202 THE JOURNAL OF GEOLOGY. 



tain region. King' 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^ 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 autochtho- 

 nous, at least in the Ural region, since he could trace the descent 

 of all the A7nmo7iites, except the Popanocerata from Goniatites that 

 were found in the underljnng Carboniferous. 



As has been already mentioned, the ammonite genus Medli- 

 cottia 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."^ We find that in this period the American part of 



the great western ocean has mostly become land, and only on 



'Op. cit., p. 535. 



^ Antlitz der Erde, II., p. 316. 



3 Ammoneen der Artinsk-Stufe, p. 86. 



■* Mem. Acad. Imper. Sci. St. Petersbourg, Tome 33, No. 6. 



