FOREIGN 461 



geological history, but it did not greatly affect North America. 

 Central and northern Russia were invaded by an extension of the 

 sea from the north, and in this Russian sea was developed a highly 

 characteristic fauna. Strata distinguished by the Russian fauna 

 extend through Siberia, Spitzbergen, Nova Zembla, Alaska, the 

 Black Hills of South Dakota, and the uppermost Jurassic of Cali- 

 fornia and Mexico. In peninsular India the Jura is represented 

 by the upper division of the Gondwana system, which, as before, 

 was laid down in an inland sea. The continental mass to which 

 India then belonged was cut off from Asia by a strait or sea which 

 covered the site of the Himalayas, but it may have been con- 

 nected with Australia by way of the Malay islands, or, more likely, 

 with South Africa. The great Jurassic transgression submerged 

 considerable areas of northern India, as it also covered narrow 

 areas along the eastern and western coasts of Australia. Much of 

 Madagascar was under water, but the southern portion is believed 

 to have formed part of the narrow land which extended from 

 South Africa to India. Some of eastern Africa was covered by a 

 bay of the Indian Ocean, but no marine Jurassic has been found in 

 the southern or western portions of that continent. 



The very striking faunal differences which obtain between dif- 

 ferent regions have led certain observers, especially the late Pro- 

 fessor Neumayr of Vienna, to the conclusion that climatic zones 

 had already been established in Jurassic times, — Boreal, central 

 European, and Alpine or Equatorial zones, with corresponding 

 ones in the Southern Hemisphere. This conclusion as to climatic 

 belts is, however, a very doubtful one, and is in conflict with the 

 distribution of the several geographical faunas, for the central 

 European fauna is found in equatorial Africa, and the supposed 

 equatorial fauna occurs in the Andes 20 of latitude south of its 

 proper boundary. It is much more likely that the marked faunal 

 differences are due to varying facies, depth of water, character of 

 bottom, etc., and even more to the partly isolated sea-basins and 

 the changing connections which were established between them. 

 There is no cogent evidence to show that the Jurassic climate was 

 less mild, equable, and uniform than that of preceding periods. 



