. Elements of geology : a text-book for colleges and for the general reader. Geology. V Fig. 652. Fig. 653. Fig. 650. Fig. 651. Figs. 648-653.âJurassic Lamellibranchs and Brachiopods of England: 648. Ostrea Sowerbyi. 649. Pecten fibrosus. 650. Ostrea Marshii. 651. Khynchouella varians. 652. Terebratula sphae- roidalis. 653. Terebratula digona (after Nicholson). Ammonites.âThe Ammonite family, which is distinguished, as already explained (p. 313,), by the dorsal position of the siphuncle and the complexity of the suture, is represented in extreme abun- dance by the type- genus Ammonites. * Abou
. Elements of geology : a text-book for colleges and for the general reader. Geology. V Fig. 652. Fig. 653. Fig. 650. Fig. 651. Figs. 648-653.âJurassic Lamellibranchs and Brachiopods of England: 648. Ostrea Sowerbyi. 649. Pecten fibrosus. 650. Ostrea Marshii. 651. Khynchouella varians. 652. Terebratula sphae- roidalis. 653. Terebratula digona (after Nicholson). Ammonites.âThe Ammonite family, which is distinguished, as already explained (p. 313,), by the dorsal position of the siphuncle and the complexity of the suture, is represented in extreme abun- dance by the type- genus Ammonites. * About 500 species of this genus are known, ranging in time from the Trias- sic through the Cre- taceous. They are therefore character- istic of the Meso- zoic. They varied extremely in shape, and in size from half Fig. 654.âAmmonites Humphreysianus. n , -â an inch to a yard or more in diameter. The accompanying figures represent some of the most common species. In the genus Ammonites the distinguishing character of the family, viz., the complexity of the suture, reached its highest point. In this genus, the edge of the septa, which was only zigzag in Goniatite, and lobed in the Ceratite, becomes most elaborately frilled. We give in Fig. 659 the form of suture in the type-genera of the different orders of shelled Cephalopods, in the order of their first appearance. In each. * This genus is now broken up into many, but it is still convenient to retain the name for a very distinct group of 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.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1892
