°372 LE JOURNAL IOP GLROLO GVA 
to that of Europe and Asia while quite different from that of the 
southern regions. 
This striking change in the faunal relations of North America 
means something more than a mere migration; it means that in 
Lower and Middle Devonian times some barrier cut off the 
European and Asiatic faunas from those of America, and that in 
the Upper Devonian this barrier was removed while one was 
interposed between the northern and the southern regions. 
Professor W. Waagen™ has shown that this continued during the 
Carboniferous and Permian. 
CARBONIFEROUS FAUNAS. 
Lower Carboniferous—In a previous paper? the writer has 
shown that the Lower Carboniferous fauna of California was 
derived directly from the preceding Devonian, since so many 
species that in the Mississippi Valley or eastern region would be 
considered characteristic of the Devonian still survive. This 
survival has been used by Professor H. 5. Williams,3 and the 
writer,t to show that the reappearances of older forms in younger 
rocks have been due to migrations consequent upon the shifting 
of physical barriers. 
Affinities vo, the fauna——The Lower Carboniferous, or Baird 
Shales, fauna of California is intermediate in character, as it is 
in geographic position between the eastern American and the 
Russian and Asiatic. It differs from the typical American fauna 
in the survival of so many Devonian types and the presence of 
some Eurasian elements. It belongs to the zone of Productus 
giganteus or the lower part of C, of the Russian section. 
Upper Carboniferous—TVhe Upper Carboniferous fauna of Cali- 
fornia seems to have been developed directly out of older species 
in the same region, since there is known no complication of ele- 
ments brought in by the migration from outside the Pacific Car- 
t Paleontologia Indica, Salt Range Fossils, Geological Results. 
2Jour. GEOL., Vol. II., No. 6, The Metamorphic Series of Shasta County, Cali- 
fornia. 
3Am. Jour. Sci., III. Series, Vol. XLIX., pp. 94-I01. 
4Jour. GEOL., Vol IL., p. 198, and Vol. I1., p. 598. 
