. The museum of natural history, with introductory essay on the natural history of the primeval world : being a popular account of the structure, habits, and classification of the various departments of the animal kingdom, quadrupeds, birds, reptiles, fishes, shells, and insects, including the insects destructive to agriculture . ,and would extend up to and beyond the Rhine. The Permian formation is usually divided by geolo-gists into tliree series of strata :— The New Red Sandstone (the lowest) ; Magnesian Limestone, or Zechstcin (next in order) ; andPermian, or Sandstone of the Vosges (upper
. The museum of natural history, with introductory essay on the natural history of the primeval world : being a popular account of the structure, habits, and classification of the various departments of the animal kingdom, quadrupeds, birds, reptiles, fishes, shells, and insects, including the insects destructive to agriculture . ,and would extend up to and beyond the Rhine. The Permian formation is usually divided by geolo-gists into tliree series of strata :— The New Red Sandstone (the lowest) ; Magnesian Limestone, or Zechstcin (next in order) ; andPermian, or Sandstone of the Vosges (uppermost).The fossil remains of the new red sandstone, which attains a thickness of from 300 to 600 feet, and is foundover great part of Germany, in the Vosges, and inEngland, are very few. The dark schist beds of the magnesian limestone,which both in England and Germany attains a thick-ness of about 450 feet, are remarkably rich in thememorials of peculiar genera of fishes. The Permian strata, which also occur in England,and in the government of Perm, in Russia (whence theirname), on a very extensive scale, are characterized byscattered evidences of past organic life. The principal points to which the attention of thenaturalist may here he directed are:— Certain forms of Sauroid fishes, as the rakconiscusand Plalysomus ;. Labyrinthodon restored. Oiie-twentietli size. Tlie Labyrinthodont reptiles; The Bird-like and Reptilian footpi^nls (Tchiiilcs) onthe new red sandstone ; and The first appearance of Mammalian life, under amarsupial form, in the DromatJieriuia. In the Palmoniscus, the Plalysomus, and other fishesof the Permian period, we find the upper tail-fin muchlonger tiian the lower, tlie vertebral column being con-tinued in the upper caudal lobe, as in the Ambbjplcrujiof the coal measures, and the sturgeon and shark ofexisting seas. This arrangement Agassiz calls hetero-cercal. These genera, in all probability, lived in theshore-waters, and never ventured far out
Size: 1760px × 1420px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlibraryofcongressformerownerdsi, bookpublisherlondon
