SLODIES LOR STUDENTS: 485 
But during the Lower Trias the Arctic, the Himalayan, and 
the American provinces had closely allied faunas, and might be 
grouped together in contrast to the Mediterranean. In the Mid- 
dle Trias, however, the American Triassic province was being 
gradually cut off from the Arctic, and communication established 
with the Mediterranean. This connection through the Himalayan 
province was very complete in the Upper Trias, and all three 
might be grouped under one region, the Mediterranean-Indian- 
American. 
Neumayr* has worked out the provinces of Jurassic time, and 
grouped them in two regions, the Boreal, and the Central-Med- 
iterranean. He has also traced out for that time the distribution 
of climatic zones by means of the Boreal type, the North Tem- 
perate type, the Alpine or Equatorial, and the South Temperate. 
To the Boreal region belong the Russian, the Siberian, the 
Himalayan, and the Alaskan provinces. To the Central Medi- 
terranean region belong the Northern European, the Alpine, the 
Salt Range, the Southern Indian, the Australasian, South Amer- 
ican, and the Western American. But during Upper Jura the 
Western American province took on an Arctic character, and 
certainly became part of the Boreal region. Thus these regions 
and provinces will not hold good for any long-time division, but 
were always, though slowly, changing. 
The study of the distribution of fossil faunas as influenced by 
climate was begun by Ferdinand Roemer,’ who recognized that 
the Cretaceous of England, northern France and Germany has a 
fauna similar to that of New Jersey, and that the faunas of south- 
ern Europe, north Africa, and Texas are similar. These differ- 
ences Roemer ascribed to climate, noting that at that time, as 
today, in America the isothermal lines came much further south 
than in Europe. Neumayr3 has carried these studies forward, 
correlating the various observations made since Roemer’s time. 
t “Geogr. Verbreitung der Juraformation,” and “Klimatische Zonen warend Jura 
und Kreidezeit.” e 
2 Kreidebildungen von Texas, Bonn, 1852. 
3 Klimatische Zonen warend Jura und Kreidezeit. 
