues of the survey ... Paleontology. 789 In \^ H^i /' Psammodus ? semicylindricus, Newberry and Worthen, .Geo. Sur. 111., Vol. 2, 1866, page, 109, plate 11, figs. 4,4(?, upper surface of profile of a fish tooth somewhat like McCoy's Irish sub-carboniferous P. canalicuLatus^ Brit. Pal. Foss. p. 643, plate 3 g, fig. 12, but without its characteristic plications and its rounded crown. The shagreen-like roughness of the triturating surface is com- mon to several species of this and allied genera; but is only shown where the enamel coating is unworn; disappearing from long used teeth; and due to raised rings about the ends of the enamled tubes; evidently intended to prevent the teeth from slipping over the smooth shells which the fish had to crush to feed on the soft enclosed animals; in worn teeth the rough ness is made by the walls of the tubes. Warsaw, 111. Keokuk limestone. XL Psammodus springeri, St. John and Worthen, Geo. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lesley, J. P. (J. Peter), 1819-1903; Pennsylvania. Board of Commissioners for the Second Geological Survey. Harrisburg, Board of Commissioners for the Geological Survey
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