782 T. C. CHAMBERLIN 
Mediterranean tract into eastern Europe and perhaps to the Cas- 
pian-Ural region of Asia; indeed, it is not altogether improbable 
that straits or narrow seas may have connected with the apex of 
the Indian ocean. At least in the later Permian) times) the 
marine faunas of India and of Europe were notably similar, 
and in the early Mesozoic they became so nearly identical as 
to make a connection along this line extremely probable. 
Effect of the supposed geographic changes on atmospheric circu- 
lation.—While none of these postulated changes involve great 
terrestrial movements, or depart widely from the rather definite 
indications of the phenomena concerned, it will be seen upon a 
study of the resulting distribution of land and water that they 
probably profoundly affected the circulation of the atmosphere. 
The limitation of the Atlantic at the north by the European- 
American connection rendered it essentially an equatorial and 
warm temperate ocean. Its present high-latitude connection, 
involving the transportation of vast quantities of ice and cold 
water into it from polar regions and the reciprocal loss of heat 
borne into the high latitudes by the Gulf Stream, was eliminated. 
The atmospheric function of the Atlantic was, therefore, radically 
changed. That great oblique factor to which was assigned so 
large a function in the localization of Pleistocene glaciation, was 
largely absent from the Permo-Carboniferous circulation. To 
the similar restriction attributed to the north Pacific a minor 
limitation of a like kind may be assigned. Instead, therefore, 
of a polar sea exchanging its thermal properties with an equa- 
torial sea, as at present, there would be substituted a prevailing 
polar land, relieved probably only by the deep basin of the 
Arctic sea, whose limited extent and land-locked situation would 
render it little more significant in general climatology than the 
present Mediterranean. 
On the other hand, very notable oblique features appear in 
the equatorial and southern regions. The postulated changes of 
the Pacific Ocean, by shutting off its connections with the Indian 
Ocean, probably brought into effective influence its long north- 
westerly and southeasterly trend, now neutralized by its 
