. Elements of geology : a text-book for colleges and for the general reader. Geology. Fig. 805. Fig. 806. Figs. 801-806.—Cretaceous Fishes— Placoids: 804. Otodus (after Leidy). 805. Ptychodus Mor- toni (after Leidy). Teleosts: 806. Portheus molossus—Tooth, natural size (after Cope). The Hybodonts were essentially a Mesozoic type; the Squalodonts are essentially Tertiary and modern. The two types coexist in the Cre- taceous, the former passing out, the latter increasing, and finally dis- placing the former. The accompanying figure (Fig. 810) represents the succession, rise, culmination, and dec
. Elements of geology : a text-book for colleges and for the general reader. Geology. Fig. 805. Fig. 806. Figs. 801-806.—Cretaceous Fishes— Placoids: 804. Otodus (after Leidy). 805. Ptychodus Mor- toni (after Leidy). Teleosts: 806. Portheus molossus—Tooth, natural size (after Cope). The Hybodonts were essentially a Mesozoic type; the Squalodonts are essentially Tertiary and modern. The two types coexist in the Cre- taceous, the former passing out, the latter increasing, and finally dis- placing the former. The accompanying figure (Fig. 810) represents the succession, rise, culmination, and decline of the three families of sharks. Cope gives ninety-seven species of North American Cretaceous fishes known in 1875. Of these, if we include the Chimera family, an aberrant type of Placoids very common in the Cretaceous, forty-five were Placoids. The rest are mostly Teleosts, for the Ganoids are rap-. 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 LeConte, Joseph, 1823-1901. New York : D. Appleton and Co.
Size: 1001px × 2497px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1892
