NEGATIVE CONTINENTAL ELEMENTS 459 



affected by the northern part of this ocean until the late Devonic and 

 early Mississippi^ while during the late Pennsylvanic its faunas did not 

 extend beyond Colorado and New Mexico. Barring the invasion of the 

 Logan sea, it was ever afterward restricted more and more to the edge of 

 the North American continent. In other words, the western side of the 

 entire continent was progressively enlarged and pushed up higher and 

 higher, thus restricting this ocean to its ever deepening basin. 



Poseidon ocean. — Throughout the Paleozoic the northern Atlantic 

 waters were separated from the southern Atlantic by the great continent 

 Gondwana, uniting Africa and South America across the medial region of 

 the present Atlantic. It is, therefore, not correct to speak of the northern 

 Atlantic until the present form of this ocean has been attained, which 

 seemingly had its inception late in the Mesozoic. Von Ihering 64 has 

 named the southern Atlantic waters south of Gondwana Nereus (he writes 

 it Nereis), evidently after the father of the 50 Nereids. The northern 

 Atlantic he regards as a part of Suess' Tethys (he writes it Thetis, one 

 of the daughters of Nereus, but Suess distinctly refers to the consort of 

 Oceanus, Tethys), the ancient Mediterranean that extended from the 

 Atlantic to the Pacific and of which the present Mediterranean is the re- 

 mainder. Since Tethys has its own and very distinct geologic history, and 

 seemingly always had restricted communication with the northern Atlan- 

 tic, it will be best to use this term in the sense given it by Suess. 65 As 

 the northern Atlantic has an independent evolution from the southern 

 Atlantic, it is here proposed to call the former the Poseidon ocean, after 

 "the lord of the sea," known to the Eomans as Neptune. 



"His home is a cavern in the depths of the sea, and not only does he know 

 all the secrets of his element, but, like the sea-gods of the Babylonians and 

 Germans, he possesses in general immeasurable wisdom. But he who would 

 question him must first overpower him in a wrestle, and force him, despite his 

 power of assuming like water itself a variety of shapes, to communicate to 

 him his knowledge" (Steuding). 



Repeatedly during the Paleozoic the waters of the Poseidon ocean en- 

 tered the continental seas and there dispersed their faunas. At no time, 

 however, did this life dominate these seas as did that derived from the 

 Pacific realm during the early Paleozoic, and later that of the Mexico 

 mediterranean. Subsequent to the earliest Mississippic the North Atlan- 

 tic was excluded by land barriers, and in the Saint Lawrence sea after late 

 Pennsylvanic time it did not again leave a record of its life. Near the 



64 Von Ihering : Archhelenis und Archinotis, 1907, p. 310, and map. 



65 Suess : Antlitz der Erde, III, pt. 1, 1901, p. 25. Natural Science, vol. 2, 1893, p. 



183. 



