Page:The Journal of geology (IA journalofgeology21894univers).pdf/216

This page has been proofread, but needs to be validated.
202
THE JOURNAL OF GEOLOGY.

tain region. King[1] further concluded that the Carboniferous in California, west of the old shore line, indicated shallow bays that permitted the western extension of the upper Paleozoic deposits, while the bulk of them was stopped by the bold coast. There are evidences of land areas in the Rocky mountains, Wahsatch mountains, New Mexico, and Nevada, but from the facts now known it seems more probable that these were large islands or archipelagos, rather than continents.

The Permian Pacific Ocean.

The outlines of the great western ocean can be traced in Permian times also, but with much more circumscribed limits. Open sea deposits of this age are known in Texas, in the Salt Range, on the west slope of the Urals, on the island of Sicily, and in scattering places in central Asia. In all these the genera are nearly the same, except that the Arcestes types are confined to the more southern regions. This similarity indicates plainly a connection of these deposits.

Suess[2] argues that the open sea Permian fauna wandered in from the south, and that the Mesozoic types of Ammonites were foreign to the northern regions.

Karpinsky,[3] on the contrary, holds that they were autochthonous, at least in the Ural region, since he could trace the descent of all the Ammonites, except the Popanocerata from Goniatites that were found in the underlying Carboniferous.

As has been already mentioned, the ammonite genus Medlicottia is not a foreigner on this side of the Permian Pacific ocean, because its ancestor, Pronorites, is found here too.

The Triassic Pacific ocean.—Our knowledge of the Triassic Pacific ocean is based on the work of Mojsisovics, "Arktische Triasfaunen."[4] We find that in this period the American part of the great western ocean has mostly become land, and only on

  1. ↑ Op. cit., p. 535.
  2. ↑ Antlitz der Erde, II., p. 316.
  3. ↑ Ammoneen der Artinsk-Stufe, p. 86.
  4. ↑ Mem. Acad. Imper. Sci. St. Petersbourg, Tome 33, No. 6.
This article is issued from Wikisource. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.